Assessment of Auditory Attention and Motor Function Using 15o H2o PET

Abstract:
Abstract: The objective of this study was to map areas of cerebral activation in human brain that distinguish motor function and auditory attention. We developed a new procedure for imaging brain regions during auditory attention in which performance is monitored without oral or motor responses. Subjects were instructed to mentally note target syllables occurring amidst nontarget syllables. Attention to targets was confirmed by comparing target and nontarget event-related potentials. 15O H2O PET identified areas of enhanced rCBF in 8 healthy adults. The Listen Attention vs. Listen Only contrast revealed two significant areas of activation (p<.05). One region was centered at right anterior cingulate gyrus (BA 32, 9, 24) and extended to ventral supplementary motor area (SMA) and cortex lining the cingulate sulcus (BA 6, 8). The other was centered in left premotor area (BA 6). Data suggest neuronal priming of premotor cortex under conditions in which no motor response is required. Target monitoring activates anterior cingulate gyrus, evidence for involvement of the anterior attention system. MRI normalization will be used to more precisely identify specific subregions of activation within cingulate gyrus as it borders SMA.