Hand use predicts the structure of representations in sensorimotor cortex.

Authors

Naveed Ejaz, Institute of Cognitive Neuroscience, University College London, London, UK
Masashi Hamada, Department of Neurology, University of Tokyo, Tokyo, Japan
Jörn Diedrichsen, Institute of Cognitive Neuroscience, University College London, London, UK

Document Type

Article

Publication Date

7-1-2015

Journal

Nature neuroscience

Volume

18

Issue

7

First Page

1034

Last Page

1040

URL with Digital Object Identifier

10.1038/nn.4038

Abstract

Fine finger movements are controlled by the population activity of neurons in the hand area of primary motor cortex. Experiments using microstimulation and single-neuron electrophysiology suggest that this area represents coordinated multi-joint, rather than single-finger movements. However, the principle by which these representations are organized remains unclear. We analyzed activity patterns during individuated finger movements using functional magnetic resonance imaging (fMRI). Although the spatial layout of finger-specific activity patterns was variable across participants, the relative similarity between any pair of activity patterns was well preserved. This invariant organization was better explained by the correlation structure of everyday hand movements than by correlated muscle activity. This also generalized to an experiment using complex multi-finger movements. Finally, the organizational structure correlated with patterns of involuntary co-contracted finger movements for high-force presses. Together, our results suggest that hand use shapes the relative arrangement of finger-specific activity patterns in sensory-motor cortex.