The effect of saccadic eye movements on the sensor-level magnetoencephalogram

Gawne, Timothy J.; Killen, Jeffrey F.; Tracy, John M.; Lahti, Adrienne C.

doi:10.1016/j.clinph.2016.12.013

Cited by 6 publications

(7 citation statements)

References 15 publications

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“…Saccadic eye movements generate non-neural signals, recorded by the MEG mostly in frontal sensors (Gawne et al, 2017). While ICA is commonly used as a way to remove eye-movement artifacts, we chose to keep the signal as is, as removing ICA components related to eye movements may also remove temporally associated neural activity.…”

Section: Meg Data Preparationmentioning

confidence: 99%

“…The rotation of the eyeball and the contraction of the periocular muscles can be detected by the MEG sensors, contaminating the signal with non-neural sources (Carl et al, 2012;Gawne et al, 2017;Keren et al, 2010). In particular, the eye dipole rotation generates low frequency artifacts, strongest at sensors located fronto-laterally (Gawne et al, 2017). Inspection of the time course of the ERFs (Supplementary materials Fig.…”

Section: Control Analysesmentioning

confidence: 99%

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Changes in neural activity around the time of saccades: Separate contributions of visual and non-visual signals on MEG alpha and theta band activity

Acunzo¹,

Melcher²

2021

Preprint

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Visual processing mainly occurs during fixation, periods separated by saccadic eye movements, necessitating a close coordination between sensory and motor systems. It has been suggested that the intention to make a saccade can modulate neural activity, including predictive changes, suppression of peri-saccadic retinal input and trans-saccadic integration. Consistent with this idea, modulations of neural activity around the time of saccades have been reported in non-human species, showing non-visually mediated, extraretinal responses in specific brain regions. In humans, however, peri-saccadic whole-brain activity has mainly been studied in the context of a perceptual task, making it difficult to disentangle activity related to the task, visual transients from retinal stimulation and non-visual (saccade-related) responses. We measured magnetoencephalography (MEG) theta (3–7 Hz) and alpha (8–12 Hz) activity during voluntary horizontal saccade execution between two fixation points. To distinguish between visually and non-visually mediated activity, participants engaged in three tasks: voluntary saccades in near-darkness, fixation with visual input shifted to simulate the saccade, and volitional saccades in total darkness. Using correlational analyses, we found that patterns of neural activity are consistent with contributions of two separate mechanisms, one related to saccades (non-visual/extraretinal) and the other linked to the processing of visual input at the beginning of the new fixation (visual/retinal). Changes in occipital alpha power and instantaneous frequency showed a similar time course in near-dark and simulated saccade conditions, suggesting an effect of visually evoked responses. In contrast, alterations in parietal-occipital theta power and phase clustering were consistent with a non-visually-driven (extraretinal) mechanism, with similar multivariate patterns for near-dark and full-darkness conditions. Some effects, such as theta phase reset and alterations in alpha power, showed separable contributions of both the saccade and visual transient, with differing time courses. This combination of visual and non-visual mechanisms may support sensorimotor integration during active vision.

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Section: Meg Data Preparationmentioning

confidence: 99%

Section: Control Analysesmentioning

confidence: 99%

Changes in neural activity around the time of saccades: Separate contributions of visual and non-visual signals on MEG alpha and theta band activity

Acunzo¹,

Melcher²

2021

Preprint

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“…It has been reported that saccadic eye movements cause noise, especially in the high-frequency bands (Gawne, Killen, Tracy, & Lahti, 2017). Therefore, it was necessary to control for saccadic eye movements during our tasks and analyses.…”

Section: Magnetoencephalography and Magnetic Resonance Imaging Datamentioning

confidence: 99%

Timing of phase‐amplitude coupling is essential for neuronal and functional maturation of audiovisual integration in adolescents

et al. 2020

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“…First, the rotation of the eye creates a rotation of an electrical dipole located between the cornea and the retina, called the corneoretinal dipole (CRD). The CRD causes large frontal modulations of scalp EEG (Lins, Picton, Berg, & Scherg, ) and magnetoencephalogram (MEG; Gawne, Killen, Tracy, & Lahti, ; Oakley, Sullivan, Roeder, & Flynn, ). Second, saccades (mostly vertical ones) are accompanied by ballistic eyelid movements, which are manifested on the scalp very similarly to the CRD, but for a slightly longer duration (Barry & Jones, ; Plöchl, Ossandón, & König, ).…”

Section: Introductionmentioning

confidence: 99%

“…Second, saccades (mostly vertical ones) are accompanied by ballistic eyelid movements, which are manifested on the scalp very similarly to the CRD, but for a slightly longer duration (Barry & Jones, ; Plöchl, Ossandón, & König, ). Third, the recruitment of muscle units of the extraocular muscles while executing saccades produces a saccadic spike potential (SP)—a transient signal deflection that is observed in occipitoparietal EEG electrodes (Keren, Yuval‐Greenberg, & Deouell, ; Thickbroom & Mastaglia, ; Yuval‐Greenberg & Deouell, ), frontal and temporal MEG sensors (Carl, Açık, König, Engel, & Hipp, ; Gawne et al, ), and at certain regions in human intracranial recordings (Jerbi et al, ; Kovach et al, ). Fourth, and most problematic, is the visual cortical activity that is correlated with the execution of saccades (saccade‐related visual activity; SVA).…”

Section: Introductionmentioning

confidence: 99%

Reducing saccadic artifacts and confounds in brain imaging studies through experimental design

Tal

Yuval-Greenberg

2018

Psychophysiology

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Saccades constitute a major source of artifacts and confounds in brain imaging studies. Whereas some artifacts can be removed by omitting segments of data, saccadic artifacts cannot be typically eliminated by this method because of their high occurrence rate even during fixation (1-3 per second). Some saccadic artifacts can be alleviated by offline-correction algorithms, but these methods leave nonnegligible residuals and cannot mitigate the saccade-related visual activity. Here, we propose a novel yet simple approach for diminishing saccadic artifacts and confounds through experimental design. We suggest that specific tasks can lead to substantially less saccade occurrences around the time of stimulus presentation, starting from slightly before its onset and lasting for a few hundred milliseconds. In three experiments, we compared the frequency and size of saccades in a variety of tasks. Results of Experiment 1 showed that a foveal change-detection task reduced the number and sizes of saccades, relative to a parafoveal orientation-discrimination task. Experiment 2 replicated this finding with a parafoveal object recognition task. Experiment 3 showed that both foveal and parafoveal continuous change detection tasks induced fewer and smaller saccades than a discrete orientation-discrimination task. We conclude that adding a foveal or a parafoveal continuous task reduces saccades' number and size. This would lead to better artifact correction and enable the omission of contaminated data segments. This study may be the first step toward developing saccade-free experimental designs.

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The effect of saccadic eye movements on the sensor-level magnetoencephalogram

Abstract: We have here characterized the MEG saccadic artifact in both the spatial and the frequency domains for saccades of different directions. This could be important in ruling in or ruling out artifact in MEG recordings.

Cited by 6 publications

References 15 publications

Changes in neural activity around the time of saccades: Separate contributions of visual and non-visual signals on MEG alpha and theta band activity

Changes in neural activity around the time of saccades: Separate contributions of visual and non-visual signals on MEG alpha and theta band activity

Timing of phase‐amplitude coupling is essential for neuronal and functional maturation of audiovisual integration in adolescents

Reducing saccadic artifacts and confounds in brain imaging studies through experimental design

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