Research Paper Outline
The Developing Brain in Different Communities: How Exposure to Musical Training Alters Neural Pathways Increasing Incidence of Absolute Pitch
1. Abstract
• Absolute pitch (AP) is the ability to identify any pitch by name without a reference tone¬ an ability that has puzzled many scientists as the neural networks and perceptual-cognitive mechanisms are not yet fully understood. By contrasting individuals with AP and those without, differences in neural correlates can be detected. Including more groups of musicians with AP, such as those with developmental disorders and congenital defects, aids in the understanding of both genetic and environmental factors. Through absolute pitch tasks and imaging techniques such as functional MRIs, differences in neural networks are exposed. Hyperconnectivity between the superior, medium and inferior temporal gyrus as well as heightened activity in the posterior dorsolateral frontal cortex and leftward hemispheric asymmetry of the surface area of the planum temporal are all physical characteristics displayed by musicians with AP. Based on examinations of many different groups, these physical markers, and their relation to AP, indicate that musical training before a critical point development allow for direct connections due to brain plasticity that develop into an auditory system capable of differentiating stimuli.
2. Introduction
a. What is absolute pitch (AP)?
i. Absolute pitch is the ability to identify any pitch or note by name without any external reference. For those without it, it is difficult to understand but is comparable to seeing a blue car and being able to identify the same shade of paint at the store just from memory.
ii. Absolute pitch is quite rare, it is estimated that one to five in every 10,000 people has absolute pitch. However certain communities tend to have a higher prevalence of absolute pitch than others; those who begin studying music before the age of six, musicians with developmental disorders, and blind musicians have higher reported percentages of absolute pitch.
b. To better understand the attainment of absolute pitch, research methods including functional imaging and cross examination between AP musicians and non-AP musicians are used to understand the underlying connection between the brain, relative pitch, and absolute pitch.
c. While it may just seem like a musical quirk AP can be useful to more than musicians. Studying absolute pitch can help us create a map of perceptual and mnemonic pathways in the brain, that can be applied to other areas of research.
3. Background
a. Breakdown of auditory pathways
i. Focus on brain regions but briefly discuss peripheral structures (outer, middle and inner ear)
ii. Information from the peripheral auditory system is carried to the central auditory nuclei via auditory nerve
b. Discuss differences between absolute and relative pitch
i. Absolute pitch is accurate and immediate recognition of notes
ii. Relative pitch is a stepwise action from a given note (ex. if a c is played the musician can accurately identify an e)
c. Discuss possible neural markers for AP
i. Planum temporal¬, left posterior dorsolateral frontal region, Broca’s area
d. Bring in different groups commonly used in studies;
i. musicians with AP vs those without (and relative pitch)
ii. blind and seeing musicians with AP
iii. patients with Williams syndrome and autism (developmental disorders)
4. Those who have AP and those without it
a. Many musicians with AP began classical music training before the “critical point”
i. 6-7 years old
ii. Drastic decrease in number of musicians with AP who began their training after this age
b. significant percentage of musicians who have AP also have siblings with AP
i. shows that not only the age the musician started training but also genetics could play a role
c. physical characteristics
i. more activity in posterior dorsolateral frontal cortex
1. conditional associative memory required to correctly match notes to note names
ii. Cortical thickness in dorsal premotor, ventral premotor and pars opercularis of the frontal lobe
1. Premotor- anticipate reaction in response to auditory and visual stimuli
2. Pars opercularis- (Brodmann area 44)
a. Possibly related to music perception
b. Also involved in motor aspect of speech
5. Neurological differences in those who are characterized as having absolute pitch and those with relative pitch
a. Those with absolute pitch are sometimes born with it and musicians can learn relative pitch if they are given a note and make steps upwards starting with the given note
b. AP musicians show ability to retain isolated information, ability to narrow attention processing, and superior auditory perception
c. No one single gene that differentiates
d. More posterior dorsolateral frontal cortex activity and left superior temporal succulus
i. demonstrates the importance of the STS in the identification and categorization of sounds
1. more activity in the sts during early encoding
ii. increased reliance on working memory in non-AP subjects
iii. parietal activity may account for pitch judgements and melodic transposition
e. suggests differences in encoding of notes and working-memory separates AP and non-AP musicians.
i. Relative or absolute could be learned based on both cognitive style and age learned(preoperational)
f. Suggests that critical point is 5-7 years with significant reduction after 7 years old
g. Explain mental pathways and processes involved
h. Discuss critical age for development
6. AP in blind vs. seeing musicians
a. How reliance on hearing affects perception of sound
b. Differences in brain activities
c. Blind individuals show leftward asymmetry in planum temporale whereas seeing musicians do not
d. Blind show more use of the parietal and occipital lobe
i. age that they start music is much later than sighted musicians, 8.5 years old rather than before the age of 7
ii. also did not show asymmetry in the Planum temporale
e. increased prevalence of AP in blind musicians
f. congenitally blind musicians and musicians with early loss of vision tend to have higher reported percentages of AP
i. if blind before the critical point (6-7 years old) higher chance that the brain will adapt to lack of vision and acquire AP
ii. become blind after critical point- still have higher percentages of AP, however not as high as those without sight before the critical point
1. brain adapts to loss of vision making auditory perception better than sighted musicians
2. less percentages than those who are congenitally blind show the importance of development during the critical stage- indicate that connections and plasticity play a large role in determining AP
7. How do developmental disorders come into play?
a. AP in patients with Williams syndrome and Autism
i. Can also have a genetic basis-Williams syndrome and autism- also have limited working memory
1. These show not physical but developmental age affects the critical point of attaining AP
b. Developmental disorders such as autism are characterized by Hyperconnectivity in the brain
i. Both AP and autism are characterized by abnormal white matter connectivity within local regions of sensory processing areas
ii. Higher prevalence in Autistic musicians indicates that there could be a correlation between hyperconnectivity in sensory regions
c. Does age determine the critical point or the development of the patient?
i. Autistic patients can start musical training later and still have high percentages of AP
d. Brain functioning in AP musicians with developmental disorders vs. AP musicians without developmental disorders
8. Conclusion
a. What else can be studied
i. Brain mapping
ii. Gender and cultural differences
1. Higher prevalence in Eastern Asians
a. Is this because of cultural differences such as stressed importance on musical training or genetic differences
b. What do we know so far?
i. AP is heavily reliant on the development of the brain before the critical point
ii. genetic factors- supported- but markers not yet found
iii. different neural activity characteristics