Figure 13.

A neural circuit model for egocentric/allocentric multiplexing of signals in the FEF and SEF. The egocentric (Te) and allocentric information (T’e) arrive through the dorsal and ventral streams, respectively, and enter the FEF and the SEF as two separate visual inputs, egocentric (Te) input to the visual (V, dark orange) neurons and allocentric input to VM neurons (light orange). This processed visual information through the fronto-striato-thalamic loop (Chatham and Badre, 2015) is then relayed to the memory network (purple) with a considerable cross talk (yellow arrow) between the FEF and SEF VM-motor memory circuit, wherein the decorrelated scaling/multiplexing of the landmark-shift signal occurs with the egocentric flow. Finally, the first integrated signal arrives at the FEF motor circuitry from the most recent multiplexed memory (through continuous coordination between VM-motor memory circuits of the FEF and the SEF), becoming fully integrated in the final motor burst (gaze command) of both areas (notably only SEF VM neurons contribute). The final outputs project to SC and directly to the brainstem, which implements further reference frame transformations (RFTs) from visual to motor coordinates for eye and head motion. Note: as the LIP, DLPFC, and FEF share working memory loops, these brain areas may continuously provide egocentric/allocentric multiplexing signals. The gray arrows indicate the information flow between neuronal classes.