Hippocampus最新文献

{"title":"Cover Image, Volume 34, Issue 10","authors":"Maria Jieun Hwang,&nbsp;Sang Ah Lee","doi":"10.1002/hipo.23640","DOIUrl":"https://doi.org/10.1002/hipo.23640","url":null,"abstract":"<p>The cover image is based on the article <i>Scene construction processes in the anterior hippocampus during temporal episodic memory retrieval</i> by Maria Jieun Hwang and Sang Ah Lee (https://doi.org/10.1002/hipo.23624).\u0000\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 10","pages":"C1"},"PeriodicalIF":2.4,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.23640","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142272999","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}

{"title":"Issue Information - Editorial Board","authors":"","doi":"10.1002/hipo.23563","DOIUrl":"https://doi.org/10.1002/hipo.23563","url":null,"abstract":"","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 10","pages":"505"},"PeriodicalIF":2.4,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.23563","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142275026","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}

{"title":"P2X7 expression patterns in the developing Fmr1-knockout mouse hippocampus","authors":"Matthew Napier,&nbsp;Ashish Kumar,&nbsp;Natasha Szulist,&nbsp;Dale Martin,&nbsp;Angela L. Scott","doi":"10.1002/hipo.23634","DOIUrl":"10.1002/hipo.23634","url":null,"abstract":"<p>Fragile-X Syndrome (FXS) is the leading monogenetic cause of intellectual disability among children but remains without a cure. Using the <i>Fmr1</i> <i>KO</i> mouse model of FXS, much work has been done to understand FXS hippocampus dysfunction. Purinergic signaling, where ATP and its metabolites are used as signaling molecules, participates in hippocampus development, but it is unknown if purinergic signaling is affected in the developing <i>Fmr1</i> <i>KO</i> hippocampus. In our study, we characterized the purinergic receptor P2X7. We first found that P2X7 was reduced in <i>Fmr1 KO</i> whole hippocampus tissue at P14 and P21, corresponding to the periods of neurite outgrowth and synaptic refinement in the hippocampus. We then evaluated the cell-specific expression of P2X7 with immunofluorescence and found differences between WT and <i>Fmr1 KO</i> mice in P2X7 colocalization with hippocampal microglia and neurons. P2X7 colocalized more with microglia at P14 and P21, but there was a sex-specific reduction in P2X7 colocalization with neurons. In contrast, male mice at P14 and P21 showed reduced neuronal P2X7 colocalization compared to females, but only females showed reduced absolute neuronal P2X7 expression across the dorsal hippocampal formation. Together, our results suggest that P2X7 expression is altered during <i>Fmr1</i>-KO hippocampal development, potentially influencing several developmental processes in the <i>Fmr1-</i>KO hippocampus formation.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 11","pages":"633-644"},"PeriodicalIF":2.4,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.23634","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263911","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}

{"title":"Anatomo-functional changes in neural substrates of cognitive memory in developmental amnesia: Insights from automated and manual Magnetic Resonance Imaging examinations","authors":"Loïc J. Chareyron,&nbsp;W. K. Kling Chong,&nbsp;Tina Banks,&nbsp;Neil Burgess,&nbsp;Richard C. Saunders,&nbsp;Faraneh Vargha-Khadem","doi":"10.1002/hipo.23638","DOIUrl":"10.1002/hipo.23638","url":null,"abstract":"<p>Despite bilateral hippocampal damage dating to the perinatal or early childhood period and severely impaired episodic memory, patients with developmental amnesia continue to exhibit well-developed semantic memory across the developmental trajectory. Detailed information on the extent and focality of brain damage in these patients is needed to hypothesize about the neural substrate that supports their remarkable capacity for encoding and retrieval of semantic memory. In particular, we need to assess whether the residual hippocampal tissue is involved in this preservation, or whether the surrounding cortical areas reorganize to rescue aspects of these critical cognitive memory processes after early injury. We used voxel-based morphometry (VBM) analysis, automatic (FreeSurfer) and manual segmentation to characterize structural changes in the brain of an exceptionally large cohort of 23 patients with developmental amnesia in comparison with 32 control subjects. Both the VBM and the FreeSurfer analyses revealed severe structural alterations in the hippocampus and thalamus of patients with developmental amnesia. Milder damage was found in the amygdala, caudate, and parahippocampal gyrus. Manual segmentation demonstrated differences in the degree of atrophy of the hippocampal subregions in patients. The level of atrophy in CA-DG subregions and subicular complex was more than 40%, while the atrophy of the uncus was moderate (−24%). Anatomo-functional correlations were observed between the volumes of residual hippocampal subregions in patients and selective aspects of their cognitive performance, viz, intelligence, working memory, and verbal and visuospatial recall. Our findings suggest that in patients with developmental amnesia, cognitive processing is compromised as a function of the extent of atrophy in hippocampal subregions. More severe hippocampal damage may be more likely to promote structural and/or functional reorganization in areas connected to the hippocampus. In this hypothesis, different levels of hippocampal function may be rescued following this variable reorganization. Our findings document not only the extent, but also the limits of circuit reorganization occurring in the young brain after early bilateral hippocampal damage.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 11","pages":"645-658"},"PeriodicalIF":2.4,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.23638","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263908","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}

{"title":"Curved multiplanar reformatting allows the accurate histological delineation of hippocampal subfields","authors":"Devon James Hupka,&nbsp;Andrew Abey,&nbsp;Ehsan Misaghi,&nbsp;Justine Gargula,&nbsp;Trevor Adam Steve","doi":"10.1002/hipo.23637","DOIUrl":"10.1002/hipo.23637","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Hippocampal subfields perform specific roles in normal cognitive functioning and have distinct vulnerabilities in neurological disorders. However, measurement of subfields with MRI is technically difficult in the head and tail of the hippocampus. Recent studies have utilized curved multiplanar reconstruction (CMPR) to improve subfield visualization in the head and tail, but this method has not yet been applied to histological data.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We utilized BigBrain data, an open-source database of serially sectioned histological data for our analyses. The left hippocampus was segmented according to histological criteria by two raters in order to evaluate intra- and inter-rater reliability of histology-based segmentation throughout the long axis. Segmentation according to our previous protocol for the hippocampal body was then compared to these histological measurements to evaluate for histological validity. Agreement between segmentations was evaluated using Dice similarity coefficients (DSCs).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Intra-rater reliability (DSCs) of histological segmentation was excellent for all subfields: CA1 (0.8599), CA2 (0.7586), CA3/CA4/DG (0.8907), SLM (0.9123), subiculum (0.8149). Similarly, inter-rater reliability analysis demonstrated excellent agreement (DSCs) for all subfield locations: CA1 (0.8203), CA2 (0.7253), CA3/CA4/DG (0.8439), SLM (0.8700), subiculum (0.7794). Finally, histological accuracy (DSCs) for our previous protocol was excellent for all subfields: CA1 (0.8821), CA2 (0.8810), CA3/CA4/DG (0.9802), SLM (0.9879), subiculum (0.8774). When subfields in the hippocampus head, body, and tail were analyzed independently, DSCs also showed excellent agreement.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>CMPR allows reliable subfield segmentation based on histological criteria throughout the hippocampal head, body, and tail. Our previous protocol for the hippocampal body can be applied to provide histologically valid subfield measurements throughout the entire hippocampal long axis.</p>\u0000 </section>\u0000 </div>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 11","pages":"625-632"},"PeriodicalIF":2.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.23637","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142203809","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}

{"title":"Hippocampal storage and recall of neocortical “What”–“Where” representations","authors":"Edmund T. Rolls,&nbsp;Chenfei Zhang,&nbsp;Jianfeng Feng","doi":"10.1002/hipo.23636","DOIUrl":"10.1002/hipo.23636","url":null,"abstract":"<p>A key question for understanding the function of the hippocampus in memory is how information is recalled from the hippocampus to the neocortex. This was investigated in a neuronal network model of the hippocampal system in which “What” and “Where” neuronal firing rate vectors were applied to separate neocortical modules, which then activated entorhinal cortex “What” and “Where” modules, then the dentate gyrus, then CA3, then CA1, then the entorhinal cortex, and then the backprojections to the neocortex. A rate model showed that the whole system could be trained to recall “Where” in the neocortex from “What” applied as a retrieval cue to the neocortex, and could in principle be trained up towards the theoretical capacity determined largely by the number of synapses onto any one neuron divided by the sparseness of the representation. The trained synaptic weights were then imported into an integrate-and-fire simulation of the same architecture, which showed that the time from presenting a retrieval cue to a neocortex module to recall the whole memory in the neocortex is approximately 100 ms. This is sufficiently fast for the backprojection synapses to be trained onto the still active neocortical neurons during storage of the episodic memory, and this is needed for recall to operate correctly to the neocortex. These simulations also showed that the long loop neocortex–hippocampus–neocortex that operates continuously in time may contribute to complete recall in the neocortex; but that this positive feedback long loop makes the whole dynamical system inherently liable to a pathological increase in neuronal activity. Important factors that contributed to stability included increased inhibition in CA3 and CA1 to keep the firing rates low; and temporal adaptation of the neuronal firing and of active synapses, which are proposed to make an important contribution to stabilizing runaway excitation in cortical circuits in the brain.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 11","pages":"608-624"},"PeriodicalIF":2.4,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.23636","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142106946","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}

{"title":"Time cells in the retrosplenial cortex","authors":"Dev Laxman Subramanian,&nbsp;David M. Smith","doi":"10.1002/hipo.23635","DOIUrl":"10.1002/hipo.23635","url":null,"abstract":"<p>The retrosplenial cortex (RSC) is a key component of the brain's memory systems, with anatomical connections to the hippocampus, anterior thalamus, and entorhinal cortex. This circuit has been implicated in episodic memory and many of these structures have been shown to encode temporal information, which is critical for episodic memory. For example, hippocampal time cells reliably fire during specific segments of time during a delay period. Although RSC lesions are known to disrupt temporal memory, time cells have not been observed there. In this study, we reanalyzed archival RSC neuronal firing data during the intertrial delay period from two previous experiments involving different behavioral tasks, a blocked alternation task and a cued T-maze task. For the blocked alternation task, rats were required to approach the east or west arm of a plus maze for reward during different blocks of trials. Because the reward locations were not cued, the rat had to remember the goal location for each trial. In the cued T-maze task, the reward location was explicitly cued with a light and the rats simply had to approach the light for reward, so there was no requirement to hold a memory during the intertrial delay. Time cells were prevalent in the blocked alternation task, and most time cells clearly differentiated the east and west trials. We also found that RSC neurons could exhibit off-response time fields, periods of reliably inhibited firing. Time cells were also observed in the cued T-maze, but they were less prevalent and they did not differentiate left and right trials as well as in the blocked alternation task, suggesting that RSC time cells are sensitive to the memory demands of the task. These results suggest that temporal coding is a prominent feature of RSC firing patterns, consistent with an RSC role in episodic memory.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 11","pages":"598-607"},"PeriodicalIF":2.4,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142106947","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}

{"title":"Estrogens dynamically regulate neurogenesis in the dentate gyrus of adult female rats","authors":"Shunya Yagi,&nbsp;Ahmad Mohammad,&nbsp;Yanhua Wen,&nbsp;Ariel A. Batallán Burrowes,&nbsp;Samantha A. Blankers,&nbsp;Liisa A. M. Galea","doi":"10.1002/hipo.23633","DOIUrl":"10.1002/hipo.23633","url":null,"abstract":"<p>Estrone and estradiol differentially modulate neuroplasticity and cognition. How they influence the maturation of new neurons in the adult hippocampus, however, is not known. The present study assessed the effects of estrone and estradiol on the maturation timeline of neurogenesis in the dentate gyrus (DG) of ovariectomized (a model of surgical menopause) young adult Sprague–Dawley rats using daily subcutaneous injections of 17β-estradiol, estrone or vehicle. Rats were injected with a DNA synthesis marker, 5-bromo-2-deoxyuridine (BrdU), and were perfused 1, 2, or 3 weeks after BrdU injection and daily hormone treatment. Brains were sectioned and processed for various markers including: sex-determining region Y-box 2 (Sox2), glial fibrillary acidic protein (GFAP), antigen kiel 67 (Ki67), doublecortin (DCX), and neuronal nuclei (NeuN). Immunofluorescent labeling or co-labelling of BrdU with Sox2 (progenitor cells), Sox2/GFAP (neural progenitor cells), Ki67 (cell proliferation), DCX (immature neurons), NeuN (mature neurons) was used to examine the trajectory and maturation of adult-born neurons over time. Estrogens had early (1 week of exposure) effects on different stages of neurogenesis (neural progenitor cells, cell proliferation and early maturation of new cells into neurons) but these effects were less pronounced after prolonged treatment. Estradiol enhanced, whereas estrone reduced cell proliferation after 1 week but not after longer exposure to either estrogen. Both estrogens increased the density of immature neurons (BrdU/DCX-ir) after 1 week of exposure compared to vehicle treatment but this increased density was not sustained over longer durations of treatments to estrogens, suggesting that the enhancing effects of estrogens on neurogenesis were short-lived. Longer duration post-ovariectomy, without treatments with either of the estrogens, was associated with reduced neural progenitor cells in the DG. These results demonstrate that estrogens modulate several aspects of adult hippocampal neurogenesis differently in the short term, but may lose their ability to influence neurogenesis after long-term exposure. These findings have potential implications for treatments involving estrogens after surgical menopause.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 11","pages":"583-597"},"PeriodicalIF":2.4,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.23633","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142008688","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}

{"title":"Issue Information - Editorial Board","authors":"","doi":"10.1002/hipo.23562","DOIUrl":"https://doi.org/10.1002/hipo.23562","url":null,"abstract":"","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 9","pages":"453"},"PeriodicalIF":2.4,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.23562","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141991618","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}

{"title":"Spatial memory encoding is associated with the anterior and posterior hippocampus: An fMRI activation likelihood estimation meta-analysis","authors":"Madeline A. Sullivan,&nbsp;Haley A. Fritch,&nbsp;Scott D. Slotnick","doi":"10.1002/hipo.23632","DOIUrl":"10.1002/hipo.23632","url":null,"abstract":"<p>It has been hypothesized that differential processing occurs along the longitudinal (anterior–posterior) axis of the hippocampus. One hypothesis is that spatial memory (during both encoding and retrieval) is associated with the posterior hippocampus. An alternative hypothesis is that memory encoding (either spatial or nonspatial) is associated with the anterior hippocampus and memory retrieval is associated with the posterior hippocampus. Of importance, during spatial memory encoding, the spatial–posterior hypothesis predicts posterior hippocampal involvement, whereas the encoding–retrieval hypothesis predicts anterior hippocampal involvement. To distinguish between these hypotheses, we conducted a coordinate-based fMRI activation likelihood estimation (ALE) meta-analysis of 26 studies (with a total of 435 participants) that reported hippocampal activity during spatial memory encoding and/or spatial memory retrieval. Both spatial memory encoding and spatial memory retrieval produced extensive activity along the longitudinal axis of the hippocampus as well as the entorhinal cortex, the perirhinal cortex, and the parahippocampal cortex. Critically, the contrast of spatial memory encoding and spatial memory retrieval produced activations in both the anterior hippocampus and the posterior hippocampus. That spatial memory encoding produced activity in both the anterior and posterior hippocampus can be taken to reject strict forms of the spatial–posterior hypothesis, which stipulates that all forms of spatial memory produce activity in the posterior hippocampus, and the encoding–retrieval hypothesis, which stipulates that all forms of encoding versus retrieval produce activity in only the anterior hippocampus. Our results indicate that spatial memory encoding can involve the anterior hippocampus and the posterior hippocampus.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 11","pages":"575-582"},"PeriodicalIF":2.4,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141987840","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}