Withdrawal of voluntary inhibition unravels the off state of the spontaneous blink generator

Moraitis, Timoleon; Ghosh, Arko

doi:10.1016/j.neuropsychologia.2014.09.010

Cited by 5 publications

(6 citation statements)

References 31 publications

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“…However, the model does not account for any external task-related influences. In another study (28) it was proposed that blinks are generated by an oscillating blink generator. However, both studies used voluntary blink suppression.…”

Section: Discussionmentioning

confidence: 99%

“…Although numerous empirical studies have established the importance of blinking, quantitative explanations have been scarce. Current models assume a linear increase in urge when blinking is suppressed (27) or an oscillating blink generator (28), but both models considered voluntary blink suppression and do not incorporate any task-related influences. One reason might be that environmental regularities and task-related costs are usually complex and unknown.…”

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confidence: 99%

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Humans quickly learn to blink strategically in response to environmental task demands

Hoppe

Helfmann

Rothkopf

2018

Proc. Natl. Acad. Sci. U.S.A.

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Eye blinking is one of the most frequent human actions. The control of blinking is thought to reflect complex interactions between maintaining clear and healthy vision and influences tied to central dopaminergic functions including cognitive states, psychological factors, and medical conditions. The most imminent consequence of blinking is a temporary loss of vision. Minimizing this loss of information is a prominent explanation for changes in blink rates and temporarily suppressed blinks, but quantifying this loss is difficult, as environmental regularities are usually complex and unknown. Here we used a controlled detection experiment with parametrically generated event statistics to investigate human blinking control. Subjects were able to learn environmental regularities and adapted their blinking behavior strategically to better detect future events. Crucially, our design enabled us to develop a computational model that allows quantifying the consequence of blinking in terms of task performance. The model formalizes ideas from active perception by describing blinking in terms of optimal control in trading off intrinsic costs for blink suppression with task-related costs for missing an event under perceptual uncertainty. Remarkably, this model not only is sufficient to reproduce key characteristics of the observed blinking behavior such as blink suppression and blink compensation but also predicts without further assumptions the well-known and diverse distributions of time intervals between blinks, for which an explanation has long been elusive.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Humans quickly learn to blink strategically in response to environmental task demands

Hoppe

Helfmann

Rothkopf

2018

Proc. Natl. Acad. Sci. U.S.A.

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“…A realistic model should account for this variation. In addition to such temporal characteristics, changes in blinking rates often provide less common distributions of inter-blink intervals (IBIs) in cognitive tasks [ 6 ], [ 11 ]. Thus, an adequate model should reproduce the diverse distributions of spontaneous blinking.…”

Section: Introductionmentioning

confidence: 99%

Threshold-varying integrate-and-fire model reproduces distributions of spontaneous blink intervals

et al. 2018

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Spontaneous blinking is one of the most frequent human behaviours. While attentionally guided blinking may benefit human survival, the function of spontaneous frequent blinking in cognitive processes is poorly understood. To model human spontaneous blinking, we proposed a leaky integrate-and-fire model with a variable threshold which is assumed to represent physiological fluctuations during cognitive tasks. The proposed model is capable of reproducing bimodal, normal, and widespread peak-less distributions of inter-blink intervals as well as the more common popular positively skewed distributions. For bimodal distributions, the temporal positions of the two peaks depend on the baseline and the amplitude of the fluctuating threshold function. Parameters that reproduce experimentally derived bimodal distributions suggest that relatively slow oscillations (0.11–0.25 Hz) govern blink elicitations. The results also suggest that changes in blink rates would reflect fluctuations of threshold regulated by human internal states.

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“…Control processes for the Kohnstamm phenomenon may involve multiple regions of the central nervous system. It is therefore convenient to speak of a 'Kohnstamm generator' when considering how a particular aftercontraction responds to input (De Havas et al, 2015;Ghosh, Rothwell, & Haggard, 2014;Moraitis & Ghosh, 2014). In this context the Kohnstamm generator is a functionally defined unit whose precise location within the central nervous system is not known.…”

Section: Introductionmentioning

confidence: 99%

Voluntary motor commands reveal awareness and control of involuntary movement

et al. 2016

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The capacity to inhibit actions is central to voluntary motor control. However, the control mechanisms and subjective experience involved in voluntarily stopping an involuntary movement remain poorly understood. Here we examined, in humans, the voluntary inhibition of the Kohnstamm phenomenon, in which sustained voluntary contraction of shoulder abductors is followed by involuntary arm raising. Participants were instructed to stop the involuntary movement, hold the arm in a constant position, and 'release' the inhibition after ∼2s. Participants achieved this by modulating agonist muscle activity, rather than by antagonist contraction. Specifically, agonist muscle activity plateaued during this voluntary inhibition, and resumed its previous increase thereafter. There was no discernible antagonist activation. Thus, some central signal appeared to temporarily counter the involuntary motor drive, without directly affecting the Kohnstamm generator itself. We hypothesise a form of "negative motor command" to account for this novel finding. We next tested the specificity of the negative motor command, by inducing bilateral Kohnstamm movements, and instructing voluntary inhibition for one arm only. The results suggested negative motor commands responsible for inhibition are initially broad, affecting both arms, and then become focused. Finally, a psychophysical investigation found that the perceived force of the aftercontraction was significantly overestimated, relative to voluntary contractions with similar EMG levels. This finding is consistent with the hypothesis that the Kohnstamm generator does not provide an efference copy signal. Our results shed new light on this interesting class of involuntary movement, and provide new information about voluntary inhibition of action.

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Withdrawal of voluntary inhibition unravels the off state of the spontaneous blink generator

Cited by 5 publications

References 31 publications

Humans quickly learn to blink strategically in response to environmental task demands

Humans quickly learn to blink strategically in response to environmental task demands

Threshold-varying integrate-and-fire model reproduces distributions of spontaneous blink intervals

Voluntary motor commands reveal awareness and control of involuntary movement

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