Don’t Look! It’s Object-Based: Identifying a Distractor Produces Inhibition in an Allocentric Reference Frame for Saccades

Poster Session D - Monday, April 15, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Coleman E. Olenick¹ (colenick@uoguelph.ca), Heather Jordan¹, Mazyar Fallah¹; ¹University of Guelph

Studies of object-based inhibition show inhibition in additive spatial and object-based frames of reference (e.g. Jordan & Tipper, 1994). Recent studies have shown that during the active perceptual decision-making process, saccade trajectories to a target are shifted towards the distractor. Once the process is completed, and the distractor inhibited, trajectories shift away from the distractor (Kehoe, et al, 2018, 2021; Giuricich, et al, 2023). The magnitudes of the saccade deviations provide a sensitive measure of target-distractor competition, where both objects are encoded in an egocentric reference frame, i.e. object location is represented relative to fixation. Given prior findings showing object-based inhibition mediated by an allocentric reference frame i.e. objects are represented relative to each other in the scene and independent of fixation, we investigated whether the distractor is inhibited relative to the target or fixation in our perceptual decision-making task which uses a purely eye movement response. Using a saccadic response delayed match-to-sample task where the target and distractor varied in both allocentric and egocentric distances, only egocentric reference frames contributed to shifts in saccade trajectories towards the distractor during active decision-making. In contrast, when the perceptual decision-making process was complete and the distractor was inhibited, both ego- and allocentric reference frames independently contributed to trajectory shifts away from the distractor. This is consistent with additive spatial and object-based inhibitory mechanisms. Therefore, we suggest that distractor inhibition is maintained in cortical visual rather than oculomotor areas.

Topic Area: PERCEPTION & ACTION: Motor control