Propofol and dexmedetomidine sedation share the similar functional activity but distinct functional synchronization----a resting-state functional magnetic resonance imaging study

Propofol and dexmedetomidine sedation share the similar functional activity but distinct functional synchronization----a resting-state functional magnetic resonance imaging study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Propofol and dexmedetomidine sedation share the similar functional activity but distinct functional synchronization----a resting-state functional magnetic resonance imaging study Minyu Jian, Jiayi Zhang, Guiyu Li, Ruquan Han, Chengwei Wang, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7853532/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 02 Mar, 2026 Read the published version in Scientific Reports → Version 1 posted 11 You are reading this latest preprint version Abstract There is insufficient unified research on the effects of propofol and dexmedetomidine on brain functional activity and synchronization. We collected resting-state functional magnetic resonance imaging (rsfMRI) data from 21 healthy subjects in four different levels of consciousness induced by propofol (awake, mild sedation, deep sedation, and recovery), and other 21 healthy subjects in three different levels of consciousness induced by dexmedetomidine (awake, mild sedation and recovery). The results showed that with the increasing of sedation levels of propofol or dexmedetomidine, fractional amplitude of low-frequency fluctuations (fALFF) and regional homogeneity (ReHo) values decreased in the frontal lobe, while they increased in the temporal and parietal lobes. Under propofol sedation, functional connectivity (FC) decreased both within and between sensorimotor network and attention network, and within and between the frontoparietal network (FPN) and default mode network (DMN). Simultaneously, a small number of increased connections were observed between the FPN, DMN, and other networks. Under dexmedetomidine sedation, generally decreased FC was observed in the whole brain. This study shows consistent effects on brain functional activity, but distinct impacts on functional synchronization, providing new insights into the understanding of anesthetic mechanisms. Health sciences/Medical research Health sciences/Neurology Biological sciences/Neuroscience Propofol dexmedetomidine functional activity functional synchronization functional magnetic resonance imaging Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Introduction Despite advances in the understanding of the mechanisms for a variety of anesthetics, the specifics of why general anesthesia cause unconsciousness remain unclear. Propofol and dexmedetomidine are commonly used in clinical anesthesia. Propofol is a gamma-aminobutyric acidergic drug that increases inhibitory tone in neurons 1 – 3 . Dexmedetomidine is an alpha-2 adrenergic agonist that activates endogenous sleep pathways 4 , 5 . The mechanisms of the two anesthetics are different, and research on their effects on brain function is still insufficient. Resting-state functional magnetic resonance imaging (rsfMRI) is ideally suited for exploring brain function of participants who are incapable of following instructions of goal-directed tasks 6 . Anesthetic induce different states of consciousness by altering the functional activity of specific brain regions and the functional connectivity (FC) 7 . Common measures of brain function include amplitude of low-frequency fluctuations (fALFF), regional homogeneity (ReHo) and FC. The fALFF are defined as the ratio of power spectrum of low-frequency to that of the entire frequency range to reflect brain neural activity during rest 8 . ReHo detects the local synchronization of low-frequency oscillations using Kendall’s coefficient of concordance. It represents the similarity between the time series of a given voxel and that of its nearest neighbors 9 . FC is defined as the temporal correlation between pairs of time series extracted from regions of interest or voxels. Previous studies have shown that the impact of propofol on the brain is described as the changes in prefrontal activity as well as alterations in FC 10,11 . Similarly, dexmedetomidine can also regulate FC within and between resting state networks, and affect low frequency fluctuation amplitude (ALFF) 12 , 13 . Electroencephalogram (EEG)-based studies have shown that both dexmedetomidine-induced unconsciousness and propofol-induced unconsciousness are associated with slow/delta oscillations 14 . However, there is still a lack of unified studies on the effects of propofol and dexmedetomidine on brain functional activity and FC. In this study, we acquired rsfMRI data from 21 healthy subjects in four states of consciousness induced by propofol (awake, mild sedation, deep sedation, and recovery) and other 21 healthy subjects in three states of consciousness (awake, mild sedation, and recovery) induced by dexmedetomidine. fALFF, ReHo and FC were measured for a unified study, aiming to explore the effects of propofol and dexmedetomidine on brain functional activity and synchronization through comprehensive analysis of these indicators. Results Demographic data There was no significant difference in age, gender, education level, nationality, and Body Mass Index (BMI) between two groups ( p > 0.05) (Table 1 ). The vital signs among different sedation states showed no significant difference under propofol and dexmetomidine sedition, respectively ( p > 0.05) (see Supplementary Table S1 and S2). The propofol effect-site target concentration at different levels of sedation during the study period were also shown in Supplementary Table S1 . Table 1 Demographic data between propofol group and dexmetomidine group. Measurements Propofol group( n = 21) Dexmedetomidine group( n = 21) p value Gender, n (%) 0.912 Male 18(85.7) 16(76.2) Female 3(14.3) 5(23.8) Age(years) 25.6 ± 2.4 25.4 ± 2.9 0.907 Nationality, n (%) > 0.999 Non-han nationality 0(0) 0(0) Han nationality 21(100) 21(100) education level, n (%) 0.751 senior high school and below 9(42.9) 7(33.3) senior high school and above 12(57.1) 14(66.7) BMI(kg/m 2 ) 25.88 ± 0.55 25.74 ± 0.57 0.865 The fALFF values changes under different sedation states induced by propofol Compared to the awake state, the fALFF values in the frontal regions (including the superior frontal gyrus and middle frontal gyrus), supramarginal gyrus and cerebelum significantly decreased, while the superior temporal gyrus, calcarine, paracentral lobule and middle occipital gyrus showed a significant increase in mild sedation state induced by propofol. Compared to the awake state, the fALFF values significantly decreased and spread across the entire frontal region, with a peak at left middle frontal gyrus. The area with a significant decrease in fALFF values in the temporal gyrus expanded. The fALFF values in the supramarginal gyrus, angular gyrus, cerebelum decreased significantly, while it in parietal gyrus significantly increased. Calcarine's fALFF values no longer declined significantly in the deep sedation state induced by propofol. Compared to the deep state induced by propofol, the fALFF values in the temporal gyrus and parietal gyrus significantly decreased, while the fALFF values in the frontal regions and calcarine significantly increased in the recovery state. There was no significant difference between awake and recovery after propofol sedation (Fig. 1 ). Detailed results are presented in the supplementary Table S3. The fALFF values changes under different sedation states induced by dexmedetomidine Compared to the awake state, the fALFF values in the frontal regions with a peak at frontal inferior orbital gyrus and middle temporal pole significantly decreased, while cerebellum, the temporal and occipital regions (with a peak at fusiform) showed a significant increase in the mild sedation state induced by dexmedetomidine. Compared to the mild state induced by dexmedetomidine, the fALFF values in the middle occipital gyrus, middle temporal gyrus and fusiform significantly decreased in the recovery state. There was no significant difference between awake and recovery after dexmedetomidine sedation (Fig. 2 ). Detailed results are presented in the supplementary Table S4. The ReHo values changes under different sedation states induced by propofol The trend of ReHo value changes under mild sedation induced by propofol is similar to that of fALFF, with a decrease observed in the frontal gyrus, supramarginal gyrus, and cerebellar regions and an increase in the putamen, precentra, precuneus, rolandic operculum and lingual gyrus. As the sedation of propofol deepens, ReHo values significantly decreases in supramarginal gyrus, parietal inferior gyrus, calcarine and the entire frontal region, and an increase in the temporal and parietal regions. In the recovery state, the ReHo values in the superior temporal regions and paracentral lobule significantly decreases, while the ReHo values in the frontal regions, calcarine, cerebelum and supramarginal gyrus significantly increases. There was no significant difference between awake and recovery after propofol sedation (Fig. 3 ). Detailed results are presented in the supplementary Table S5. The ReHo values changes under different sedation states induced by dexmedetomidine Compared to the awake state, ReHo values decreased in the middle frontal gyrus, temporal pole, middle temporal gyrus, caudate gyrus, and cerebellar regions, while it increased in the postcentral gyrus, occipital regions (with a peak at fusiform) and superior temporal in the mild sedation state induced by dexmedetomidine. In the recovery state, the previously increased ReHo values in the occipital gyrus, fusiform and postcentral gyrus significantly decreased. There was no significant difference between awake and recovery after dexmedetomidine sedation (Fig. 4 ). Detailed results are presented in the supplementary Table S6. The FC changes under different sedation states induced by propofol After propofol sedation, the decrease in FC first appears between the SMN and DAN. As the depth of propofol sedation increases, the FC within and between the SMN, DAN, and VAN decreases, and the FC within the FPN and DMN also decreases. At the same time, a small number of increasing connections were observed within and between FPN, DMN and other networks. The VN network shows a trend of first increasing and then decreasing. No significant differences were observed between the recovery state and the awake state (Fig. 5 and Fig. 6 ). The FC changes under different sedation states induced by dexmedetomidine In the mild sedation state induced by dexmedetomidine, we observed a general decrease in FC across the entire brain. The recovery state showed no significant differences compared to the awake state (Fig. 7 ). Discussion This study aims to explore the changes in brain functional activity and synchronization under propofol and dexmedetomidine sedation, explaining the different mechanism of these two anesthetics. Our results suggest that, both anesthetics reduce functional activity in the frontal lobe and cerebellum, while increasing activity in the temporal and parietal lobes. Furthermore, propofol and dexmedetomidine have distinct effects on functional synchronization between brain regions. Propofol mainly reduces connectivity in the SMN, VAN, FPN and DMN, while dexmedetomidine has a more pronounced impact on FC, leading to a general reduction in FC under mild sedation. Functional activity changes between different states fALFF is the ratio of power spectrum of low frequency to that of the entire frequency range, may effectively suppress non-specific signal components in the rsfMRI, and therefore would significantly improve the sensitivity and specificity in detecting regional spontaneous brain activity 8 . ReHo measures the similarity or synchronization between the time series of a given voxel and its nearest neighbors 9 . These two indicators complement each other and comprehensively reveal the changes in brain function activity after anesthesia. The study found that the effects of propofol and dexmedetomidine on brain functional activity showed similar results. The decrease of frontal functional activity under mild and deep sedation states is worth exploring. The frontal lobes contribute to conscious perception and cognitive functions 20 , 21 . Previous studies have shown that anesthetics preferentially inhibit activity in higher-order information processing areas, particularly the frontal lobes 22 . This result suggests that a loss of frontal executive function may be the primary factor in propofol-induced and dexmedetomidine-induced unconsciousness. The fALFF and ReHo in the temporal lobe and parietal lobe increased significantly with the increase of sedation depth. Research on EEG indicates that the gamma band power in the temporal lobe increases, which may reflect the formation of declarative memory under propofol sedation 23 . Study has also found that under dexmedetomidine sedation, ALFF in the resting state BOLD signals in the somatosensory motor areas significantly increased 12 . We also found an interesting result. After mild propofol sedation, the fALFF and ReHo in the occipital lobe increased. However, after deep propofol sedation, this increase disappeared. Under mild dexmedetomidine sedation, the increase in fALFF and ReHo in the occipital lobe was more pronounced. Therefore, we speculate that in the low-dose phase, the occipital lobe may be temporarily activated. In the future, continuous depth of the same anesthetic should be used for further verification. FC changes between different states In this study, we used the Brainnetome Atlas to evaluate the effect of anesthesia on FC between gray matter regions of the brain, which complements the research on FC based on functional networks. There is currently controversy over the impact of propofol on SMN 24 – 26 . Our study found that under propofol sedation, the coordination within and between the SMN and VAN was suppressed. This suggest that propofol-induced disconnection may occur within low-order resting-state functional networks and between high-order networks and low-order networks 10 , 26 , 27 . Furthermore, there has been debates regarding the FC changes within FPN and DMN, as well as with other networks 10 , 24 , 28 , 29 . In this study, many connections within the FPN and DMN, as well as between them and other networks were decreased, while some connections increased. This provides a more detailed observation of the functional synchrony changes in the FPN and DMN. Although previous studies have suggested that disruptions in high-order resting-state functional networks during propofol-induced unresponsive seem to be a hallmark of the unresponsive state 10 , 25 , 30 . Some connections within the FPN, DMN, and between them and other networks were noticeably increased under deep sedation. This may suggest that during propofol deep sedation, the brain still maintains a certain level of functional collaboration. After dexmedetomidine sedation, we observed a general decrease in FC across the entire brain, which is similar to the results previously assessed. Previous study suggested that FC within and between resting state networks is modulated by dexmedetomidine, and a significant reduction in FC strength, during the wakefulness to unconsciousness 12 , 13 . More importantly, compared to the awake state, we did not observe significant differences in FC in the recovery state, which may reflect the short-term effects of anesthesia on brain function coordination. FC returned to the awake state in healthy volunteers, confirming the safety of propofol and dexmedetomidine. Limitations In this study, firstly, although we discussed the effects of both propofol and dexmedetomidine on brain function, the inconsistent depths of anesthesia in this study hindered the comparison of the effects of the two anesthetics on brain function directly. Furthermore, the number of datasets in this study is limited. But through meticulous analysis of the limited yet representative data, we have been able to preliminarily reveal the functional activity and FC changes at propofol and dexmedetomidine. Methods This study was conducted at Beijing Tiantan Hospital, Capital Medical University, Beijing, China (NCT 033443873). The Institutional Review Board of Beijing Tiantan Hospital has approved the study (KY2017-036-02). This study was performed in accordance with the Declaration of Helsinki. Written informed consent was obtained from all subjects participating in the trial. The study followed the Consolidated Standards of Reporting Trials (CONSORT) 2010 reporting guidelines. Participants Forty-two healthy adult volunteers were assigned into propofol group or dexmedetomidine group, with twenty-one subjects in each group. All participants were native Chinese speakers and had no histories of neurological, psychiatric conditions, or structural brain abnormalities. The exclusion criteria were as follows: (1) metal implants in the body; (2) intracranial lesions or systemic comorbidities; (3) a history of drug abuse or alcohol abuse; (4) allergy to propofol; (5) claustrophobia; (6) left-handed. Sedation protocol Two certified anesthesiologists were responsible for the monitoring and safety of the volunteers. Subjects were asked to fast for at least 8 hours before sedation. Upon arrival, standard American Society of Anesthesiologists monitoring was continuously performed including electrocardiography, heart rate, blood pressure, pulse oxygen saturation, and respiratory rate. A 20-gauge IV cannula was used for fluid and sedation administration. Throughout the sedation and MRI scans, the subjects breathed spontaneously with a nasal catheter of oxygen (6 L/min). Dexmedetomidine was administered as a bolus at 1 µg/kg over a period of 15 min; it was then administered at 0.6 µg/kg/h by continuous intravenous infusion to maintain sedation. Target-controlled infusion (TCI) of propofol was delivered by a syringe pump (B. Braun, Germany). The initial effect-site target concentration was set at 0.5ug/ml and increased step-up by every 0.2 ug/ml. The level of consciousness in both group was evaluated every 5 min by using the Observer’s Assessment of Alertness/Sedation (OAA/S) Scale. Subjects wore headphones throughout the experiment and were thus spoken to through an MRI speaker. All communications occurred between MRI acquisitions, and subjects were instructed to respond verbally. No motor response was involved, thus avoiding the introduction of motion artifact. Image acquisition All fMRI data were obtained using a 3.0 T MRI system (Siemens Medical Systems Prisma) at Beijing Neurosurgical Institute. Before sedation, images were acquired using a high-resolution three-dimensional T1- weighted brain volume MRI sequence with the following parameters: repetition time, 2300ms; echo time, 2.27ms; flip angle, 8°; fleld of view, 256 × 256 mm 2 ; matrix, 256 × 256; voxel size, 1 × 1 × 1 mm 3 ; slice thickness, 1 mm; and 192 sagittal slices. We then used an echo-planar imaging sequence to perform rsfMRI in different clinical states. In dexmedetomidine group, normal wakefulness (OAA/S Scale score 5), mild sedation (OAA/S Scale score 3–4), and recovery of consciousness (OAA/S Scale score 5) were collected. In propofol group, normal wakefulness (OAA/S Scale score 5), mild sedation (OAA/S Scale score 3–4), deep sedation (OAA/S Scale score 1–2), and recovery of consciousness (OAA/S Scale score, 5) were collected. For each state, the typical scan duration was 15min. The scanning parameters were as follows: repetition time, 2000 ms; echo time, 30 ms; flip angle, 75°; field of view, 192 × 192 mm 2 ; matrix = 64 × 64; slice thickness, 4 mm; voxel size, 3 × 3 × 4.4 mm 3 ; 32 slices; and 200 volumes. Image preprocessing The functional image preprocessing steps included the following using Brant ( http://brant.brainnetome.org ) 15 . (1) The first ten time points were removed for signal equilibrium and to allow the participants to adapt at to the scanning noise. (2) Slice-time correction. (3) Realignment to the mean functional image. (4) Normalization to the Montreal Neurological Institute space. (5) Regression of nuisance signals, including linear trends, six motion parameters and signals representing cerebrospinal fluid and white matter. (6) Temporal scrubbing using motion “spikes” (threshold of framewise displacement = 0.5) was performed. (7) Band-pass filtering (0.01–0.1 Hz) was performed to reduce non-neuronal contributions to blood oxygen level-dependent (BOLD) fluctuations. (8) Spatial smoothing with a 6 mm Gaussian Kernel. Computation of fALFF, ReHo and FC To quantify the intensity of spontaneous brain activity in a region, fALFF was calculated by using the brant toolbox. The BOLD time series of all brain voxels were transformed into the frequency domain through Fourier transform and the power spectrum was calculated. The fALFF index is the total power of the 0.01–0.1 Hz frequency band divided by that of the entire frequency range. Subsequently, the fALFF was smoothed with a smoothing kernel of 6 mm and z-score normalization. ReHo is the Kendall's coefficient of coherence between the seed voxel and its nearest neighboring 26 voxels, representing the degree of spontaneous activity near the seed voxel. The higher the intensity of voxels in the ReHo map, the more similar the time series of adjacent voxels. Since spatial smoothing artificially enhances ReHo and reduces its reliability 16 , the ReHo map was calculated from non-smoothed time series. Subsequently, spatial smoothing was applied using a 6 mm Gaussian kernel and z-score normalization was performed on the ReHo map. FC between gray matter regions of the brain was calculated based on the Brainnetome Atlas 17 , and a 246 × 246 FC matrix (excluding cerebellum) was obtained. The Pearson correlation between the average time series of any brain region in each subject was then calculated and Fisher’s z-transforms was performed on the correlation matrix. The threshold for FC was set to r > 0.2 to eliminate interference from noise 18 . Statistical analysis To investigate the differences in fALFF and ReHo induced by anesthetic at the group level, paired t-test was performed on fALFF and ReHo maps between different sedation states. The significance threshold was set to p < 0.05 and multiple comparisons correction was performed using the false discovery rate (FDR). Clusters with voxels greater than 50 were selected using the dpabi toolbox 19 . Similarly, the paired t-test was performed on the FC matrices between different sedation states. The significance threshold was set to p < 0.01, and FDR was used for multiple comparisons correction of different connections. Conclusions This study systematically revealed the reversible regulatory mechanisms of propofol and dexmedetomidine on brain functional activity and synchronization. The results showed that these two anesthetics had consistent effects on brain functional activity but exhibited differences in regulating functional connectivity. Specifically, both propofol and dexmedetomidine significantly reduced functional activity in the frontal lobe and cerebellum, while enhancing functional activity in the temporal and parietal lobes. Notably, in terms of functional synchronization, propofol primarily reduced the connectivity strength between the SMN, VAN, FPN, and DMN networks, while dexmedetomidine induced a widespread decrease in brain-wide connectivity. These findings not only clarify the differential regulatory patterns of different anesthetics on functional activity and functional synchronization but also provide important theoretical evidence for understanding the neural mechanisms of anesthesia-induced loss of consciousness. Declarations Acknowledgements We sincerely appreciate all the participants who took part in this study. Their time, effort, and cooperation were invaluable to this research. Funding We acknowledge funding provided by the National Natural Science Foundation of China (No. 82371910, 61901465, 82271284) and the Beijing Hospital Management Center Youth Talent Development Program "Young Sprouts" (QML20230509). Author contributions L.H conceived and designed the study and supervised the entire research process. J.M, L.G, H.R, W.C, L.F, L.Y and W.X collected the raw data, and performed the experiments. Z.Jand Z.F analyzed the MRI data. J.M, H.R and Z.R secured the funding. J.M and Z.J drafted the manuscript. All authors reviewed and approved the final manuscript, and agree to be accountable for all aspects of the work. Data availability statement The data that support the findings of this study are available from the corresponding author upon reasonable request." Disclosures The authors report no competing interests. References Brown EN, Lydic R, Schiff ND: General anesthesia, sleep, and coma. 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Supplementary Files SupplementaryMaterials.pdf Cite Share Download PDF Status: Published Journal Publication published 02 Mar, 2026 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 02 Dec, 2025 Reviews received at journal 25 Nov, 2025 Reviews received at journal 24 Nov, 2025 Reviewers agreed at journal 28 Oct, 2025 Reviewers agreed at journal 28 Oct, 2025 Reviewers agreed at journal 27 Oct, 2025 Reviewers invited by journal 27 Oct, 2025 Editor assigned by journal 27 Oct, 2025 Editor invited by journal 27 Oct, 2025 Submission checks completed at journal 26 Oct, 2025 First submitted to journal 26 Oct, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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10:03:36","extension":"html","order_by":19,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":96633,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7853532/v1/ae280d033c826eb033f45218.html"},{"id":95525306,"identity":"6d43ea06-ae7f-4c55-8789-27cdde8a3afc","added_by":"auto","created_at":"2025-11-10 10:04:45","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":290381,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePaired t-test of fALFF between awake, mild sedation induced by propofol, deep sedation induced by propofol and recovery.\u003c/strong\u003eWarm colors indicate higher fALFF in the second state of each paired comparison. Cool colors indicate higher fALFF in the frist state of each paired comparison. The significance of results is reported at \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7853532/v1/8dfa4d49b763532de225a341.png"},{"id":95340572,"identity":"149622c4-0cc0-4084-b193-98f2dfe36753","added_by":"auto","created_at":"2025-11-07 01:29:09","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":203166,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePaired t-tests of fALFF between awake, mild sedation induced by dexmedetomidine and recovery.\u003c/strong\u003e Warm colors indicate higher fALFF in the second state of each paired comparison. Cool colors indicate higher fALFF in the first state of each paired comparison. The significance of results is reported at \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7853532/v1/e4a1c142a26bf778977fde1a.png"},{"id":95524305,"identity":"707f7286-3e79-486b-a6ab-781ee601cc73","added_by":"auto","created_at":"2025-11-10 10:02:36","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":276944,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePaired t-tests of ReHo between awake, wakefulness, mild sedation induced by propofol, deep sedation induced by propofol and recovery states.\u003c/strong\u003e Warm colors indicate higher fALFF in the second state of each paired comparison. Cool colors indicate higher fALFF in the first state of each paired comparison. The significance of results is reported at \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7853532/v1/3c829530a9f5e0e4eae5b767.png"},{"id":95340574,"identity":"9b63d4eb-a514-4f97-a57d-bb75b7a23a9c","added_by":"auto","created_at":"2025-11-07 01:29:09","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":190601,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePaired t-tests of ReHo between awake, mild sedation induced by dexmedetomidine and recovery states.\u003c/strong\u003e Warm colors indicate higher fALFF in the second state of each paired comparison. Cool colors indicate higher fALFF in the first state of each paired comparison. The significance of results is reported at \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7853532/v1/3d9d12b56a7cd6f86c1cf676.png"},{"id":95524126,"identity":"21ec2012-7023-4153-aafc-b32fed2b657c","added_by":"auto","created_at":"2025-11-10 10:02:18","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":309371,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBrain maps showing significant differences in FC between awake, mild sedation induced by propofol, deep sedation induced by propofol and recovery states.\u003c/strong\u003e The red lines indicate higher in connections in the second state of each paired comparison, and the blue lines indicate higher connections in the first state of each paired comparison. Different node colors represent different functional networks.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7853532/v1/d0d638ec364c7b91c33d6265.png"},{"id":95525202,"identity":"ff2bfdae-f901-45ad-9d9f-e464e760aadb","added_by":"auto","created_at":"2025-11-10 10:04:31","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":169740,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePaired t-tests ofFC between awake, mild sedation induced by propofol, deep sedation induced by propofol and recovery states.\u003c/strong\u003e Warm colors indicate higher FC in the second state of each paired comparison. Cool colors indicate higher FC in the first state of each paired comparison. The significance of results is reported at \u003cem\u003ep \u003c/em\u003e\u0026lt; 0.01.\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-7853532/v1/518f5a8bf4d331349362bff4.png"},{"id":95525304,"identity":"ece4e26b-67ab-4fd8-b752-635ab0548838","added_by":"auto","created_at":"2025-11-10 10:04:45","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":990724,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePaired t-tests of FC between awake, mild sedation induced by dexmedetomidine and recovery states.\u003c/strong\u003e Cool colors indicate higher FC in the first state of each paired comparison. The significance of results is reported at \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.01.\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-7853532/v1/da61786e7b4265d357cb4014.png"},{"id":104251810,"identity":"653f4d8a-84aa-4554-acb1-14a7887d64f5","added_by":"auto","created_at":"2026-03-09 16:15:29","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3532228,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7853532/v1/7a55ced0-9b06-44be-8ba8-17b143d8dfb4.pdf"},{"id":95340568,"identity":"25f041a1-45b9-4b82-be11-e871395e4b8e","added_by":"auto","created_at":"2025-11-07 01:29:08","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":147793,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryMaterials.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7853532/v1/e97d28644bc2d7c7223ec3fc.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Propofol and dexmedetomidine sedation share the similar functional activity but distinct functional synchronization----a resting-state functional magnetic resonance imaging study","fulltext":[{"header":"Introduction","content":"\u003cp\u003eDespite advances in the understanding of the mechanisms for a variety of anesthetics, the specifics of why general anesthesia cause unconsciousness remain unclear. Propofol and dexmedetomidine are commonly used in clinical anesthesia. Propofol is a gamma-aminobutyric acidergic drug that increases inhibitory tone in neurons\u003csup\u003e\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. Dexmedetomidine is an alpha-2 adrenergic agonist that activates endogenous sleep pathways\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. The mechanisms of the two anesthetics are different, and research on their effects on brain function is still insufficient.\u003c/p\u003e\u003cp\u003eResting-state functional magnetic resonance imaging (rsfMRI) is ideally suited for exploring brain function of participants who are incapable of following instructions of goal-directed tasks\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. Anesthetic induce different states of consciousness by altering the functional activity of specific brain regions and the functional connectivity (FC)\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. Common measures of brain function include amplitude of low-frequency fluctuations (fALFF), regional homogeneity (ReHo) and FC. The fALFF are defined as the ratio of power spectrum of low-frequency to that of the entire frequency range to reflect brain neural activity during rest\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. ReHo detects the local synchronization of low-frequency oscillations using Kendall\u0026rsquo;s coefficient of concordance. It represents the similarity between the time series of a given voxel and that of its nearest neighbors\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. FC is defined as the temporal correlation between pairs of time series extracted from regions of interest or voxels. Previous studies have shown that the impact of propofol on the brain is described as the changes in prefrontal activity as well as alterations in FC\u003csup\u003e10,11\u003c/sup\u003e. Similarly, dexmedetomidine can also regulate FC within and between resting state networks, and affect low frequency fluctuation amplitude (ALFF)\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. Electroencephalogram (EEG)-based studies have shown that both dexmedetomidine-induced unconsciousness and propofol-induced unconsciousness are associated with slow/delta oscillations\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. However, there is still a lack of unified studies on the effects of propofol and dexmedetomidine on brain functional activity and FC.\u003c/p\u003e\u003cp\u003eIn this study, we acquired rsfMRI data from 21 healthy subjects in four states of consciousness induced by propofol (awake, mild sedation, deep sedation, and recovery) and other 21 healthy subjects in three states of consciousness (awake, mild sedation, and recovery) induced by dexmedetomidine. fALFF, ReHo and FC were measured for a unified study, aiming to explore the effects of propofol and dexmedetomidine on brain functional activity and synchronization through comprehensive analysis of these indicators.\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eDemographic data\u003c/h2\u003e\u003cp\u003eThere was no significant difference in age, gender, education level, nationality, and Body Mass Index (BMI) between two groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05) (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The vital signs among different sedation states showed no significant difference under propofol and dexmetomidine sedition, respectively (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05) (see Supplementary Table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e and S2). The propofol effect-site target concentration at different levels of sedation during the study period were also shown in Supplementary Table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDemographic data between propofol group and dexmetomidine group.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMeasurements\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePropofol group(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;21)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eDexmedetomidine group(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;21)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003ep\u003c/em\u003e value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGender, \u003cem\u003en\u003c/em\u003e(%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.912\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMale\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e18(85.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16(76.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFemale\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3(14.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5(23.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge(years)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e25.6\u0026thinsp;\u0026plusmn;\u0026thinsp;2.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e25.4\u0026thinsp;\u0026plusmn;\u0026thinsp;2.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.907\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNationality, \u003cem\u003en\u003c/em\u003e(%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u0026gt;\u0026thinsp;0.999\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNon-han nationality\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0(0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0(0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHan nationality\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e21(100)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e21(100)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eeducation level, \u003cem\u003en\u003c/em\u003e(%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.751\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003esenior high school and below\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e9(42.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7(33.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003esenior high school and above\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e12(57.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e14(66.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBMI(kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e25.88\u0026thinsp;\u0026plusmn;\u0026thinsp;0.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e25.74\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.865\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eThe fALFF values changes under different sedation states induced by propofol\u003c/h3\u003e\n\u003cp\u003eCompared to the awake state, the fALFF values in the frontal regions (including the superior frontal gyrus and middle frontal gyrus), supramarginal gyrus and cerebelum significantly decreased, while the superior temporal gyrus, calcarine, paracentral lobule and middle occipital gyrus showed a significant increase in mild sedation state induced by propofol.\u003c/p\u003e\u003cp\u003eCompared to the awake state, the fALFF values significantly decreased and spread across the entire frontal region, with a peak at left middle frontal gyrus. The area with a significant decrease in fALFF values in the temporal gyrus expanded. The fALFF values in the supramarginal gyrus, angular gyrus, cerebelum decreased significantly, while it in parietal gyrus significantly increased. Calcarine's fALFF values no longer declined significantly in the deep sedation state induced by propofol.\u003c/p\u003e\u003cp\u003eCompared to the deep state induced by propofol, the fALFF values in the temporal gyrus and parietal gyrus significantly decreased, while the fALFF values in the frontal regions and calcarine significantly increased in the recovery state.\u003c/p\u003e\u003cp\u003eThere was no significant difference between awake and recovery after propofol sedation (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Detailed results are presented in the supplementary Table S3.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\n\u003ch3\u003eThe fALFF values changes under different sedation states induced by dexmedetomidine\u003c/h3\u003e\n\u003cp\u003eCompared to the awake state, the fALFF values in the frontal regions with a peak at frontal inferior orbital gyrus and middle temporal pole significantly decreased, while cerebellum, the temporal and occipital regions (with a peak at fusiform) showed a significant increase in the mild sedation state induced by dexmedetomidine.\u003c/p\u003e\u003cp\u003eCompared to the mild state induced by dexmedetomidine, the fALFF values in the middle occipital gyrus, middle temporal gyrus and fusiform significantly decreased in the recovery state.\u003c/p\u003e\u003cp\u003eThere was no significant difference between awake and recovery after dexmedetomidine sedation (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Detailed results are presented in the supplementary Table S4.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\n\u003ch3\u003eThe ReHo values changes under different sedation states induced by propofol\u003c/h3\u003e\n\u003cp\u003eThe trend of ReHo value changes under mild sedation induced by propofol is similar to that of fALFF, with a decrease observed in the frontal gyrus, supramarginal gyrus, and cerebellar regions and an increase in the putamen, precentra, precuneus, rolandic operculum and lingual gyrus.\u003c/p\u003e\u003cp\u003eAs the sedation of propofol deepens, ReHo values significantly decreases in supramarginal gyrus, parietal inferior gyrus, calcarine and the entire frontal region, and an increase in the temporal and parietal regions.\u003c/p\u003e\u003cp\u003eIn the recovery state, the ReHo values in the superior temporal regions and paracentral lobule significantly decreases, while the ReHo values in the frontal regions, calcarine, cerebelum and supramarginal gyrus significantly increases.\u003c/p\u003e\u003cp\u003eThere was no significant difference between awake and recovery after propofol sedation (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Detailed results are presented in the supplementary Table S5.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\n\u003ch3\u003e\u003c/h3\u003e\n\u003cdiv class=\"Heading\"\u003e\u003cb\u003eThe ReHo values changes under different sedation states induced by dexmedetomidine\u003c/b\u003e\u003c/div\u003e\u003cp\u003eCompared to the awake state, ReHo values decreased in the middle frontal gyrus, temporal pole, middle temporal gyrus, caudate gyrus, and cerebellar regions, while it increased in the postcentral gyrus, occipital regions (with a peak at fusiform) and superior temporal in the mild sedation state induced by dexmedetomidine.\u003c/p\u003e\u003cp\u003eIn the recovery state, the previously increased ReHo values in the occipital gyrus, fusiform and postcentral gyrus significantly decreased.\u003c/p\u003e\u003cp\u003eThere was no significant difference between awake and recovery after dexmedetomidine sedation (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Detailed results are presented in the supplementary Table S6.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eThe FC changes under different sedation states induced by propofol\u003c/h2\u003e\u003cp\u003eAfter propofol sedation, the decrease in FC first appears between the SMN and DAN. As the depth of propofol sedation increases, the FC within and between the SMN, DAN, and VAN decreases, and the FC within the FPN and DMN also decreases. At the same time, a small number of increasing connections were observed within and between FPN, DMN and other networks. The VN network shows a trend of first increasing and then decreasing. No significant differences were observed between the recovery state and the awake state (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eThe FC changes under different sedation states induced by dexmedetomidine\u003c/h3\u003e\n\u003cp\u003eIn the mild sedation state induced by dexmedetomidine, we observed a general decrease in FC across the entire brain. The recovery state showed no significant differences compared to the awake state (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study aims to explore the changes in brain functional activity and synchronization under propofol and dexmedetomidine sedation, explaining the different mechanism of these two anesthetics. Our results suggest that, both anesthetics reduce functional activity in the frontal lobe and cerebellum, while increasing activity in the temporal and parietal lobes. Furthermore, propofol and dexmedetomidine have distinct effects on functional synchronization between brain regions. Propofol mainly reduces connectivity in the SMN, VAN, FPN and DMN, while dexmedetomidine has a more pronounced impact on FC, leading to a general reduction in FC under mild sedation.\u003c/p\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003eFunctional activity changes between different states\u003c/h2\u003e\u003cp\u003efALFF is the ratio of power spectrum of low frequency to that of the entire frequency range, may effectively suppress non-specific signal components in the rsfMRI, and therefore would significantly improve the sensitivity and specificity in detecting regional spontaneous brain activity\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. ReHo measures the similarity or synchronization between the time series of a given voxel and its nearest neighbors\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. These two indicators complement each other and comprehensively reveal the changes in brain function activity after anesthesia. The study found that the effects of propofol and dexmedetomidine on brain functional activity showed similar results. The decrease of frontal functional activity under mild and deep sedation states is worth exploring. The frontal lobes contribute to conscious perception and cognitive functions\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e,\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e. Previous studies have shown that anesthetics preferentially inhibit activity in higher-order information processing areas, particularly the frontal lobes\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. This result suggests that a loss of frontal executive function may be the primary factor in propofol-induced and dexmedetomidine-induced unconsciousness.\u003c/p\u003e\u003cp\u003eThe fALFF and ReHo in the temporal lobe and parietal lobe increased significantly with the increase of sedation depth. Research on EEG indicates that the gamma band power in the temporal lobe increases, which may reflect the formation of declarative memory under propofol sedation\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. Study has also found that under dexmedetomidine sedation, ALFF in the resting state BOLD signals in the somatosensory motor areas significantly increased\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eWe also found an interesting result. After mild propofol sedation, the fALFF and ReHo in the occipital lobe increased. However, after deep propofol sedation, this increase disappeared. Under mild dexmedetomidine sedation, the increase in fALFF and ReHo in the occipital lobe was more pronounced. Therefore, we speculate that in the low-dose phase, the occipital lobe may be temporarily activated. In the future, continuous depth of the same anesthetic should be used for further verification.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003eFC changes between different states\u003c/h2\u003e\u003cp\u003eIn this study, we used the Brainnetome Atlas to evaluate the effect of anesthesia on FC between gray matter regions of the brain, which complements the research on FC based on functional networks.\u003c/p\u003e\u003cp\u003eThere is currently controversy over the impact of propofol on SMN\u003csup\u003e\u003cspan additionalcitationids=\"CR25\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e–\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e. Our study found that under propofol sedation, the coordination within and between the SMN and VAN was suppressed. This suggest that propofol-induced disconnection may occur within low-order resting-state functional networks and between high-order networks and low-order networks\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e,\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eFurthermore, there has been debates regarding the FC changes within FPN and DMN, as well as with other networks\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e,\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e,\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. In this study, many connections within the FPN and DMN, as well as between them and other networks were decreased, while some connections increased. This provides a more detailed observation of the functional synchrony changes in the FPN and DMN. Although previous studies have suggested that disruptions in high-order resting-state functional networks during propofol-induced unresponsive seem to be a hallmark of the unresponsive state\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e,\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e. Some connections within the FPN, DMN, and between them and other networks were noticeably increased under deep sedation. This may suggest that during propofol deep sedation, the brain still maintains a certain level of functional collaboration.\u003c/p\u003e\u003cp\u003eAfter dexmedetomidine sedation, we observed a general decrease in FC across the entire brain, which is similar to the results previously assessed. Previous study suggested that FC within and between resting state networks is modulated by dexmedetomidine, and a significant reduction in FC strength, during the wakefulness to unconsciousness\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eMore importantly, compared to the awake state, we did not observe significant differences in FC in the recovery state, which may reflect the short-term effects of anesthesia on brain function coordination. FC returned to the awake state in healthy volunteers, confirming the safety of propofol and dexmedetomidine.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\u003ch2\u003eLimitations\u003c/h2\u003e\u003cp\u003eIn this study, firstly, although we discussed the effects of both propofol and dexmedetomidine on brain function, the inconsistent depths of anesthesia in this study hindered the comparison of the effects of the two anesthetics on brain function directly. Furthermore, the number of datasets in this study is limited. But through meticulous analysis of the limited yet representative data, we have been able to preliminarily reveal the functional activity and FC changes at propofol and dexmedetomidine.\u003c/p\u003e\u003c/div\u003e"},{"header":"Methods","content":"\u003cp\u003eThis study was conducted at Beijing Tiantan Hospital, Capital Medical University, Beijing, China (NCT 033443873). The Institutional Review Board of Beijing Tiantan Hospital has approved the study (KY2017-036-02). This study was performed in accordance with the Declaration of Helsinki. Written informed consent was obtained from all subjects participating in the trial. The study followed the Consolidated Standards of Reporting Trials (CONSORT) 2010 reporting guidelines.\u003c/p\u003e\u003ch2\u003eParticipants\u003c/h2\u003e\u003cp\u003eForty-two healthy adult volunteers were assigned into propofol group or dexmedetomidine group, with twenty-one subjects in each group. All participants were native Chinese speakers and had no histories of neurological, psychiatric conditions, or structural brain abnormalities. The exclusion criteria were as follows: (1) metal implants in the body; (2) intracranial lesions or systemic comorbidities; (3) a history of drug abuse or alcohol abuse; (4) allergy to propofol; (5) claustrophobia; (6) left-handed.\u003c/p\u003e\u003ch2\u003eSedation protocol\u003c/h2\u003e\u003cp\u003eTwo certified anesthesiologists were responsible for the monitoring and safety of the volunteers. Subjects were asked to fast for at least 8 hours before sedation. Upon arrival, standard American Society of Anesthesiologists monitoring was continuously performed including electrocardiography, heart rate, blood pressure, pulse oxygen saturation, and respiratory rate. A 20-gauge IV cannula was used for fluid and sedation administration. Throughout the sedation and MRI scans, the subjects breathed spontaneously with a nasal catheter of oxygen (6 L/min).\u003c/p\u003e\u003cp\u003eDexmedetomidine was administered as a bolus at 1 µg/kg over a period of 15 min; it was then administered at 0.6 µg/kg/h by continuous intravenous infusion to maintain sedation. Target-controlled infusion (TCI) of propofol was delivered by a syringe pump (B. Braun, Germany). The initial effect-site target concentration was set at 0.5ug/ml and increased step-up by every 0.2 ug/ml. The level of consciousness in both group was evaluated every 5 min by using the Observer’s Assessment of Alertness/Sedation (OAA/S) Scale.\u003c/p\u003e\u003cp\u003eSubjects wore headphones throughout the experiment and were thus spoken to through an MRI speaker. All communications occurred between MRI acquisitions, and subjects were instructed to respond verbally. No motor response was involved, thus avoiding the introduction of motion artifact.\u003c/p\u003e\u003ch2\u003eImage acquisition\u003c/h2\u003e\u003cp\u003eAll fMRI data were obtained using a 3.0 T MRI system (Siemens Medical Systems Prisma) at Beijing Neurosurgical Institute. Before sedation, images were acquired using a high-resolution three-dimensional T1- weighted brain volume MRI sequence with the following parameters: repetition time, 2300ms; echo time, 2.27ms; flip angle, 8°; fleld of view, 256 × 256 mm\u003csup\u003e2\u003c/sup\u003e; matrix, 256 × 256; voxel size, 1 × 1 × 1 mm\u003csup\u003e3\u003c/sup\u003e; slice thickness, 1 mm; and 192 sagittal slices. We then used an echo-planar imaging sequence to perform rsfMRI in different clinical states. In dexmedetomidine group, normal wakefulness (OAA/S Scale score 5), mild sedation (OAA/S Scale score 3–4), and recovery of consciousness (OAA/S Scale score 5) were collected. In propofol group, normal wakefulness (OAA/S Scale score 5), mild sedation (OAA/S Scale score 3–4), deep sedation (OAA/S Scale score 1–2), and recovery of consciousness (OAA/S Scale score, 5) were collected. For each state, the typical scan duration was 15min. The scanning parameters were as follows: repetition time, 2000 ms; echo time, 30 ms; flip angle, 75°; field of view, 192 × 192 mm\u003csup\u003e2\u003c/sup\u003e; matrix = 64 × 64; slice thickness, 4 mm; voxel size, 3 × 3 × 4.4 mm\u003csup\u003e3\u003c/sup\u003e; 32 slices; and 200 volumes.\u003c/p\u003e\u003ch2\u003eImage preprocessing\u003c/h2\u003e\u003cp\u003eThe functional image preprocessing steps included the following using Brant (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://brant.brainnetome.org\u003c/span\u003e\u003cspan address=\"http://brant.brainnetome.org\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e)\u003csup\u003e15\u003c/sup\u003e. (1) The first ten time points were removed for signal equilibrium and to allow the participants to adapt at to the scanning noise. (2) Slice-time correction. (3) Realignment to the mean functional image. (4) Normalization to the Montreal Neurological Institute space. (5) Regression of nuisance signals, including linear trends, six motion parameters and signals representing cerebrospinal fluid and white matter. (6) Temporal scrubbing using motion “spikes” (threshold of framewise displacement = 0.5) was performed. (7) Band-pass filtering (0.01–0.1 Hz) was performed to reduce non-neuronal contributions to blood oxygen level-dependent (BOLD) fluctuations. (8) Spatial smoothing with a 6 mm Gaussian Kernel.\u003c/p\u003e\u003ch2\u003eComputation of fALFF, ReHo and FC\u003c/h2\u003e\u003cp\u003eTo quantify the intensity of spontaneous brain activity in a region, fALFF was calculated by using the brant toolbox. The BOLD time series of all brain voxels were transformed into the frequency domain through Fourier transform and the power spectrum was calculated. The fALFF index is the total power of the 0.01–0.1 Hz frequency band divided by that of the entire frequency range. Subsequently, the fALFF was smoothed with a smoothing kernel of 6 mm and z-score normalization.\u003c/p\u003e\u003cp\u003eReHo is the Kendall's coefficient of coherence between the seed voxel and its nearest neighboring 26 voxels, representing the degree of spontaneous activity near the seed voxel. The higher the intensity of voxels in the ReHo map, the more similar the time series of adjacent voxels. Since spatial smoothing artificially enhances ReHo and reduces its reliability\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e, the ReHo map was calculated from non-smoothed time series. Subsequently, spatial smoothing was applied using a 6 mm Gaussian kernel and z-score normalization was performed on the ReHo map.\u003c/p\u003e\u003cp\u003eFC between gray matter regions of the brain was calculated based on the Brainnetome Atlas\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e, and a 246 × 246 FC matrix (excluding cerebellum) was obtained. The Pearson correlation between the average time series of any brain region in each subject was then calculated and Fisher’s z-transforms was performed on the correlation matrix. The threshold for FC was set to r \u0026gt; 0.2 to eliminate interference from noise\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003ch2\u003eStatistical analysis\u003c/h2\u003e\u003cp\u003eTo investigate the differences in fALFF and ReHo induced by anesthetic at the group level, paired t-test was performed on fALFF and ReHo maps between different sedation states. The significance threshold was set to \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05 and multiple comparisons correction was performed using the false discovery rate (FDR). Clusters with voxels greater than 50 were selected using the dpabi toolbox\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. Similarly, the paired t-test was performed on the FC matrices between different sedation states. The significance threshold was set to \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.01, and FDR was used for multiple comparisons correction of different connections.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThis study systematically revealed the reversible regulatory mechanisms of propofol and dexmedetomidine on brain functional activity and synchronization. The results showed that these two anesthetics had consistent effects on brain functional activity but exhibited differences in regulating functional connectivity. Specifically, both propofol and dexmedetomidine significantly reduced functional activity in the frontal lobe and cerebellum, while enhancing functional activity in the temporal and parietal lobes. Notably, in terms of functional synchronization, propofol primarily reduced the connectivity strength between the SMN, VAN, FPN, and DMN networks, while dexmedetomidine induced a widespread decrease in brain-wide connectivity. These findings not only clarify the differential regulatory patterns of different anesthetics on functional activity and functional synchronization but also provide important theoretical evidence for understanding the neural mechanisms of anesthesia-induced loss of consciousness.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe sincerely appreciate all the participants who took part in this study. Their time, effort, and cooperation were invaluable to this research.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe acknowledge funding provided by the National Natural Science Foundation of China (No. 82371910, 61901465, 82271284) and the Beijing Hospital Management Center Youth Talent Development Program \"Young Sprouts\" (QML20230509).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eL.H conceived and designed the study and supervised the entire research process. J.M, L.G, H.R, W.C, L.F, L.Y and W.X collected the raw data, and performed the experiments. Z.Jand Z.F analyzed the MRI data. J.M, H.R and Z.R secured the funding. J.M and Z.J drafted the manuscript. All authors reviewed and approved the final manuscript, and agree to be accountable for all aspects of the work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study are available from the corresponding author upon reasonable request.\"\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDisclosures\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors report no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBrown EN, Lydic R, Schiff ND: General anesthesia, sleep, and coma. New England Journal of Medicine 2010; 363: 2638-2650\u003c/li\u003e\n\u003cli\u003eRudolph U, Antkowiak B: Molecular and neuronal substrates for general anaesthetics. 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Frontiers in Neuroinformatics 2018; 12\u003c/li\u003e\n\u003cli\u003eZuo X-N, Xu T, Jiang L, Yang Z, Cao X-Y, He Y, Zang Y-F, Castellanos FX, Milham MP: Toward reliable characterization of functional homogeneity in the human brain: preprocessing, scan duration, imaging resolution and computational space. Neuroimage 2013; 65: 374-386\u003c/li\u003e\n\u003cli\u003eLingzhong F, Hai L, Junjie Z, Yu Z, Jiaojian W, Liangfu C, Zhengyi Y, Congying C, Sangma X, Laird AR: The Human Brainnetome Atlas: A New Brain Atlas Based on Connectional Architecture. Cerebral Cortex 2016; 26: 3508-3526\u003c/li\u003e\n\u003cli\u003eJin D, Wang P, Zalesky A, Liu B, Song C, Wang D, Xu K, Yang H, Zhang Z, Yao H: Grab‐AD: generalizability and reproducibility of altered brain activity and diagnostic classification in Alzheimer\u0026apos;s disease. 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Brain connectivity 2016; 6: 225-237\u003c/li\u003e\n\u003cli\u003eFell J, Widman G, Rehberg B, Elger CE, Fern\u0026aacute;ndez G: Human mediotemporal EEG characteristics during propofol anesthesia. Biological cybernetics 2005; 92: 92-100\u003c/li\u003e\n\u003cli\u003eGross WL, Lauer KK, Liu X, Roberts CJ, Liu S, Gollapudy S, Binder JR, Li S-J, Hudetz AG: Propofol Sedation Alters Perceptual and Cognitive Functions in Healthy Volunteers as Revealed by Functional Magnetic Resonance Imaging. Anesthesiology 2019; 131: 254-265\u003c/li\u003e\n\u003cli\u003eGuldenmund P, Vanhaudenhuyse A, Sanders R, Sleigh J, Bruno M-A, Demertzi A, Bahri MA, Jaquet O, Sanfilippo J, Baquero K: Brain functional connectivity differentiates dexmedetomidine from propofol and natural sleep. BJA: British Journal of Anaesthesia 2017; 119: 674-684\u003c/li\u003e\n\u003cli\u003eMalekmohammadi M, AuYong N, Price CM, Tsolaki E, Hudson AE, Pouratian N: Propofol-induced Changes in \u0026alpha;-\u0026beta; Sensorimotor Cortical Connectivity. Anesthesiology 2018; 128: 305-316\u003c/li\u003e\n\u003cli\u003eWang S, Li Y, Qiu S, Zhang C, Wang G, Xian J, Li T, He H: Reorganization of rich-clubs in functional brain networks during propofol-induced unconsciousness and natural sleep. NeuroImage: Clinical 2020; 25: 102188\u003c/li\u003e\n\u003cli\u003eCraig MM, Misic B, Pappas I, Adapa RM, Menon DK, Stamatakis EA: Propofol sedation-induced alterations in brain connectivity reflect parvalbumin interneurone distribution in human cerebral cortex. British journal of anaesthesia 2021; 126: 835-844\u003c/li\u003e\n\u003cli\u003eG\u0026oacute;mez F, Phillips C, Soddu A, Boly M, Boveroux P, Vanhaudenhuyse A, Bruno M-A, Gosseries O, Bonhomme V, Laureys S: Changes in Effective Connectivity by Propofol Sedation. PLoS ONE 2013; 8: e71370-\u003c/li\u003e\n\u003cli\u003eHorovitz SG, Braun AR, Carr WS, Picchioni D, Balkin TJ, Fukunaga M, Duyn JH: Decoupling of the brain\u0026apos;s default mode network during deep sleep. Proceedings of the National Academy of Sciences 2009; 106: 11376-11381\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Propofol, dexmedetomidine, functional activity, functional synchronization, functional magnetic resonance imaging","lastPublishedDoi":"10.21203/rs.3.rs-7853532/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7853532/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThere is insufficient unified research on the effects of propofol and dexmedetomidine on brain functional activity and synchronization. We collected resting-state functional magnetic resonance imaging (rsfMRI) data from 21 healthy subjects in four different levels of consciousness induced by propofol (awake, mild sedation, deep sedation, and recovery), and other 21 healthy subjects in three different levels of consciousness induced by dexmedetomidine (awake, mild sedation and recovery). The results showed that with the increasing of sedation levels of propofol or dexmedetomidine, fractional amplitude of low-frequency fluctuations (fALFF) and regional homogeneity (ReHo) values decreased in the frontal lobe, while they increased in the temporal and parietal lobes. Under propofol sedation, functional connectivity (FC) decreased both within and between sensorimotor network and attention network, and within and between the frontoparietal network (FPN) and default mode network (DMN). Simultaneously, a small number of increased connections were observed between the FPN, DMN, and other networks. Under dexmedetomidine sedation, generally decreased FC was observed in the whole brain. This study shows consistent effects on brain functional activity, but distinct impacts on functional synchronization, providing new insights into the understanding of anesthetic mechanisms.\u003c/p\u003e","manuscriptTitle":"Propofol and dexmedetomidine sedation share the similar functional activity but distinct functional synchronization----a resting-state functional magnetic resonance imaging study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-07 01:29:04","doi":"10.21203/rs.3.rs-7853532/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-02T06:42:44+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-25T12:04:37+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-24T20:20:09+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"197304304272259355923594094088197306962","date":"2025-10-28T13:32:43+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"125298684713286569116563013134787317287","date":"2025-10-28T12:16:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"179790084058099082697503979548612708510","date":"2025-10-27T22:14:17+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-10-27T22:10:59+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-10-27T21:42:59+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-10-27T11:54:34+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-10-26T06:27:13+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-10-26T06:24:25+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"6cdfb875-9c6f-4fcf-93cb-35ecaa51d2a6","owner":[],"postedDate":"November 7th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":57059462,"name":"Health sciences/Medical research"},{"id":57059463,"name":"Health sciences/Neurology"},{"id":57059464,"name":"Biological sciences/Neuroscience"}],"tags":[],"updatedAt":"2026-03-09T16:11:47+00:00","versionOfRecord":{"articleIdentity":"rs-7853532","link":"https://doi.org/10.1038/s41598-026-40974-w","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2026-03-02 16:00:00","publishedOnDateReadable":"March 2nd, 2026"},"versionCreatedAt":"2025-11-07 01:29:04","video":"","vorDoi":"10.1038/s41598-026-40974-w","vorDoiUrl":"https://doi.org/10.1038/s41598-026-40974-w","workflowStages":[]},"version":"v1","identity":"rs-7853532","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7853532","identity":"rs-7853532","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}