Music and the brain

The sensation of music in the human brain

Music and the brain is the science that studies the neural mechanisms that underlie musical behaviours in humans and animals. These behaviours include music listening, performing, composing, reading, writing, and ancillary activities. It also is increasingly concerned with the brain basis for musical aesthetics and musical emotion. Scientists working in this field may have training in cognitive neuroscience, neurology, neuroanatomy, psychology, music theory, computer science, and other allied fields.

Pitch

See also: Pitch (music)

When we hear a certain pitch, a corresponding part of the tonotopically organized basilar membrane in the inner ear responds, and sends the signal to the auditory cortex. Studies suggest that once the signal arrives, there are specific regions for each band of pitch such that the area is organized into sections of cells that are responsive to certain frequencies which range from very low to very high in pitches ^[1]. This organization may not be stable and the specific cells that are responsive to different pitches may change over days or months ^[2].

Rhythm

See also: Rhythm

The belt and parabelt areas of the right hemisphere are involved in processing rhythm. When individuals are preparing to tap out a rhythm of regular intervals (1:2 or 1:3) the left frontal cortex, left parietal cortex, and right cerebellum are all activated. With more difficult rhythms such as a 1:2.5, more areas in the cerebral cortex and cerebellum are involved.^[3]EEG recordings have also shown a relationship between brain electrical activity and rhythm perception. Snyder and Large (2005) performed a study examining rhythm perception in human subjects, finding that activity in the gamma band (20 – 60 Hz) corresponds to the 'beats' in a simple rhythm. Two types of gamma activity were found by Snyder et al: (2005); induced gamma activity, and evoked gamma activity. Evoked gamma activity was found after the onset of each tone in the rhythm; this activity was found to be phase-locked (peaks and troughs were directly related to the exact onset of the tone) and did not appear when a gap (missed beat) was present in the rhythm. Induced gamma activity, which was not found to be phase-locked, was also found to correspond with each beat. However, induced gamma activity did not subside when a gap was present in the rhythm, indicating that induced gamma activity may possibly serve as a sort of internal metronome independent of auditory input.

Tonality

See also: Tonality

The right auditory cortex is primary involved in perceiving pitch, and parts of harmony, melody and rhythm.^[3] One study by Peter Janata found that there are tonally sensitive areas in the medial prefrontal cortex, the cerebellum, the [superior Temporal sulci of both hemispheres and the Superior Temporal gyri (which has a skew towards the right hemisphere)].

Emotion

When unpleasant melodies are played, the posterior cingulate cortex activates, which indicates a sense of conflict or emotional pain.^[3] The right hemisphere has also been found to be correlated with emotion, which can also activate areas in the cingluate in times of emotional pain, specifically social rejection (Eisenberger). This evidence, along with observations, has led many musical theorists, philosophers and neuroscientists to link emotion with tonality. This seems almost obvious because the tones in music seem like a characterization of the tones in human speech, which indicate emotional content. The vowels in the phonemes of a song are elongated for a dramatic effect, and it seems as though musical tones are simply exaggerations of the normal verbal tonality.

Amusia

Main article: Amusia

Studies on those with amusia suggest different processes are involved in speech tonality and musical tonality. Congenital amusics lack the ability to distinguish between pitches and so are for example unmoved by dissonance and playing the wrong key on a piano. They also cannot be taught to remember a melody or to recite a song; however, they are still capable of hearing the intonation of speech, for example, distinguishing between “You speak French” and “You speak French?” when spoken.

Relationship to language

Language processing is a function more of the left side of the brain than the right side, particularly Broca's Area and Wernicke's area, though the roles played by the two sides of the brain in processing different aspects of language are still unclear. Music is also processed by both the left and the right sides of the brain. ^[4][5] Recent evidence further suggest shared processing between language and music at the conceptual level.^[6] It has also been found that, among music conservatory students, the prevalence of absolute pitch is much higher for speakers of tone language, even controlling for ethnic background, showing that language influences how musical tones are perceived. ^[7][8]

Musicians have been shown to have significantly more developed left planum temporales, and have also shown to have a greater word memory (Chan et al.). Chan’s study controlled for age, grade point average and years of education and found that when given a 16 word memory test, the musicians averaged one to two more words above their non musical counterparts.

Development

The musical four year olds have been found to have compared to one greater left hemisphere intrahemispheric coherence.^[9] Musicians have been found to have more developed anterior portions of the corpus callosum in a study by Cowell et al. in 1992 . This was confirmed by a study by Schlaug et al. in 1995 who found that classical musicians between the ages of 21 and 36 have significantly greater anterior corpora callosa than the non-musical control. Schlaug also found that there was a strong correlation of musical exposure before the age of seven, and a great increase in the size of the corpus callosum.^[9] These fibers join together the left and right hemispheres and indicate an increased relaying between both sides of the brain. This suggests the merging between the spatial- emotiono-tonal processing of the right brains and the linguistical processing of the left brain. This large relaying across many different areas of the brain might contribute to music’s ability to aid in memory function.

Memory

Musical training has been shown to aid memory. Altenmuller et al. studied the difference between active and passive musical instruction and found both that over a longer (but not short) period of time, the actively taught students retained much more information than the passively taught students. The actively taught students were also found to have greater cerebral cortex activation. It should also be noted that the passively taught students weren’t wasting their time; they, along with the active group, displayed greater left hemisphere activity, which is typical in trained musicians.^[9]

See also

• Biomusicology
• Cognitive Neuroscience of Music
• Cognitive Musicology
• Music cognition
• Music therapy
• Music psychology
• Systematic musicology
• Absolute pitch
• Neuroesthetics
• Eye movement in music reading

References

1. ^ Arlinger, S.; Elberling, C.; Bak, C.; Kofoed, B.; Lebech, J.; Saermark, K. (1982). "Cortical magnetic fields evoked by frequency glides of a continuous tone". EEG & Clinical Neurophysiology 54 (6): 642–653. doi:10.1016/0013-4694(82)90118-3. 
2. ^ Janata P, Birk J, Van Horn J, Leman M, Tillmann B, Bharucha J. (2002). "The cortical topography of tonal structures underlying Western music". Science 298 (5601): 2167–70. doi:10.1126/science.1076262. PMID 12481131. 
3. ^ ^{a b c} Tramo MJ. (2001). "Biology and music. Music of the hemispheres". Science 291 (5501): 54–6. doi:10.1126/science.10.1126/SCIENCE.1056899. PMID 11192009. 
4. ^ Koelsch, S., Gunter, T., Cramon, D., Zysset, S., Lohmann, G. & Friederici, A. (2002). "Bach Speaks: A Cortical Language-Network Serves the Processing of Music". NeuroImage 17 (2): 956–966. doi:10.1006/nimg.2002.1154. PMID 12377169. 
5. ^ Brown, S., Martinez, M. & Parsons, L. (2006). "Music and language side by side in the brain: a PET study of the generation of melodies and sentences". European Journal of Neuroscience 23 (10): 2791–2803. doi:10.1111/j.1460-9568.2006.04785.x. PMID 16817882. 
6. ^ Daltrozzo, J., Schön, D. (2009). Conceptual processing in music as revealed by N400 effects on words and musical targets. Journal of Cognitive Neuroscience, 21(10): 1882-1892.[1]
7. ^ Deutsch, D., Henthorn, T., Marvin, E., & Xu H-S (2006). "Absolute pitch among American and Chinese conservatory students: Prevalence differences, and evidence for a speech-related critical period". Journal of the Acoustical Society of America 119 (2): 719–722. doi:10.1121/1.2151799. PMID 16521731.  PDF Document
8. ^ Deutsch, D., Dooley, K., Henthorn, T. and Head, B. (2009). "Absolute pitch among students in an American music conservatory: Association with tone language fluency". Journal of the Acoustical Society of America 125 (4): 2398–2403. doi:10.1121/1.3081389. PMID 19354413.  Weblink PDF Document
9. ^ ^{a b c} Strickland JS. (2001). "Music and the Brain in Childhood Development". Childhood Education 78: 100–3. http://findarticles.com/p/articles/mi_qa3614/is_200101/ai_n8950759/. 

External links

• Deutsch, Diana (July 29, 2010). "Speaking in Tones: Music and Language Partner in the Brain". Scientific American Mind. http://www.scientificamerican.com/article.cfm?id=speaking-in-tones-jul10. 
• Weinberger, Norman M. (October 25, 2004). "Music and the Brain". Scientific American. http://www.sciam.com/article.cfm?chanID=sa006&articleID=0007D716-71A1-1179-AF8683414B7F0000. 
• Connection Science (2009). Special Issue "Music, Brain, & Cognition" 21(2-3).