"The Neural Orchestra" by Josie Glausiusz
Discover Magazine, September Issue
Neuroscientists have been plagued for some time as to which areas
of the brain music actually stimulates. But at the Institute of Neurology
in London, neuroscientist Richard Frackowiak is convinced that there is
not of a single "music box" in the brain; research suggests that numerous
parts of the brain are activated. Frackowiak took PET scans of several
men's brains as they listened to four different tapes. There were thirty
sequences of musical excerpts on each of four tapes; the first contained a
change in timbre for half the songs, one tape contained a change in the
pitch for half the songs, and another tape contained a change in the
rhythm for half the songs. The fourth tape was only used to determine
which type of music the subjects were familiar with.
The results indicated that the music most familiar to the men
stimulated the Broca's area located in the left hemisphere. The men
reported that the familiar tunes also brought to mind their titles or at
least a "brain search" for the title. This, in turn, was not surprising
since Broca's area is also responsible for processing the cadences of
spoken language. The change in timbre accounted for a stimulation of the
right hemisphere, the only thing to account for an activation of the right
hemisphere. The results of the change in pitch trial were the most
surprising. The pitch variations activated the precuneus, a region on the
left rear of the brain. Past studies have shown this region to be linked
with visual imagery - possibly suggesting that you may visualize the
rising and falling of a stave in your mind's eye. The study concluded
that music is processed in the front and back of the brain in a more
complex manner than previously believed.
For the past half-century, neuroscientists have postulated that
the brain "works" in a manner similar to that in which a computer works.
The foundation for this hypothesis stems from the fact that the brain is
composed of billions of neurons wired in an elaborate manner. Likewise, a
computer consists of millions of interlinked switches of minimal
individual processing ability.
Recent research has proven this model incorrect by showing that single
neurons can actually perform intricate calculations and register fine
discriminations. Also, the more a neuron is used, the stronger it becomes
- an indication of a type of development not present in computers.
Moreover, neurons have numerous electrically active components in the
incoming branches. These branches are able to regulate the amount of
incoming messages and distribute the messages to surrounding neurons
depending on the strength of the synapse. This type of intelligent
message management is much more sophisticated than that of any modern
computer.
In the past, researchers believed that the representation of information
depended on overall rate of neuron firing over periods of time; however,
it has recently been shown that some cells in monkeys' brains can adjust
the rate of firing in individual increments as little as on hundredth of a
second. This adjustment can cause a back-propagated neural spike that
will strengthen the incoming branch of the neuron while suppressing random
or unimportant messages.
This research shows that the brain should now be viewed as a
hybrid computer employing both digital pulses and analog computations.
This study reaffirmed that human neural synapses are extremely
complicated; Intel will not be creating a replacement for you brain in the
near future.