Cortical activity in the null space: permitting preparation without movement.
Neural circuits must perform computations and then selectively output the results to other circuits. Yet synapses do not change radically at millisecond timescales. A key question then is: how is communication between neural circuits controlled? In motor control, brain areas directly involved in driving movement are active well before movement begins. Muscle activity is some readout of neural activity, yet it remains largely unchanged during preparation. Here we find that during preparation, while the monkey holds still, changes in motor cortical activity cancel out at the level of these population readouts. Motor cortex can thereby prepare the movement without prematurely causing it. Further, we found evidence that this mechanism also operates in dorsal premotor cortex, largely accounting for how preparatory activity is attenuated in primary motor cortex. Selective use of 'output-null' vs. 'output-potent' patterns of activity may thus help control communication to the muscles and between these brain areas.
1] Neurosciences Program, Stanford University, Stanford, California, USA. [2] Department of Electrical Engineering, Stanford University, Stanford, California, USA. [3] Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA.
Matthew T
MT
Kaufman
1] Department of Neuroscience, Columbia University Medical Center, New York, New York, USA. [2] Grossman Center for the Statistics of Mind, Columbia University Medical Center, New York, New York, USA. [3] David Mahoney Center for Brain and Behavior Research, Columbia University Medical Center, New York, New York, USA. [4] Kavli Institute for Brain Science, Columbia University Medical Center, New York, New York, USA.
Mark M
MM
Churchland
1] Department of Electrical Engineering, Stanford University, Stanford, California, USA. [2] Department of Neurosurgery, Palo Alto Medical Foundation, Palo Alto, California, USA.
Stephen I
SI
Ryu
1] Neurosciences Program, Stanford University, Stanford, California, USA. [2] Department of Electrical Engineering, Stanford University, Stanford, California, USA. [3] Department of Bioengineering, Stanford University, Stanford, California, USA. [4] Department of Neurobiology, Stanford University, Stanford, California, USA.
Krishna V
KV
Shenoy
D000818:Animals; D003198:Computer Simulation; D004576:Electromyography; D055724:Electrophysiological Phenomena; D008253:Macaca mulatta; D008297:Male; D008959:Models, Neurological; D009044:Motor Cortex / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology; D009474:Neurons / Q000502:physiology*