Parallel interhemispheric processing in aging and alcoholism: relation to corpus callosum size

• Published in: Neuropsychologia Vol. 42; no. 2; pp. 257 - 271
• Main Authors: Schulte, T, Pfefferbaum, A, Sullivan, E.V
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 2004; Elsevier Science
• Subjects: Addictive behaviors; Adult; Adult and adolescent clinical studies; Age; Aging - pathology; Alcohol; Alcoholism; Alcoholism - pathology; Alcoholism - physiopathology; Attention; Biological and medical sciences; Case-Control Studies; Corpus callosum; Corpus Callosum - pathology; Crossed–uncrossed difference; Dominance, Cerebral; Female; Humans; Intelligence; Interhemispheric transfer; Magnetic Resonance Imaging; Male; Medical sciences; Memory; Middle Aged; MRI; Neuropsychological Tests; Photic Stimulation; Psychology. Psychoanalysis. Psychiatry; Psychomotor Performance; Psychopathology. Psychiatry; Reaction Time; Redundant targets effect; Simple reaction time; Visual Perception - physiology; Wechsler Scales; MRI; Alcohol; Simple reaction time; Interhemispheric transfer; Redundant targets effect; Crossed–uncrossed difference; Corpus callosum; Age; Human; Senescence; Redundancy; Alcoholism; Central nervous system; Alcohol: Age; Cognition; Nuclear magnetic resonance imaging; Encephalon; Vision; Reaction time; Crossed-uncrossed difference: Corpus callosum: MRI; Morphometry
• ISSN: 0028-3932; 1873-3514
• DOI: 10.1016/S0028-3932(03)00155-6

We tested parallel processing of visual information using the redundant targets effect (RTE) in 12 alcoholics and 13 matched controls. The paradigm was a simple reaction time (RT) task with targets presented in the same (uncrossed), opposite (crossed), or both (redundant) visual-fields. In older alcoholics (>50 years) the RT gain invoked by redundant targets did not exceed probability measures, suggesting compromised interhemispheric processing of parallel information in this subgroup compared with controls or younger alcoholics. The difference between crossed and uncrossed reaction times (CUD), an index of interhemispheric transfer time (ITT), was greater in older than younger subjects. Moreover, the CUD was negatively correlated with the corpus callosum (CC) total area and body in controls, supporting the concept of a structure-function relationship of interhemispheric transfer. This relationship was not found in alcoholics, although the midsagittal area of the CC, genu, and body but not intracranial volume (ICV), was significantly smaller in alcoholics than controls. These results suggest that chronic alcohol abuse together with advancing age exert subtle disruption on parallel interhemispheric processing reliant on callosal connections.