Theta Oscillations Are Sensitive to Both Early and Late Conflict Processing Stages: Effects of Alcohol Intoxication

Abstract

Prior neuroimaging evidence indicates that decision conflict activates medial and lateral prefrontal and parietal cortices. Theoretical accounts of cognitive control highlight anterior cingulate cortex (ACC) as a central node in this network. However, a better understanding of the relative primacy and functional contributions of these areas to decision conflict requires insight into the neural dynamics of successive processing stages including conflict detection, response selection and execution. Moderate alcohol intoxication impairs cognitive control as it interferes with the ability to inhibit dominant, prepotent responses when they are no longer correct. To examine the effects of moderate intoxication on successive processing stages during cognitive control, spatio-temporal changes in total event-related theta power were measured during Stroop-induced conflict. Healthy social drinkers served as their own controls by participating in both alcohol (0.6 g/kg ethanol for men, 0.55 g/kg women) and placebo conditions in a counterbalanced design. Anatomically-constrained magnetoencephalography (aMEG) approach was applied to complex power spectra for theta (4–7 Hz) frequencies. The principal generator of event-related theta power to conflict was estimated to ACC, with contributions from fronto-parietal areas. The ACC was uniquely sensitive to conflict during both early conflict detection, and later response selection and execution stages. Alcohol attenuated theta power to conflict across successive processing stages, suggesting that alcohol-induced deficits in cognitive control may result from theta suppression in the executive network. Slower RTs were associated with attenuated theta power estimated to ACC, indicating that alcohol impairs motor preparation and execution subserved by the ACC. In addition to their relevance for the currently prevailing accounts of cognitive control, our results suggest that alcohol-induced impairment of top-down strategic processing underlies poor self-control and inability to refrain from drinking.

Effects of binge drinking and hangover on response selection sub-processes-a study using EEG and drift diffusion modeling

“…The sLORETA plots show activation differences in anterior cingulate cortex (ACC) between the conditions at which evidence is accumulated to reach a decision about which response to execute. It seems that alcohol decreases the speed at which anterior cingulate networks accumulate the necessary amount of information to decide which response to select Kovacevic et al 2012). However, the N2 is not the only neurophysiological sub-process that shows a similar modulation across conditions as the drift rate (v).…”

Understanding alcohol use disorders with neuroelectrophysiology

“…Alcohol dose had an activating effect on autonomic measures of heart rate and electrodermal activity, and changes in nonlinear measures – omega complexity and synchronization likelihood – indicate increased synchrony in the theta band corresponding to increased working memory effort (Molnar et al, 2009). Moderate alcohol consumption caused spatiotemporal changes to conflict in both early and late processing stages during a Stroop task, and attenuated total event-related theta power, suggesting that alcohol-induced deficits in cognitive control may result from theta suppression in the executive network (Kovacevic et al, 2012). Slower reaction time was associated with attenuated theta power that was attributed to anterior cingulate cortex, indicating an impairment in top-down control of motor preparation and execution.…”

Laminar profile of spontaneous and evoked theta: Rhythmic modulation of cortical processing during word integration

“…EEG and MEG display prominent high delta and low theta activity (3-6Hz) in a variety of tasks requiring extended processing, working memory and executive control (Kovacevic et al, 2012; Hsieh and Ranganath, 2013). Source estimation, confirmed by intracranial recordings, indicate prominent generators in the anterior cingulate (AC) and dorsolateral prefrontal (PF) cortices (Wang et al, 2005; Cavanagh et al, 2012; Kovacevic et al, 2012).…”

“…EEG and MEG display prominent high delta and low theta activity (3-6Hz) in a variety of tasks requiring extended processing, working memory and executive control (Kovacevic et al, 2012; Hsieh and Ranganath, 2013). Source estimation, confirmed by intracranial recordings, indicate prominent generators in the anterior cingulate (AC) and dorsolateral prefrontal (PF) cortices (Wang et al, 2005; Cavanagh et al, 2012; Kovacevic et al, 2012). EEG and MEG theta are also associated with verbal and nonverbal memory retrieval (Klimesch, 1996; Bastiaansen and Hagoort, 2003; Marinkovic et al, 2012), and spatial processing (Snider et al, 2013), corresponding to the correlates of theta in the hippocampus and related structures in rodents (Hasselmo and Stern, 2013).…”