When the brain changes its mind: Oscillatory dynamics of conflict processing and response switching in a flanker task during alcohol challenge

Abstract

Despite the subjective experience of being in full and deliberate control of our actions, our daily routines rely on a continuous and interactive engagement of sensory evaluation and response preparation streams. They unfold automatically and unconsciously and are seamlessly integrated with cognitive control which is mobilized by stimuli that evoke ambiguity or response conflict. Methods with high spatio-temporal sensitivity are needed to provide insight into the interplay between automatic and controlled processing. This study used anatomically-constrained MEG to examine the underlying neural dynamics in a flanker task that manipulated S-R incongruity at the stimulus (SI) and response levels (RI). Though irrelevant, flankers evoked automatic preparation of motor plans which had to be suppressed and reversed following the target presentation on RI trials. Event-related source power estimates in beta (15–25 Hz) frequency band in the sensorimotor cortex tracked motor preparation and response in real time and revealed switching from the incorrectly-primed to the correctly-responding hemisphere. In contrast, theta oscillations (4–7 Hz) were sensitive to the levels of incongruity as the medial and ventrolateral frontal cortices were especially activated by response conflict. These two areas are key to cognitive control and their integrated contributions to response inhibition and switching were revealed by phase-locked co-oscillations. These processes were pharmacologically manipulated with a moderate alcohol beverage or a placebo administered to healthy social drinkers. Alcohol selectively decreased accuracy to response conflict. It strongly attenuated theta oscillations during decision making and partly re-sculpted relative contributions of the frontal network without affecting the motor switching process subserved by beta band. Our results indicate that motor preparation is initiated automatically even when counterproductive but that it is monitored and regulated by the prefrontal cognitive control processes under conflict. They further confirm that the regulative top-down functions are particularly vulnerable to alcohol intoxication.

Goal-Conflict EEG Theta and Biased Economic Decisions: A Role for a Second Negative Motivation System

“…These are not just different forms of conflict by definition, but also differ in terms of the regions that they have been commonly associated with (right frontal versus frontal midline). Consistent with a previous review of human frontal midline theta from the perspective of rat hippocampal theta (Mitchell et al, 2008), Beaton et al (2018) found that in the flanker task, ventrolateral prefrontal but not frontal midline conflict theta activity, was sensitive to an anxiolytic, alcohol. It therefore appears that there are at least two and possibly more independent conflict mechanisms, and each of these could influence different aspects of anxiety processing.…”

“…For example, in addition to right frontal GCSR, theta band activity, albeit from the frontal midline region, has been consistently observed during response- (Cohen, 2014), and outcome-conflict monitoring (Cavanagh and Frank, 2014). Theta band activity has also been observed in the lateral prefrontal regions in the same response-and outcome-conflict monitoring tasks (Nigbur et al, 2012;Tang et al, 2013;Beaton et al, 2018). However, conflict processing is not limited to theta processes.…”

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

“…Theta band activity is important for cognitive control, especially for response inhibition [20][21][22][23][24], and may reflect task-related response selection and control processes [18,25]. Moreover, earlier studies have already demonstrated theta oscillations to be modulated by alcohol [87,88]. Our results therefore suggest that response inhibition is poorer under an acute influence of alcohol due to decreased cognitive control processes [20].…”

Decreased event-related theta power and phase-synchrony in young binge drinkers during target detection: An anatomically-constrained MEG approach

“…Our results indicate that the oscillatory synchrony within the IFC was dysregulated in BDs and their PLV decrease was associated with alcohol intake (Figure 3). Previous studies reported that alcohol intoxication abolished PLV during a task evoking cognitive control (Beaton et al, 2017;Ehlers et al, 2012).. Altered connectivity in BDs has also been reported during wakeful restingstate as reflected in PLV measured with MEG (Correas et al, 2015). Similarly, resting-state functional connectivity MRI studies in individuals with AUD have found lower connectivity in the executive control (Kim et al, 2017;Müller-Oehring et al, 2015;Weiland et al, 2014) and reward networks (Camchong et al, 2013;Wang et al, 2016).…”

“…Early visual activity was assessed in the occipital region (Occ) while the anterior (aIFC) and posterior inferior frontal cortices (pIFC) and sensorimotor cortices (sMOT) were examined bilaterally as shown in Figure 1. Additionally, co-oscillatory interactions between cortical ROIs were estimated by calculating phase-locking values (PLV) between pairs of frontal ROIs in each hemisphere (Figure 3) (Beaton et al, 2017;Lachaux et al, 1999).…”