Gamma and beta neural activity evoked during a sensory gating paradigm: Effects of auditory, somatosensory and cross-modal stimulation

Abstract

Objective.-Stimulus-driven salience is determined involuntarily, and by the physical properties of a stimulus. It has recently been theorized that neural coding of this variable involves oscillatory activity within cortical neuron populations at beta frequencies. This was tested here through experimental manipulation of inter-stimulus interval (ISI).Methods.-Non-invasive neurophysiological measures of event-related gamma (30-50 Hz) and beta (12-20 Hz) activity were estimated from scalp-recorded evoked potentials. Stimuli were presented in a standard "paired-stimulus" sensory gating paradigm, where the S1 (conditioning) stimulus was conceptualized as long-ISI, or "high salience," and the S2 (test) stimulus as short-ISI, or "low salience." Three separate studies were conducted: auditory stimuli only (N=20 participants), somatosensory stimuli only (N=20), and a cross-modal study for which auditory and somatosensory stimuli were mixed (N=40).Results.-Early (20-150 ms) stimulus-evoked beta activity was more sensitive to ISI than temporally-overlapping gamma band activity, and this effect was seen in both auditory and somatosensory studies. In the cross-modal study, beta activity was significantly modulated by the similarity (or dissimilarity) of stimuli separated by a short ISI (0.5 s); a significant cross-modal gating effect was nevertheless detected.Conclusions.-With regard to the early sensory-evoked response recorded from the scalp, the interval between identical stimuli especially modulates beta oscillatory activity.Significance.-This is consistent with developing theories regarding the different roles of temporally-overlapping oscillatory activity within cortical neuron populations at gamma and beta frequencies, particularly the claim that the latter is related to stimulus-driven salience.

EEG source imaging during two Qigong meditations

“…EEG beta frequency activity generally indicates activation-excitation-facilitation (Lopes da Silva 1991) and increases during attention (Wrobel 2000; in particular beta-1: Kisley and Cornwell 2006;Basile et al 2010) as well as with alertness (Makeig and Inlow 1993;Lehmann et al 1995) and during various mental activities, for example, during mental representation of objects (Tallon-Baudry and Bertrand 1999).…”

β‐Band correlates of the fMRI BOLD response

“…If indeed, it is the case that b-band oscillations act as a fundamental localized gating mechanism of cortical activity, then one might expect the characteristic modulations in b-band power, well known in the sensorimotor cortex, to be a more general phenomenon. b-band ERD has previously been observed in auditory cortex in association with speech comprehension and sensory gating [Eulitz and Obleser, 2007;Kisley and Cornwell, 2006] and in the occipital regions [Bauer et al, 2006], where it has been reported alongside an increase in power in the c-band in response to a visual stimulus [Singh et al, 2002]. However, little has been reported on the amplitude of b-band effects and the stimulus dependency of these event-related modulations in power, particularly in the visual areas.…”

Oscillatory decoupling differentiates auditory encoding deficits in children with listening problems

“…Beta oscillations may reflect the sensory gating of temporal sequences as reflected by changes in power when processing repeated stimuli. Low beta generators (12-20 Hz) mediate the strength of sensory gating to stimulus pairs (Hong and Buchanan, 2008), and are sensitive to changes in the inter-stimulus interval between successive stimuli (Kisley and Cornwell, 2006). These beta modulations occur in the same time range ($25-150 ms) as changes in peak amplitudes and latencies of CAEP components to rapidly changing inter-stimulus intervals (Gilley et al, 2005), supporting sensory gating as an underlying mechanism.…”