Microconnectomics of the Primary Motor Cortex: A Multiscale Computer Model

Abstract:

The dual-output hypothesis, based on analysis of wiring patterns in M1, describes neocortex as organized around Layer-5 corticosriatal pyramidal cells (STRs) which project to other cortical areas (as well as to striatum) and Layer-5 corticospinal pyramidal cells (SPIs), which project out of cerebrum to brainstem and spinal cord.  We propose the dual-output hypothesis as a replacement for the old canonical-circuit model of Douglas and Martin.  The canonical-circuit was a major contribution in 1989, and remains today a touchstone for thinking about neocortex.  Although basic concepts from that model are valid, this model is insufficient for multiscale modeling since it implicitly uses point neurons and thereby neglects the key multiscale feature of cortex -- the large L5 pyramidal cells that span circuit layers at a higher scale.