Non-retinocentric encoding in monkey area VIP, Nature, 1997. Spatial Invariance of Visual Receptive Fields in Parietal Cortex Neurons.
Spatial information is conveyed to the primary visual cortex in retinal coordinates.
Movement trajectory programming however, requires a transformation from this sensory frame of reference into a frame appropriate for the selected part of the body, such as the eye, head or arms. In order to achieve this transformation, visual information must be combined with information from other sources. For instance, the location of an object of interest can be defined with respect to the observer s head if the position of the eyes in the orbit is known and is added to the object s retinal coordinates. More importantly, individual receptive fields of a population of VIP neurons were organized along a continuum, from eye to head coordinates.