Layer 4 of mouse neocortex differs in cell types and circuit organization between sensory areas

• Published in: Nature communications 2019-09, Vol.10 (1), p.4174-12, Article 4174
• Main Authors: Scala, Federico, Kobak, Dmitry, Shan, Shen, Bernaerts, Yves, Laturnus, Sophie, Cadwell, Cathryn Rene, Hartmanis, Leonard, Froudarakis, Emmanouil, Castro, Jesus Ramon, Tan, Zheng Huan, Papadopoulos, Stelios, Patel, Saumil Surendra, Sandberg, Rickard, Berens, Philipp, Jiang, Xiaolong, Tolias, Andreas Savas
• Format: Article
• Language: English
• Subjects: 45; 45/91; 631/378/2613; 631/378/3920; 9/74; Animals; Bioinformatik och systembiologi (metodutveckling under 10203); Biologi (Medicinska tillämpningar under 3 och lantbruksvetenskapliga under 4); Circuits; Cortex (somatosensory); Data processing; Electrophysiology; Female; Humanities and Social Sciences; Information processing; Interneurons; Interneurons - cytology; Interneurons - metabolism; Male; Medicin och hälsovetenskap; Medicinska och farmaceutiska grundvetenskaper; Mice; Morphology; multidisciplinary; Naturvetenskap; Neocortex - cytology; Neocortex - metabolism; Neural networks; Neurons; Neurons - cytology; Neurons - metabolism; Neurosciences; Neurovetenskaper; Pyramidal cells; Science; Science (multidisciplinary); Somatosensory Cortex - cytology; Somatosensory Cortex - metabolism; Somatostatin; Somatostatin - metabolism; Utvecklingsbiologi; Visual cortex; Visual pathways
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-12058-z

Layer 4 (L4) of mammalian neocortex plays a crucial role in cortical information processing, yet a complete census of its cell types and connectivity remains elusive. 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 all somatostatin-positive (SOM + ) non-fast-spiking interneurons were Martinotti cells. In contrast, in somatosensory cortex (S1), excitatory neurons were mostly stellate and SOM + interneurons were non-Martinotti. These morphologically distinct SOM + interneurons corresponded to different transcriptomic cell types and were differentially integrated into the local circuit with only S1 neurons receiving local excitatory input. We propose that cell type specific circuit motifs, such as the Martinotti/pyramidal and non-Martinotti/stellate pairs, are used across the cortex as building blocks to assemble cortical circuits. Layer 4 of the mammalian neocortex is important for cortical information processing but its cellular composition and local circuits remains elusive. The authors compared two primary sensory cortical areas of mice and found differences in cell composition and local connectivity.