musical notesNeuroscientists in Switzerland researching the neuronal basis of perfect pitch or “absolute pitch” have discovered that this rare gift may be due to a functional link between the brain’s auditory cortex and frontal lobe. According to an article published in the January 7, 2015 edition of The Journal of Neuroscience, most people can distinguish between musical notes only in relation to other notes, while people who have absolute pitch can accurately identify notes without having to rely on any reference tones. This special hearing skill is thought to be a key aspect of extraordinary musical ability, and composers Beethoven, Mozart, and Bach were all said to have had it.

The research team’s current study, led by Lutz Jäncke, PhD, in the music lab of the Department of Neuropsychology at the University of Zurich, involves musicians with absolute pitch. The researchers report that absolute pitch ability occurs in less than 1% of the normal population, and is seen 20% more frequently in professional musicians. Their research provides new information about the underlying neurophysiological and psychological processes that contribute to absolute pitch.

“Our study shows how two brain regions, namely the auditory cortex and the dorsal frontal lobe, work together for absolute pitch,” said Stefan Elmer, PhD, first author of the research article. “In the process, we combine two essentially conflicting explanatory approaches for the phenomenon.”

Two Theories for the Phenomenon of Perfect Pitch

One possible theory for the phenomenon of perfect pitch, the researchers say, is that people with this ability categorize musical notes at an early stage of sound processing. This means that they process tones in the same way they process speech. They assign the sounds to particular categories—a process that is referred to as the categorical perception of tones. This first theory assumes that, for people with absolute pitch, the tones are already processed in the primary and secondary auditory cortex in the brain. 

Based on related research conducted by Elmer on functional coupling of brain regions, the brain regions that control early perception functions (auditory cortex) or late memory functions (dorsal frontal cortex) are interwoven, even when there are no tasks to be performed.

“This coupling enables an especially efficient exchange of information between the auditory cortex and the dorsal frontal cortex in people with absolute pitch, which means that the perception and memory information can be exchanged quickly and efficiently,” Elmer explained.  

A second theory proposed by the researchers is that people with absolute pitch can subconsciously allocate musical notes or tones to memory and process them later. According to this theory, these subconscious allocations primarily take place in the upper frontal lobe, in the dorsal frontal cortex. 

“Both theories make completely different statements regarding the moment and the anatomical location of the special processing and there is evidence to support both theories,” said Jäncke.

Jäncke believes their research results help improve our understanding of perfect pitch or absolute pitch, as well as efficient auditory processing. He says that auditory perception depends on both the integrity of the auditory cortex, and on the linking of that brain region with the brain structures that process memory information. The researchers hope their study leads to the development of training measures that could improve the auditory skills of older adults as well as those with various hearing impairments.

Source: The Journal of Neuroscience, University of Zurich