The rare ability to identify musical tones without any external reference – a condition known as perfect or absolute pitch (AP) – arises from an enlargement in the brain region known as the auditory cortex, a study indicates.
Thought to occur in as few as one in 10,000 people, AP has an almost mythic reputation. It was present in some of history’s greatest composers, including Mozart, Bach and Beethoven.
Writing in the journal JNeurosci, researchers led by Larissa McKetton from York University in Toronto, Canada, point out that being able to identify and reproduce individual or collections of notes on the fly is not simply a matter of acute hearing. AP also rests on the ability to spontaneously classify and order what is heard.
The condition is uncommon, even among musicians, and it is abundantly clear that having it is not a necessary prerequisite for musical achievement.
Even for musicians who do possess AP, previous research has demonstrated that a degree of training early in life is essential for it fully develop.
There are no known cases of musicians developing AP in adulthood. Thus, there is an ongoing debate about whether perfect pitch arises from genetics or can be learned.
To further explore the question, McKetton, with colleagues Kevin DeSimone and Keith Schneider, gathered together 61 volunteers, comprising musicians with AP, similarly accomplished musicians without it, and control subjects with no musical training at all.
Each participant underwent functional magnetic resonance imaging (fMRI) while listening to a range of notes and tones.
Those with AP were found to have two significantly larger structures inside an area of the auditory cortex known as Heschl’s Gyrus. These structures produced increased responses to low-frequency and broadly tuned sounds. There was no difference in cortex architecture between the musos without AP and the control subjects.
The researchers suggest that other areas of the brain may also be implicated in the full expression of AP, including those involved with the perception of volume. The results, they say, strongly suggest that perfect pitch is strongly dependent on genetics.