Cortical centres underlying auditory temporal processing in humans: A PET study

We have used positron emission tomography (PET) to test a specific hypothes is of a neural system sub-serving auditory temporal processing (acoustical stimulus duration discrimination). Maps of the cerebral blood flow distribu tion during specific stations were obtained from five normally-hearing and otherwise healthy subjects. The auditory stimuli consisted of sounds of var ying duration and of auditorily presented words in which the duration of th e initial phoneme was manipulated. All stimuli alternated with conditions o f silence in a subtraction paradigm. The blood flow distribution was mapped with O-15-labelled water. The results demonstrated that stimuli requiring recognizing. memorizing, or attending to specific target sounds during temp oral processing generally resulted in significant activation of both fronta l lobes and the parietal lobe in the right hemisphere. Based on these resul ts, rye hypothesise that a network consisting of anterior and posterior aud itory attention and short-term memory sites subserves acoustical stimulus d uration perception and analysis (auditory temporal processing).