Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.06.25.172031v1?rss=1 Authors: Bharmauria, V., Sajad, A., Yan, X., Wang, H., Crawford, J. D. Abstract: The supplementary eye fields (SEF) subserve high-level gaze functions and possess spatially tuned response fields, but the influence of visual landmarks on SEF response fields and their role in head-unrestrained transformations are unknown. We investigated these questions using a model-fitting approach employed recently to probe target (T) to gaze (G) and landmark-centered transformations through time in visuomotor response fields (Sajad et al., 2015; Bharmauria et al., 2020). Two head-unrestrained animals were trained to saccade toward a remembered visual target, in the presence of a visual landmark that shifted during the delay, causing gaze end points to partially shift in the same direction. 256 SEF neurons were recorded, including 68 with spatially tuned response fields. Model fits to response fields established that, like the frontal eye field (FEF) and superior colliculus (SC), spatially tuned SEF responses show a visuomotor transformation along an egocentric T-G continuum in eye-centered coordinates, with relatively poor fits to other models like T-fixed-to-landmark (T'). However, response field fits against a T-T' continuum revealed a partial shift toward T' in the SEF motor code, similar to the landmark influence on gaze. Unlike FEF, only motor neurons (with no visual response) showed a transient unintegrated T-T' shift (i.e., no correlation with T-G) during the delay, and only visuomotor neurons showed an integrated shift during the final motor burst (i.e., T-T' / T-G fits correlated). Based on these findings, we propose that frontal cortex incorporates landmark-centered information into a distributed, eye-centered target-to-gaze transformation through a reciprocal, complementary prefrontal circuit. Copy rights belong to original authors. Visit the link for more info