May 10 – Last lecture Lindsey will hold review session today from 4:00-5:00 McC – 4th flr – Rm 272
Early theories emphasized similarity between language and music: communication - both have organized sounds that convey meaning semantics - both have structural relationships that provide meaning syntax - both have rules that govern how parts are combined (notes; words) can play songs/music in our heads as well as think through language have social and emotional relevance Hypothesis: similar brain areas
Quickly, data on people with head injuries said “no” 1953- Russian composer had stroke - lost ability to speak or understand speech, but could still understand and write music. many examples now Others may lose ability to understand melodies but still be able to understand language Others may be able to understand music and compose new music in head, but not be able to write it down or communicate it.
Inner hair cells of ear cochlea Cochlea auditory nerve Brainstem auditory system thalamus auditory cortex (in temporal lobe)
What areas are important in music perception? • Many – emotional areas; motor areas; auditory processing areas. • Listening to music - auditory cortex and surrounding tissue in temporal lobe • Processing of pitch, melody, timbre occurs in auditory cortex and other nearby areas of temporal cortex. • Same temporal lobe areas are activated when listening to specific music as when imagining hearing the same music. • Some things done better by right side; others more equal.
What areas are important in music perception? • Right side better at identifying what instrument is playing when same notes are played by different instruments (timbre) – • Ex. violin vs horn vs piano • Patients whose right temporal lobe has been removed cannot discriminate timbre.
Effects of experience: • Musicians’ brains become different from non-musicians. • Different brain responses to music - 25% more of auditory cortex is activated than in non-musicians. Also differences in event related potentials (electrical responses of cells)
Effects of experience: • Musicians’ brains become different from non-musicians. • Different brain responses to music - 25% more of auditory cortex is activated than in non-musicians. Also differences in event related potentials. • Musicians have enlarged areas of brain – in areas involved in music processing and playing – 130% larger. • The earlier music training began, the larger the area of brain. • In musicians who play instruments (violin), motor cortex is enlarged for control of fingers and cerebellum is enlarged (motor control and timing). • Likewise for piano players but since hands work together, corpus callossum is also enlarged. • Animal studies show cellular changes when sounds become important.
Neuronal Plasticity in Cortical Neurons Neurons in auditory cortex respond to specific frequencies. How many cells are dedicated to processing a specific frequency depends on its importance. Experience changes the brain’s pitch map by changing the number of cells that respond best to important sounds. After learning that an 8 KHz tone is important, more brain cells respond (are tuned) to 8 KHz.
How does music evoke strong emotion? • Music (no words) can evoke a sense of thrill, joy, sadness/tears, laughter • Research study – music selected that would evoke happiness, sadness, tension/fear. Recorded heart rate, blood pressure, respiration. People showed different pattern of physiological response to different patterns of music. • One woman with bilateral damage to auditory cortex in musical areas lost ability to recognize music from past or understand music as music (two songs sound identical to her) – BUT she still shows emotional reactions to music. Her intelligence, language, and memory are normal. • The emotional processing is subcortical.
Where does music trigger emotion? • Study on brain response to consonant (pleasant) versus dissonant (unpleasant sound). • Pleasant music activated reward centers of midbrain – part of limbic system. • Unpleasant music activated parahippocampal gyrus – a different area of limbic system • In musicians who report true euphoria from music (skin orgasms), reward centers light up just as for food, sex, reinforcing drugs.
Development of Music Perception • appears to be inborn just as language discrimination is • infants easily encode pitch and temporal relationships between notes (describe infant discrimination, preferential looking, and habituation testing procedures) • sensitive to musical scale – an inborn musical scale that sounds are mapped onto • prefer temporal regularity • prefer music that has scale changes in unequal intervals (organized around central tones) • infants also show emotional reactions to music • very young infants prefer consonant to dissonant music • all these characteristics are the same as in adults and appear to be present from birth in most
Music Specific Disorder – Congenital Amusia • Amusia – inability to hear fine-grained differences in pitch – “tone-deaf” • Congenital amusia – a condition present from birth in 4-5% • Inherited disorder – if one identical twin has it, 70-80% of time, the other does too • fine-grained discrimination of pitch is critical to understanding music
Music Specific Disorder – Congenital Amusia • Spoken language also uses some tone differences • In English, pitch important in intonation: raising pitch at end of sentence to indicate a question. People with amusia can discriminate English language pitch use – only gross judgment abilities needed • Half of world’s languages use pitch to indicate meaning – tonal languages – Vietnamese, Thai, Mandarin. Language-based pitch changes still do not require the same degree of discrimination ability as musical pitch. Most amusics can understand language. • Musical pitch differences are 1/6 to 1/12 an octave. Language pitch differences are ½ octave. Most normals can discriminate 1/24 of an octave. • so problem for people with amusia – fine-grained pitch perception and discrimination • area of right temporal cortex (right temporal-frontal cortex) predicted to be the area of dysfunction (based on area in normals that is active during pitch discrimination)
Savants – the real challenge for cognitive behavioral neuroscience At age 14, he played a complicated Tchaikovsky concerto after hearing it once while watching TV. All from Scientific American 2002.
Savant syndrome – an uncommon condition in which a developmentally disabled person has an astonishing ability alongside overall mental impairment (the movie “Rain Man” - 1/2000 mentally retarded or brain damaged persons have savant abilities (1/10 in autism) - most have overall IQs in 40-70 range - More common in males – 4-6 males/1 female - usually music, art, math, spatial skill Prodigious savants – talents are truly remarkable even for highly intelligent person. Only about 50 now known – alive today. - Savant syndrome can also occur after head injury in adults or in adults with dementia– less understood.
Savant syndrome prompts questions about: • General intelligence versus multiple intelligences • Stages of memory processing and circuits • Cortical versus subcortical circuits for processing • Brain plasticity, compensation, and repair