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by claude@2026-07, 2026-07-03
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This fMRI study examined how hippocampal subregions and cortical medial temporal lobe areas contribute to allocentric working memory for object–location relational binding, using 128 healthy adults who performed an object–location task with an 8-second delay and a passive viewing control condition. Across the full sample, anterior and mid hippocampal and cortical MTL regions showed engagement during study, widespread delay-phase deactivation alongside region-specific sustained responses, and posterior MTL reactivation during test, with activity patterns varying by phase. Contrary to predictions, hippocampal and cortical MTL activation did not track performance differences among younger adults, and age-related differences were observed instead, including lower anterior hippocampal activation in older adults at comparable performance and smaller correct–passive viewing differences in perirhinal and parahippocampal cortices; the authors also interpret a left temporoparietal difference as possibly reflecting verbal encoding strategy. The paper does not explicitly discuss endometriosis or adenomyosis; it was included in the corpus via a keyword match in the upstream search index.
Abstract
The hippocampus and cortices of the medial temporal lobe (MTL) are increasingly implicated in working memory, particularly for tasks requiring complex, high-resolution relational binding, but their precise contributions—particularly during delay maintenance—remain debated. Using functional magnetic resonance imaging (fMRI), we investigated the involvement of hippocampal and cortical MTL in a demanding allocentric working memory task requiring high-resolution, relational binding. During fMRI, 128 healthy human adults (92 females) aged 20–83 (mean 39) years performed a task in which object–location bindings had to be learned, maintained, and manipulated across an 8 second delay. The design included a passive viewing condition to control for perceptual and attentional demands and a staircase procedure to balance task difficulty across participants. Across the full sample, anterior and mid hippocampal subregions and cortical MTL areas were engaged during encoding. In the delay phase, we observed a non-uniform pattern, with hippocampal and entorhinal deactivation alongside perirhinal and parahippocampal activation. During test, activation occurred in posterior hippocampus and several cortical MTL regions. Contrary to predictions, hippocampal and cortical MTL activation did not vary with performance among younger adults. Instead, differences emerged in a left temporoparietal cluster, potentially reflecting verbal encoding strategies. Older adults, relative to younger adults with the most comparable performance levels, showed lower anterior hippocampal activation and smaller correct–passive viewing differences in perirhinal and parahippocampal cortices. Taken together, these findings demonstrate distinct phase-specific hippocampal and cortical MTL involvement across the temporal unfolding of allocentric working memory, with evidence of hippocampal engagement even during the delay, yet the absence of MTL-performance associations among younger adults suggests this involvement, while robust, may play a more auxiliary role.
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ABSTRACT
The hippocampus and cortices of the medial temporal lobe (MTL) regions are increasingly implicated in working memory, but their precise contributions—particularly during delay maintenance—remain debated. Using functional magnetic resonance imaging (fMRI), we investigated the involvement of hippocampal and cortical MTL in a demanding allocentric working memory task requiring relational binding. A total of 128 healthy human adults (92 females) aged 20–83 (mean 39) years performed an allocentric working memory task during fMRI, in which object–location bindings had to be learned, maintained, and manipulated across an 8 second delay. The design included a staircase procedure to balance task difficulty across participants and a passive viewing condition to control for perceptual and attentional demands. Across the full sample, anterior and mid hippocampal subregions and cortical MTL areas were engaged in all phases, showing study-related activation, widespread delay-phase deactivation with region-specific sustained responses, and posterior hippocampal and cortical MTL reactivation during test. Contrary to predictions, hippocampal and cortical MTL activation did not vary with performance among younger adults. Instead, differences emerged in a left temporoparietal cluster, potentially reflecting verbal encoding strategies. Older adults, relative to younger adults with the most comparable performance levels, showed lower anterior hippocampal activation and smaller correct–passive viewing differences in perirhinal and parahippocampal cortices. Taken together, these findings accord with hippocampal subregions and cortical MTL involvement across the temporal unfolding of allocentric working memory, but with distinct phase-specific roles.
Competing Interest Statement
The authors have declared no competing interest.
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