Advances in neuroimaging studies of alcohol use disorder (AUD)

The brain activity pattern in alcohol-use disorders under inhibition response Task

BACKGROUND

Inhibitory control impairment in alcohol use disorder (AUD) may indicate detrimental effects of chronic alcohol use on different functional systems in the brain, but the current studies lack consistency. This study aims to identify the most consistent response inhibition-related brain dysfunction based on existing data.

METHODS

We performed systematic searches of the PubMed, Embase, Web of Science, and PsychINFO databases for available studies. Anisotropic effect-size signed differential mapping was used to quantitatively analyze the differences in response inhibition-related brain activation between AUD patients and HCs. Meta regression was used to explore the relationship between brain alterations and clinical variables.

RESULTS

The brain hypoactivation or hyperactivation in AUD patients compared with HCs during the response inhibition tasks was mainly located in the prefrontal cortex including the superior frontal gyrus, inferior frontal gyrus, and middle frontal gyrus, anterior cingulate gyrus (ACC), superior temporal gyrus, occipital gyrus, and somatosensory areas including postcentral gyrus and supramarginal gyrus. The meta-regression revealed that older patients were more likely to present activation in the left superior frontal gyrus when performing the response inhibition tasks.

CONCLUSIONS

The response inhibitive dysfunctions in a distinct prefrontal-cingulate cortices may presumably reflect the core impairment in cognitive control abilities. Dysfunction in the occipital gyrus and somatosensory areas may indicate an abnormal motor-sensory and visual function in AUD. Such functional abnormalities may represent neurophysiological correlates of the executive deficits observed in AUD patients. This study has been registered in PROSPERO (number CRD42022339384).

The differential neural substrates for reward choice under gain-loss contexts and risk in alcohol use disorder: Evidence from a voxel-based meta-analysis

BACKGROUND

Making a risky decision is a complex process that involves the evaluation of both the values of the options and the associated risk level; this process is distinct from reward processing in gain versus loss contexts. Although disrupted reward processing in mesolimbic dopamine circuitry is suggested to underlie pathological incentive processing in patients with alcohol use disorder (AUD), the differential neural processes subserving these motivational tendencies for risk situations or gain/loss choices in decision-making have not been identified.

METHODS

To examine the common or distinct neural mechanisms in the evaluation of risk versus outcomes for AUD, we conducted two separate coordinate-based meta-analyses of functional neuroimaging studies by using Seed-Based d Mapping software to evaluate 13 studies investigating gain and loss processing and 10 studies investigating risky decision-making.

RESULTS

During gain and loss processing, relative to healthy controls, AUD patients showed reduced activation in the mesocortical-limbic circuit, including the orbital prefrontal cortex (OFC), dorsal striatum, insula, hippocampus, cerebellum, cuneus cortex and superior temporal gyrus, but hyperactivation in the inferior temporal gyrus and paracentral lobule (extending to the middle cingulate cortex (MCC) and precuneus). During decision-making under risk, AUD patients exhibited hypoactivity of the prefrontal and cingulate cortices, including the posterior cingulate cortex (extending to the MCC), middle frontal gyrus, medial prefrontal cortex, dorsolateral prefrontal cortex, OFC and anterior cingulate cortex.

CONCLUSIONS

Our results extend existing neurological evidence by showing that a reduced response in the mesocortical-limbic circuit is found in gain versus loss processing, with decreased responsivity in cortical regions in risk decision-making. Our results implicate dissociable neural circuit responses for gain-loss processing and risk decision-making, which contribute to a better understanding of the pathophysiological mechanism underlying nondrug incentive and risk processing in individuals with AUD.