HippocampusPub Date : 2026-09-14DOI: 10.1002/hipo.70130
Bryan Montero-Herrera, Chadsley M. Wessinger, Jennifer L. Etnier, Eric S. Drollette, Kyoung Shin Park, Matthew P. Herring, Derek C. Monroe
{"title":"Physical Activity Is Associated With Age-Related Differences in Hippocampal Macrostructure and Microstructure in Middle-Aged and Older Adults","authors":"Bryan Montero-Herrera, Chadsley M. Wessinger, Jennifer L. Etnier, Eric S. Drollette, Kyoung Shin Park, Matthew P. Herring, Derek C. Monroe","doi":"10.1002/hipo.70130","DOIUrl":"10.1002/hipo.70130","url":null,"abstract":"<div>\u0000 \u0000 <p>Physical activity is found to promote healthy brain aging that is often indexed by hippocampal structure and function; however, evidence from cross-sectional studies remains limited and inconsistent, particularly for hippocampal morphology. Discrepancies in the literature may be explained by a historical focus on volumetric analyses, which obscure nuanced changes in cortical geometry, particularly in heavily folded regions of the hippocampus. In this study, we conducted a cross-sectional analysis to examine whether moderate-to-vigorous physical activity (MVPA) was associated with hippocampal macrostructure (thickness and surface area) and microstructure (T1w/T2w ratio) among 555 cognitively healthy adults (ages 36–90 years) from the Human Connectome Project–Aging cohort. Weekly MVPA was measured using the International Physical Activity Questionnaire, and participants were categorized as low-active (≥ 0–< 150 min/week), moderately active (≥ 150–< 300 min/week), or highly active (≥ 300 min/week) according to the World Health Organization 2020 guidelines on physical activity. Hippocampal thickness, surface area, and T1w/T2w ratio were derived from unfolded hippocampal surfaces using HippUnfold. Multivariate general linear models tested linear and quadratic age effects and MVPA × age interactions separately for each hemisphere, controlling for demographic and health covariates. Among the low-active group, age was associated with widespread multivariate differences in hippocampal macrostructure and microstructure, characterized by lower regionally specific thickness and surface area and by a higher T1w/T2w ratio. MVPA moderated age-related changes in the left hippocampus, with significant effects observed in the moderate- and high-MVPA groups. These effects were characterized by greater surface area and T1w/T2w ratio and were associated with lower thickness values. These results suggest that individuals who meet or exceed physical activity recommendations exhibit distinct age-related differences in hippocampus macrostructure and microstructure compared with those who do not.</p>\u0000 </div>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"36 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148968188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
HippocampusPub Date : 2026-09-11DOI: 10.1002/hipo.70126
Hye Ja Kang, Maria Jieun Hwang, Ji Sun Kim, Ji Yeon Kim, Marie-Agathe Crampon de Place, Sang Ah Lee
{"title":"The Human Subiculum and Its Role in Spatiotemporal Memory and Mental Imagery","authors":"Hye Ja Kang, Maria Jieun Hwang, Ji Sun Kim, Ji Yeon Kim, Marie-Agathe Crampon de Place, Sang Ah Lee","doi":"10.1002/hipo.70126","DOIUrl":"https://doi.org/10.1002/hipo.70126","url":null,"abstract":"<p>Traditionally viewed as a mere relay station of the hippocampal formation, the subiculum is emerging as a computational hub of the medial temporal lobe, essential for multiplexed neural representations guiding behavior. While foundational animal research has revealed that its sophisticated cytoarchitecture allows for conjunctive coding of spatiotemporal information, our understanding of how such neural properties translate to human cognitive function remains incomplete. The evolutionary expansion of its anterior region and the enhancement of its anatomical complexity and widespread neocortical connectivity imply that the function of the human subiculum may extend beyond the spatial domain. In this review, we examine how the subiculum may serve as a scaffold for goal-directed spatiotemporal computations in humans and speculate on its role in supporting abstract cognitive functions such as mental imagery and episodic simulation.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"36 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.70126","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148943346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
HippocampusPub Date : 2026-09-09DOI: 10.1002/hipo.70127
Alexandra S. Budd, Kevin Grant Solar, Myrlene Gee, Krista Nelles, Brooklyn Mankasingh, Zahinoor Ismail, Eric E. Smith, Michael Martyna, Fang Ba, Sanjay Kalra, Christian Beaulieu, Richard Camicioli
{"title":"High-Resolution Diffusion Tensor Imaging of the Hippocampus and Associations With Neuropsychiatric Symptoms in Lewy Body Diseases","authors":"Alexandra S. Budd, Kevin Grant Solar, Myrlene Gee, Krista Nelles, Brooklyn Mankasingh, Zahinoor Ismail, Eric E. Smith, Michael Martyna, Fang Ba, Sanjay Kalra, Christian Beaulieu, Richard Camicioli","doi":"10.1002/hipo.70127","DOIUrl":"10.1002/hipo.70127","url":null,"abstract":"<p>Parkinson's disease (PD) encompasses motor and neuropsychiatric symptoms (NPS) including depression, anxiety, and apathy. Cognitive subtypes—PD with mild cognitive impairment (PD-MCI) and PD with dementia (PDD)—and the related Dementia with Lewy Bodies (DLB) exist within the spectrum of Lewy body disease (LBD). While NPS are a major comorbidity, established imaging biomarkers are not available, nor is the neuronal basis well known. Additionally, prevalence of NPS may be linked to cognitive status. The hippocampus is implicated in the development of NPS and may undergo microstructural changes that are not reflected in volume changes. High-resolution diffusion tensor imaging (DTI) was used to identify hippocampal changes in LBD compared to healthy controls (HC) and examine the relationship with NPS within the LBD group, both through association with DTI measures as well as comparison of cognitive subgroups. The hippocampus was manually segmented in 38 LB spectrum participants (aged 58–87 years, 32% female) and 35 HC (aged 50–83 years, 54% female) on high-resolution (1 × 1 × 1 mm<sup>3</sup>) DTI. The LBD group (LBD-All) was divided into LBD-Cognitively Impaired (LBD-CI) and LBD-Cognitively Unimpaired (LBD-CU). Hippocampal volume, mean diffusivity (MD), and fractional anisotropy (FA) were extracted and compared across groups. Relationships between significantly different hippocampal measures and depression, anxiety, and apathy were explored within the LBD-All group. Hippocampal FA was lower in LBD-All relative to HC; however, no differences in MD or volume were observed. Hippocampal FA was positively associated with depression scores within LBD-All. There were no differences in volume, MD, or FA between LBD-CI and LBD-CU. Lower hippocampal fractional anisotropy in the LBD spectrum relative to HC potentially reflects microstructure alterations; however, higher hippocampal FA in LBD with more severe depression suggests more complex microstructural changes such as altered synaptic density, Lewy neurite organization, or neuroplastic changes.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"36 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.70127","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148919226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
HippocampusPub Date : 2026-09-09DOI: 10.1002/hipo.70129
Liam T. Ralph, Shinwon Kang, Lauren A. Joe, Patrick Tidball, Ahmad R. Israwi, Meng Tian, Ashish Kadia, Lijia Zhang, Fuzi Jin, Rachael Ingram, Zuner A. Bortolotto, Stafford L. Lightman, Becky L. Conway-Campbell, Joanne E. Nash, Janice Robertson, Clarrisa A. Bradley, Marina Gertsenstein, Lauryl M. J. Nutter, John Georgiou, Graham L. Collingridge
{"title":"Cover Image, Volume 36, Issue 5","authors":"Liam T. Ralph, Shinwon Kang, Lauren A. Joe, Patrick Tidball, Ahmad R. Israwi, Meng Tian, Ashish Kadia, Lijia Zhang, Fuzi Jin, Rachael Ingram, Zuner A. Bortolotto, Stafford L. Lightman, Becky L. Conway-Campbell, Joanne E. Nash, Janice Robertson, Clarrisa A. Bradley, Marina Gertsenstein, Lauryl M. J. Nutter, John Georgiou, Graham L. Collingridge","doi":"10.1002/hipo.70129","DOIUrl":"https://doi.org/10.1002/hipo.70129","url":null,"abstract":"<p>The cover image is based on the article <i>Diurnal Regulation of Hippocampal Synaptic Plasticity in Aged Rats and the Role of the Circadian Clock Gene Per1</i> by by Liam T. Ralph et al., https://doi.org/10.1002/hipo.70118.\u0000\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"36 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.70129","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
HippocampusPub Date : 2026-09-03DOI: 10.1002/hipo.70119
Daniel Reznik, Piotr Majka, Marcello G. P. Rosa, Menno P. Witter, Christian F. Doeller
{"title":"Phylogeny of Cortical-Hippocampal Projections Reveals Selective Elimination of Input From Sensory Regions","authors":"Daniel Reznik, Piotr Majka, Marcello G. P. Rosa, Menno P. Witter, Christian F. Doeller","doi":"10.1002/hipo.70119","DOIUrl":"10.1002/hipo.70119","url":null,"abstract":"<p>The study of cross-species differences in the organization of the cerebral cortex received significant attention during the past century. However, the evolutionary principles governing changes in brain connectivity and their impact on cognition remain poorly understood. In the current study, we analyzed differences in anatomical input from the cerebral cortex to the hippocampal region across six species spanning more than 100 million years of mammalian evolution—the tenrec, rat, cat, marmoset, macaque and human. Our results demonstrate that, unlike direct transmodal cortical input, direct unimodal cortical input to the hippocampal region was selectively eliminated with the increase in brain size. Additionally, input from primary sensory regions was eliminated prior to input from non-primary sensory regions. Our findings suggest that hippocampus-related processes in different species operate on fundamentally different types of information, potentially underpinning cross-species differences in hippocampus-dependent cognition. Furthermore, our findings outline the evolutionary trajectory of the anatomical circuitry associating the human hippocampal region with the neocortex.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"36 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13542335/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148887287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
HippocampusPub Date : 2026-09-01DOI: 10.1002/hipo.70132
Johaly Anguiano-Buenfil, Isabel Sollozo-Dupont, Luis A Márquez, Angelica Zepeda, Emilio J Galván
{"title":"Prenatal Stress Induced by Maternal Immune Activation Disrupts GABAergic Inhibition and Mossy Fiber Plasticity in the Rat Dentate Gyrus-CA3 Circuit.","authors":"Johaly Anguiano-Buenfil, Isabel Sollozo-Dupont, Luis A Márquez, Angelica Zepeda, Emilio J Galván","doi":"10.1002/hipo.70132","DOIUrl":"10.1002/hipo.70132","url":null,"abstract":"<p><p>Viral infections during critical periods of pregnancy trigger inflammatory responses that alter offspring brain development and behavior, resulting in psychiatric disorder-associated phenotypes. This condition is commonly referred to as prenatal stress induced by maternal immune activation (MIA). Here, we investigate the effects of MIA on the neurophysiological properties of the dentate gyrus-CA3 circuit, a hippocampal circuit critical for cortical input processing and memory formation, and increasingly implicated in psychiatric disorders. Pregnant Sprague-Dawley dams were systemically administered polyinosinic:polycytidylic acid (poly I:C), a synthetic double-stranded RNA that elicits a viral-like immune response by activating the Toll-like receptor 3 (TLR3)-NF-kB signaling pathway. Extracellular recordings were performed on acute slices of male offspring at postnatal days 61-80. MIA increased the antidromic population spike amplification at the mossy fiber (MF)-granule cell layer response without modifying the antidromic responses at the CA3-CA3 commissural-associational fibers. Paired pulses with short interstimulus intervals revealed decreased levels of phasic and tonic GABAergic inhibition. In addition, MIA reduced coupling between presynaptic fiber volleys and MF field excitatory postsynaptic potentials (MF fEPSP). At the level of synaptic plasticity, MIA impaired frequency-dependent facilitation and decreased MF fEPSP paired-pulse facilitation, two hallmark forms of short-term plasticity at the MF-CA3 synapse. Lastly, MF-mediated long-term potentiation (MF LTP) and long-term depression (MF LTD) showed altered magnitudes in MIA slices. Collectively, our results indicate that MIA alters neuronal processing and output in the DG-CA3 hippocampal network, supporting the contribution of maternal inflammation to long-term circuit dysfunction associated with viral infections during pregnancy.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"36 5","pages":"e70132"},"PeriodicalIF":2.9,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13592174/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149012198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
HippocampusPub Date : 2026-08-28DOI: 10.1002/hipo.70118
Liam T. Ralph, Shinwon Kang, Lauren A. Joe, Patrick Tidball, Ahmad R. Israwi, Meng Tian, Ashish Kadia, Lijia Zhang, Fuzi Jin, Rachael Ingram, Zuner A. Bortolotto, Stafford L. Lightman, Becky L. Conway-Campbell, Joanne E. Nash, Janice Robertson, Clarrisa A. Bradley, Marina Gertsenstein, Lauryl M. J. Nutter, John Georgiou, Graham L. Collingridge
{"title":"Diurnal Regulation of Hippocampal Synaptic Plasticity in Aged Rats and the Role of the Circadian Clock Gene Per1","authors":"Liam T. Ralph, Shinwon Kang, Lauren A. Joe, Patrick Tidball, Ahmad R. Israwi, Meng Tian, Ashish Kadia, Lijia Zhang, Fuzi Jin, Rachael Ingram, Zuner A. Bortolotto, Stafford L. Lightman, Becky L. Conway-Campbell, Joanne E. Nash, Janice Robertson, Clarrisa A. Bradley, Marina Gertsenstein, Lauryl M. J. Nutter, John Georgiou, Graham L. Collingridge","doi":"10.1002/hipo.70118","DOIUrl":"https://doi.org/10.1002/hipo.70118","url":null,"abstract":"<p>Period circadian regulator 1 (PER1) regulates circadian gene expression and is critical for spatial memory. However, its role in regulating synaptic plasticity between diurnal phases remains largely unknown. Here, we examined long-term potentiation (LTP) and long-term synaptic depression (LTD) in hippocampal slices prepared from aged male <i>Per1</i> knockout (<i>Per1</i> KO) rats and their wildtype (WT) littermates during the light/inactive and dark/active phases. In WT rats, theta-burst stimulation (TBS) consistently induced stable LTP that was greater during the dark relative to the light phase. In contrast, in <i>Per1</i> KO rats, TBS resulted in synaptic potentiation that decayed to baseline levels within ~90 min in both phases. Notably, WT rats readily expressed LTD following 1 Hz low-frequency stimulation (LFS) during the dark phase but not the light phase. By comparison, in <i>Per1</i> KO rats, LTD was inducible by LFS during both the dark and light phases. LTD in both WT and <i>Per1</i> KO rats was dependent on the activation of <i>N</i>-methyl-<span>d</span>-aspartate receptors. Basal synaptic transmission was reduced and GluA1 S845 phosphorylation was increased during the dark phase in both WT and <i>Per1</i> KO rats. Together, our findings identify PER1 as a key regulator of synaptic plasticity between diurnal phases in aged rats.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"36 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.70118","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
HippocampusPub Date : 2026-08-27DOI: 10.1002/hipo.70125
Thomas P. Reber, Leila Chaieb, Marlene Derner, Valeri Borger, Rainer Surges, Florian Mormann, Juergen Fell
{"title":"Single-Unit Activity in the Human Medial Temporal Lobe Reflects Reduced Error Monitoring During Mind Wandering","authors":"Thomas P. Reber, Leila Chaieb, Marlene Derner, Valeri Borger, Rainer Surges, Florian Mormann, Juergen Fell","doi":"10.1002/hipo.70125","DOIUrl":"10.1002/hipo.70125","url":null,"abstract":"<p>Mind wandering (MW) has been frequently reported to impair task performance. In this study, we investigated the hypothesis that it also affects error monitoring and adjustment. Several recent studies suggest that the hippocampus and adjacent regions significantly contribute to error monitoring. Therefore, we analyzed single-unit recordings from the medial temporal lobe (MTL) in presurgical epilepsy patients performing an attention task, which included interspersed experience sampling probes. Behavioral performance data revealed reduced error adjustment during periods of MW compared to task-focused attention. Analysis of single-unit recordings showed population responses related to performance errors within the hippocampus and adjacent regions, supporting the idea that MTL regions contribute to error monitoring. Importantly, this error-related population activity was significantly reduced during periods of MW compared to task focus. Together, our findings clearly support the hypothesis that MW impairs both error monitoring and adjustment.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"36 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.70125","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148827759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
HippocampusPub Date : 2026-08-24DOI: 10.1002/hipo.70124
Nima Talaei, Jordan DeKraker, Bradley G. Karat, Ali R. Khan, Stefan Köhler
{"title":"Association Between Anterior Hippocampal Gyrification and Episodic Memory Performance in Neurotypical Young Adults","authors":"Nima Talaei, Jordan DeKraker, Bradley G. Karat, Ali R. Khan, Stefan Köhler","doi":"10.1002/hipo.70124","DOIUrl":"10.1002/hipo.70124","url":null,"abstract":"<p>The hippocampus is critical for episodic memory. The relationship between its structural variability and individual differences in episodic memory performance among neurotypical young adults, however, remains unclear. Previous studies have not consistently found associations between hippocampal volume and episodic memory or other aspects of hippocampally dependent performance in this population. Here, we moved beyond volumetric approaches and tested whether more fine-grained morphometric features, particularly gyrification, are related to behavioral performance. To obtain these measures, we used HippUnfold, a deep learning-based segmentation tool that models the hippocampus as a folded cortical ribbon and uniquely quantifies local variability in folding patterns, including in the hippocampal head. We focused on an open-access dataset with high-resolution MRI scans and multiple behavioral measures on hippocampal-dependent tasks, including episodic and semantic components of the Autobiographical Interview. To improve segmentation quality for the high-resolution images in this dataset, we trained an nnU-Net segmentation model for HippUnfold that was optimized for high-resolution T2w images. Volumetric and surface-based measures were computed for 186 participants (97 female). We found no reliable associations between hippocampal volumetric measures, including subfield volumes, and behavioral performance. In contrast, surface-based analysis of hippocampal gyrification revealed significant bilateral clusters in the anterior hippocampus, both of which were associated with measures of episodic but not semantic autobiographical memory. The right hemisphere cluster was located in the subiculum and CA1, whereas the left hemisphere cluster was primarily situated in the subiculum. These findings demonstrate the utility of surface-based hippocampal morphometry for linking hippocampal structure to behavioral performance. They suggest that even in neurotypical young adults individual differences in episodic memory are tied to structural hippocampal variation.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"36 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13501942/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148808500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
HippocampusPub Date : 2026-08-21DOI: 10.1002/hipo.70123
Pankhuri Singhal, Victoria L. Templer, Robert R. Hampton
{"title":"Dissociation of Memory for Order and Memory for Items by Concurrent Cognitive Load in Rhesus Monkeys (Macaca mulatta)","authors":"Pankhuri Singhal, Victoria L. Templer, Robert R. Hampton","doi":"10.1002/hipo.70123","DOIUrl":"https://doi.org/10.1002/hipo.70123","url":null,"abstract":"<div>\u0000 \u0000 <p>Memory of the order in which events occurred addresses the “when” component of episodic-like memory in animals. Seminal work demonstrated that normal rats remember the order in which they encountered odors, and hippocampal lesions selectively impaired this memory for order while leaving recognition performance intact. This work inspired us to develop an image-order paradigm to model episodic memory in monkeys. Monkeys saw five images in sequence and at test reported which of two images appeared first. Unlike the case with rats, hippocampal lesions did not impair memory for order, raising questions about which memory systems monkeys used in this task. Because the memory intervals were short in the image-order task, monkeys may have used nonhippocampal-dependent working memory instead of long-term memory. To test this possibility, we introduced a concurrent cognitive load between the study and test phases of the image-order task. We hypothesized that if monkeys were using working memory to remember the order of the images, concurrent cognitive load would impair performance. We also tested recognition performance as a control, because familiarity-based recognition is relatively resistant to concurrent cognitive load. Memory for order was much more attenuated by concurrent cognitive load than recognition. These results indicate that monkeys used working memory to solve this image-order task, making it a poor model of long-term episodic memory. The findings also provide clear evidence for a dissociation between working memory-dependent order memory and familiarity-based recognition memory.</p>\u0000 </div>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"36 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148785030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}