Spatiotemporal Content of Saccade Transients

Mostofi, Naghmeh; Zhao, Zhetuo; Intoy, Janis; Boi, Marco; Victor, Jonathan D.; Rucci, Michele

doi:10.1016/j.cub.2020.07.085

Cited by 38 publications

(39 citation statements)

References 73 publications

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“…Our findings indicate that the pupil size may index saccadic decision time, and may be used as a biomarker for disease with impairments in motor inhibition, for example, in ADHD, schizophrenia and Parkinson 's disease (Chamberlain et al, 2006;Joti et al, 2007;Wang et al, 2016;Thakkar et al, 2018). In short, taking aforementioned neurophysiological, psychopharmacological studies and our present study together, it appears that the FEF and SC strongly influence the pupil dynamics to optimize perisaccadic visual perception and minimize saccade transients (Mostofi et al, 2020).…”

Section: Model Simulationsupporting

confidence: 62%

Pupillary aperture is a potential biomarker of movement preparation

Pandey

Ray

2021

Preprint

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In response to variable light intensity, the pupils reflexively constrict or dilate to maintain a uniform retinal illumination. The pupillary light reflex (PLR) pathway receives projections from two important areas in primates’ brain that plan rapid saccadic eye-movement – frontal eye field (FEF) and superior colliculus (SC). The speed with which neurons in these areas increase firing rate to a threshold determines latency of a saccade. Micro-stimulation of FEF/SC neurons below this threshold modulates the magnitude of PLR. Nonetheless, how the saccade latency and pupil dynamics are related remains unknown. Our study shows that the appearance of a bright stimulus evokes pupil constriction at higher rate when the latency of impending saccade to the stimulus is shorter. This inverse relationship between the rate of pupil constriction and the saccade latency is robust irrespective of the reward outcome. In a homeomorphic biomechanical model of pupil, we have projected build-up signal similar to FEF and SC activity to the parasympathetic and sympathetic divisions of the PLR pathway, respectively. Model simulation mimics the observed data to indicate that the FEF and SC activity for eye movement modulates autonomic input to the pupillary muscle plant. A striking similarity between the dynamics of pupil constriction and stochastic rise in neural activity for saccade elicitation suggests that PLR is a potential proxy of movement preparation, and not mere an indicator of attentional orientation. Our study suggests a mechanism of how the retinal luminosity is timely regulated to aid perception by minimizing visual transients due to gaze orientation.

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Section: Model Simulationsupporting

confidence: 62%

Pupillary aperture is a potential biomarker of movement preparation

Pandey

Ray

2021

Preprint

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Section: Discussionmentioning

confidence: 99%

“…This prediction is consistent with previous findings 64 as well with the relatively low level of suppression measured in our experiments. More broadly, the idea of active space-time encoding argues that, rather than being insensitive to the retinal image motion caused by saccades, the visual system uses these luminance modulations to encode visual information during post-saccadic fixation 59 (see also [65][66][67]). The structure of these visual signals is consistent with the sensitivity enhancements at low spatial frequencies measured with saccades 68 , as well as with the dependence of this perceptual facilitation on saccade amplitude 45 .…”

Section: Discussionmentioning

confidence: 99%

“…On the retina, both saccades and drifts equalize (whiten) the power spectra of natural scenes within a low spatial frequency range. But a trade-o↵ exists between power and bandwidth in this region: the larger a saccade, the narrower the whitening bandwidth and the higher the power it contains 59 . These modulations are likely to play an important role in the strong responses elicited by the onset of a new fixation in the early visual system [60][61][62][63] .…”

Section: Discussionmentioning

confidence: 99%

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Foveal vision at the time of microsaccades

Intoy¹,

Mostofi

Rucci

2021

Preprint

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Humans use rapid eye movements (saccades) to inspect stimuli with the foveola, the region of the retina where receptors are most densely packed. It is well established that visual sensitivity is generally attenuated during these movements, a phenomenon known as saccadic suppression. This effect is commonly studied with large, often peripheral, stimuli presented during instructed saccades. However, little is known about how saccades modulate the foveola and how the resulting dynamics unfold during natural visual exploration. Here we measured the foveal dynamics of saccadic suppression in a naturalistic high-acuity task, a task designed after primate’s social grooming, which—like most explorations of fine patterns—primarily elicits minute saccades (microsaccades). Leveraging on recent advances in gaze-contingent display control, we were able to systematically map the peri-saccadic time-course of sensitivity across the foveola. We show that contrast sensitivity is not uniform across this region and that both the extent and dynamics of saccadic suppression vary within the foveola. Suppression is stronger and faster in the most central portion, where sensitivity is generally higher and selectively rebounds at the onset of a new fixation. These results shed new light on the modulations experienced by foveal vision during the saccade-fixation cycle and explain some of the benefits of microsaccades.

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“…Recent insights demonstrate that the alternating cycle of fixations and eye movements modifies the spectral content of visual input in a way that appears highly adaptive in our natural environment (6,7). The new results of Schweitzer and Rolfs now show that the brain adapts even specific parts of the spectral content of the retinal motion streak generated by an eye movement.…”

Section: Improving Artificial Visual Systemsmentioning

confidence: 98%