Final answer:
PET imaging studies focusing on the comparison of different pitches of sound activate Heschl's gyrus in the right hemisphere of the brain, which is located within the auditory cortex of the temporal lobe.
Step-by-step explanation:
PET imaging studies have revealed that comparing different pitches of sound typically activates specific regions of the brain associated with auditory processing. When a sound is heard, hair cells within the ear are stimulated and generate neural impulses that are sent to the auditory nerve and then travel to the brain. The processing of auditory information primarily occurs in the auditory cortex located within the temporal lobe, which is equipped to decode 'what' information of the sounds we hear, such as the pitch. Although the pitch of a sound can be encoded through both the rate of action potentials and the place where these cells are located within the basilar membrane, higher frequency sounds are typically encoded using place cues. Consequently, when comparing different pitches, Heschl's gyrus in the auditory cortex is activated, particularly within the right hemisphere.