Pre-saccadic perception: Separate time courses for enhancement and spatial pooling at the saccade target

Abstract

We interact with complex scenes using eye movements to select targets of interest. Studies have shown that the future target of a saccadic eye movement is processed differently by the visual system. A number of effects have been reported, including a benefit for perceptual performance at the target (“enhancement”), reduced influences of backward masking (“un-masking”), reduced crowding (“un-crowding”) and spatial compression towards the saccade target. We investigated the time course of these effects by measuring orientation discrimination for targets that were spatially crowded or temporally masked. In four experiments, we varied the target-flanker distance, the presence of forward/backward masks, the orientation of the flankers and whether participants made a saccade. Masking and randomizing flanker orientation reduced performance in both fixation and saccade trials. We found a small improvement in performance on saccade trials, compared to fixation trials, with a time course that was consistent with a general enhancement at the saccade target. In addition, a decrement in performance (reporting the average flanker orientation, rather than the target) was found in the time bins nearest saccade onset when random oriented flankers were used, consistent with spatial pooling around the saccade target. We did not find strong evidence for un-crowding. Overall, our pattern of results was consistent with both an early, general enhancement at the saccade target and a later, peri-saccadic compression/pooling towards the saccade target.

Post-Saccadic Face Processing Is Modulated by Pre-Saccadic Preview: Evidence from Fixation-Related Potentials

“…Although the exact mechanisms that cause this reduction in neural activity remain a matter of debate, reduced neural response can be considered a hallmark of prediction. In contrast, spatial attention allocated to the saccade target before the movement (Hoffman and Subramaniam, 1995;Deubel and Schneider, 1996;Deubel, 2008;Zhao et al, 2012;van Koningsbruggen and Buonocore, 2013;Buonocore et al, 2017) should be associated with an enhancement of the P1 and N1 components of the fixation-related ERP (Eimer, 2000;Mohamed et al, 2009;Sreenivasan et al, 2009;Churches et al, 2010;Meyberg et al, 2015). Although attention is deployed to the saccade target before the execution of the eye movement, our results clearly show a reduction, rather than enhancement, of the N170 component when a face preview was available.…”

“…An alternative view of visual stability focuses on the role of the spatial shift of attention toward the peripheral target before saccade execution (Hoffman and Subramaniam, 1995;Deubel and Schneider, 1996;Zhao et al, 2012;Buonocore et al, 2017), with this attentional shift playing a preeminent role (Mathô t and Theeuwes, 2011;Melcher, 2011). The key idea is that selective attention is already present at the beginning of the new fixation, leading to attentional facilitation of post-saccadic processing (for review, see Mathô t and Theeuwes, 2011).…”

Post-saccadic face processing is modulated by pre-saccadic preview: Evidence from fixation-related potentials

“…It is important to note that the overall pattern of results is not consistent with hypotheses based on a primary role for spatial attention or for priming. Prior to saccade execution attention is allocated to the saccade target (Hoffman and Subramaniam, 1995; Deubel and Schneider, 1996; Zhao et al, 2012; Buonocore et al, 2017) and such allocation might be associated with an enhancement of the P1 and N1 components of the fixation-related ERP (see also: Eimer, 2000; Mohamed et al, 2009; Sreenivasan et al, 2009; Churches et al, 2010; Meyberg et al, 2015). Results from a number of paradigms have in fact shown that stimuli that might be relevant as peripheral previews can lead to an increased evoked response.…”

“…An alternative view on active prediction focusses instead on the spatial shift of attention towards the peripheral stimulus. Prior to saccade execution, attention is directed towards the saccade target (Hoffman and Subramaniam, 1995; Deubel and Schneider, 1996; Zhao et al, 2012; Buonocore et al, 2017) and this attentional shift has been implicated in many theories of stable perception (Mathôt and Theeuwes, 2011; Melcher, 2011). A key idea here is that selective attention is immediately present at the beginning of the new fixation, leading to attentional facilitation of post-saccadic processing (for review, see Mathôt and Theeuwes, 2011).…”

Time-dependent inhibition of covert shifts of attention

“…These studies have mostly shown speeding of simple detection responses, but covert orienting can also improve the discimination of spatial frequency and lower the contrast threshold for orientation discimination (Barbot et al 2012 ; Cameron et al 2002 ; Carrasco 2011 ; Fernández et al 2019 ; Lee et al 1999 ; Pestilli and Carrasco 2005 ; Solomon 2004 ). These changes in visual sensitivity are tightly coupled with the planning of eye movements (Buonocore et al 2017b ; Deubel and Schneider 1996 ; Hoffman and Subramaniam 1995 ; Remington 1980 ; Shepherd et al 1986 ; Zhao et al 2012 ) as implied by the observation of pre-saccadic perceptual enhancements at the target location of an upcoming saccade (Hanning et al 2019 ; Kowler et al 1995 ; Li et al 2016 , 2019 ; Montagnini and Castet 2007 ; Ohl et al 2017 ; Rolfs and Carrasco 2012 ). Indeed, the influential premotor theory of attention posits that covert orienting is nothing other than the preparation of an eye movement without its execution (premotor theory of attention, Rizzolatti et al 1987 ; Sheliga et al 1994 , 1995 ).…”