Figure 7.

Schematic representation of the balanced network model of MCx. At each point the excitatory and inhibitory populations of neurons are interconnected and receive a command input from outside the MCx. The excitatory neurons also project to both the excitatory and inhibitory neurons in other cortical points. The figure shows two cortical points and for simplicity only the connections from point 1 to point 2 are shown (red lines). The corticospinal axons would emanate from a sub-group of the excitatory neurons at each point. The external command input makes synaptic contact with excitatory and inhibitory neurons simultaneously. The coupling within the intra-motor-cortical network neurons leads to a balanced state and linear summation of the separate outputs, as explained in the text.