Mouse hippocampal CA1 VIP interneurons detect novelty in the environment and support recognition memory

• Published in: Cell reports (Cambridge) Vol. 43; no. 4; p. 114115
• Main Authors: Tamboli, Suhel, Singh, Sanjay, Topolnik, Dimitry, El Amine Barkat, Mohamed, Radhakrishnan, Risna, Guet-McCreight, Alexandre, Topolnik, Lisa
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 23.04.2024; Elsevier
• Subjects: Animals; CA1 Region, Hippocampal - cytology; CA1 Region, Hippocampal - metabolism; CA1 Region, Hippocampal - physiology; CP: Neuroscience; Exploratory Behavior - physiology; Interneurons - metabolism; Interneurons - physiology; Male; Memory - physiology; Mice; Mice, Inbred C57BL; Parvalbumins - metabolism; Pyramidal Cells - metabolism; Pyramidal Cells - physiology; Recognition, Psychology - physiology; Somatostatin - metabolism; Vasoactive Intestinal Peptide - metabolism; CP: Neuroscience
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2024.114115

In the CA1 hippocampus, vasoactive intestinal polypeptide-expressing interneurons (VIP-INs) play a prominent role in disinhibitory circuit motifs. However, the specific behavioral conditions that lead to circuit disinhibition remain uncertain. To investigate the behavioral relevance of VIP-IN activity, we employed wireless technologies allowing us to monitor and manipulate their function in freely behaving mice. Our findings reveal that, during spatial exploration in new environments, VIP-INs in the CA1 hippocampal region become highly active, facilitating the rapid encoding of novel spatial information. Remarkably, both VIP-INs and pyramidal neurons (PNs) exhibit increased activity when encountering novel changes in the environment, including context- and object-related alterations. Concurrently, somatostatin- and parvalbumin-expressing inhibitory populations show an inverse relationship with VIP-IN and PN activity, revealing circuit disinhibition that occurs on a timescale of seconds. Thus, VIP-IN-mediated disinhibition may constitute a crucial element in the rapid encoding of novelty and the acquisition of recognition memory. [Display omitted] •Hippocampal CA1 VIP-INs shape spatial exploration by detecting novelty•VIP-INs and pyramidal neurons (PNs) are co-active when encountering novel changes•VIP-IN and PN co-activity inversely scales with activity of SST-INs and PV-INs•VIP-IN-mediated disinhibition supports novelty encoding and recognition memory Tamboli et al. discover “novelty cells” in the mouse hippocampal CA1 area that belong to a family of vasoactive intestinal polypeptide-expressing interneurons (VIP-INs). In freely behaving mice, VIP-INs become highly active during spatial exploration in novel environments, enabling rapid encoding of spatial information and regulating the recognition memory.