Measurement of the extraocular spike potential during saccade countermanding

Godlove, David C.; Garr, Anna K.; Woodman, Geoffrey F.; Schall, Jeffrey D.

doi:10.1152/jn.00896.2010

Cited by 24 publications

(25 citation statements)

References 74 publications

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“…stable fixation) under conditions previously shown to have imbalanced activity across the saccade map in SC (Paré & Hanes 2003; see also Hanes, et al 1998). This finding is consistent with our previous discovery of a small but reliable decrease of the extraocular electromyogram (EMG) before and during SSRT (Godlove et al, 2011). The few microsaccades that escaped inhibition tended to be directed toward the target location as expected based on this imbalance.…”

Section: Discussionsupporting

confidence: 93%

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Microsaccade production during saccade cancelation in a stop-signal task

Godlove

Schall

2016

Vision Research

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We obtained behavioral data to evaluate two alternative hypotheses about the neural mechanisms of gaze control. The “fixation” hypothesis states that neurons in rostral superior colliculus (SC) enforce fixation of gaze. The “microsaccade” hypothesis states that neurons in rostral SC encode microsaccades rather than fixation per se. Previously reported neuronal activity in monkey SC during the saccade stop-signal task leads to specific, dissociable behavioral predictions of these two hypotheses. When subjects are required to cancel partially-prepared saccades, imbalanced activity spreads across rostral and caudal SC with a reliable temporal profile. The microsaccade hypothesis predicts that this imbalance will lead to elevated microsaccade production biased toward the target location, while the fixation hypothesis predicts reduced microsaccade production. We tested these predictions by analyzing the microsaccades produced by 4 monkeys while they voluntarily canceled partially prepared eye movements in response to explicit stop signals. Consistent with the fixation hypothesis and contradicting the microsaccade hypothesis, we found that each subject produced significantly fewer microsaccades when normal saccades were successfully canceled. The few microsaccades escaping this inhibition tended to be directed toward the target location. We additionally investigated interactions between initiating microsaccades and inhibiting normal saccades. Reaction times were longer when microsaccades immediately preceded target presentation. However, pre-target microsaccade production did not affect stop-signal reaction time or alter the probability of canceling saccades following stop signals. These findings demonstrate that imbalanced activity within SC does not necessarily produce microsaccades and add to evidence that saccade preparation and cancelation are separate processes.

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Section: Discussionsupporting

confidence: 93%

“…Titanium headposts were surgically implanted to facilitate head restraint during eye tracking. Surgical methods have been described in detail (Godlove et al, 2011). …”

Section: Methodsmentioning

confidence: 99%

Microsaccade production during saccade cancelation in a stop-signal task

Godlove

Schall

2016

Vision Research

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“…In the skeletomotor system, therefore, the "point of no return" may be therefore a conceptual notion without any underlying neural substrate. In contrast in the oculomotor system, we speculate that the point of no return is embodied in the brain stem circuit via the potent inhibition of OPNs on the saccadic burst generator (Scudder et al 2002), highlighting a fundamental difference between the oculomotor and skeletomotor systems (Godlove et al 2011). According to our proposition that head orienting escapes OPN inhibition (effectively allowing a lower threshold for initiating orienting head movements, as conceptualized in Fig.…”

Section: Discussionmentioning

confidence: 88%

“…As recently noted (Godlove et al 2011), partial responses in the oculomotor system could be a powerful tool for understanding motor control in saccadic tasks. Although partial responses do not appear to be present in a proxy of extraocular EMG activation via electroencephalography (Godlove et al 2011), we suggest that head-only movements, and more precisely the underlying profile of neck muscle recruitment, provides exactly this type of measure.…”

Section: Discussionmentioning

confidence: 91%

“…Saccades are easily detected, and there is no evidence for ocular motility or extraocular muscle recruitment during cancelled trials (Godlove et al 2011). Reports have differed on whether small-to medium-sized (less than ϳ10 -15°in amplitude) noncancelled saccades can be hypometric or not (Colonius et al 2001;Godlove et al 2011;Hanes and Schall 1995;Ozyurt et al 2003;Paré and Hanes 2003), although large noncancelled gaze shifts can certainly be arrested in midflight (Corneil and Elsley 2005;Goonetilleke et al 2010). On the whole, it appears that the processes preceding saccade initiation have a ballistic component: once initiated, a rapid saccade will be launched, even if the later part of the trajectory can be modified.…”

Section: Discussionmentioning

confidence: 99%

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Validation of a within-trial measure of the oculomotor stop process

Goonetilleke

Wong

2012

Journal of Neurophysiology

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The countermanding (or stop signal) task requires subjects try to withhold a planned movement upon the infrequent presentation of a stop signal. We have previously proposed a within-trial measure of movement cancellation based on neck muscle recruitment during the cancellation of eye-head gaze shifts. Here, we examined such activity after either a bright or dim stop signal, a manipulation known to prolong the stop signal reaction time (SSRT). Regardless of stop signal intensity, subjects generated an appreciable number of head-only errors during successfully cancelled gaze shifts (compensatory eye-in-head motion ensured gaze stability), wherein subtle head motion toward a peripheral target was ultimately stopped by a braking pulse of antagonist neck muscle activity. Both the SSRT and timing of antagonist muscle recruitment relative to the stop signal increased for dim stop signals and decreased for longer stop signal delays. Moreover, we observed substantial variation in the distribution of antagonist muscle recruitment latencies across our sample. The magnitude and variance of the SSRTs and antagonist muscle recruitment latencies correlated positively across subjects, as did the within-subject changes across bright and dim stop signals. Finally, we fitted our behavioral data with a race model architecture that incorporated a lower threshold for initiating head movements. This model allowed us to estimate the efferent delay between the completion of a central stop process and the recruitment of antagonist neck muscles; the estimated efferent delay remained consistent within subjects across stop signal intensity. Overall, these results are consistent with the hypothesis that neck muscle recruitment during a specific subset of cancelled trials provides a peripheral expression of oculomotor cancellation on a single trial. In the discussion, we briefly speculate on the potential value of this measure for research in basic or clinical domains and consider current issues that limit more widespread use.

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Reduced Proactive Control Processes Associated With Behavioral Response Inhibition Deficits in Autism Spectrum Disorder

et al. 2020

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Impairments in inhibitory control are common in individuals with autism spectrum disorder (ASD) and associated with multiple clinical issues. Proactive (i.e., delaying response onset) and reactive control mechanisms (i.e., stopping quickly) contribute to successful inhibitory control in typically developing individuals and may be compromised in ASD. We assessed inhibitory control in 58 individuals with ASD and 63 typically developing controls aged 5–29 years using an oculomotor stop‐signal task during which participants made rapid eye movements (i.e., saccades) toward peripheral targets (i.e., GO trials) or inhibited saccades (i.e., STOP trials). Individuals with ASD exhibited reduced ability to inhibit saccades, reduced reaction time slowing (GO RT slowing), and faster stop‐signal reaction times (SSRT) compared to controls. Across participants, stopping accuracy was positively related to GO RT slowing, and increased age was associated with higher stopping accuracy and GO RT slowing. Our results indicate that failures to proactively delay prepotent responses in ASD underpin deficits of inhibitory control and may contribute to difficulties modifying their behavior according to changes in contextual demands. These findings implicate frontostriatal brain networks in inhibitory control and core symptoms of ASD. Lay Summary Difficulties stopping actions are common in individuals with autism spectrum disorder (ASD) and are related to repetitive behaviors. This study compared the ability to stop eye movements in individuals with ASD and healthy peers. We found that individuals with ASD were less able to stop eye movements and that this difficulty was related to a reduced ability to delay their eye movements before seeing the cue to stop, not their ability to react quickly to this cue.

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Measurement of the extraocular spike potential during saccade countermanding

Cited by 24 publications

References 74 publications

Microsaccade production during saccade cancelation in a stop-signal task

Microsaccade production during saccade cancelation in a stop-signal task

Validation of a within-trial measure of the oculomotor stop process

Reduced Proactive Control Processes Associated With Behavioral Response Inhibition Deficits in Autism Spectrum Disorder

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