The Journal of Neuroscience, 2001, 21:RC130:1-5
RAPID COMMUNICATION
Visual Motion Responses of Neurons in the Caudal Area PE
of Macaque Monkeys
Salvatore
Squatrito1,
Milena
Raffi1,
Maria Grazia
Maioli1, and
Alexandra
Battaglia-Mayer2
1 University of Bologna, Department of Human and
General Physiology, 40127 Bologna, Italy, and
2 University of Rome "La Sapienza", Department of Human
Physiology and Pharmacology, 00185 Rome, Italy
Area PE of macaques has traditionally been considered a
somatosensory association cortex. Recent studies, however, suggest that
neurons of this and neighboring areas are involved in the visual
control of movement, especially arm movement. We investigated the
neuronal sensitivity to local visual stimuli of this region by
recording neuronal activity in two behaving macaque monkeys trained in
a simple visual fixation task. Recordings were performed from the
dorsal surface of the caudal pole of the superior parietal lobule
(SPL). Classical receptive fields (RFs) were mapped by using
conventional static or moving luminous figures. We found that many
neurons in this area were selectively activated by moving visual
stimuli. Cell responses were tuned to the movement direction. RFs were
usually large; their mean surface covered some 30 × 30° of the
visual field. The fovea was often included into RF, in many cases it
was along a RF side. The center of RFs was mainly located in the
contralateral hemifield, although RFs having the center ipsilaterally
sited were also found. No evident retinotopy was found. Visual neurons
were especially concentrated in a region of the SPL likely
corresponding to area PEc. These results suggest that the caudal
part of area PE contains neuronal populations specifically signaling
local visual motion, possibly encoding the direction of moving objects.
These signals might well be suited for sensorimotor integration
mechanisms aimed at motor acts.
Key words:
extrastriate cortex; superior parietal lobule; area PEc; visual motion; visuomotor integration; macaque monkey
Copyright © Society for Neuroscience 0270-6474//$05.00/0