Reduced fMRI activation of an occipital area in recently detoxified alcohol-dependent patients in a visual and acoustic stimulation paradigm.

Chronic alcohol consumption is associated with neural damage that manifests in deficits in information processing. Previous studies evaluated higher cognitive functions such as working memory, but basic sensory information processing circuits have never been investigated before. Therefore, we applied a simple visual and acoustic stimulation paradigm in this functional magnetic resonance imaging (fMRI) pilot study. Nine recently detoxified male alcohol-dependent patients and nine healthy volunteers were presented a well-established 6-Hz checkerboard and auditory stimuli in the form of drumbeats in a block-design fMRI paradigm. During visual and acoustic stimulation, alcoholics and controls activated widespread occipital and temporal brain areas, as well as parts of the dorsolateral prefrontal cortex and thalamus. In a comparison of the stimulation-induced activation of alcoholics and controls, the alcoholics showed a significantly lower blood oxygen level dependent (BOLD) signal in an extended bilateral occipital area (P < 0.001) as compared with healthy controls. In no region was the BOLD signal significantly higher in the alcohol-dependent subjects compared with controls. The reason for the new finding of a highly significant lower activation of the occipital cortex is unclear. It is in line with studies of neuropsychological tests in recently detoxified alcohol-dependent patients that also reported deficits in visual abilities. Attention deficits or a persisting neuronal alteration in the first weeks of alcohol abstinence may have contributed to this result.