Use of time differences in normal hearing - cortical processing of promontorial stimuli

Although perceived variably by the subjects, the stimulus itself activated bilateral secondary somatosensory cortex, suggesting differential stimulation of multiple sensory modalities. Only TDL raised blood flow in both posterior middle temporal gyri (MTG) and the right prefrontal cortex. As the right posterior MTG is known to be active during duration discrimination of different modalities and in the perception of words containing manipulated phonemes, we conclude that recruitment of this part of the right hemisphere is important to the comprehension of speech containing mostly temporal cues. The study shows that stimulus-induced activation reflects the goal of the task rather than the nature of the stimulus.