Changes in power and coherence of brain activity in human sensorimotor cortex during performance of visuomotor tasks. Aoki, F., Fetz, E. E., Shupe, L., Lettich, E., & Ojemann, G. A. Biosystems, 63:89-99, 2001.
abstract   bibtex   
Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195-7290, USA. fumi.aoki@neuro.ki.se Electrocorticograms (ECoG) were recorded using subdural grid electrodes in forearm sensorimotor cortex of six human subjects. The subjects performed three visuomotor tasks, tracking a moving visual target with a joystick-controlled cursor; threading pieces of tubing; and pinching the fingers sequentially against the thumb. Control conditions were resting and active wrist extension. ECoGs were recorded at 14 sites in hand- and arm-sensorimotor area, functionally identified with electrical stimulation. For each behavior we computed spectral power of ECoG in each site and coherence in all pair-wise sites. In three out of six subjects, gamma-oscillations were observed when the subjects started the tasks. All subjects showed widespread power decrease in the range of 11-20 Hz and power increase in the 31-60 Hz ranges during performance of the visuomotor tasks. The changes in gamma-range power were more vigorous during the tracking and threading tasks compared with the wrist extension. Coherence analysis also showed similar task-related changes in coherence estimates. In contrast to the power changes, coherence estimates increased not only in gamma-range but also at lower frequencies during the manipulative visuomotor tasks. Paired sites with significant increases in coherence estimates were located within and between sensory and motor areas. These results support the hypothesis that coherent cortical activity may play a role in sensorimotor integration or attention.
@article{ Aoki_etal01,
  author = {Aoki, F. and Fetz, E. E. and Shupe, L. and Lettich, E. and Ojemann,
	G. A.},
  title = {Changes in power and coherence of brain activity in human sensorimotor
	cortex during performance of visuomotor tasks},
  journal = {Biosystems},
  year = {2001},
  volume = {63},
  pages = {89-99},
  abstract = {Department of Physiology and Biophysics, University of Washington,
	Seattle, WA 98195-7290, USA. fumi.aoki@neuro.ki.se
	
	Electrocorticograms (ECoG) were recorded using subdural grid electrodes
	in forearm sensorimotor cortex of six human subjects. The subjects
	performed three visuomotor tasks, tracking a moving visual target
	with a joystick-controlled cursor; threading pieces of tubing; and
	pinching the fingers sequentially against the thumb. Control conditions
	were resting and active wrist extension. ECoGs were recorded at 14
	sites in hand- and arm-sensorimotor area, functionally identified
	with electrical stimulation. For each behavior we computed spectral
	power of ECoG in each site and coherence in all pair-wise sites.
	In three out of six subjects, gamma-oscillations were observed when
	the subjects started the tasks. All subjects showed widespread power
	decrease in the range of 11-20 Hz and power increase in the 31-60
	Hz ranges during performance of the visuomotor tasks. The changes
	in gamma-range power were more vigorous during the tracking and threading
	tasks compared with the wrist extension. Coherence analysis also
	showed similar task-related changes in coherence estimates. In contrast
	to the power changes, coherence estimates increased not only in gamma-range
	but also at lower frequencies during the manipulative visuomotor
	tasks. Paired sites with significant increases in coherence estimates
	were located within and between sensory and motor areas. These results
	support the hypothesis that coherent cortical activity may play a
	role in sensorimotor integration or attention.}
}

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