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Susumu Tonegawa. Lim, Rosary Yuting. Massachusetts Institute of Technology. Department of Brain and Cognitive Sciences. Massachusetts Institute of Technology. Department of Brain and Cognitive Sciences 2021-03-22T17:06:35Z 2021-03-22T17:06:35Z 2020 2020 https://hdl.handle.net/1721.1/130185 1241087637 Thesis: Ph. D. in Neuroscience, Massachusetts Institute of Technology, Department of Brain and Cognitive Sciences, September, 2020 Cataloged from student-submitted PDF version of thesis. Includes bibliographical references (pages 76-90). During social interactions, humans and social animals can distinguish not only familiar and novel conspecifics (social recognition) but also between multiple familiar individuals (social specification). Recent studies have implicated hippocampal sub-region dorsal CA2 (dCA2) in social recognition and identified social recognition memory engram in downstream ventral CA1 (vCA1). However, the anatomical site for the storage of social specification memory and its underlying neuroscientific mechanisms are poorly known. Here, we report that social specification memory engrams are stored in vCA1 while social information encoded in dCA2 becomes sharpened as it travels from dCA2 to vCA1 microcircuits within CA2, thereby acquiring a progressive increase in specification through repeating motifs of feed-forward inhibition. Both the inhibition of GABAergic inhibitory neurons in CA2 and reduced activity of excitatory neurons by ablation of oxytocin receptors in the dCA2 to vCA1 microcircuits impair social memory specification. These results suggest that the vCA1 and the multiple feed-forward inhibition motifs in the dCA2 to vCA1 microcircuits are crucial for social memory specification. by Rosary Yuting Lim. Ph.D. in Neuroscience Ph.D.inNeuroscience Massachusetts Institute of Technology, Department of Brain and Cognitive Sciences 90 pages eng Massachusetts Institute of Technology MIT theses may be protected by copyright. Please reuse MIT thesis content according to the MIT Libraries Permissions Policy, which is available through the URL provided. http://dspace.mit.edu/handle/1721.1/7582 Brain and Cognitive Sciences. Hippocampal microcircuits for social memory specification Thesis application/pdf 2021-03-22T17:06:05Z Publication Doctoral Brain unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="86a99c3d-26f3-4f89-b89e-c7b5735c0042"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Hippocampal microcircuits for social memory specification</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2020</PublicationDate> <Authors> <Author> <DisplayName>Lim, Rosary Yuting.</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Brain and Cognitive Sciences.</Keyword> <Abstract>During social interactions, humans and social animals can distinguish not only familiar and novel conspecifics (social recognition) but also between multiple familiar individuals (social specification). Recent studies have implicated hippocampal sub-region dorsal CA2 (dCA2) in social recognition and identified social recognition memory engram in downstream ventral CA1 (vCA1). However, the anatomical site for the storage of social specification memory and its underlying neuroscientific mechanisms are poorly known. Here, we report that social specification memory engrams are stored in vCA1 while social information encoded in dCA2 becomes sharpened as it travels from dCA2 to vCA1 microcircuits within CA2, thereby acquiring a progressive increase in specification through repeating motifs of feed-forward inhibition. Both the inhibition of GABAergic inhibitory neurons in CA2 and reduced activity of excitatory neurons by ablation of oxytocin receptors in the dCA2 to vCA1 microcircuits impair social memory specification. These results suggest that the vCA1 and the multiple feed-forward inhibition motifs in the dCA2 to vCA1 microcircuits are crucial for social memory specification.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>