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Vishal Bharmauria, Amirsaman Sajad, Adrian Schütz, Xiaogang Yan, Hongying Wang, J. Douglas Crawford; Predictive role of supplementary eye fields for egocentric/allocentric integration. Journal of Vision 2020;20(11):977. doi: https://doi.org/10.1167/jov.20.11.977.
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The brain could encode object location either in egocentric (relative to self) or allocentric (relative to another object) coordinates. Human behavioral experiments have shown that the visual system optimally combines egocentric (ego) and allocentric (allo) cues for goal-directed action (Byrne and Crawford 2011; Klinghammer et al. 2015, 2017). However, the neural mechanisms of this phenomenon are unknown. Recently, it was reported that the frontal eye fields (FEF) re-integrate ego and allo cues during memory and gaze motor responses following a landmark shift (Bharmauria et al. BioRxiv2019). Do the supplementary eye fields (SEF) play the same or different role? Here, we tested > 250 SEF sites in two monkeys trained on a cue-conflict delayed saccade task where the landmark (L) surreptitiously shifted during the delay (just after a visual mask presentation) and the monkey was cued to make gaze shifts toward remembered targets relative to a shifted allocentric landmark (L’). Behaviorally, the shifted landmark caused the gaze end-points to deviate about 1/3 in the direction of landmark shift. We then fit spatial models against response fields during visual, memory, and motor activity. This showed that the SEF exhibits the same fundamental egocentric transformation, i.e., target to gaze (T-G) observed previously between FEF visual and motor responses (Sajad. et al. 2015, 2016). However, the most significant allo shift (nearly halfway along T-T’) occurred much earlier, just before the mask onset and landmark shift. Further, in SEF, correlated integration of egocentric (T-G) and allocentric (T-T’) information occurred as early as the initial visual response, and then reappeared before and during the final motor burst. In summary, both the FEF and SEF participate in ego-allo integration for gaze. However, SEF seems to predict the future allocentric transformation (likely based on past exposure to many trials), whereas FEF incorporates the actual event into the gaze.
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