En. Eskandar et Ja. Assad, Dissociation of visual, motor and predictive signals in parietal cortex during visual guidance, NAT NEUROSC, 2(1), 1999, pp. 88-93
The role of the posterior parietal cortex (PPC) in the visual guidance of m
ovements was studied in monkeys trained to use a joystick to guide a spot t
o a target. Visual and motor influences were dissociated by transiently occ
luding the spot and by varying the relationship between the direction of jo
ystick and spot movements. We found a strong segregation of function in PPC
during visual guidance. Neurons in area MST were selectively modulated by
the direction of visible moving stimuli, whereas neurons in area MIP were s
electively modulated by the direction of hand movement. In contrast, the se
lectivity of cells in the lateral intraparietal area (LIP) did not directly
depend on either visual input or motor output, but rather seemed to encode
a predictive representation of stimulus movement. These predictive signals
may be an important link in visuomotor transformations.