Fig. 3.

Proposed microcircuitry for the assembly of visual remapping within FEF. Cortical visual and subcortical corollary discharge (CD) inputs target excitatory and inhibitory neurons in layer IV. These long-range projections are excitatory. Remapping is piecewise in the recipient neurons (↑, presaccadic increase in visual sensitivity; ↓, presaccadic decrease; RF, receptive field; FF, future field). Only putative excitatory neurons (Exc) and presumed low-threshold spiking (LTS) inhibitory interneurons show presaccadic changes to their visual sensitivity. Putative parvalbumin-positive neurons (not shown) have visual responses, but they do not change before saccades. Layer IV projects predominantly to layers II/III via excitatory interneurons (reviewed in Shin and Sommer 2012). The changes in visual sensitivity at the RF and FF must be inverted and combined to create the full remapping that is found in layer V corticotectal neurons. Whether the resultant, full remapping is sent to extrastriate visual areas is unknown, but it is depicted here as a hypothesis. White triangles, excitatory synapses; black triangles, inhibitory synapses.