The spatial and temporal properties of attentional selectivity for saccades and reaches

Abstract

The preparation and execution of saccades and goaldirected movements elicits an accompanying shift in attention at the locus of the impending movement. However, some key aspects of the spatiotemporal profile of this attentional shift between eye and hand movements are not resolved. While there is evidence that attention is improved at the target location when making a reach, it is not clear how attention shifts over space and time around the movement target as a saccade and a reach are made to that target. Determining this spread of attention is an important aspect in understanding how attentional resources are used in relation to movement planning and guidance in real world tasks. We compared performance on a perceptual discrimination paradigm during a saccadealone task, reach-alone task, and a saccade-plus-reach task to map the temporal profile of the premotor attentional shift at the goal of the movement and at three surrounding locations. We measured performance relative to a valid baseline level to determine whether motor planning induces additional attentional facilitation compared to mere covert attention. Sensitivity increased relative to movement onset at the target and at the surrounding locations, for both the saccade-alone and saccade-plus-reach conditions. The results suggest that the temporal profile of the attentional shift is similar for the two tasks involving saccades (saccade-alone and saccade-plus-reach tasks), but is very different when the influence of the saccade is removed. In this case, performance in the saccade-plusreach task reflects the lower sensitivity observed when a reach-alone task is being conducted. In addition, the spatial profile of this spread of attention is not symmetrical around the target. This suggests that when a saccade and reach are being planned together, the saccade drives the attentional shift, and the reach-alone carries little attentional weight.

Theory of visual attention (TVA) in action: Assessing premotor attention in simultaneous eye-hand movements

“…Similar to previous studies (Hanning et al, 2018;Jonikaitis & Deubel, 2011), we found that visual attention was allocated in parallel to both effector targets during simultaneous eye-hand movement preparation. This is in contrast to previous behavioral studies observing that the eye carries more attentional weight than the hand during simultaneous eye hand movements, yielding attentional competition between the two effector systems when two separate targets have to be selected (Khan et al, 2011;Stewart, Verghese, & Ma-Wyatt, 2019). Yet, our results show that the deployment of attention towards one effector target was unaffected by the simultaneous motor preparation of the other effector system.…”

Transsaccadic integration benefits are not limited to the saccade target

“…The spatial pattern of integration benefits could also be reflective of attentional allocation to these task-relevant locations across the saccade. Whereas many studies have shown a specificity of presaccadic attention at the saccade target (Deubel and Schneider 1996; Hoffman and Subramaniam 1995; Kowler et al 1995), there is also evidence to suggest that attentional benefits may be observed at surrounding locations (Castet et al 2006; Harrison et al 2012; Stewart and Ma-Wyatt 2017; Stewart et al 2019), and that locations other than the saccade target can be attentionally selected based on both features, and the location of behaviorally relevant stimuli on previous trials (White et al 2013). This attention to task-relevant, nonsaccade targets emerges as rapidly as 30 ms after a saccade (Yao et al 2016a).…”

“…Given the assumption of independence of pre- and postsaccadic signals, the maximum possible benefit from integration is statistically limited by MLE: this method has been applied to multisensory integration (Ernst and Bülthoff 2004), where small benefits are also observed. Presaccadic attentional benefits have also been measured in a similarly small range (Li et al 2016; Rolfs and Carrasco 2012; Stewart et al 2019). Rather than integration benefits being a definitive measure of how much perceptual stability can be attributed to transaccadic integration, we think rather that these measured benefits are a hint of what might be going on in the visual system: presaccadic information and postsaccadic information are initially processed independently, and if they are attributed to the same source, then they are weighted and integrated into a single transsaccadic percept.…”

Dissociable Contribution of Extrastriate Responses to Representational Enhancement of Gaze Targets

“…The deployment of visuospatial attention is tightly linked with the execution of saccadic eye movements (Awh, Armstrong, & Moore, 2006). Numerous studies have shown that shifts in attention precede eye movements, improving both the sensitivity to and discriminability of visual targets of the upcoming saccade (Stewart, Verghese, & Ma-Wyatt, 2019;Born, Ansorge, & Kerzel, 2013;Peterson, Kramer, & Irwin, 2004;Deubel & Schneider, 1996;Hoffman & Subramaniam, 1995) and promoting their entry into working memory (Hanning, Jonikaitis, Deubel, & Szinte, 2016). To what extent the neural basis of this presaccadic boost in perception, that is, overt attention, overlaps with that of covert attention has not been examined.…”