Abstract
How is the primary motor cortex (M1) organized to control fine finger movements? We investigated the population activity in M1 for single finger flexion and extension, using 7T functional magnetic resonance imaging (fMRI) in human participants, and compared these results to the neural spiking patterns recorded in monkeys performing the identical task. fMRI activity patterns were distinct for movements of different fingers, but quite similar for flexion and extension of the same finger. In contrast, spiking patterns in monkeys were quite distinct for both fingers and directions, similar to what was found for muscle activity patterns in humans. Given that fMRI reflects predominantly input and recurrent activity, these results suggest an architecture in which neural populations that control flexion or extension of the same finger receive similar inputs and interact tightly with each other, but produce distinct outputs.
