Hippocampus最新文献

{"title":"Distinct engrams control fear and extinction memory","authors":"Jordana Griebler Luft,&nbsp;Bruno Popik,&nbsp;Débora Aguirre Gonçalves,&nbsp;Fabio Cardoso Cruz,&nbsp;Lucas de Oliveira Alvares","doi":"10.1002/hipo.23601","DOIUrl":"10.1002/hipo.23601","url":null,"abstract":"<p>Memories are stored in engram cells, which are necessary and sufficient for memory recall. Recalling a memory might undergo reconsolidation or extinction. It has been suggested that the original memory engram is reactivated during reconsolidation so that memory can be updated. Conversely, during extinction training, a new memory is formed that suppresses the original engram. Nonetheless, it is unknown whether extinction creates a new engram or modifies the original fear engram. In this study, we utilized the Daun02 procedure, which uses c-Fos-lacZ rats to induce apoptosis of strongly activated neurons and examine whether a new memory trace emerges as a result of a short or long reactivation, or if these processes rely on modifications within the original engram located in the basolateral amygdala (BLA) and infralimbic (IL) cortex. By eliminating neurons activated during consolidation and reactivation, we observed significant impacts on fear memory, highlighting the importance of the BLA engram in these processes. Although we were unable to show any impact when removing the neurons activated after the test of a previously extinguished memory in the BLA, disrupting the IL extinction engram reactivated the aversive memory that was suppressed by the extinction memory. Thus, we demonstrated that the IL cortex plays a crucial role in the network involved in extinction, and disrupting this specific node alone is sufficient to impair extinction behavior. Additionally, our findings indicate that extinction memories rely on the formation of a new memory, supporting the theory that extinction memories rely on the formation of a new memory, whereas the reconsolidation process reactivates the same original memory trace.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 5","pages":"230-240"},"PeriodicalIF":3.5,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139939949","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":"Issue Information - Editorial Board","authors":"","doi":"10.1002/hipo.23556","DOIUrl":"https://doi.org/10.1002/hipo.23556","url":null,"abstract":"","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 3","pages":"125"},"PeriodicalIF":3.5,"publicationDate":"2024-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.23556","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139908918","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":"Distinct roles of Bdnf I and Bdnf IV transcript variant expression in hippocampal neurons","authors":"Svitlana V. Bach,&nbsp;Allison J. Bauman,&nbsp;Darya Hosein,&nbsp;Jennifer J. Tuscher,&nbsp;Lara Ianov,&nbsp;Kelsey M. Greathouse,&nbsp;Benjamin W. Henderson,&nbsp;Jeremy H. Herskowitz,&nbsp;Keri Martinowich,&nbsp;Jeremy J. Day","doi":"10.1002/hipo.23600","DOIUrl":"10.1002/hipo.23600","url":null,"abstract":"<p>Brain-derived neurotrophic factor (<i>Bdnf</i>) plays a critical role in brain development, dendritic growth, synaptic plasticity, as well as learning and memory. The rodent <i>Bdnf</i> gene contains nine 5′ non-coding exons (<i>I</i>–<i>IXa</i>), which are spliced to a common 3′ coding exon (<i>IX</i>). Transcription of individual <i>Bdnf</i> variants, which all encode the same BDNF protein, is initiated at unique promoters upstream of each non-coding exon, enabling precise spatiotemporal and activity-dependent regulation of <i>Bdnf</i> expression. Although prior evidence suggests that <i>Bdnf</i> transcripts containing exon <i>I</i> (<i>Bdnf I</i>) or exon <i>IV</i> (<i>Bdnf IV</i>) are uniquely regulated by neuronal activity, the functional significance of different <i>Bdnf</i> transcript variants remains unclear. To investigate functional roles of activity-dependent <i>Bdnf I</i> and <i>IV</i> transcripts, we used a CRISPR activation system in which catalytically dead Cas9 fused to a transcriptional activator (VPR) is targeted to individual <i>Bdnf</i> promoters with single guide RNAs, resulting in transcript-specific <i>Bdnf</i> upregulation. <i>Bdnf I</i> upregulation is associated with gene expression changes linked to dendritic growth, while <i>Bdnf IV</i> upregulation is associated with genes that regulate protein catabolism. Upregulation of <i>Bdnf I</i>, but not <i>Bdnf IV</i>, increased mushroom spine density, volume, length, and head diameter, and also produced more complex dendritic arbors in cultured rat hippocampal neurons. In contrast, upregulation of <i>Bdnf IV</i>, but not <i>Bdnf I</i>, in the rat hippocampus attenuated contextual fear expression. Our data suggest that while <i>Bdnf I</i> and <i>IV</i> are both activity-dependent, BDNF produced from these promoters may serve unique cellular, synaptic, and behavioral functions.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 5","pages":"218-229"},"PeriodicalIF":3.5,"publicationDate":"2024-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.23600","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139740940","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.23555","DOIUrl":"https://doi.org/10.1002/hipo.23555","url":null,"abstract":"","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 2","pages":"51"},"PeriodicalIF":3.5,"publicationDate":"2024-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.23555","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139494587","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":"Medial positioning of the hippocampus and hippocampal fissure volume in developmental topographical disorientation","authors":"Agustina Fragueiro,&nbsp;Claire Cury,&nbsp;Federica Santacroce,&nbsp;Ford Burles,&nbsp;Giuseppe Iaria,&nbsp;Giorgia Committeri","doi":"10.1002/hipo.23599","DOIUrl":"10.1002/hipo.23599","url":null,"abstract":"<p>Developmental topographical disorientation (DTD) refers to the lifelong inability to orient by means of cognitive maps in familiar surroundings despite otherwise well-preserved general cognitive functions, and the absence of any acquired brain injury or neurological condition. While reduced functional connectivity between the hippocampus and other brain regions has been reported in DTD individuals, no structural differences in gray matter tissue for the whole brain neither for the hippocampus were detected. Considering that the human hippocampus is the main structure associated with cognitive map-based navigation, here, we investigated differences in morphological and morphometric hippocampal features between individuals affected by DTD (<i>N</i> = 20) and healthy controls (<i>N</i> = 238). Specifically, we focused on a developmental anomaly of the hippocampus that is characterized by the incomplete infolding of hippocampal subfields during fetal development, giving the hippocampus a more round or pyramidal shape, called incomplete hippocampal inversion (IHI). We rated IHI according to standard criteria and extracted hippocampal subfield volumes after FreeSurfer's automatic segmentation. We observed similar IHI prevalence in the group of individuals with DTD with respect to the control population. Neither differences in whole hippocampal nor major hippocampal subfield volumes have been observed between groups. However, when assessing the IHI independent criteria, we observed that the hippocampus in the DTD group is more medially positioned comparing to the control group. In addition, we observed bigger hippocampal fissure volume for the DTD comparing to the control group. Both of these findings were stronger for the right hippocampus comparing to the left. Our results provide new insights regarding the hippocampal morphology of individuals affected by DTD, highlighting the role of structural anomalies during early prenatal development in line with the developmental nature of the spatial disorientation deficit.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 4","pages":"204-216"},"PeriodicalIF":3.5,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139424671","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":"The analysis of H.M.'s brain: A brief review of status and plans for future studies and tissue archive","authors":"David G. Amaral,&nbsp;Jean Augustinack,&nbsp;Helen Barbas,&nbsp;Matthew Frosch,&nbsp;John Gabrieli,&nbsp;Jennifer Luebke,&nbsp;Pasko Rakic,&nbsp;Douglas Rosene,&nbsp;Richard J. Rushmore","doi":"10.1002/hipo.23597","DOIUrl":"10.1002/hipo.23597","url":null,"abstract":"<p>The famous amnesic patient Henry Molaison (H.M.) died on December 2, 2008. After extensive in situ magnetic resonance imaging in Boston, his brain was removed at autopsy and transported to the University of California San Diego. There the brain was prepared for frozen sectioning and cut into 2401, 70 μm coronal slices. While preliminary analyses of the brain sections have been reported, a comprehensive microscopic neuroanatomical analysis of the state of H.M.'s brain at the time of his death has not yet been published. The brain tissue and slides were subsequently moved to the University of California Davis and the slides digitized at high resolution. Initial stages of producing a website for the public viewing of the images were also carried out. Recently, the slides, digital images, and tissue have been transferred to Boston University for permanent archiving. A new steering committee has been established and plans are in place for completion of a freely accessible H.M. website. Research publications on the microscopic anatomy and neuropathology of H.M.'s brain at the time of his death are also planned. We write this commentary to provide the hippocampus and memory neuroscience communities with a brief summary of what has transpired following H.M.'s death and outline plans for future publications and a tissue archive.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 2","pages":"52-57"},"PeriodicalIF":3.5,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.23597","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139377493","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":"Impaired perceptual discrimination of complex objects in older adults at risk for dementia","authors":"Lydia Jiang,&nbsp;Jessica Robin,&nbsp;Nathanael Shing,&nbsp;Negar Mazloum-Farzaghi,&nbsp;Natalia Ladyka-Wojcik,&nbsp;Niroja Balakumar,&nbsp;Nicole D. Anderson,&nbsp;Jennifer D. Ryan,&nbsp;Morgan D. Barense,&nbsp;Rosanna K. Olsen","doi":"10.1002/hipo.23598","DOIUrl":"10.1002/hipo.23598","url":null,"abstract":"<p>Tau pathology accumulates in the perirhinal cortex (PRC) of the medial temporal lobe (MTL) during the earliest stages of the Alzheimer's disease (AD), appearing decades before clinical diagnosis. Here, we leveraged perceptual discrimination tasks that target PRC function to detect subtle cognitive impairment even in nominally healthy older adults. Older adults who did not have a clinical diagnosis or subjective memory complaints were categorized into “at-risk” (score &lt;26; <i>n</i> = 15) and “healthy” (score ≥26; <i>n</i> = 23) groups based on their performance on the Montreal Cognitive Assessment. The task included two conditions known to recruit the PRC: faces and complex objects (greebles). A scene condition, known to recruit the hippocampus, and a size control condition that does not rely on the MTL were also included. Individuals in the at-risk group were less accurate than those in the healthy group for discriminating greebles. Performance on either the face or size control condition did not predict group status above and beyond that of the greeble condition. Visual discrimination tasks that are sensitive to PRC function may detect early cognitive decline associated with AD.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 4","pages":"197-203"},"PeriodicalIF":3.5,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.23598","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139377492","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":"Comparison of head direction cell firing characteristics across thalamo-parahippocampal circuitry","authors":"Benjamin J. Clark,&nbsp;Patrick A. LaChance,&nbsp;Shawn S. Winter,&nbsp;Max L. Mehlman,&nbsp;Will Butler,&nbsp;Ariyana LaCour,&nbsp;Jeffrey S. Taube","doi":"10.1002/hipo.23596","DOIUrl":"10.1002/hipo.23596","url":null,"abstract":"<p>Head direction (HD) cells, which fire persistently when an animal's head is pointed in a particular direction, are widely thought to underlie an animal's sense of spatial orientation and have been identified in several limbic brain regions. Robust HD cell firing is observed throughout the thalamo-parahippocampal system, although recent studies report that parahippocampal HD cells exhibit distinct firing properties, including conjunctive aspects with other spatial parameters, which suggest they play a specialized role in spatial processing. Few studies, however, have quantified these apparent differences. Here, we performed a comparative assessment of HD cell firing characteristics across the anterior dorsal thalamus (ADN), postsubiculum (PoS), parasubiculum (PaS), medial entorhinal (MEC), and postrhinal (POR) cortices. We report that HD cells with a high degree of directional specificity were observed in all five brain regions, but ADN HD cells display greater sharpness and stability in their preferred directions, and greater anticipation of future headings compared to parahippocampal regions. Additional analysis indicated that POR HD cells were more coarsely modulated by other spatial parameters compared to PoS, PaS, and MEC. Finally, our analyses indicated that the sharpness of HD tuning decreased as a function of laminar position and conjunctive coding within the PoS, PaS, and MEC, with cells in the superficial layers along with conjunctive firing properties showing less robust directional tuning. The results are discussed in relation to theories of functional organization of HD cell tuning in thalamo-parahippocampal circuitry.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 4","pages":"168-196"},"PeriodicalIF":3.5,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139097687","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":"Effects of healthy aging and mnemonic strategies on verbal memory performance across the adult lifespan: Mediating role of posterior hippocampus","authors":"Kim Ngan Hoang,&nbsp;Yushan Huang,&nbsp;Esther Fujiwara,&nbsp;Nikolai Malykhin","doi":"10.1002/hipo.23592","DOIUrl":"10.1002/hipo.23592","url":null,"abstract":"<p>In this study, we aimed to understand the contributions of hippocampal anteroposterior subregions (head, body, tail) and subfields (cornu ammonis 1-3 [CA1-3], dentate gyrus [DG], and subiculum [Sub]) and encoding strategies to the age-related verbal memory decline. Healthy participants were administered the California Verbal Learning Test-II to evaluate verbal memory performance and encoding strategies and underwent 4.7 T magnetic resonance imaging brain scan with subsequent hippocampal subregions and subfields manual segmentation. While total hippocampal volume was not associated with verbal memory performance, we found the volumes of the posterior hippocampus (body) and Sub showed significant effects on verbal memory performance. Additionally, the age-related volume decline in hippocampal body volume contributed to lower use of semantic clustering, resulting in lower verbal memory performance. The effect of Sub on verbal memory was statistically independent of encoding strategies. While total CA1-3 and DG volumes did not show direct or indirect effects on verbal memory, exploratory analyses with DG and CA1-3 volumes within the hippocampal body subregion suggested an indirect effect of age-related volumetric reduction on verbal memory performance through semantic clustering. As semantic clustering is sensitive to age-related hippocampal volumetric decline but not to the direct effect of age, further investigation of mechanisms supporting semantic clustering can have implications for early detection of cognitive impairments and decline.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 2","pages":"100-122"},"PeriodicalIF":3.5,"publicationDate":"2023-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.23592","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139032309","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":"Knockout of NMDARs in CA1 and dentate gyrus fails to impair temporal control of conditioned behavior in mice","authors":"Jasmin A. Strickland,&nbsp;Joseph M. Austen,&nbsp;Rolf Sprengel,&nbsp;David J. Sanderson","doi":"10.1002/hipo.23593","DOIUrl":"10.1002/hipo.23593","url":null,"abstract":"<p>The hippocampus has been implicated in temporal learning. Plasticity within the hippocampus requires NMDA receptor-dependent glutamatergic neurotransmission. We tested the prediction that hippocampal NMDA receptors are required for learning about time by testing mice that lack postembryonal NMDARs in the CA1 and dentate gyrus (DG) hippocampal subfields on three different appetitive temporal learning procedures. The conditional knockout mice (<i>Grin1</i>^{<i>ΔDCA1</i>}) showed normal sensitivity to cue duration, responding at a higher level to a short duration cue than compared to a long duration cue. Knockout mice also showed normal precision and accuracy of response timing in the peak procedure in which reinforcement occurred after 10 s delay within a 30 s cue presentation. Mice were tested on the matching of response rates to reinforcement rates on instrumental conditioning with two levers reinforced on a concurrent variable interval schedule. Pressing on one lever was reinforced at a higher rate than the other lever. <i>Grin1</i>^{<i>ΔDGCA1</i>} mice showed normal sensitivity to the relative reinforcement rates of the levers. In contrast to the lack of effect of hippocampal NMDAR deletion on measures of temporal sensitivity, <i>Grin1</i>^{<i>ΔDGCA1</i>} mice showed increased baseline measures of magazine activity and lever pressing. Furthermore, reversal learning was enhanced when the reward contingencies were switched in the lever pressing task, but this was true only for mice trained with a large difference between relative reinforcement rates between the levers. The results failed to demonstrate a role for NMDARs in excitatory CA1 and DG neurons in learning about temporal information.</p>","PeriodicalId":13171,"journal":{"name":"Hippocampus","volume":"34 3","pages":"126-140"},"PeriodicalIF":3.5,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.23593","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138884884","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}