{
  "abstract": "The posterior parietal cortex integrates somatosensory information with signals supporting action, spatial cognition, and multisensory processing, yet the fine-scale topographic relationship between the intraparietal sulcus (IPS) and primary somatosensory cortex (S1) remains poorly understood. Here, we used resting-state fMRI in 10 awake rhesus macaques to characterize functional connectivity between four S1 subregions (areas 3a, 3b, 1, and 2) and 223 single-voxel seeds densely sampling an IPS-centered parietal territory. Across S1 subregions and hemispheres, IPS-S1 connectivity exhibited a highly structured spatial organization characterized by systematic anteroposterior and mediolateral gradients and a prominent semi-oval topology following the geometry of the intraparietal sulcus. Connectivity was generally stronger toward the cortical banks and convexities and weaker near the sulcal fundus, a pattern that could not be explained by reduced local temporal signal-to-noise ratio. Unsupervised hierarchical clustering independently recovered this spatial organization and identified connectivity-defined subdivisions that only partially corresponded to classical cytoarchitectonic boundaries. Along the S1 mediolateral axis, prominent troughs in cluster-averaged connectivity profiles corresponded to several previously described somatotopic transitions, allowing to consistently map putative boundaries between tongue and face representations and between hand and trunk-leg representations. Based on these boundaries, individual IPS clusters exhibited connectivity with multiple S1 body-part sectors, with the pattern of connectivity across these sectors varying across IPS clusters and S1 subregions. Together, our findings reveal that IPS-S1 functional connectivity is organized by a large-scale sulcal topology while preserving fine-grained features of S1 somatotopic organization. These findings suggest that the functional organization of the IPS is shaped by multiple spatial dimensions, including large-scale sulcal topology and the organization of S1 subregions and body-part representations, which may together contribute to the functional specialization of individual IPS regions.",
  "abstract_shown": true,
  "affiliations": [
    "Institut des Sciences Cognitives Marc Jeannerod, UMR5229, CNRS-University of Lyon 1, Lyon, France"
  ],
  "article_type": "New results",
  "arxiv": null,
  "author_total": 6,
  "authors": [
    {
      "name": "W.-A. Sheng"
    },
    {
      "name": "S. Clavagnier"
    },
    {
      "name": "M. Froesel"
    },
    {
      "name": "T. Heed"
    },
    {
      "name": "W. Vanduffel"
    },
    {
      "affs": [
        0
      ],
      "name": "S. Ben Hamed"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8smy5kzc86y0c.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.09.19.752858",
  "fulltext_url": "https://www.biorxiv.org/content/10.64898/2026.09.19.752858v1.full",
  "id": "8smy5kzc86y0c",
  "issns": [],
  "landing_url": "https://www.biorxiv.org/content/10.64898/2026.09.19.752858v1",
  "language": null,
  "licence": "CC-BY-NC",
  "licence_label": "CC BY-NC",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "biorxiv",
      "neuroscience"
    ],
    [
      "openalex",
      "2805|Functional Brain Connectivity Studies"
    ]
  ],
  "openalex": "W7214287554",
  "pdf_url": "https://www.biorxiv.org/content/10.64898/2026.09.19.752858v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-19",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/8smy5kzc86y0c.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:24:29Z",
      "native_id": "10.64898/2026.09.19.752858",
      "source": "biorxiv",
      "url": "https://www.biorxiv.org/content/10.64898/2026.09.19.752858v1"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "biorxiv:neuroscience",
      "subfield": "neuroscience"
    }
  ],
  "title": "Topographic and somatotopic organization of functional connectivity between the intraparietal sulcus and primary somatosensory cortex in macaque monkeys",
  "title_text": "Topographic and somatotopic organization of functional connectivity between the intraparietal sulcus and primary somatosensory cortex in macaque monkeys",
  "type": "preprint",
  "updated_at": "2026-10-30T12:24:29Z",
  "url": "https://research.draconitic.com/paper/8smy5kzc86y0c",
  "venue": "bioRxiv",
  "versions": []
}