Connectivity of neuronal populations within and between areas of primate somatosensory cortex

E. Pálfi, L. Zalányi, M. Ashaber, C. Palmer, O. Kántor, A. W. Roe, R. M. Friedman, L. Négyessy

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Functions of the cerebral cortex emerge via interactions of horizontally distributed neuronal populations within and across areas. However, the connectional underpinning of these interactions is not well understood. The present study explores the circuitry of column-size cortical domains within the hierarchically organized somatosensory cortical areas 3b and 1 using tract tracing and optical intrinsic signal imaging (OIS). The anatomical findings reveal that feedforward connections exhibit high topographic specificity, while intrinsic and feedback connections have a more widespread distribution. Both intrinsic and inter-areal connections are topographically oriented across the finger representations. Compared to area 3b, the low clustering of connections and small cortical magnification factor supports that the circuitry of area 1 scaffolds a sparse functional representation that integrates peripheral information from a large area that is fed back to area 3b. Fast information exchange between areas is ensured by thick axons forming a topographically organized, reciprocal pathway. Moreover, the highest density of projecting neurons and groups of axon arborization patches corresponds well with the size and locations of the functional population response reported by OIS. The findings establish connectional motifs at the mesoscopic level that underpin the functional organization of the cerebral cortex.

Original languageEnglish
Pages (from-to)2949-2971
Number of pages23
JournalBrain Structure and Function
Issue number6
StatePublished - Jul 1 2018


  • Cortical hierarchy
  • Cortical magnification
  • Horizontal connections
  • Optical intrinsic signal imaging
  • Tract tracing


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