L4 - Music and the brain Flashcards
role of outer ear
Pinnae and ear canal
amplifies certain frequencies, important for locating sounds
role of middle ear
malleus, incus and stapes
converts airborne vibrations to liquid borne vibrations
role of inner ear
cochlea and semicircular canals (SCC)
important for senses of both hearing (cochlear) and balance (SCC)
converts liquid-borne vibrations to neural impulses.
pure tones
sounds with a sinusoid waveform (when pressure change is plotted against time)
pitch
the perceived property of sounds that enables them to be ordered from low to high
loudness
the perceived intensity of the sound
fundamental frequency
the lowest frequency component of a complex sound that determines the perceived pitch
from ear to brain
outer - middle - inner
4-5 synapses from ear to cortex
- medial geniculate nucleus projects to the primary auditory cortex (also called core)
- core area is surrounded by secondary auditory cortex (including belt and parabelt)
- info ascends nd descends in the pathway
organisation of the auditory nerve and auditory cortex
tonotopic
primary and secondary auditory cortex
- primary located in Heschl’s gyrus in the temporal lobes and is surrounded by adjacent secondary auditory cortex area
- secondary made up of planum polare and planum temporal (belt and parabelt?)
the membrane in the cochlear…
basilar membrane
mechanical properties of the basilar membrane:
the end nearest the oval window is narrow and stiffer - so maximal deflection to high-frequency sounds
the end nearest the spiral shape is wider and more elastic and shows maximal deflection to low-frequency sounds.
neuroanatomy of music
prefrontal cortex: activated when the note is unexpected
motor cortex: important for playing and dancing music
cerebellum: important for balance and dancing and emotional reaction to music
belt and parabelt regions
make up the secondary audiotyr cortical areas
belt region: has many projects from primary auditory cortex
parabelt region: received projections from adjacent belt region
auditory versus visual system (thalamocortical route)
auditory : medial geniculate nucleus projects to primary audtory cortex
visual : lateral geniculate nucleus projects to primary visual cortex
auditory versus visual system: temporal and spatial sensitivity
auditory: temporal > spatial
visual: spatial > temporal
neurons in the core/belt regions
in the core - neurons respond to narrowly defined frequencies
in the belt regions - neurons to a broader range
what do neurons in the auditory cortex respond to:
Respond to:
- frequnecy
- loudness
- spatial locations
the basilar membrane contains:
hair cells linked to receptors
- sound induces mechanical movement of the basilar membrane and hair cells on it
- these movements induce a flow of ions through STRECTH-SENSITIVE ION CHANNELS
musical development
newborn: percieve and remember pitch sequences, percieve a beat, sensitivity to contour, preference for consonance
4-6 years - respond to TONAL more then atonal music
7 years - sensitive to rules of harmony
10 years - understand finer aspects of key structure
12 years - develop tastes and recognition fo sytles
mozart effect
- claims that people perfom better on tests of spatial abilities after listening to music composed by Mozart
- evidence been found for the effect being an artifact of arousal and mood
congenital amusia
- this is a lifelong disease where you cannot tell the difference between two tones (no pitch perception)
- difficulty in eprceiving, making sens of music
- ‘tone-deafness
- associated with R Hemispher abnormalities in white and gray matter desntiy in R auditory cortex and IFG
e.g. Hyde et al 2006 found: reduced white matter in right IFG
Peretz et al 2005: increased grary mater in auditory cortex
amusia
- unaware when music off key
- difficulty dscriminating melodies without lyrics
- disliking of musical sounds and avoidance
- no spatial difficulties
pitch perception problems in amusia (Foxton et al 2004)
- many amuics have problems telling whether melody goes up or down - affects small changes which are often used in music (semitones)
- problems with pitch direction
speech problem (Liu et al 2010)
- most have difficutlies with speech but only with subtle changes
- have problems with contour
pitch is important
- most languages are tonal
intonation (questions?)
speaker identity
pitch memory problems in amusia (Williamson and Stewart, 2010)
tone span (how many tones can you remember) digit span (similar test)
- amusics have issues
anatomical measures supported functionally
Peretz et al 2009:
- ERPs measured in amusic Ps whilst they monitored sequences for pitch changes
- difference seen in P600 component
- amusics can track quarter tone pitch differences, showing an early right-laterized neg brain response N200 (but UNAWARE)
shared syntactic integration resource hypothesis
Patel 2003
- does the brain use the same circuits to process grammar of music and language?
syntactic overlap between music and language
Patel, 1998
The woman paid the baker and TAKE the bread home – P 600
The woman paid the baker and TOOK the zebra home – N 400
- violation in syntax = took not take
- violation in semantic = why is zebra in bakery
found: responses are hgihlighy similar in vicinity of 600ms following incongruity
- overlap at p600 = music and language share same resources for processing grammar
What did Thompson Forde et al 2012 find
- music and language share mechanisms that trigger emotional responses
- common evolutionary link of language and music
the chills effect
musicc can elicit physchological (MOOD) and physiological changes (SHIVERS, GOOSE BUMPS, TINGLING)
music induced emotion - euphoria or the chills effects has been shown to recruit reward motivational circuit: basal forebrain, midbrain, OFC regions and DEACTIVATE amygdala
brain areas associated wtih chills
nucleus accumbens, orbitofrontal cortex and ventral tegmental area
why do we move to the beat?
basal gangia - has an evolutionary modifcation for beat perception
musical expertise
- auditory perception consequence of dynamic processes involving cortical and subcortcial regions
- reflecting bottom-up and top-down processing
effect of musical training
- motor cortex activvated
- auditory cortex activated (even if cannot hear)
- therefore must be an overlap - interacting closely (Baumann et al 2005)
how do musicians differ from non-musicians
- differnces observed in PLANUM TEMPORAL and DORSOLATERAL PREFRONTAL CORTEX (specifically on left)
- left laterisation fo musicians
- left posterior temporal gyrus (near Wernickes)
- left lateral frontal cortex (in or near Brocas)
inter-aural time differnce
differnce in timign between a soudn arriving in each ear (used to localise sounds)
inter-aural itnensity difference
the differnce in loiduness between a sound arriving in each ear (used to localise sound)
head-related transfer function
an internal model of sounds get distorted by the unique shape of one’s own head and ears
