Brain atrophy in long-term abstinent alcoholics who demonstrate impairment on a simulated gambling task

Abstract

We recently demonstrated impairment on the Simulated Gambling Task (SGT) in long-term abstinent alcoholics (AbsAlc). Brain regions that have been shown to be necessary for intact SGT performance are the ventromedial prefrontal cortex (VMPFC) and the amygdala; patients with VMPFC or amygdalar damage demonstrate SGT impairments similar to those of substance abusing populations. We examined these brain regions, using T1-weighted MRIs, in the 101 participants from our previous study using voxel-based morphometry (VBM). VBM was performed using a modification we developed (Fein et al., 2006) of Baron's procedure, (Baron et al., 2001), in which we use skullstripped images as input. We also restricted the analysis to a ROI consisting of the amygdala and VMPFC as defined by the Talairach Daemon resource. Compared to the controls, the AbsAlc participants had significant foci of reduced gray matter density within the amygdala. Thus, SGT decision-making deficits are associated with reduced gray matter in the amygdala, a brain region previously implicated in similar decision-making impairments in neurological samples. This structurally based abnormality may be the result of long-term alcohol abuse or dependence, or it may reflect a pre-existing factor that predisposes one to severe alcoholism. From an image analysis perspective, this work demonstrates the increased sensitivity that results from using skull-stripped inputs and from restricting the analysis to a ROI. Without both of these methodological advances, no statistically significant finding would have been forthcoming from this work.

Shared Genetic Factors Influence Amygdala Volumes and Risk for Alcoholism

“…Others have demonstrated that amygdala decrements are not related to the duration of abstinence (Durazzo et al, 2011;Fein et al, 2006;Makris et al, 2008;Wrase et al, 2008). One interpretation of this finding is that amygdala volumes are permanently damaged by alcohol-related neurotoxicity, and do not normalize with extended sobriety.…”

“…For instance, a crosssectional voxel-based morphometry investigation showed smaller amygdala volumes among alcoholics who had been abstinent for an average of 7 years, and no relationship between amygdala volume and abstinence duration (Fein et al, 2006), pointing either to pre-existing abnormalities or to lack of normalization with extended sobriety. Later work confirmed this finding, reporting that reduced left amygdala volumes in alcoholism were unrelated to duration of sobriety, and that this reduction was primarily restricted to the basolateral amygdala, a region that has a central role in incentive salience , possibly reflecting pre-existing reward pathway decrements.…”

Smaller feedback ERN amplitudes during the BART are associated with a greater family history density of alcohol problems in treatment-naïve alcoholics

“…prefrontal cortex), impairments in decision-making and electrophysiological error responding may be caused by common anatomical deficiencies involved in alcoholism. From the other perspective, our recent work in long-term abstinent alcoholics suggests that reduced amygdala volumes are associated with decision-making impairments that persist into long-term abstinence (Fein et al, 2006). Bechara has shown that individuals with amygdala lesions show impaired decisionmaking, hypothesizing that such individuals fail to attach appropriate negative emotional valence to the negative consequences of behavior (Bechara et al, 1999).…”

Longitudinal Mapping of Gyral and Sulcal Patterns of Cortical Thickness and Brain Volume Regain during Early Alcohol Abstinence

“…However, most cross-sectional and longitudinal brain volume studies obtained baseline measurements several weeks after cessation of drinking [7,[12][13][14][15] . Obviously, those studies may miss the early short-term recovery effect and may underestimate the extent of brain impairment and the potential magnitude of recovery.…”