Neural correlates of correct and failed response inhibition in heavy versus light social drinkers: an fMRI study during a go/no-go task by healthy participants.

The ability to suppress responses that are inappropriate, as well as the mechanisms monitoring the accuracy of actions in order to compensate for errors, is central to human behavior. Neural alterations that prevent stopping an inaccurate response, combined with a decreased ability of error monitoring, are considered to be prominent features of alcohol abuse. Moreover, (i) alterations of these processes have been reported in heavy social drinkers (i.e. young healthy individuals who do not yet exhibit a state of alcohol dependence); and (ii) through longitudinal studies, these alterations have been shown to underlie subsequent disinhibition that may lead to future alcohol use disorders. In the present functional magnetic resonance imaging study, using a contextual Go/No-Go task, we investigated whether different neural networks subtended correct inhibitions and monitoring mechanisms of failed inhibitory trials in light versus heavy social drinkers. We show that, although successful inhibition did not lead to significant changes, neural networks involved in error monitoring are different in light versus heavy drinkers. Thus, while light drinkers exhibited activations in their right inferior frontal, right middle cingulate and left superior temporal areas; heavy drinkers exhibited activations in their right cerebellum, left caudate nucleus, left superior occipital region, and left amygdala. These data are functionally interpreted as reflecting a "visually-driven emotional strategy" vs. an "executive-based" neural response to errors in heavy and light drinkers, respectively. Such a difference is interpreted as a key-factor that may subtend the transition from a controlled social heavy consumption to a state of clinical alcohol dependence.

Increased cortical activity in binge drinkers during working memory task: a preliminary assessment through a functional magnetic resonance imaging study.

BACKGROUND: Cerebral dysfunction is a common feature of both chronic alcohol abusers and binge drinkers. Here, we aimed to study whether, at equated behavioral performance levels, binge drinkers exhibited increased neural activity while performing simple cognitive tasks. METHODS: Thirty-two participants (16 binge drinkers and 16 matched controls) were scanned using functional magnetic resonance imaging (fMRI) while performing an n-back working memory task. In the control zero-back (N0) condition, subjects were required to press a button with the right hand when the number "2" was displayed. In the two-back (N2) condition, subjects had to press a button when the displayed number was identical to the number shown two trials before. RESULTS: fMRI analyses revealed higher bilateral activity in the pre-supplementary motor area in binge drinkers than matched controls, even though behavioral performances were similar. Moreover, binge drinkers showed specific positive correlations between the number of alcohol doses consumed per occasion and higher activity in the dorsomedial prefrontal cortex, as well as between the number of drinking occasions per week and higher activity in cerebellum, thalamus and insula while performing the N2 memory task. CONCLUSIONS: Binge alcohol consumption leads to possible compensatory cerebral changes in binge drinkers that facilitate normal behavioral performance. These changes in cerebral responses may be considered as vulnerability factors for developing adult substance use disorders.

BOLD response to deviant face detection informed by P300 event-related potential parameters: a simultaneous ERP-fMRI study.

INTRODUCTION: Faces are multi-dimensional stimuli conveying parallel information about identity and emotion. Although event-related potential (ERP) studies have disclosed a P300 component in oddball responses to both deviant identity and emotional target faces, it is hypothesized that partially different neural processes should subtend emotion vs. identity within the core network of face processing. In the present study, we used simultaneous ERP-fMRI recordings and ERP-informed analysis of functional magnetic resonance imaging (fMRI) data to evidence the specific neural networks underlying P300 generation in response to different deviant emotional vs. identity faces. METHOD: 18 participants were scanned during a visual oddball task in which they had to detect 3 types of deviant faces representing a change in emotion-fear or happiness-or in identity, within a series of frequent neutral ones. Amplitude and latency parameters of the P300 component, recorded for each type of deviant faces, were used to constrain fMRI analyses. RESULTS: Analysis of fMRI data informed by single-trial parameters of the P300 component disclosed specific activation patterns for fearful, happy and identity deviant faces. For fearful faces, P300 amplitudes were associated with BOLD changes in the left fusiform gyrus whereas latencies were linked to left superior orbito-frontal and right fusiform activations. P300 amplitude modulations for happy deviant faces involved the left posterior cingulate gyrus and right parahippocampal regions whereas P300 latencies related to the right insula and left caudate regions. Finally, identity deviant faces were associated with widespread activities involving cortical and subcortical regions when P300 amplitudes were considered, and P300 latencies were associated with activity in right hippocampal/parahippocampal regions. DISCUSSION: Our results suggest the existence of differential cerebral functional processes involved in the responses to deviant face stimuli, depending on the quality of the deviance (fear vs. happiness vs. identity).

Comprehensive functional mapping scheme for non-invasive primary sensorimotor cortex mapping.

We introduce a novel multimodal scheme for primary sensorimotor hand area (SM1ha) mapping integrating multiple functional indicators from functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG). Ten right-handed healthy subjects (19-33 years; 5 females, 5 males) and four patients (24-64 years; 2 females, 2 males) suffering from space-occupying brain lesion close to the central sulcus were studied. Functional indicators of the SM1ha were obtained from block-design fMRI motor protocol, and six MEG protocols: somatosensory evoked fields to electrical median-nerve stimulation, mu-rhythm suppression (~10 and ~20 Hz), corticomuscular coherence, and corticokinematic coherence with and without finger contacts. To assess the spatial spread of the functional indicators, their coordinates were subjected to principal component analysis to produce a centered ellipsoid with axis along principal components. Five to seven functional indicators were obtained for each participant. In all participants, the ellipsoid co-localized with the anatomical SM1ha. In healthy subjects, 50-100% of functional indicators were located within 10 mm from the center of the ellipsoid. In patients, 17-100% of functional indicators were located within 10 mm from the center of the ellipsoid. In conclusion, the multimodal scheme proposed led to a functional mapping of SM1ha that co-localized with anatomical SM1ha in all participants. The spread of the SM1ha functional indicators in some patients with brain lesions highlights the potential benefit of the proposed multimodal approach to assess the reliability of the non-invasive SM1ha mapping.