Layer-specific connectivity and functional impact of Chrna2+ layer 5
Martinotti cells in the primary motor cortex
Abstract
The cortical somatostatin interneuron population includes several
diverse cell types, among them the Martinotti cells. Layer-specific
differences in connectivity and function between different subtypes of
Martinotti cells are becoming apparent, which require contemporary
studies to investigate cortical interneurons in a layer and subtype
specific manner. In this study, we investigate the connectivity of a
subtype of Chrna2+ layer 5 Martinotti cells in the primary motor cortex,
using a monosynaptic retrograde rabies viral tracer. We found direct
input from pyramidal cells and local parvalbumin interneurons. In
addition, we found long-range direct inputs from the motor thalamus,
substantia innominata of the basal forebrain and globus pallidus. Based
on the observed input pattern, we tested and found an increased number
of falls in the hanging wire test upon temporary overexcitation of
Chrna2+ layer 5 Martinotti cells. These results suggest that Chrna2+
Martinotti cells in the motor cortex are involved in sensorimotor
integration.