The amusic brain: in tune, out of key, and unaware

• Published in: Brain (London, England : 1878) Vol. 132; no. 5; pp. 1277 - 1286
• Main Authors: Peretz, Isabelle, Brattico, Elvira, Järvenpää, Miika, Tervaniemi, Mari
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.05.2009; Oxford Publishing Limited (England)
• Subjects: Analysis of Variance; auditory ERPs; Auditory Pathways - physiology; Auditory Perception; Awareness; Biological and medical sciences; Brain Hemisphere Functions; Case-Control Studies; Cerebral circulation. Blood-brain barrier. Choroid plexus. Cerebrospinal fluid. Circumventricular organ. Meninges; Cognitive Processes; congenital amusia; conscious awareness; Control Groups; Electroencephalography; Female; Frontal Lobe - physiology; Functional Laterality; Fundamental and applied biological sciences. Psychology; Genetics; Humans; Intonation; Judgment; Male; Medical sciences; melodies; Middle Aged; Music; Neurological Impairments; Neurological Organization; Neurology; Neuropsychological Tests; Pattern Recognition, Physiological - physiology; Perceptual Disorders - diagnosis; Perceptual Disorders - psychology; pitch perception; Pitch Perception - physiology; Psychophysics; Vertebrates: nervous system and sense organs; auditory ERPs; melodies; pitch perception; conscious awareness; congenital amusia; Nervous system diseases; Congenital; Awareness; Central nervous system; Perception; Encephalon
• ISSN: 0006-8950; 1460-2156; 1460-2156
• DOI: 10.1093/brain/awp055

Like language, music engagement is universal, complex and present early in life. However, ∼4% of the general population experiences a lifelong deficit in music perception that cannot be explained by hearing loss, brain damage, intellectual deficiencies or lack of exposure. This musical disorder, commonly known as tone-deafness and now termed congenital amusia, affects mostly the melodic pitch dimension. Congenital amusia is hereditary and is associated with abnormal grey and white matter in the auditory cortex and the inferior frontal cortex. In order to relate these anatomical anomalies to the behavioural expression of the disorder, we measured the electrical brain activity of amusic subjects and matched controls while they monitored melodies for the presence of pitch anomalies. Contrary to current reports, we show that the amusic brain can track quarter-tone pitch differences, exhibiting an early right-lateralized negative brain response. This suggests near-normal neural processing of musical pitch incongruities in congenital amusia. It is important because it reveals that the amusic brain is equipped with the essential neural circuitry to perceive fine-grained pitch differences. What distinguishes the amusic from the normal brain is the limited awareness of this ability and the lack of responsiveness to the semitone changes that violate musical keys. These findings suggest that, in the amusic brain, the neural pitch representation cannot make contact with musical pitch knowledge along the auditory-frontal neural pathway.