Beta Peak Frequencies at Rest Correlate with Endogenous GABA+/Cr Concentrations in Sensorimotor Cortex Areas

Abstract

Neuronal oscillatory activity in the beta band (15–30 Hz) is a prominent signal within the human sensorimotor cortex. Computational modeling and pharmacological modulation studies suggest an influence of GABAergic interneurons on the generation of beta band oscillations. Accordingly, studies in humans have demonstrated a correlation between GABA concentrations and power of beta band oscillations. It remains unclear, however, if GABA concentrations also influence beta peak frequencies and whether this influence is present in the sensorimotor cortex at rest and without pharmacological modulation. In the present study, we investigated the relation between endogenous GABA concentration (measured by magnetic resonance spectroscopy) and beta oscillations (measured by magnetoencephalography) at rest in humans. GABA concentrations and beta band oscillations were measured for left and right sensorimotor and occipital cortex areas. A significant positive linear correlation between GABA concentration and beta peak frequency was found for the left sensorimotor cortex, whereas no significant correlations were found for the right sensorimotor and the occipital cortex. The results show a novel connection between endogenous GABA concentration and beta peak frequency at rest. This finding supports previous results that demonstrated a connection between oscillatory beta activity and pharmacologically modulated GABA concentration in the sensorimotor cortex. Furthermore, the results demonstrate that for a predominantly right-handed sample, the correlation between beta band oscillations and endogenous GABA concentrations is evident only in the left sensorimotor cortex.

Excitatory-Inhibitory Balance within EEG Microstates and Resting-state fMRI Networks: Assessed via Simultaneous PET-MR-EEG Imaging

“…This is in support of other EEG studies which have shown the involvement of GABAA receptors in the beta oscillations (13-28 Hz) (Porjesz et al, 2002). Furthermore, studies using MRS have also demonstrated an association between GABA concentration and EEG signals in the beta band in the sensorimotor cortex (Baumgarten et al, 2016), auditory gating in schizophrenia (Rowland et al, 2013), and in the working memory load processing capacity in the dorsolateral prefrontal cortex (Yoon, Grandelis and Maddock, 2016). As microstates represent a fragmented low-pass filtered version of the DMN and considering that GABAA receptors mainly mediate synaptic inhibition, our results confirm, from a different perspective, the importance of the inhibitory processes mediated by GABAA receptors in the DMN during rest.…”

Neural Flip-Flops I: Short-Term Memory

“…The spectrum of frequencies has been partitioned into bands according to the behavioral and mental state associated with the frequencies in each band. Within each band the distribution of frequencies is unimodal [12][13][14][15]. The ratios of consecutive EEG band boundaries [16] and the ratios of consecutive EEG band peak frequencies [12][13][14][15] are 2.…”

“…By the octave relationship of the means and intersections of the PDFs in frequencies that are commonly cited as partition points separating the EEG frequency bands and peak frequencies of three of the bands. The regression is based on 57 data points [12][13][14][15][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55]. (Estimates of peak frequencies apparently have not been found for the lower frequency delta and theta bands [49].)…”

Beta oscillations in the sensorimotor cortex correlate with disease and remission in benign epilepsy with centrotemporal spikes

“…We further observed possible relationships between duration seizure‐free and power in the alpha and gamma frequencies. While GABA‐mediated changes would be expected to involve the beta and gamma bands (Whittington, Traub, Kopell, Ermentrout, & Buhl, ), the decrease in power is unlikely to directly reflect changes in GABA activity alone (Baumgarten et al, ; Muthukumaraswamy et al, ) and the underlying mechanisms supporting these observations remain unknown. We did not find a relationship between beta power and the presence of spikes or spike rate in the seizure onset zone.…”

“…Beta power is known to change heterochronically over childhood and thought to reflect normal cortical maturation (Chu, Leahy, Pathmanathan, Kramer, & Cash, 2014). Changes in beta power can also indicate state of consciousness (Engel & Fries, 2010) and can be modulated by GABA levels, which may be aberrant in seizure disorders (Baumgarten et al, 2016;Jensen et al, 2005;Khazipov et al, 2004). How and whether beta power relates to state of consciousness and seizure course has not been previously examined in BECTS.…”