{1445} revision 3 modified: 03-06-2019 02:51 gmt

Neocortical layer 4 in adult mouse differs in major cell types and circuit organization between primary sensory areas

  • Using whole-cell recordings with morphological recovery, we identified one major excitatory and seven inhibitory types of neurons in L4 of adult mouse visual cortex (V1).
  • Nearly all excitatory neurons were pyramidal and almost all Somatostatin-positive (SOM+) neurons were Martinotti cells.
  • In contrast, in somatosensory cortex (S1), excitatory cells were mostly stellate and SOM+ cells were non-Martinotti.
  • These morphologically distinct SOM+ interneurons correspond to different transcriptomic cell types and are differentially integrated into the local circuit with only S1 cells receiving local excitatory input.
  • Our results challenge the classical view of a canonical microcircuit repeated through the neocortex.
  • Instead we propose that cell-type specific circuit motifs, such as the Martinotti/pyramidal pair, are optionally used across the cortex as building blocks to assemble cortical circuits.
  • Note preponderance of axons.
  • Classifications:
    • Pyr pyramidal cells
    • BC Basket cells
    • MC Martinotti cells
    • BPC bipolar cells
    • NFC neurogliaform cells
    • SC shrub cells
    • DBC double bouquet cells
    • HEC horizontally elongated cells.
  • Using Patch-seq