EVIDENCE FROM 2 GENETIC SYNDROMES FOR A DISSOCIATION BETWEEN VERBAL AND VISUAL-SPATIAL SHORT-TERM-MEMORY

Williams and Down syndromes, two genetic syndromes of abnormal neurode velopment, are characterized by specific neuropsychological profiles a nd unique patterns of brain morphology. We find that the superior lang uage ability of subjects with Williams syndrome is accompanied by sign ificantly better performance ona verbal short-term memory task. Conver sely, subjects with Down syndrome perform significantly better on a vi sual-spatial short-term memory task. This double dissociation provides neurogenetic evidence for the distinction between short-term storage for verbal and for visual-spatial stimuli.