Cognitive motor control in human pre-supplementary motor area studied by subdural recording of discrimination/selection-related potentials.
To clarify the functional role of human pre-supplementary motor area (pre-SMA) in 'cognitive' motor control as compared with other non-primary motor cortices (SMA-proper and lateral premotor areas) and prefrontal area, we recorded epicortical field potentials by using subdural electrodes in five epileptic patients during presurgical evaluation, whose pre-SMA, SMA-proper, prefrontal and lateral premotor areas were defined by electric cortical stimulation and recent anatomical orientations according to the bicommissural plane and callosal grid system. An S1-Go/NoGo choice and delayed reaction task (S1-choice paradigm) and a warned choice Go/NoGo reaction task (S2-choice paradigm) with inter-stimulus intervals of 2 s were employed. The results showed (i) transient potentials with onset and peak latencies of about 200 and 600 ms, respectively, after S1 in the S1-choice paradigm mainly at pre-SMA and to a lesser degree at the prefrontal and lateral premotor areas, but not in the S2-choice paradigm. At SMA-proper, a similar but much smaller potential was seen after S1 in both S1- and S2-choice paradigms and (ii) slow sustained potentials between S1 and S2 in both S1- and S2-choice paradigms in all of the non-primary motor areas investigated (pre-SMA, SMA-proper and lateral premotor areas) and prefrontal area. It is concluded that pre-SMA plays a more important role in cognitive motor control which involves sensory discrimination and decision making or motor selection for the action after stimuli, whereas SMA-proper is one of the main generators of Bereitschaftspotential preceding self-paced, voluntary movements. In the more general anticipation of and attention to the forthcoming stimuli, non-primary motor cortices including pre-SMA, SMA-proper and lateral premotor area, and the prefrontal area are commonly involved.
Ikeda
A
A
Department of Brain Pathophysiology, Kyoto University School of Medicine, Japan. akio@kuhp.kyoto-u.ac.jp
Yazawa
S
S
Kunieda
T
T
Ohara
S
S
Terada
K
K
Mikuni
N
N
Nagamine
T
T
Taki
W
W
Kimura
J
J
Shibasaki
H
H
D000328:Adult; D001931:Brain Mapping; D004192:Discrimination, Psychological / Q000502:physiology*; D004569:Electroencephalography; D004576:Electromyography; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology*; D013355:Subdural Space; D014836:Volition / Q000502:physiology*