Pre-stimulus alpha oscillations over somatosensory cortex predict tactile misperceptions

Abstract

Cite this article as: Matt Craddock, Ellen Poliakoff, Wael El-deredy, Ekaterini Klepousniotou and Donna M. Lloyd, Pre-stimulus alpha oscillations over somatosensory cortex predict tactile misperceptions, Neuropsychologia, http://dx.doi.org/10. 1016/j.neuropsychologia.2016.12.030 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractFluctuations 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 supraand 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 prestimulus oscillatory power in the somatosensory alpha range exhibited a negative linear 2 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 clusterbased 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.

Unsuccessful reduction of high‐frequency alpha activity during cognitive activation in schizophrenia

“…49 The baseline high-frequency alpha power predicted a tactile misperception of the somatosensory system. 50 In the present study, the high-frequency alpha rhythm represented a sensory blocking or modulation, and the decrease of brain activity was associated with elevated alpha rhythms. A negative correlation between alpha power and glucose metabolic rates has previously been reported in healthy participants.…”

Brain dynamics for confidence-weighted learning

“…Beta-band power in particular is associated with feedback signals (Bastos et al, 2015), stronger attention and top-down control (Buschman and Miller, 2007;Salazar et al, 2012), and the prioritization of the current brain states over new inputs (Spitzer and Haegens, 2017). In support to this view, stronger low frequency (<30 Hz) oscillations attenuate early evoked sensory responses (Iemi et al, 2019), increase the criterion of perceptual detection (resulting in fewer detections) by modulating baseline excitability (Limbach and Corballis, 2016;Benwell et al, 2017;Craddock et al, 2017;Iemi et al, 2017) and degrade performance in perceptual decisions (Haegens et al, 2011).…”

Alpha Activity Reflects the Magnitude of an Individual Bias in Human Perception

“…In line with such a neural underpinning, a series of studies suggested that reduced alpha power correlates with enhanced perceptual sensitivity (Ergenoglu, et al, 2004;Hanslmayr, et al, 2007;van Dijk, Schoffelen, Oostenveld, & Jensen, 2008;Mathewson, Gratton, Fabiani, Beck, & Ro, 2009;Busch, Dubois, & VanRullen, 2009;Obleser & Weisz, 2012). Yet, recent studies suggested a different picture whereby the alpha power does not modulate perceptual sensitivity or accuracy per se but rather reflects a bias in perceptual decision making (Limbach & Corballis, 2016;Iemi, Chaumon, Crouzet, & Busch, 2017;Samaha, Iemi, & Postle, 2017;Craddock, Poliakoff, El-deredy, Klepousniotou, & Lloyd, 2017;Iemi & Busch, 2018;Wöstmann, Waschke, & Obleser, 2018). While the precise role of alpha in a mechanistic cascade of sensory-decision processes remains debated, we here consider alpha oscillations from a new perspective, through the prism of idiosyncratic and temporary biases.…”

“…One neural signature involved in this process supposedly is alpha band activity (van Kerkoerle, et al, 2014;Michalareas, et al, 2016;Sherman, Kanai, Seth, & VanRullen, 2016;Mayer, Schwiedrzik, Wibral, Singer, & Melloni, 2016), generally known to shape the perception of forthcoming stimuli (Ergenoglu, et al, 2004;Hanslmayr, et al, 2007;van Dijk, Schoffelen, Oostenveld, & Jensen, 2008;Mathewson, Gratton, Fabiani, Beck, & Ro, 2009). Recent studies have suggested that pre-stimulus alpha activity may reflect the criterion used to commit a specific response and may hence reflect a perceptual or decisional bias (Limbach & Corballis, 2016;Iemi, Chaumon, Crouzet, & Busch, 2017;Craddock, Poliakoff, El-deredy, Klepousniotou, & Lloyd, 2017;Iemi & Busch, 2018;Rohe, Ehlis, & Noppeney, 2019). Along such a role in perceptual decision making, alpha activity was shown to correlate with subjective awareness (Benwell, et al, 2017;Lange, Oostenveld, & Fries, 2013;Gulbinaite, İlhan, & VanRullen, 2017) and decision confidence (Samaha, Iemi, & Postle, 2017;Wöstmann, Waschke, & Obleser, 2018).…”