Biology subjects

Harris, G. J.

Publications and source records attributed to Harris, G. J..

5 recordsLinked to original sources

bioRxiv2021

Alcohol cues elicit different abnormalities in brain networks of abstinent men and women with alcohol use disorders

We employed fMRI in 84 men and women with and without a history of alcohol use disorders (ALC and NC, respectively), to explore how gender interacts with alcoholism as reflected in brain activity elicited by alcohol cues. Brain activation was measured in a working memory task (delayed matching-to-sample) with emotional faces as the sample and match cues. During the delay period, intervening distractors were either reward-salient cues (alcoholic beverages) or neutral cues (nonalcoholic beverages or scrambled pictures). ALC women (ALCw) had higher accuracy than ALC men (ALCm). Analyses of scans during the viewing of distractor images revealed significant group-by-gender interactions. Compared to NC men, ALCm evidenced lower activation contrast between reward-salient cues and neutral cues in default mode network regions (including superior prefrontal and precuneus areas), while ALCw had more activation than NC women. Similar interactions were observed for task-regions (including superior parietal, lateral occipital, and prefrontal areas). Region of interest analyses showed that the ALC group had significantly higher levels of activation throughout reward-related circuitry during alcohol distractor interference than during scrambled picture interference. These results suggest that abstinent ALCm and ALCw differ in processing reward-salient cues, which can impact treatment and recovery. HighlightsBrain reward regions activate highly when individuals with a history of alcohol use disorders view alcoholic beverages. The brain regions identified subserve vision, memory, and judgement. Opposite abnormalities in activation patterns appeared for alcoholic men and women.

neuroscience↗

bioRxiv2019

Hippocampal subfield volumes in abstinent men and women with a history of alcoholism

Alcohol use disorder (AUD) has been associated with abnormalities in hippocampal volumes, but these relationships have not been fully explored with respect to sub-regional volumes, nor in association with individual characteristics such as gender differences, age, and memory. The present study examined the impact of those variables in relation to hippocampal subfield volumes in abstinent men and women with a history of AUD. Using Magnetic Resonance Imaging at 3 Tesla, we obtained brain images from 67 participants (31 women) with AUD and 63 healthy control (NC) participants (30 women) without AUD. We used Freesurfer 6.0 to segment the hippocampus into 12 regions. These were imputed into mixed models to examine the relationships of brain volume with AUD group, gender, age, drinking history, and memory. The AUD group had approximately 5% smaller CA1, hippocampal tail, and molecular layer regions than the NC group. Age was negatively associated with volumes for the AUD group in the hippocampal tail, subiculum, and presubiculum. The relationships for delayed and immediate memory with hippocampal tail volume differed for AUD and NC groups: Higher scores were associated with smaller volumes in the AUD group, but larger volumes in the NC group. Length of sobriety was associated with decreasing CA1 volume in women (0.02% per year) and increasing volume size in men (0.03% per year). These findings confirm and extend evidence that AUD, gender, age, and abstinence differentially impact volumes of component parts of the hippocampus. The course of abstinence on CA1 volume differed for men and women, and the differential relationships of subregional volumes to age and memory could indicate a distinction in the impact of AUD on functions of the hippocampal tail.

neuroscience↗

bioRxiv2019

Brain Responsivity to Emotional Faces Differs in Alcoholic Men and Women

Inclusion of women in alcoholism research has shown that gender differences contribute to unique profiles of cognitive, emotional, and neuropsychological dysfunction. We employed functional magnetic resonance imaging (fMRI) of abstinent long-term alcoholics (21 women [ALCw] and 21 men [ALCm]) and demographically-similar nonalcoholic controls (21 women [NCw] and 21 men [NCm]) to explore how gender and alcoholism interact to influence emotional processing and memory. Participants completed a delayed match-to-sample emotional face memory fMRI task. While the results corroborated reports implicating amygdalar, superior temporal, and cerebellar involvement in emotional processing overall, the alcoholic participants showed hypoactivation of the left intraparietal sulcus to encoding the identity of the emotional face stimuli. The nonalcoholic participants demonstrated more reliable gender differences in neural responses to encoding the identity of the emotional faces than did the alcoholic group, and widespread neural responses to these stimuli were more pronounced in the NCw than in the NCm. By comparison, gender differences among ALC participants were either smaller or in the opposite direction (higher brain activation in ALCm than ALCw). Specifically, Group by Gender interaction effects indicated stronger responses to emotional faces by ALCm than ALCw in the left superior frontal gyrus and the right inferior frontal sulcus, while NCw had stronger responses than NCm. However, this pattern was inconsistent throughout the brain, with results suggesting the reverse direction of gender effects in the hippocampus and anterior cingulate cortex. Together, these findings demonstrated that gender plays a significant role in the profile of functional brain abnormalities observed in alcoholism.

neuroscience↗

bioRxiv2018

Alcoholism Gender Differences in Brain Responsivity to Emotional Stimuli

Men and women may use alcohol to regulate their emotions differently, with corresponding differences in neural responses. We examined how photographs of emotional stimuli impacted brain activity obtained through functional magnetic resonance imaging (fMRI) from 42 alcoholic (25 women) and 46 nonalcoholic (24 women) participants. Brain responsivity was blunted in alcoholic compared to nonalcoholic groups. Further analyses indicated significant gender differences in the impact of alcoholism. Brain activation of the alcoholic men (ALCM) was significantly lower than that of the alcoholic women (ALCW) and nonalcoholic men (NCM) in regions including the inferior parietal gyrus, anterior cingulate gyrus, and postcentral gyrus, whereas activation was higher in the ALCW than in the nonalcoholic women (NCW) in superior frontal and supramarginal cortical regions. The reduced brain reactivity of ALCM and increases for ALCW highlighted divergent brain regions and gender effects, suggesting possible differences in the underlying basis for development of alcohol use disorders.

neuroscience↗

bioRxiv2017

Cerebral White Matter Sex Dimorphism in Alcoholism: A Diffusion Tensor Imaging Study

Background: Excessive alcohol consumption is associated with widespread brain damage, including abnormalities in frontal and limbic brain regions. In a prior study of neuronal circuitry connecting the frontal lobes and limbic system structures in abstinent alcoholic men, we demonstrated decreases in white matter fractional anisotropy (FA) on diffusion tensor magnetic resonance imaging (dMRI). In the present study, we examined sex differences in alcoholism-related abnormalities of white matter connectivity. Methods: dMRI scans were acquired from 49 abstinent alcoholic individuals (26 women) and 41 nonalcoholic controls (22 women). Tract-based spatial statistical tools were used to estimate regional FA of white matter tracts and to determine sex differences and their relation to measures of alcoholism history. Results: Sex-related differences in white matter connectivity were observed in association with alcoholism: Compared to nonalcoholic men, alcoholic men had diminished FA in portions of the corpus callosum, the superior longitudinal fasciculi II and III, and the arcuate fasciculus and extreme capsule. In contrast, alcoholic women had higher FA in these regions. Sex differences also were observed for correlations between corpus callosum FA and length of sobriety. Conclusions: Sexual dimorphism in white matter microstructure in abstinent alcoholics may implicate underlying differences in the neurobehavioral liabilities for developing alcohol abuse disorders, or for sequelae following abuse.

neuroscience↗