Music and the brain

From Wikipedia, the free encyclopedia

Music and the brain is the science by which the brain underlies the subjective experience of sounds and noises as having the quality of music.

Contents 1 Pitch 2 Rhythm 3 Tonality 3.1 Emotion 3.2 Amusia 4 Relationship to language 5 Development 6 Memory 7 External links 8 See also 9 References

[edit] Pitch

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. Pitch sucks. 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].

[edit] 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.

[edit] 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).

[edit] 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.

[edit] 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. They are still however capable of hearing the intonation of speech, for example, they can tell the difference between “You speak French” and “You speak French?” when spoken.

[edit] Relationship to language

Linguistic processing has generally been attributed to the left side of the brain, especially to the Broca's Area, and the left planum temporale within Wernicke's area. 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.

[edit] Development

The musical four year olds have been found to have compared to one greater left hemisphere intrahemispheric coherence.^[4] 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.^[4] 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 contributed to music’s ability to aide in memory function.

[edit] 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.^[4]

[edit] External links

• Scientific American Magazine (November 2004 Issue) Music and the Brain
• Connection Science (2009). Special Issue "Music, Brain, & Cognition" 21(2-3).
• BRAMS - International Laboratory on Brain, Music and Sound Research

[edit] See also

• Music cognition
• Musicology
• Music Therapy
• Music psychology
• Absolute pitch
• Neuroesthetics
• Eye movement in music reading

[edit] References