Anatomical circuits for flexible spatial mapping by single neurons in posterior parietal cortex
Primate lateral intraparietal area (LIP) is critical for cognitive processing. Its contribution to categorization and decision-making has been causally linked to neurons' spatial sensorimotor selectivity. We reveal the intrinsic anatomical circuits and neuronal responses within LIP that provide the substrate for this flexible generation of motor responses to sensory targets. Retrograde tracers delineate a loop between two distinct operational compartments, with a sensory-like, point-to-point projection from ventral to dorsal LIP and an asymmetric, more widespread projection in reverse. Neurophysiological recordings demonstrate that especially more ventral LIP neurons exhibit motor response fields that are spatially distinct from its sensory receptive field. The different associations of response and receptive fields in single neurons tile visual space. These anatomical circuits and neuronal responses provide the basis for the flexible allocation of attention and motor responses to salient or instructive visual input across the visual field.