Face Selective Neural Activity: Comparisons Between Fixed and Free Viewing

Auerbach-Asch, Carmel R; Bein, Oded; Deouell, Leon Y.

doi:10.1007/s10548-020-00764-7

Cited by 14 publications

(28 citation statements)

References 89 publications

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“…In these studies, the observer controls the spatial and temporal properties of the stimulus by controlling the saccades, whereas flashed stimuli are often presented at random times and could disrupt the ongoing processing. Nevertheless, the emerging picture is that FRPs are similar to ERPs, although not identical, with evidence including the ERP components of N170 for faces 61 , P1 for checkerboard stimuli 64 , and P300 in visual search 60 , 65 . In the current study we compared eye movements under event-related and fixation-related conditions (Figs.…”

Section: Discussionmentioning

confidence: 99%

Fixation-related saccadic inhibition in free viewing in response to stimulus saliency

Kadosh

Bonneh

2022

Sci Rep

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Microsaccades that occur during fixation were studied extensively in response to transient stimuli, showing a typical inhibition (Oculomotor Inhibition, OMI), and a later release with a latency that depends on stimulus saliency, attention, and expectations. Here, we investigated the hypothesis that in free viewing every saccade provides a new transient stimulation that should result in a stimulus-dependent OMI like a flashed presentation during fixation. Participants (N = 16) freely inspected static displays of randomly oriented Gabor texture images, with varied contrast and spatial frequency (SF) for periods of 10 s each. Eye tracking recordings were divided into epochs triggered by saccade landing (> 1 dva), and microsaccade latency relative to fixation onset was computed (msRT). We found that the msRT in free viewing was shorter for more salient stimuli (higher contrast or lower SF), as previously found for flashed stimuli. It increased with saccade size and decreased across successive saccades, but only for higher contrast, suggesting contrast-dependent repetition enhancement in free viewing. Our results indicate that visual stimulus-dependent inhibition of microsaccades also applies to free viewing. These findings are in agreement with the similarity found between event-related and fixation-related potentials and open the way for studies combining both approaches to study natural vision.

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Section: Discussionmentioning

confidence: 99%

Fixation-related saccadic inhibition in free viewing in response to stimulus saliency

Kadosh

Bonneh

2022

Sci Rep

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“…Apart from this discrepancy, however, both studies found fixation-locked preview effects when contrasting valid with invalid trials, which hints at the context-dependence of trans-saccadic perception. Besides this context-dependence, active and passive viewing conditions imply different scalp distribution of ERP components as illustrated for instance for the N170 (Auerbach-Asch et al, 2020). These findings suggest that other classic visual ERP components and, thus, the processes indexed by these components take a different form in active vision.…”

Section: Discussionmentioning

confidence: 86%

“…Scene understanding can also increase over time as we look around, but the time course of extrafoveal preview effects in such naturalistic situations has yet to be explored. A first starting point could be a preview paradigm that allows for saccade-fixation sequences instead of the rather restrictive setting of only one saccade (see for example Auerbach-Asch et al, 2020).…”

Section: An Active-vision Interpretation Of Preview Effectsmentioning

confidence: 99%

The extrafoveal preview paradigm as a measure of predictive, active sampling in visual perception

2021

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A key feature of visual processing in humans is the use of saccadic eye movements to look around the environment. Saccades are typically used to bring relevant information, which is glimpsed with extrafoveal vision, into the high-resolution fovea for further processing. With the exception of some unusual circumstances, such as the first fixation when walking into a room, our saccades are mainly guided based on this extrafoveal preview. In contrast, the majority of experimental studies in vision science have investigated "passive" behavioral and neural responses to suddenly appearing and often temporally or spatially unpredictable stimuli. As reviewed here, a growing number of studies have investigated visual processing of objects under more natural viewing conditions in which observers move their eyes to a stationary stimulus, visible previously in extrafoveal vision, during each trial. These studies demonstrate that the extrafoveal preview has a profound influence on visual processing of objects, both for behavior and neural activity. Starting from the preview effect in reading research we follow subsequent developments in vision research more generally and finally argue that taking such evidence seriously leads to a reconceptualization of the nature of human visual perception that incorporates the strong influence of prediction and action on sensory processing. We review theoretical perspectives on visual perception under naturalistic viewing conditions, including theories of active vision, active sensing, and sampling. Although the extrafoveal preview paradigm has already provided useful information about the timing of, and potential mechanisms for, the close interaction of the oculomotor and visual systems while reading and in natural scenes, the findings thus far also raise many new questions for future research.

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“…Jongkees & Colzato, 2016; Stern et al, 1994), as well as to research done using fMRI or other modalities. More importantly, initial research suggests that there might be significant differences in frequently investigated neuronal processing components under free viewing compared to attempted fixation (s.a. in the N170 Auerbach-Asch et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

“…Stern et al, 1994;Jongkees and Colzato, 2016), as well as to research done using fMRI or other modalities difficult if not impossible. More importantly, initial research suggests that there might be significant differences in frequently investigated neuronal processing components under free viewing compared to attempted fixation (s.a. in the N170 Auerbach-Asch et al, 2020). When interested in spontaneous gaze patterns and related brain processes, a fixation task is not an option.…”

Section: Fixation Task Improves Eeg Snr and Does Not Significantly Impact Ratings But Does Introduce Cognitive Loadmentioning

confidence: 99%

Naturalistic viewing conditions can increase task engagement and aesthetic preference but have only minimal impact on EEG Quality

Welke

Vessel

2021

Preprint

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Free gaze and the use of dynamically changing video stimuli are typically avoided in EEG exper- iments to avoid artefacts and confounds related to uncontrolled eye movements. Yet, often it is unclear whether these artificial secondary manipulations might have unwanted effects on the pri- mary measures of interest and for a growing number of research questions removing them would be beneficial: Among those is the investigation of visual aesthetic experiences, which typically involve open-ended exploration of highly variable stimuli. Here we aimed to quantify the effect of fixation task and using still vs. movie stimuli on EEG signal quality and several behavioral and physiological measures of interest during an aesthetic rating task. Participants observed scenes from landscapes and dance performances and rated each stimulus for both aesthetic appeal and their state of boredom while watching it. The scenes were presented either as dynamic video clips or static pictures, and participants observed them either with unconstrained gaze or under attempted fixation We recorded EEG, ECG and eyetracking from 43 participants. An auditory stream of 40Hz amplitude modulated pink noise was played during each trial and signal-to-noise-ratio (SNR) of the auditory steady-state response measured at the scalp was extracted as a proxy measure for overall EEG signal quality. The study including hypotheses and a priori power analysis was preregistered. We found that both behavioral ratings were influenced by the experimental conditions: boredom and aesthetic ratings were positively affected by dynamic video stimuli, indicating that these are experienced as more engaging; both these effects were stronger in dance. As already reported before, landscape stimuli were experienced as more appealing. Fixaton task, on the other hand, had no significant effect on the ratings which is encouraging given how canonically it is applied. Eye movements were significantly affected not only by viewing task, but by stimulus dynamics and content as well: we observed fewer eyeblinks, saccades and microsaccades in video stimuli, and fewer saccades but more microsaccades in dance than in landscape stimuli, with several significant interactions. EEG SNR, to our surprise, was barely affected by fixation task - despite only minimal preprocessing and no trial rejection. We nevertheless believe that the new metric is sensitive to capture noise: it was significantly correlated with the number of eye blinks, and after cleaning the dataset with an ICA based preprocessing pipeline the significant effect of fixation task and the correlation with blink rate vanished. We see these as promising results indicating that at least in the lab more liberal experimental conditions could be achieved without significant loss of signal quality. Specifically the use of dynamic video material bears a lot of potential for future investigations in human neurophysiological studies.

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Face Selective Neural Activity: Comparisons Between Fixed and Free Viewing

Cited by 14 publications

References 89 publications

Fixation-related saccadic inhibition in free viewing in response to stimulus saliency

Fixation-related saccadic inhibition in free viewing in response to stimulus saliency

The extrafoveal preview paradigm as a measure of predictive, active sampling in visual perception

Naturalistic viewing conditions can increase task engagement and aesthetic preference but have only minimal impact on EEG Quality

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