Visual Alcohol Cue-Reactivity and Cognitive Control in Non-Dependent Heavy Alcohol Drinkers Assessed by Simultaneous fNIRS-EEG.

OBJECTIVE: Addictive behavior is characterized by fast automatic responses to drug-related cues (termed cue reactivity) and deficient cognitive control. The ability to detect errors is a prerequisite for an adaptive increase of cognitive control to prevent further errors. In the current study, cue-reactivity effects on cognitive control were assessed via hemodynamic activity within the dorsolateral prefrontal cortex (dlPFC) using functional near-infrared spectroscopy (fNIRS) and simultaneous electroencephalography (EEG), assessing error monitoring (error-related negativity/error negativity, ERN/Ne) and error adaption in subsequent trials (N2). Nondependent social drinkers were the focus in this multimodal approach. METHOD: Effects of alcohol consumption patterns and the personality trait of impulsivity were assessed in n = 55 social drinkers. Hemodynamic activity within the dlPFC (cognitive control), error monitoring (ERN/Ne), post-error conflict monitoring (N2), error rates, and post-error slowing (PES) were measured during a modified Eriksen flanker task cued by beverage pictures. RESULTS: ERN/Ne amplitudes were reduced during alcohol-cued trials. Post-error adaption was reflected in increased dlPFC activity after errors, whereas N2 amplitudes were reduced. There was a correlation of impulsivity and alcohol-cued ERN/Ne amplitude that was mediated by alcohol consumption pattern. CONCLUSIONS: Impulsivity-related decreases in error monitoring during cue reactivity were mediated by alcohol consumption pattern. However, cognitive control was not affected by cue reactivity, suggesting more complex interactions than previously assumed.

Neural correlates of mindful emotion regulation in high and low ruminators.

Depressive rumination is considered a prominent risk factor for the occurrence, severity, and duration of depressive episodes. A variety of treatment options have been developed to treat depressive rumination of which mindfulness based programs are especially promising. In the current study, we investigated the neural underpinnings of a short mindfulness intervention and mindful emotion regulation in high and low trait ruminators in an ecologically valid environment using functional near-infrared spectroscopy (fNIRS). Participants were randomly assigned to a mindfulness instruction (MT) group or an instructed thinking (IT) group. Participants in the MT group were trained to either focus their attention mindfully on their breath or their emotions, while the IT group focused their attention on the past or future. Afterwards, all participants underwent an emotion regulation paradigm in which they either watched negative or neutral movie clips. During both paradigms cortical hemodynamic changes were assessed by means of fNIRS. Participants in the MT group showed lower activity in the cognitive control network (CCN) during the focus on breath condition in comparison to the focus on emotion condition. Additionally, oxygenated hemoglobin in the MT group tended to be lower than in the IT group. Further, self-reports of emotional distress during the instruction paradigm were reduced in the MT group. During the emotion regulation paradigm, we observed reduced emotional reactivity in terms of emotional distress and avoidance in the MT group in comparison to the IT group. Furthermore, on a neural level, we observed higher CCN activity in the MT group in comparison to the IT group. We did not find any effect of rumination, neither on the intervention nor on the emotion regulation task. The results of this pilot study are discussed in light of the present literature on the neural correlates of mindfulness based interventions in rumination and emphasize the use of fNIRS to track neural changes in situ over the course of therapy.

Cue Reactivity Essentials: Event-Related Potentials During Identification of Visual Alcoholic Stimuli in Social Drinkers.

OBJECTIVE: Cue reactivity is an automatic reaction to alcohol-related cues, contributing to the maintenance of drinking behavior and relapse in alcohol dependency. The identification of valid cue-reactivity features is a prerequisite for its clinical application. We were interested in the effects of visual features of alcohol cues (e.g., color) on cue reactivity. Assuming its development at a pre-pathological stage, we analyzed cue reactivity in heavy social drinkers, with light social drinkers as controls. We investigated whether cue reactivity was independent of visual features at an attentional (P100) and a motivational level (late positive potential, LPP). METHOD: Event-related potentials (ERPs; P100, LPP) were analyzed during a visual beverage classification task in heavy social drinkers and light social drinkers (N = 34 university students). Photographs of beverages were classified as alcoholic or nonalcoholic. Two additional stimulus sets depicted unrecognizable scrambled visual information and recognizable black silhouettes of the original beverages. Analysis of contrast waves inferred content (unrecognized scrambled trials subtracted from original) and color information (recognized shape trials subtracted from original) during visual processing. Linear regression was used to predict Alcohol Use Disorders Identification Test (AUDIT) scores from ERPs. RESULTS: In heavy social drinkers, alcoholic-content LPP was increased and P100 latency was shorter compared with nonalcoholic cues. Linear regression for alcohol content condition in the overall sample revealed shorter P100 latency and increased LPP amplitude predicting AUDIT scores. None of those effects were significant in the visual-feature control condition. CONCLUSIONS: Alcohol cue reactivity in heavy social drinkers was related to faster early attentional processes and motivational salience. The effect occurred independently of visual features in the pictures.

Prefrontal functional connectivity measured with near-infrared spectroscopy during smoking cue exposure.

Cue reactivity (CR) is an important concept for relapse in substance use disorders (SUD). Although cue exposure (CE) therapy is discussed as relapse prevention, current approaches still need improvement considering its efficacy. From a neurobiological perspective, CR is related to an over-activation in sensitized subcortical structures, their projections to motivationally relevant cortical structures (e.g. orbitofrontal cortex, OFC) and deficient prefrontal inhibitory control. Therefore, we analyzed prefrontal cortical activation and its relation to craving during smoking CE. We focused on the OFC-as a projection area of sensitized subcortical structures-due its importance in the processing of reinforcement value and the dorsolateral prefrontal cortex (dlPFC) based on its importance for behavioral inhibition. Functional near-infrared spectroscopy (fNIRS) was used to assess hemodynamics in prefrontal regions during smoking CE in 24 subjects (n = 12 occasional smokers, n = 12 controls). Subjective craving intensity (minimum craving as marker of baseline inhibition, range as marker of inhibition time course) was additionally assessed. Craving ratings indicated that CR was elicited solely in smokers, not controls. Those subjective ratings correlated with hemodynamic activity in OFC (craving range) and dlPFC (minimum craving). OFC activation was found earlier throughout the CE in smokers compared to controls. Connectivity (seed-based correlation) between OFC and dlPFC was increased in smokers. fNIRS can capture prefrontal hemodynamic activity involved in CR elicited during CE and is therefore a promising method to investigate CR and its implications for relapse prevention in SUD.

State-dependent altered connectivity in late-life depression: a functional near-infrared spectroscopy study.

There is a large body of evidence showing a substantial relationship between depression and deficits in cognitive functioning. Especially in late-life depression, cognitive impairments are associated with worse treatment progress and are considered a risk factor for neurodegenerative disorders. However, little is known about the differences in neural processing and coupling during rest and cognitive functions in patients with late-life depression compared to healthy elderly individuals. The study at hand aims to investigate the cognitive control network in late-life depression during a cognitive task and at rest by means of functional near-infrared spectroscopy. Hemodynamic responses were measured at rest and during the Trail Making Test using functional near-infrared spectroscopy in a matched sample of 49 depressed and 51 nondepressed elderly subjects (age range: 51-83 years; 64.1 ± 6.58 [mean ± standard deviation]). Functional connectivity (FC) and network metrics were derived from the data and analyzed with respect to differences between the subject groups. Depressed and nondepressed subjects showed significant differences in FC both at rest and during task performance. Depressed subjects showed reduced FC in a left frontopolar cortical network during task performance and increased FC in a left frontoparietal cortical network at rest. Depressed elderly subjects showed altered FC and network organization during different mental states. Higher FC at rest may be an indicator of self-referential processes such as rumination that may reduce FC during task performance due to an overtaxed executive control system.