Pre-stimulus alpha oscillations over somatosensory cortex predict tactile misperceptions

Craddock, Matt and Poliakoff, Ellen and El-deredy, Wael and Klepousniotou, Ekaterini and Lloyd, Donna M. (2017) Pre-stimulus alpha oscillations over somatosensory cortex predict tactile misperceptions. Neuropsychologia, 96 . pp. 9-18. ISSN 0028-3932

Full content URL: https://doi.org/10.1016/j.neuropsychologia.2016.12...

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Pre-stimulus alpha oscillations over somatosensory cortex predict tactile misperceptions
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Abstract

Fluctuations of pre-stimulus oscillatory activity in the somatosensory alpha band (8-14 Hz) observed using human EEG and MEG have been shown to influence the detection of supra- and peri-threshold somatosensory stimuli. However, some reports of touch occur even without a stimulus. We investigated the possibility that pre-stimulus alpha oscillations might also influence these false reports of touch known as tactile misperceptions. We recorded EEG while participants performed the Somatic Signal Detection Task (SSDT), in which participants must detect brief, peri-threshold somatosensory targets. We found that pre-stimulus oscillatory power in the somatosensory alpha range exhibited a negative linear relationship with reporting of touch at electrode clusters over both contralateral and ipsilateral somatosensory regions. As pre-stimulus alpha power increased, the probability of reporting a touch declined; as it decreased, the probability of reporting a touch increased. This relationship was stronger on trials without a somatosensory stimulus than on trials with a somatosensory stimulus, although was present for both trial types. Spatio-temporal cluster-based permutation analysis also found that pre-stimulus alpha was lower on trials when touch was reported irrespective of whether it was present over contralateral and ipsilateral somatosensory cortices, as well as left frontocentral areas. We argue that alpha power may reflect changes in response criterion rather than sensitivity alone. Low alpha power relates to a low barrier to reporting a touch even when one is not present, while high alpha power is linked to less frequent reporting of touch overall. © 2017 Elsevier Ltd

Keywords:adult, alpha rhythm, Article, controlled study, correlational study, electrode, electroencephalogram, female, human, human experiment, male, oscillatory potential, parietal cortex, perceptive discrimination, primary somatosensory cortex, Somatic Signal Detection Task, stimulus response, tactile misperception, temporal lobe, touch, adolescent, analysis of variance, brain mapping, electroencephalography, middle aged, physical stimulation, physiology, somatosensory cortex, time factor, young adult, Adolescent, Humans, Signal Detection, Psychological, Time Factors, Touch Perception, Young Adult
Subjects:C Biological Sciences > C850 Cognitive Psychology
C Biological Sciences > C800 Psychology
C Biological Sciences > C830 Experimental Psychology
Divisions:College of Social Science > School of Psychology
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ID Code:30950
Deposited On:28 Feb 2018 20:46

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