Verbal fluency tasks as semantic fluency (FS) and phonemic fluency
(FF) are often used in clinical practice. On the basis of neuroimaging studies and
clinical trials, FS and FF are thought to have the different neural bases and different
diagnostic value. FS indicates the efficiency of semantic memory while FF is
related to executive functions. In our study, brain activation associated with the
performance (silent) of two tasks of verbal fluency (semantic fluency: animals, vehicles
and phonemic: letters k and f) was examined. Brain activation was measured
with functional magnetic resonance 3T during a block schema tasks in 35 healthy
individuals. The results show discrete differences in brain activation between FS
and FF. FS involved large activation, especially in the lateral and medial structures
of temporal lobe and inferior frontal gyrus (triangular part), whereas FF involved
activity in the frontal areas, i.e. IFG (opercular part), basal ganglia and cerebellum.
These data are discussed in relation to the clinical practice.
Key words: neural mechanisms, semantic fluency, phonemic fluency, fMRI