[CS] Bharucha Lecture Notes

[Jaime Davila]

Elton Joe wrote:
> Here are my notes from the Bharucha lecture, in case anyone wants
> them.  It's paraphrases mixed in with my own questions and comments.
> 
> My main question is one of basic neuroscience:  What happens,
> biologically, when part of the brain "lights up," and what is going on
> (or not going on, in comparison) in the rest of the brain?

It's measuring blood flow. The more blood that is flowing into an area, 
the more that area lights up. All of the brain areas have blood flow, 
but the flow increases in some of them.

> 
> 
> elton
> 
> MUSIC, BRAIN, AND CULTURE
> Jamshed Bharucha
> 
> Former editor, journal "Music Perception"
> 
> It has often been said that culture and brain biology are two separate domains.
> 
> However, we "carry our culture in our brains".
> 
> We have only begun to talk about culture through cognitive science,
> but it will be the norm in 10 years.
> 
> Slide of MRI brain scans with "activity" marked.
> "Activity" is "greater than chance".
> So what is activity, and what is chance?  What is going on in the
> areas of the brain not marked, and why is "less" going on there?
> 
> Neuroscientists strive for more accuracy in measurement (voxel-size
> and temporally).  What would greater accuracy show?
> 
Right now, when you see one of those color spot in an MRI image, the 
increases blood flow might be in one piece of that box but not in 
others. Or it might be in the whole box. The system doesn't have enough 
precision to distinguish. More accurate machinery would allow for a more 
detailed image. Would that help? Maybe. It sure wouldn't hurt.

> Auditory cortex is marked by greater activity during the listening of
> music.  (Machine noise is filtered out statistically - it does
> activate the auditory cortex as well.)
> 
> These particular scans show activity localized to the left hemisphere
> side of the auditory cortex.  The norm is on both sides.
> 
> Study:
> 
> Participants listened to a particular melody in all 24 major and minor keys.
> 
> The music you normally hear within a culture is highly constrained in
> terms of transitions from one key to the next.
> 
> Transitions - C maj -> G maj is more frequent than C maj -> F# maj
> 
> Found that uneducated listeners were still able to distinguish key transitions.
> 

You mean musically untrained, right?

> Which part of the brain is correlated with usual/unusual key change?
> 
> Hypothesized that the auditory cortex would be involved, since it
> lights up during music listening.
> 
> Frontal cortex lit up instead, which indicates that there may be
> cultural factors involved.
> 
> Idea:  brain internalizes culture automatically by being embedded in it.
> 
> Study:
> 
> Group of college students with little experience with Indian culture.
> Group of college students who grew up in India and had exposure to
> Hindi and Indian music.  (bilingual and bicultural musically)
> 
> Western and Indian classical music
> Western and Indian pop music
> English and Hindi speech
> 
> Participants listened while in an MRI machine, but were not asked to
> attend to a particular task (this would be used in an ideal
> experiment).
> 
> What about singing during the music?  Wouldn't this activate music and
> speech at the same time (assuming the brain processes them
> differently)?  Is singing music or speech?

You start singing, a bunch of other stuff has to come into action. 
Including those areas of the body that deal with facial movements.

In terms of experiments that look into this, I think that would be 
enough movement to keep the MRI machine from getting a decent image.

> 
> Brain vector - a set of numbers that indicate the level of activity in
> each of the areas measured.
> 
> Brain vectors were paired up to calculate the similarities between participants.
> 
> Multi-dimensional scaling (statistical analysis) was used to place
> participants in an abstract mathematical space.
> 
> Brains which were similar were close together, and brains which were
> dissimilar were far apart.
> 
> "Cultural space maps on to brain space"
> 
> Classical music (Western/Indian) shows distinct separation between the
> two groups
> 
> Used vocal music to keep the voice aspect constant, but Western
> classical music was in non-English languages (Italian, German, etc.)
> and Indian classical music was in non-Hindi languages (such as
> Sanskrit).
> 
> How was classical music defined?  Similar to the problem of defining
> speciation, how does one distinguish between variation within a
> particular style vs. variation between styles?
> 
> NEURAL NETWORKS
> How might the brain predict pitches according to cultural bias? 
> (simulation project)
> 
> Layers of neurons with connections between layers.  Connections have
> particular strengths.
> 
> If a particular sine wave is played, particular neurons light up.  In
> other words, particular parts of the auditory cortex are tuned to
> particular frequencies.  (First layer neurons are innately tuned)
> 
> Second layers correspond to some sort of cultural conditioning.  The
> neuron in the second layer that lights up the most due to a set of
> stimuli from the first layer is the "winner" - it corresponds to this
> particular stimulus the most and gets stronger.  (Uh oh, grandfather
> cell - what happens when you need to represent different things with
> the same neurons?  Can one neuron do more than one thing?  What
> "measures" the whole process?)
> 
> Hebian learning - essentially the neural network connection strength theory
> 
> Strengths of the connections (synapses) can be plotted on
> multidimensional graphs.
> 
> Theory applied to cultural bias building:
> When a new stimulus is presented, the vector that it is closest to is
> reinforced or tuned to the cultural environment.
> 
> "Self-organizing models" - Bharucha says this is how the brain MUST
> and WILL learn cultural bias.
> 
> Indian scales - they sound foreign to the Western ear.
> There are scales (such as Lydian) that fell out of usage by Western music.
> (although they have been picked up by jazz)
> 
> FLATTED SECOND
> The flatted second is common in Indian scales, but not in Western
> scales.  Therefore, the Indian brain would infer that the flatted
> second was present if all of the other scale tones were played.  The
> Greek modes have some flatted seconds.
> 
> The brain fills in musically from fragments in order to make a
> complete scale it can recognize.
> 
> You can move through your environment more easily if you can make
> predictions about what to expect culturally.  This is similar to
> prototype theories of aesthetics, and in general the idea of schemata.
> 
> MOZART EFFECT
> Theory was that Mozart contains certain intervals that make you smart.
> 
> However, when only one voice was changed by half a step, there was
> absolutely no effect.

I think you might not be stating that correctly. What he said was there 
was no difference between people listening to the original Mozart and 
the distorted version. Had the original causes improvements but the 
distorted version failed to cause improvement, it would be corroborating 
the Mozart effect.

> 
> ORIGIN OF MUSIC
> pre-linguistic auditory communication
> music is closely linked to movement (dance, etc.)
> 
> TALENT
> Is talent due to prior tuning of the neural networks?  How does it happen?
> 
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-- 

******************************************************
Jaime J. Davila
Assistant Professor of Computer Science
Hampshire College
School of Cognitive Science
jdavila at hampshire dot edu
http://helios.hampshire.edu/jdavila
*******************************************************