Oculomotor freezing reflects tactile temporal expectation and aids tactile perception

Abstract

The oculomotor system keeps the eyes steady in expectation of visual events. Here, recording microsaccades while people performed a tactile, frequency discrimination task enabled us to test whether the oculomotor system shows an analogous preparatory response for unrelated tactile events. We manipulated the temporal predictability of tactile targets using tactile cues, which preceded the target by either constant (high predictability) or variable (low predictability) time intervals. We find that microsaccades are inhibited prior to tactile targets and more so for constant than variable intervals, revealing a tight crossmodal link between tactile temporal expectation and oculomotor action. These findings portray oculomotor freezing as a marker of crossmodal temporal expectation. Moreover, microsaccades occurring around the tactile target presentation are associated with reduced task performance, suggesting that oculomotor freezing mitigates potential detrimental, concomitant effects of microsaccades and revealing a crossmodal coupling between tactile perception and oculomotor action.

Oculomotor inhibition precedes temporally expected auditory targets

“…These results suggest that oculomotor activity was adjusted to reach a minimum at the onset of the anticipated auditory target. These findings, consistent with our results in the visual 3 and tactile 13 domains, reveal that the execution of oculomotor events is modulated by target’s predictability, even when the target is auditory.…”

Pre-stimulus inhibition of eye movements reflects temporal expectation rather than time estimation

“…Nevertheless, as in the previous studies, that used a similar procedure but required an immediate motor response to the target (Amit et al, 2019;Tal-Perry & Yuval-Greenberg, 2020), we found stronger inhibition for fixed relative to varied conditions. The result suggests that pre-stimulus oculomotor inhibition occurs regardless of whether a response to the stimulus is required, and is consistent with previous evidence showing no correlation between the oculomotor inhibition effect and reaction time (Abeles et al, 2020;Amit et al, 2019;Dankner et al, 2017, but see Badde et al, 2020 for a different result). This finding provides additional support for the hypothesis that this marker reflects a general temporal expectation process to an upcoming event, regardless of whether responses were planned or not, making it a useful marker for studying temporal expectation irrespective of its motor consequence.…”

“…In line with these studies, in the present finding we observe no effect of saccadic events on behavioral outcome for both the duration and the tilt tasks. However, in a recent study, using a tactile discrimination task, such a benefit was found, as oculomotor inhibition prior to target onset was associated with enhanced tactile perception (Badde et al, 2020). Thus, it is possible that the oculomotor inhibition is advantageous for perception under specific circumstances, but at this stage, it is unknown what are the factors that determine this relation, and consequently whether the oculomotor inhibition effect has a functional role in the perception of an anticipated target.…”

“…In a series of studies, we have demonstrated pre-stimulus oculomotor inhibition using various paradigms, modalities and temporal structures. In these studies we have manipulated temporal expectations in various ways including rhythms (Dankner et al, 2017), cueassociations (Abeles et al, 2020Amit et al, 2019;Badde et al, 2020;Tal-Perry & Yuval-Greenberg, 2020) and hazard-rate probabilities (Tal-Perry & Yuval-Greenberg, 2020), as well as in different modalities including visual (Amit et al, 2019;Dankner et al, 2017;Tal-Perry & Yuval-Greenberg, 2020), auditory (Abeles et al, 2020) and tactile (Badde et al, 2020).…”

“…Recent studies established a tight link between temporal predictability and the oculomotor systemin anticipation for the onset of predictable targets, oculomotor behaviors, such as saccades, are inhibited. This pre-target oculomotor inhibition effect was demonstrated across multiple temporal structures (Amit et al, 2019;Dankner et al, 2017;Denison et al, 2019;Tal-Perry & Yuval-Greenberg, 2020) as well as in different modalities (Abeles et al, 2020;Amit et al, 2019;Badde et al, 2020), and was shown to covary with target probability (Tal-Perry & Yuval-Greenberg, 2020). In these previous studies, the oculomotor inhibition effect was interpreted as the direct or indirect outcome of implicit processes involved in the formation of temporal expectation.…”