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Decoding intention at sensorimotor timescales.

Salvaris M, Haggard P - PLoS ONE (2014)

Bottom Line: Several Brain Computer Interface applications have used motor imagery of repetitive actions to achieve this goal.These systems are relatively successful, but only if the intention is sustained over a period of several seconds; much longer than the timescales identified in psychophysiological studies for normal preparation for voluntary action.The implications for volition are considered.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cognitive Neuroscience, University College London, London, United Kingdom.

ABSTRACT
The ability to decode an individual's intentions in real time has long been a 'holy grail' of research on human volition. For example, a reliable method could be used to improve scientific study of voluntary action by allowing external probe stimuli to be delivered at different moments during development of intention and action. Several Brain Computer Interface applications have used motor imagery of repetitive actions to achieve this goal. These systems are relatively successful, but only if the intention is sustained over a period of several seconds; much longer than the timescales identified in psychophysiological studies for normal preparation for voluntary action. We have used a combination of sensorimotor rhythms and motor imagery training to decode intentions in a single-trial cued-response paradigm similar to those used in human and non-human primate motor control research. Decoding accuracy of over 0.83 was achieved with twelve participants. With this approach, we could decode intentions to move the left or right hand at sub-second timescales, both for instructed choices instructed by an external stimulus and for free choices generated intentionally by the participant. The implications for volition are considered.

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The three protocols used.(far left) Participant carried out real repetitive movements. (centre) Participant carried out repetitive motor imagery and received online feedback. (far right) Simple precueing task where the participant simply reacted as quickly as possible.
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pone-0085100-g001: The three protocols used.(far left) Participant carried out real repetitive movements. (centre) Participant carried out repetitive motor imagery and received online feedback. (far right) Simple precueing task where the participant simply reacted as quickly as possible.

Mentions: The first calibration session can be seen in figure 1. An annulus subtending 2.25 degrees of visual angle appeared at the centre of the screen. After a brief interval, an arrow appeared at the centre of the screen instructing the participant which index finger to use on that trial. The annulus turned progressively red along a clockwise manner, rotating at 90 degrees/s for 500 ms, at which point it turned orange, indicating that participants should begin repetitive finger movement (but without depressing the response key) at a rate of around 2 Hz. After a further 3.5 seconds the annulus and central arrow turned green. The participant was required to respond within 1 s using the same finger they were tapping during the intervening orange phase. The data during the orange phase was used to train the initial BCI model, which could be used for decoding motor imagery during the second session.


Decoding intention at sensorimotor timescales.

Salvaris M, Haggard P - PLoS ONE (2014)

The three protocols used.(far left) Participant carried out real repetitive movements. (centre) Participant carried out repetitive motor imagery and received online feedback. (far right) Simple precueing task where the participant simply reacted as quickly as possible.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3921113&req=5

pone-0085100-g001: The three protocols used.(far left) Participant carried out real repetitive movements. (centre) Participant carried out repetitive motor imagery and received online feedback. (far right) Simple precueing task where the participant simply reacted as quickly as possible.
Mentions: The first calibration session can be seen in figure 1. An annulus subtending 2.25 degrees of visual angle appeared at the centre of the screen. After a brief interval, an arrow appeared at the centre of the screen instructing the participant which index finger to use on that trial. The annulus turned progressively red along a clockwise manner, rotating at 90 degrees/s for 500 ms, at which point it turned orange, indicating that participants should begin repetitive finger movement (but without depressing the response key) at a rate of around 2 Hz. After a further 3.5 seconds the annulus and central arrow turned green. The participant was required to respond within 1 s using the same finger they were tapping during the intervening orange phase. The data during the orange phase was used to train the initial BCI model, which could be used for decoding motor imagery during the second session.

Bottom Line: Several Brain Computer Interface applications have used motor imagery of repetitive actions to achieve this goal.These systems are relatively successful, but only if the intention is sustained over a period of several seconds; much longer than the timescales identified in psychophysiological studies for normal preparation for voluntary action.The implications for volition are considered.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cognitive Neuroscience, University College London, London, United Kingdom.

ABSTRACT
The ability to decode an individual's intentions in real time has long been a 'holy grail' of research on human volition. For example, a reliable method could be used to improve scientific study of voluntary action by allowing external probe stimuli to be delivered at different moments during development of intention and action. Several Brain Computer Interface applications have used motor imagery of repetitive actions to achieve this goal. These systems are relatively successful, but only if the intention is sustained over a period of several seconds; much longer than the timescales identified in psychophysiological studies for normal preparation for voluntary action. We have used a combination of sensorimotor rhythms and motor imagery training to decode intentions in a single-trial cued-response paradigm similar to those used in human and non-human primate motor control research. Decoding accuracy of over 0.83 was achieved with twelve participants. With this approach, we could decode intentions to move the left or right hand at sub-second timescales, both for instructed choices instructed by an external stimulus and for free choices generated intentionally by the participant. The implications for volition are considered.

Show MeSH