Transcript Hearing: From Molecules to Music

The Neuroscience of Music
Main points
• Music is like language
– Characterized by rhythmic sequential sounds
– Has syntax: “rules” by which a sequence of notes is ordered
– Conveys information
Main points
• Music is unlike language
– Set of sounds is arguably smaller
– Information content and rate is vastly greater in language
– Musicianship is not nearly as prevalent: not everyone is a
musician
• Although only a small number of people are actually “amusic”
– Language is rarely used by groups
• compare People's Mic to a symphony
Main points
• Music is universal e.g.:
– Neolithic flutes produce
similar musical intervals
• Thus music hasn’t changed
much in 35,000 years!
– All moms sing to their
babies
– Very young children can
move with rhythm
What has Cognitive Neuroscience
figured out about music:
– Relationship between language and music?
– Are musician’s brains different?
What has Cognitive Neuroscience
figured out about music:
• Evidence from neuropsychology:
– Aphasia is a speech production and comprehension problem
– Amusia is a music production and comprehension problem
– Aphasia and Amusia are doubly-dissociable
• Aphasics can sing in tune but the lyrics are distorted
• Amusics speak normally (including prosody)
This suggests that music and language are
processed by different brain regions
What has Cognitive Neuroscience
figured out about music:
• Evidence from experimental psychology:
– Non-musicians exhibit “left-ear advantage” for melody and
“right-ear advantage” for speech comprehension
– Musicians exhibit “right-ear advantage” for both melody and
speech
This suggests that music and language are
processed by different brain regions in nonmusicians but overlapping regions in
musicians
Functional imaging of Language and Music
• Evidence from functional Neuroimaging
• Listening to music and listening to speech engage
overlapping brain regions particularly:
•
Auditory cortex
•
dorsal pre-motor cortex (also for production)
Why do you think these would be overlapping?
Functional imaging of Language and Music
• Listening to music and listening to speech engage
overlapping brain regions particularly:
•
Auditory cortex
•
dorsal pre-motor cortex (also for production)
Why do you think these would be overlapping?
…because speech and music are both auditory!
Functional imaging of Language and Music
• Listening to music and listening to speech engage
overlapping brain regions particularly:
•
Auditory cortex
•
dorsal pre-motor cortex (also for production)
• However, one general observation is that music
processes tend to engage more right-hemisphere
structures than left
– Note this is generally the opposite of language processes,
which tend to be strongly left-lateralized
How does musical training affect the brain?
• Skilled musicians are unique in that they
– Start at a young age
– Spend lots of time on practice
– Does this lead to a difference in brain functional anatomy?
Musicians differ from non-musicians
• Ohinishi et al. 2001 compared musicians to nonmusicians in a passive (music) listening task
Non- Musicians
Musicians
Musicians differ from non-musicians
• Ohinishi et al. 2001 compared musicians to nonmusicians in a passive (music) listening task
Musicians - more activity on
the left side
Non-musicians - more
activity on the right side
Musicians – additional
activity in premotor area
near Broca’s
Musicians differ from non-musicians
• To see differences more clearly they subtract one image from
another:
– Differences are in Planum Temporale and Dorsolateral Prefronatal Cortex –
especially on the left side
Musicians differ from non-musicians
• To see differences more clearly they subtract one image from
another:
– Differences are in or near speech production and comprehension regions
Broca’s
area
Wernicke’s Area
Perfect Pitch
• Absolute (or “perfect”) pitch is
the ability to name a pitch
class (a “note”) without any
reference
– Not same as “relative pitch”
•
Very rare
•
More common in:
– East asians (tonal language)
– Early music training
– Autism spectrum disorder and
synesthesia
Perfect Pitch
• Psyche Loui et al. (2010)
– showed that people with perfect pitch have denser white-matter connection
between superior and middle temporal gyri
Compare these tracts
AP1
AP2
Controls
Tone Deafness
• What about people who are really bad at music?
–
Congenital Amusia – difficulty producing and perceiving melody despite mostly normal
speech
Normal connections between
auditory and frontal cortex
Sparse connections between
auditory and frontal cortex in
amusia
Summary: the connection
between speech and music
• In all listeners, music seems to engage the systems
in the right hemisphere that are the counterparts of
language-specific regions in the right hemisphere
Summary: the connection
between speech and music
• In all listeners, music seems to engage the systems
in the right hemisphere that are the counterparts of
language-specific regions in the right hemisphere
• In very broad terms, musical training seems to push
music processes onto language structures
– Left lateralization for musicians
– Left posterior temporal gyrus (in or near Wernicke’s)
– Left lateral frontal cortex (in or near Broca’s)