SPATIAL INVARIANCE OF VISUAL RECEPTIVE-FIELDS IN PARIETAL CORTEX NEURONS

Spatial information is conveyed to the primary visual cortex in retina l coordinates, Movement trajectory programming, however, requires a tr ansformation from this sensory frame of reference into a frame appropr iate for the selected part of the body, such as the eye, head or arms( 1-4). To achieve this transformation, visual information must be combi ned with information from other sources: for instance, the location of an object of interest can be defined with respect to the observer's h ead if the position of the eyes in the orbit is known and is added to the object's retinal coordinates, Here we show that in a subdivision o f the monkey parietal lobe, the ventral intraparietal area (VIP), the activity of visual neurons is modulated by eye-position signals, as in many other areas of the cortical visual system(5-10). We find that in dividual receptive fields of a population of VIP neurons are organized along-a continuum, from eye to head coordinates, In the latter case, neurons encode the azimuth and/or elevation of a visual stimulus, inde pendently of the direction in which the eyes are looking, thus represe nting spatial locations explicitly in at least a head-centred frame of reference.