Anterior frontal cortex and the effect of proactive interference in word pair learning--results of Brain-SPECT

Technetium-99m-HMPAO-Brain-SPECT was performed twice in each of 12 right-handed students. The control condition was a standard word pair learning task. In the experimental condition, subjects had to overcome the detrimental effect that older memories exerted on the acquisition of new information (controlling proactive inhibition): they were presented with taxonomically similar words, which could easily be mixed up, and which reappeared in each list, but in different pairings. Results revealed an increase in right anterior frontal flow indices with the experimental condition. These results parallel the observed increase in negative event-related DC potential shifts. UHL et al. [J. cognit. Neurosci. 2, 373, 1990] recorded at frontopolar (Fp3, Fp4) scalp projections, although the extent of modulation was much higher for DC potentials (100%) than it was for SPECT (3%) thus suggesting different sensitivity.