title: Saccade execution suppresses discrimination at distractor locations rather than enhancing the saccade goal location.
abstract: As we have limited processing abilities with respect to the plethora of visual information entering our brain, spatial selection mechanisms are crucial. These mechanisms result in both enhancing processing at a location of interest and in suppressing processing at other locations; together, they enable successful further processing of locations of interest. It has been suggested that saccade planning modulates these spatial selection mechanisms; however, the precise influence of saccades on the distribution of spatial resources underlying selection remains unclear. To this end, we compared discrimination performance at different locations (six) within a work space during different saccade tasks. We used visual discrimination performance as a behavioral measure of enhancement and suppression at the different locations. A total of 14 participants performed a dual discrimination/saccade countermanding task, which allowed us to specifically isolate the consequences of saccade execution. When a saccade was executed, discrimination performance at the cued location was never better than when fixation was maintained, suggesting that saccade execution did not enhance processing at a location more than knowing the likelihood of its appearance. However, discrimination was consistently lower at distractor (uncued) locations in all cases where a saccade was executed compared with when fixation was maintained. Based on these results, we suggest that saccade execution specifically suppresses distractor locations, whereas attention shifts (with or without an accompanying saccade) are involved in enhancing perceptual processing at the goal location.
authors.affiliation: School of Optometry, University of Montreal, Room 260-25, 3744 Jean Brilliant, Montreal, QC, H3T 1P1, Canada.
authors.forename: Aarlenne Z
authors.initials: AZ
authors.lastname: Khan
authors.affiliation: Centre for Neuroscience Studies and Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Blohm
authors.affiliation: Centre de Recherche en Neurosciences de Lyon (CRNL), ImpAct team, Inserm U1028, CNRS UMR 5292, Bron, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Pisella
authors.affiliation: Centre for Neuroscience Studies and Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada.
authors.forename: Douglas P
authors.initials: DP
authors.lastname: Munoz
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D003463:Cues; D004192:Discrimination, Psychological; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006040:Goals; D006801:Humans; D008297:Male; D011930:Reaction Time; D012438:Saccades / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: countermanding; covert attention; human; pre-saccadic attentional facilitation; saccade inhibition; saccade planning