The Cognitive Neuroscience of Music

As can be seen in Figure 13.2, amusics’performance is at chance in the music test whereas

their scores are fairly high and lie within normal limits for nonmusical material, be they song

lyrics or environmental sounds. The results clearly show the music specificity of the disorder.

In conclusion, congenital amusia appears as a new class of learning disabilities that are

domain specific. Affected individuals appear to be born without the essential wiring ele-

ments for developing a normally functioning system for music, while achieving a high

degree of proficiency in their professional and social life. This impairment seems to result,

at least in some cases, from a more elemental problem that makes the individual unable to

hear the pitch-relevant variations in music. Although it seems unlikely that a single defec-

tive mechanism, such as a pitch defect, is responsible for the proper operation of all pro-

cessing components that subserve musical functions, it may be the case that a single

essential defective component brings the development of the musical system to a halt. In

this perspective,fine-grained pitch perception might be an essential component around

which the musical system develops in a normal brain.^19

The existence of congenital amusia coupled with the music-savant syndrome strongly

suggests the presence of early pressures for the normal development of neural networks

that are dedicated to music. Identification of these neural bases as well as of their associ-

ated heritability should provide crucial elements in the debate surrounding the existence of

biological foundations for musicality.

Brain stimulation

Investigations with epileptic patients provides the third source of evidence that speaks for

the existence of neural networks that are dedicated to music. Indeed, in a few individuals,

198     

Figure 13.2 Number of correct responses obtained by 12 amusics and 20 matched controls in the memory
recognition of studied melodies, lyrics, and environmental sounds. Error bars represent standard error from the
mean. Chance level is at 20 correct responses.

40

35

30

25

20

15

10

5

0

Tunes Lyrics Env sounds

Memory recognition test

Correct responses

Chance level

Congenital amusics

Controls