THE FUNCTIONAL NEUROANATOMY OF SIMPLE AND COMPLEX SEQUENTIAL FINGER MOVEMENTS - A PET STUDY

The brain regions activated by simple repetitive and sequential finger movements of different length were localized by measuring regional ce rebral blood flow (rCBF) with PET The experimental design consisted of finger movements cued by auditory pacing at 0.5 HZ. In all conditions of different sequence length the contralateral primary sensorimotor a nd premotor cortex, supplementary motor area and ipsilateral cerebella r cortex were activated. These areas showed a large increase in activa tion from rest to simple repetitive movement, and a further increase w ith the shortest sequence, suggesting art executive role in running se quences. The ipsilateral premotor area (Brodmann area 6), bilateral po sterior parietal areas (Brodmann area 7) and precuneus showed art incr ease in rCBF related only to the length of the sequences, without any change from rest to simple repetitive movement. These areas are more s electively related to sequence performance. This finding is consistent with the hypothesis that these areas function in the storage of motor sequences in spatial working memory. Our results suggest that sequent ial finger movements recruit discrete sets of brain areas with differe nt functions.