Acute Alcohol Effects on Response Inhibition Depend on Response Automatization, but not on GABA or Glutamate Levels in the ACC and Striatum

Abstract

Alcohol increases GABAergic signaling and decreases glutamatergic signaling in the brain. Variations in these neurotransmitter levels may modulate/predict executive functioning. Matching this, strong impairments of response inhibition are one of the most consistently reported cognitive/behavioral effects of acute alcohol intoxication. However, it has never been investigated whether baseline differences in these neurotransmitters allow to predict how much alcohol intoxication impairs response inhibition, and whether this is reflected in neurophysiological measures of cognitive control. We used MR spectroscopy to assess baseline (i.e., sober) GABA and glutamate levels in the anterior cingulate cortex (ACC) and striatum in n = 30 healthy young males, who were subsequently tested once sober and once intoxicated (1.01 permille). Inhibition was assessed with the sustained attention to response task (SART). This paradigm also allows to examine the effect of different degrees of response automatization, which is a known modulator for response inhibition, but does not seem to be substantially impaired during acute intoxication. As a neurophysiological correlate of response inhibition and control, we quantified EEG-derived theta band power and located its source using beamforming analyses. We found that alcohol-induced response inhibition deficits only occurred in the case of response automatization. This was reflected by decreased theta band activity in the left supplementary motor area (SMA), which may reflect modulations in the encoding of a surprise signal in response to inhibition cues. However, we did not find that differences in baseline (i.e., sober) GABA or glutamate levels significantly modulated differences in the size of alcohol-induced inhibition deficits.

Non-invasive Brain Stimulation for the Treatment of Gilles de la Tourette Syndrome

“…In addition, reactive inhibition tested in a stop-signal reaction time task was normal in GTS, but the brain activation pattern during this task differed from healthy controls ( 83 ). Whereas right pre-SMA activation correlated with successful stopping in healthy controls in keeping with previously reported stop signal task-related activations ( 122 , 123 ) and a general role of the pre-SMA/SMA in inhibitory control ( 124 – 127 ), this was not the case in GTS. Instead, in the activation contrast “successful stopping” vs. “Go,” there was a positive correlation between tic severity and right SMA-proper, but not pre-SMA activation, in GTS ( 83 ).…”

“…Tic frequency, tic intensity and urge sensations were reduced significantly in two patients. However, in a case series study, Behler et al (199) were not able to replicate these promising findings (127). The most recent study on tDCS in GTS included ten subjects examining immediate effect of 20 minutes of cathodal tDCS over the SMA compared to sham intervention (106).…”

On the functional role of striatal and anterior cingulateGABA+ in stimulus‐response binding

“…The study was conducted in accordance with the declaration of Helsinki and approved by the ethics committee of the TU Dresden. Lastly, please note that most of the participants included in this sample were also included in the sample of a previous publication by our group (Bensmann, Zink, Werner, Beste, & Stock, 2020; Stock, Bensmann, Zink, Münchau, & Beste, 2019).…”

“…MRS data acquisition and processing followed the protocol previously described by Bensmann et al (2020): We measured GABA+ concentrations in the striatum and the ACC using 1H‐MR‐spectroscopy. Structural MRI and MRS data were acquired using a 3T Prisma scanner (Siemens Healthineers, Erlangen, Germany) with a 32‐channel (receive only) headcoil.…”

Alcohol intoxication, but not hangover, differentially impairs learning and automatization of complex motor response sequences

“…For each alcohol manipulation group, the experimental procedure and the alcohol administration followed protocols that had already been used in previous studies on alcohol intoxication or alcohol hangover, respectively 12 , 15 , 26 , 92 . An overview of the study protocols is provided in Figs.…”