Effect of unilateral temporal-lobe excision on perception and imagery of songs

Auditory imagery for songs was studied in two groups of patients with left or right temporal-lobe excision for control of epilepsy, and a group of matched normal control subjects. Two tasks were used. In the perceptual task, subjects saw the text of a familiar song and simultaneously heard it sung. On each trial they judged if the second of two capitalized lyrics was higher or lower in pitch than the first. The imagery task was identical in all respects except that no song was presented, so that subjects had to generate an auditory image of the song. The results indicated that all subjects found the imagery task more difficult than the perceptual task, but patients with right temporal-lobe damage performed significantly worse on both tasks than either patients with left temporal-lobe lesions or normal control subjects. These results support the idea that imagery arises from activation of a neural substrate shared with perceptual mechanisms, and provides evidence for a right temporal- lobe specialization for this type of auditory imaginal processing.

Perceived and Imagined Tempos of Familiar Songs

Two studies investigated the similarity of metronome settings to perceived and imagined familiar songs by subjects unselected for musical ability. In Study 1, mean tempo settings in the two tasks were about 100 beats per minute. Songs with slower perceived tempos tended to be faster in the imagery task and vice versa. In Study 2, subjects set fastest and slowest acceptable tempos for the same set of songs in the imagery mode. These settings were positively correlated with the preferred tempo for the song. Most subjects thought that there were limits on how fast or slow a song could be imagined. These results suggest that tempo is explicitly represented in auditory imagery.