{
  "abstract": "Vasoactive intestinal peptide-expressing interneurons (VIP-INs) gate hippocampal inhibition during novel experience, but the long-range signals that engage these cells remain poorly understood. Here we identify median raphe (MnR) projections as a brainstem pathway that tunes dorsal CA1 VIP-IN recruitment through coordinated glutamatergic and serotonergic mechanisms. Anatomical mapping and optogenetic recordings showed that MnR axons innervate multiple VIP-IN subtypes, while transcriptomic and pharmacological analyses revealed fast glutamatergic excitation together with serotonin receptor-dependent modulation of synaptic and intrinsic responsiveness. In vivo calcium imaging showed that novelty preferentially recruited a speed-coupled VIP-IN ensemble, and inhibition of MnR input selectively reduced the magnitude of this response. A hippocampal circuit model linked this pathway to dendritic disinhibition and place-cell recruitment. Behaviorally, inhibition of MnR input preserved exploratory engagement but disrupted the organization of spatial sampling and impaired object-location memory. Thus, MnR input organizes hippocampal disinhibition to support novelty-guided exploration and memory encoding.",
  "abstract_shown": true,
  "affiliations": [
    "Laval University"
  ],
  "article_type": "New results",
  "arxiv": null,
  "author_total": 13,
  "authors": [
    {
      "name": "X. Luo"
    },
    {
      "name": "R. Radhakrishnan"
    },
    {
      "name": "A. Guet-McCreight"
    },
    {
      "affs": [
        0
      ],
      "name": "D. Topolnik"
    },
    {
      "name": "A. Bergeron"
    },
    {
      "name": "V. Dulam"
    },
    {
      "name": "L. D. Coulombe"
    },
    {
      "name": "M. Besner"
    },
    {
      "name": "J. Fortin-Houde"
    },
    {
      "name": "J. Davies"
    },
    {
      "name": "F. Michaud"
    },
    {
      "name": "B. Amilhon"
    },
    {
      "affs": [
        0
      ],
      "name": "L. Topolnik"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/1k703hssr6x3y.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.09.17.752379",
  "fulltext_url": "https://www.biorxiv.org/content/10.64898/2026.09.17.752379v1.full",
  "id": "1k703hssr6x3y",
  "issns": [],
  "landing_url": "https://www.biorxiv.org/content/10.64898/2026.09.17.752379v1",
  "language": null,
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "biorxiv",
      "neuroscience"
    ],
    [
      "openalex",
      "2805|Memory and Neural Mechanisms"
    ]
  ],
  "openalex": "W7213536516",
  "pdf_url": "https://www.biorxiv.org/content/10.64898/2026.09.17.752379v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-17",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/1k703hssr6x3y.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:23:05Z",
      "native_id": "10.64898/2026.09.17.752379",
      "source": "biorxiv",
      "url": "https://www.biorxiv.org/content/10.64898/2026.09.17.752379v1"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "biorxiv:neuroscience",
      "subfield": "neuroscience"
    }
  ],
  "title": "Median raphe input to dorsal CA1 shapes VIP interneuron recruitment and novelty-guided spatial memory",
  "title_text": "Median raphe input to dorsal CA1 shapes VIP interneuron recruitment and novelty-guided spatial memory",
  "type": "preprint",
  "updated_at": "2026-10-30T12:23:05Z",
  "url": "https://research.draconitic.com/paper/1k703hssr6x3y",
  "venue": "bioRxiv",
  "versions": []
}