A PET study of pointing with visual feedback of moving hands.
Kentaro Inoue, Ryuta Kawashima, Kazunori Satoh, Shigeo Kinomura, Ryoi Goto,
Masamichi Koyama, Motoaki Sugiura, Masatoshi Ito and Hiroshi Fukuda.
Department of Nuclear Medicine and Radiology, Institute of Development,
Aging and Cancer, Tohoku University, Cyclotron and Radioisotope Center, Tohoku
University.
APStracts 4:239N, 1997.
ABSTRACT
This study was conducted to determine where in the human brain visual feedback
of hand movements is processed to allow accurate pointing. Regional cerebral
blood flow (rCBF) was measured with positron emission tomography (PET) and
H215O in nine normal volunteers while performing one control and two reaching
tasks. In all tasks, visual stimuli were presented on a head mounted display
(HMD). A target board was placed in front of the subjects bearing six red
light emitting diodes (LEDs) aligned on a circle with a green LED at its
center. The center green LED and one of the six red LEDs, randomly selected,
were repeatedly switched on and off, alternatively. In the control task,
subjects were instructed to gaze at the lit LED. In the two reaching tasks,
the reaching with visual feedback (RwithF) task and the reaching without
visual feedback (RwithoutF) task, they had to point to the lit red LED with
their right index fingers. In the RwithF task, their right hands were visible
on the HMD before touching the target, whereas in the RwithoutF task, they
were not visible. For each subject, subtraction images of each reaching task
minus the control and the RwithF task minus the RwithoutF task were calculated
after transformation of PET images into the standard brain shape with an
adjustable computerized brain atlas. These subtraction rCBF images were then
averaged among the subjects and significant changes of rCBF were identified.
Significant increases in rCBF not only in the RwithF task minus control image
but also in the RwithF task minus the RwithoutF task image were observed in
the supramarginal cortex, the premotor cortex and the posterior cingulate
cortex of the left hemisphere, the caudate nucleus and the thalamus of the
right hemisphere and the right cerebellum and vermis. These results indicate
that the supramarginal cortex, the premotor cortex and the posterior cingulate
cortex of the left hemisphere and the cerebellum are involved in integrating
visual feedback of hand movements and execution of accurate pointing.
Received 10 April 1997; accepted in final form 8 September 1997.
APS Manuscript Number J291-7.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 7 October 1997