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Hippocampal circuits for episodic social memory| title | Hippocampal circuits for episodic social memory |
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| start_date | 2024/06/20 |
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| schedule | 15h15 |
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| online | no |
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| location_info | Room B10, Alexandra House |
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| summary | Social memory enables an animal to engage in adaptive social interactions based on the recollection of past rewarding or aversive experiences with conspecifics. The discrimination of past safety- or threat-associated experiences with a conspecific, social fear discrimination, is of particular importance for the appropriate choice of approach and avoidance behaviors. Failure to make this distinction may lead to social withdrawal and social avoidance, prominent symptoms of several neuropsychiatric disorders such as social anxiety disorder. Prior work has demonstrated that the hippocampal cornu ammonis 2 (CA2) region is critical for the discrimination of novel versus familiar conspecifics (social novelty recognition memory; SNRM) but not for canonical hippocampus-dependent spatial and contextual memory. By using a fear conditioning paradigm that has both social and spatial components (social/spatial fear conditioning or SFC), we expand beyond the study of SNRM to investigate social episodic memories including the recollection of the valence or spatial location required to inform an animal's decision to approach or avoid a conspecific. We find that pyramidal neurons (PNs) of the hippocampal CA1 region are required for discrimination of a threat-associated spatial location but are not necessary to discriminate a threat-associated conspecific (CS+) from a safety-associated conspecific (CS-). In contrast, CA2 PNs are not required to discriminate spatial location of a threat but are required for social threat discrimination. Thus, the targeted silencing of CA2 PNs results in generalized avoidance fear behaviour towards the CS- and CS+ mice. One-photon calcium imaging from CA2 reveals that SFC modified the CA2 social representations of the CS+ and CS- in a manner that enhanced the ability of CA2 activity to discriminate the two individuals and led to the incorporation of a generalized or abstract representation of social valence into social identity representations. These results indicate that spatial and social threat discrimination are carried out independently by hippocampal CA1 and CA2 regions, respectively and that the hippocampal CA2 region plays a unique role in the recollection of past social interactions. |
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| responsibles | Allen |
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Workflow history| from state (1) | to state | comment | date |
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| submitted | published | | 2024/06/12 12:12 UTC |
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