Topic 13: Music Flashcards
What is amusia?
the term amusia refers to a deficit in musical perception that cannot be attributed to a more general auditory dysfunction, intellectual disability, or lack of musical exposure
some people are born with amusia (the congenital form) and some people “develop” it later in life (acquired amusia)
How does the heterogeneity associated with acquired forms of amusia complicate our understanding of the underlying neural mechanisms?
this can be true for various reasons, including…
differences in the areas/extent of damage
comorbidities with other potentially confounding conditions, deficits, etc.
individual differences related to preferences (did you regularly enjoy listening to music before developing amusia), experience (did you ever undergo musical training?), etc.
What is “pitch-based” amusia?
amusia can be evident in difficulty singing in-tune, detecting out-of tune singing, and recognizing melodies in different contexts (e.g. without lyrics)
people with (pitch-based) amusia cannot reliably detect deviations in pitch that are smaller than two semitones (in contrast to matched controls, who can often detect differences that are several magnitudes smaller)
What brain locations are implicated in acquired amusia?
acquired amusia typically results from lesions in/around the right superior temporal gyrus ad insula (among other things, this area is important processes involving integrating inputs across modalities, salience detection, self-awareness, etc.)
the fact that such lesions sometimes only affect either pitch perception or perception of temporally-relevant information (rhythm and meter) suggests dissociable neural mechanisms
What were the results of the Liegeois-Chauvel et al. (1998) study on pitch perception deficits?
examined patients who had undergone surgery for severe epilepsy and found those with…
…left hemisphere resections had deficits more restricted to perception of pitch interval
…right hemisphere resections had impaired contour and pitch interval perception
How do amusia patients demonstrate perception without awareness?
even though amusics can’t detect (consciously notice/report) differences in pitch that are less than two semitones, their brain still responds differently to variations i pitch that are as small as an eighth of a tone
this suggests that early stages of sensory processing are largely intact but something else (maybe later in a hierarchical sequence of processes, i.e. downstream) is causing the deficits observed in this population
What is the imaging evidence for amusia?
amusia patients demonstrate several early-stage ERP components that are that are comparable to matched controls (MMN, N100, ERN), yet their P3b and P600 components (which are both tied to the conscious detection of a deviant tone) are different in patients with amusia (as compared to controls)
the P3b component tends to occur for events that are judged to be improbable (i.e. unexpected), such as a third beep in a series that has a slightly different pitch than the first two, while the P600 is often related to linguistic processing
changes in the BOLD signal (as measured using fMRI) are also sensitive to smaller gradations in tone that what ca be consciously reported, once again implicating a neural response that is (at least somewhat) dissociated from conscious processing
What are the right frontotemporal abnormalities associated with amusia?
various abnormalities observed in the right frontotemporal network of amusia patients have been observed, including:
right inferior frontal gyrus (contains Broca’s area)
right superior temporal gyrus (auditory association cortex)
right arcuate fasciculus (connects the temporal cortex and parts of parietal with frontal)
these abnormalities include difficulties in white matter, gray matter, and connectivity patterns
What is a model to explain the perception without awareness that occurs in amusia?
one model to explain the “perception without awareness” that occurs in amusia hypothesizes that the IFG typically processes (by amplifying and refining) the signals that are sent from the STG to provide top-down mediated contributions to their interpretation
in amusics, this step is thought to break down ad therefore interferes with the processes that would otherwise allow conscious detection of subtle changes in auditory stimuli (e.g. a change in pitch that is less than two semitones)
What are the steps in the reentrant model of visual object perception proposed by Mumford (1991)?
- thalamus acts as the destination for feedback processing and the site of integration of information from multiple higher-level brain regions
- the initial feedforward sweep of signals progresses through regions important for object recognition (e.g., IT cortex)
- multiple abstract representations get activated in other parts of cortex (e.g. related to memory) that correspond to plausible perceptual hypotheses (“maybe that is a dog?”
- feedback is sent to the thalamus, which then compared the abstract representations that get activated to the direct sensory input being received via the retinal image
- the hypothesis with the closest match for the sensory input “wins” and that leads to conscious awareness of what you think you’re seeing
this model views the thalamus as handling “dynamic” representations, whereas cortical regions handle “static” ones
What is developmental dyslexia?
affects the accuracy/fluidity of reading
phonetic representations seem to still be processed in the left STG in a relatively typical way for this population
however, abnormalities in the connectivity between the STG and IFG are thought to prevent conscious access to them
What is congenital prosopagnosia?
is a deficit related to facial recognition
the right fusiform face area (FFA) shows relatively normal responses within this population, yet there is a reductio in white matter connecting the FFA to frontal and temporal regions
What do Royal, Paquette, and Tranchant (2019) suggest that dyslexia, prosopagnosia, and amusia have in common?
a breakdown in the communication pathways between a core sensory area and a higher-order brain region that are required for the conscious detection of subtle perceptual differences
What are some possible treatments for amusia?
as a suggestive (but not directly relevant) reference point, Costanzo et al. (2016) reported the use of tDCS improved reading behavior in a sample with dyslexia
more specifically tied to amusia, Schaal, Pfeifer, Krause, and Pollock (2015) found that transcranial alternating current stimulation (tACS) improved pitch memory in amusics
What is musical anhedonia?
perhaps unsurprisingly given the nature of their deficits, amusics tend not to seek out music for recreational purposes
musical anhedonia refers to a lack of pleasure derived from listening to music
What is the musical anhedonia case study of IR?
case study IR developed acquired amusia after cerebral aneurysms (in the left/right cerebral arteries)
she lost her ability to perceive slight variations in pitch, yet continued to enjoy listening to music and dancing
indicates an apparent dissociation between pitch perception and the potential for reward related to musical experiences
What is the musical anhedonia case study by Hirel et al. (2014)?
the case study developed acquired amusia after a stroke affecting the superior temporal gyrus (STG), primary auditory cortex, as well as parts of the middle temporal gyrus (MTG), amygdala, and insula
he could accurately perceive emotional content in various domains (including music) but was worse than controls at identifying the intensity of emotion within musical pieces
also reported a loss of emotional engagement (and interest) with music
this seem consistent with the hypothesis that musical anhedonia could result from a disconnection between the perception and experience of an emotion
What is the relationship between musical anhedonia and activity in the nucleus accumbens?
individuals with musical anhedonia demonstrate reduced levels of activity in the nucleus accumbens while listening to music
importantly, this is despite the fact that (activity in) this region resembles that of controls during a gambling task
this would seem to imply the reward centre is more or less working typically, yet certain kinds of input that would usually produce feelings of reward i the average person do not do so in this population… could this implicate differences in connectivity?
What areas have decreased functional connectivity in musical anhedonia?
this population also shows decreased functional connectivity between right auditory cortex and the ventral striatum
this is in contrast to participants with above average responses to music, which show enhanced connectivity between those regions
all taken together, the various work done on musical anhedonia implies a role for connections between auditory areas and subcortical structures associated with reward-network-relevant activity in response to musical stimuli
What are binaural beats?
binaural beats are auditory stimuli that present slightly different frequencies to each ear (e.g. 124 Hz to the left ear and 114 Hz to the right ear)
these stimuli can produce an illusion which results in the perception of a tone that is equivalent to the different in frequencies being presented
What are the mechanisms of binaural beats?
the mechanisms that lead to the illusion are not well understood but are thought to originate in subcortical structures (reticular activating system and the inferior colliculus) which are presumed to engage in “phase locking” behavior to represent the sound
this phase locking then spreads to the cortex and has the potential to exert various effects there (e.g. on cognition)
What is phase locking?
a synchronization between the sound wave and pattern of hair cell firing
What are the ways that the effects of binaural beats operate?
more specifically, these stimuli are thought to have the potential to alter neural oscillations (the frequency that neurons are firing at) to match the frequency of the stimuli being represented, i.e. entertainment
e.g. present a 10 Hz (alpha) frequency binaural beat (e.g. 210 in left ear, 200 in right ear, 210 -200 = 10) to increase the umber of neurons “operating” (i.e. firing) at the alpha frequency
What are neural oscillations?
have been hypothesized to play a role in various functions/processes
e.g. beta-band activity may play a role in beat/rhythm perception, memory-relevant processes, and/or general arousal
gamma associated with intentional/controlled (top-down mediated) retrieval of memories
alpha associated with lower arousal and divergent thinking
How do binaural beats affect neural oscillations?
this effect can be observed using EEG
we also know that some studies have reported various cognitive effects that seem to be associated with exposure to binaural beats
however, it is not entirely clear how this works, and whether the hypothesized mechanisms (modulating the frequency that neurons are firing at) is actually the most proximal (i.e. direct) cause of any associated effects (i.e. are the changes in oscillations caused by binaural beats responsible for changes in cognition?)
What are the various lines of evidence that form the hypothesis that dopamine promotes creative thinking?
a positive mood can enhance creativity
people with schizophrenia (which may involve atypically high levels of dopamine in certain parts of the brain) often demonstrate higher than average levels of creativity, as compared to the general population
people sometimes (at least subjectively) feel more creative under the influence of various substances that alter dopamine function
What is convergent thinking?
involves looking for a singular solution to what could be considered a relatively well-defined problem
What is divergent thinking?
represents a style of thinking that allows idea generation, in a context where the selection criteria are relatively vague and more than one solution is correct
What is the frontal dopaminergic pathway?
is thought to support focused attention on a specific target
this may be particularly important for convergent thinking (which the remote associates test is thought to measure)
What is the striatal dopaminergic pathway?
is thought to support mental flexibility, including the ability to switch between different kinds of mental representations
this may be particularly important for divergent thinking (which the unusual uses task is thought to measure)
What is spontaneous eye blink rate (EBR)?
spontaneous eye blink rate (EBR) is related to striatal dopaminergic activity, so measuring this may provide an estimate of the relative level of dopaminergic activity in that pathway at a given point in time
previous work has found that EBR is correlated with performance on divergent thinking tasks
What was the hypothesis of the Reedijk, Bolders, and Hommel (2013) study?
tested the hypothesis that creative thinking can be enhanced by presenting binaural beats
What stimuli were manipulated in the Reedijk, Bolders, and Hommel (2013) study?
they manipulated what stimuli participants were exposed to prior to completing a series of experimental tasks
binaural beats representing the alpha frequency (10 Hz)
binaural beats representing the gamma frequency (40 Hz)
a control condition consisting of a constant 340 Hz tone
What was measured in the Reedijk, Bolders, and Hommel (2013) study?
performance in two creativity tasks:
alternative uses test (thought to primarily measure divergent thinking)
remote associates test (thought to primarily measure convergent thinking)
self-reported mood (using both the positive/negative affect scale and an affect grid)
spontaneous eye-blink rate (to estimate dopaminergic levels in the striatal pathway)
they also controlled for time of testing
What is an example of the alternative uses test?
how many unusual/alternate uses can you think of for a coffee mug
What is an example of the remote associate test?
e.g. pine, crab, sauce
solution = apple
pineapple, crab apple, apple sauce
What were the results of the Reedijk, Bolders, and Hommel (2013) study?
they found that presenting either type of binaural beat tested (alpha and gamma) enhanced performance on divergent thinking (as assessed with the alternate uses test)
no apparent effect on convergent thinking (as assessed with the remote associates test), nor any moderating effect of mood (i.e. changes in self reported mood did not predict changes in performance)
participants with low EBRs (which suggests they have relatively low dopaminergic activity in that pathway) experienced larger benefits for the alpha binaural beats
participants with high EBRs tended to respond differently, either not showing these benefits or, in some cases, actually performing worse
What was the interpretation of the results of the Reedijk, Bolders, and Hommel (2013) study?
the fact that the manipulations affected divergent but not convergent creative thinking speaks to these two aspects of creativity being dissociable (e.g. different underlying processes/mechanisms, etc., like STM and LTM)
the benefits observed suggest binaural beats ca affect cognitive processes, like creativity, and can enhance those processes under certain circumstances
the moderating affect of baseline dopamine levels (i.e. people with low EBRs benefited in ways those those with high EBRs did not) suggest binaural beats are not necessarily a widely generalizable cognitive aid (speaking to the importance of considering individual differences)
all taken together, the method allowed for measurement of not only effects on behavior but also the mechanisms which are potentially supporting these effects
What is the correlational evidence for the effects of musical training?
musical training can enhance auditory-motor network
variation in brain structure associated with this network are sometimes related to performance
What kinds of variables do researchers typically measure to investigate effects of musical training?
differences in grey matter (e.g. neuronal bodies)
differences in white matter (e.g. axons)
differences in connectivity patterns (e.g., resting state, functional, etc.)
What is Heschl’s gyrus?
also known as the transverse temporal gyri
refer to various gyri in/around primary auditory cortex
What is a gyrus?
a ridge or fold between two clefts on the cerebral surface of the brain
What are the structural differences in the auditory region found in musicians compared to non-musicians?
enhancements in various auditory regions are most commonly reported difference in the brains of musicians (as compared to non-musicians), especially Heschl’s gyrus
larger cortical thickness and/or grey matter volume
What variations are changes in Heschl’s gyrus related to?
number of hours spent practicing
EEG and MEG responses to auditory stimuli
performance in various musical tasks (e.g. melody discrimination, rhythm reproduction)
What are the auditory differences in the auditory region found in musicians compared to non-musicians?
although not quite as common as changes to Heschl’s gyrus, various enhancements in motor regions are also frequently reported (e.g. cerebellum, basal ganglia)
the motor cortex is larger in trained musicians
this difference in more pronounced in those who began training at a younger age
Why are differences in the corpus callosum of musicians frequently reported?
could relate to the fact that music draws on various processes that can sometimes be lateralized in either hemisphere
the earlier training starts, the more apparent these differences are
variation in the corpus callosum is also related to hour spent practicing
What are the structural differences in white matter found in musicians compared to non-musicians?
musicians also have greater white-matter integrity (measured using DTI) in the arcuate fasciculus, a pathway connecting frontal, parietal, and auditory-relevant regions
among other things, the AF connects Broca and Wernicke’s areas, which may help explain it’s importance for producing/understanding language
What are the structural differences in grey matter and cortical thickness found in musicians compared to non-musicians?
larger grey matter volume in various parietal regions involved in sensorimotor transformations/planning relevant for playing instruments
both grey matter volume and cortical thickness (in various parts of the brain) have been found to be predictive of performance in a melody discrimination test
What were the methods of the Hyde et al. (2009) study on developmental impacts of music?
longitudinal studies can allow the investigation of causal relationships
randomly assigned two groups of 5 to 8 year olds to either a piano lesson condition or a control condition and collected various kinds of data over a 15 month period
What were the results of the Hyde et al. (2009) study on developmental impacts of music?
no differences at baseline
those in piano lessons showed grey matter enhancements in auditory and motor cortex and enlargement of the corpus callosum
volume of auditory cortex –> predicted melody/rhythm test performance
volume of motor cortex –> predicted performance in a test of fine-motor skills
What were the methods of the Habibi et al. (2017) study on developmental impacts of music?
randomly assigned participants ranging from 6 to 8 ears to a musical training program
What were the results of the Habibi et al. (2017) study on developmental impacts of music?
greater white-matter integrity in the corpus callosum after two years
reduced cortical thinning in right (compared to left) posterior auditory cortex
changes occurred in similar regions of auditory-motor network that have been found to differ in correlational studies with adults that have undergone musical training
Why are the interactions between development and training a methodological/interpretative challenge?
we have lots of evidence for experience-dependent plasticity in various domains
we also know that children who begin musical training at a younger age show more pronounced effects, such as larger increases in the volume of motor cortex and the surface area of the corpus callosum
but age of onset of training is typically confounded with years of practice (i.e. the earlier you start, the more practice you tend to have had)
How did the Steele et al. (2013) study match several potentially confounding variables?
years of musical experience
years of formal training
hours of current practice
various cognitive measures (auditory working memory, non-verbal IQ)
measured performance on musical skills (rhythm reproduction, melody discrimination)
What were the results of the Steele et al. (2013) study on the interactions between development and musical training?
larger increases in the volume of the premotor cortex (which is related to performance in a rhythm reproduction task)
enhanced white-mater integrity in the corpus callosum
better performance in a rhythm reproduction task
What is the explanation for the contradiction in cerebellum changes in the brains of musicians?
the contradiction in the direction of change in the cerebellum found for early trained musicians may relate to how the organization of the cerebellum develops
peak growth in the cerebellum occurs much later in most parts of the cortex
this suggests effects of training on the cerebellum may be rather different than the same on the cortex
What is the evidence for near-transfer effects in musical training?
better pitch perception/production correlated with better performance on phonemic awareness tests
this relationship held even after controlling for various potentially mediating factors (e.g. intelligence)
What were the methods of the Habibi (2016) study on transfer effects?
randomly assigned children to one of three groups:
a musical training condition
a sports training condition
a passive control condition
What were the results of the Habibi (2016) study on transfer effects?
the children in the musical training group showed enhanced abilities to detect subtle auditory changes (behaviorally)
this was also reflected in changes to their ERPs (reduced P1 amplitude and latency while passively listening to piano tones)
note that is isn’t necessarily clear whether this change is related simply to enhanced auditory processing, attentional control, both, something else, etc. (which could have implications for whether you consider this to be near transfer, far transfer, etc.)
