Object Representation in the Ventral Premotor Cortex (area F5) of the
Monkey.
Akira Murata, Luciano Fadiga, Leonardo Fogassi, Vittorio Gallese, Vassilis
Raos1 and Giacomo Rizzolatti1..
Istituto di Fisiologia Umana, Universit_ di Parma, Via Gramsci 14, 43100
Parma, Italy; First Department of Physiology, Nihon University School of
Medicine, Tokyo 173, Japan..
APStracts 4:129N, 1997.
ABSTRACT
Visual and motor properties of single neurons of monkey ventral premotor
cortex (area F5) were studied in a behavioral paradigm consisting of four
conditions: Object grasping in light, object grasping in dark, object
fixation, and fixation of a spot of light. The employed objects were six
different 3-D geometric solids. Two main types of neurons were distinguished:
OmotorO neurons (n=25) and OvisuomotorO neurons (n=24). OMotorO neurons
discharged in association with grasping movements. Most of them (n=17)
discharged selectively during a particular type of grip. Different objects, if
grasped in similar way, determined similar neuronal motor reponses.
OVisuomotor" neurons also discharged during active movements, but, in
addition, they fired also in response to the presentation of 3-D objects. The
majority of "visuomotor" neurons (n=16) showed selectivity for one or few
objects. The response was present both in object grasping in light and in
object fixation conditions. OVisuomotorO neurons that selectively discharged
to the presentation of a given object discharged also selectively during
grasping of that object. In conclusion, object shape is coded in F5 even when
a response to that object is not required. The possible visual or motor nature
of this object coding is discussed.
Received 23 May 1997; accepted in final form 2 July 1997.
APS Manuscript Number J428-7.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 24 July 1997