The rotating tilted lines illusion for the evaluation of cognitive abnormalities

Background The population receptive field (pRF) in vision reflects the functional receptive field arising from millions of overlapping single receptive fields across visual areas and eccentricities. pRFs are typically estimated with fMRI to gain insight into visual processing. Alternative methods of pRF estimation, such as using optical illusions, have been explored only sparingly. In this study, we explore the rotating tilted lines illusion (RTLI), in which a circle formed by tilted lines appears to rotate as it expands or contracts in the visual field (e.g., from moving the head back and forth). New Method We propose a novel set of computer-generated animations of the RTLI that measure the visual and temporal characteristics of the illusory rotation, enabling quantitative estimation of the spatial extent and temporal dynamics of the pRF. Results We derived pRF size estimates consistent with those estimated from fMRI and electrophysiological methods. We then projected changes in RTLI percept trends according to abnormalities in visual processing in autism spectrum disorder (ASD), schizophrenia (SZ), aging, and Alzheimer’s disease (AD). Comparison with existing methods Compared to fMRI and electrophysiology, RTLI-based pRF estimation is accessible, low-cost, and feasible at home or during inpatient visits without specialized equipment. Conclusions We show that our novel method can approximate pRFs, which in turn can be potentially applied for early detection, probing the progress, and treatment screening in AD, SZ and ASD.