How the brain hears sound- tick-tock, tick-tock!
New research published by Dr. Daniel Bendor, University College London discusses the concept of how our brain captures sound information by the timing of its activity.
When asked about the motivation behind the study, Dr. Bendor reports, "The brain uses different neural codes (languages) to describe our sensory world. For hearing, our brain can represent a sound by either the magnitude (how loud or soft the sound is) or timing of activity in brain cells. As a result, our work uncovered a simple mechanism by which the brain can generate these two types of responses."
Typically, our brain receives two different kinds of inputs - namely excitatory and inhibitory.
As the name suggests, excitatory inputs enhance and inhibitory inputs prevent the activity of brain cells.
Imagine the gas and brake pedals of a car.
The gas pedal moves the car while the brake stops it. The excitatory inputs are like the gas pedal and the inhibitory inputs resemble the brake pedals for a brain cell.
Similar to when your car either moves or stops in response to the accelerator or brake, the combination of these inputs could make the neurons active or silent.
This study makes use of a mathematical model neuron, with equations to mimic the excitatory and inhibitory signals in response to a sound input. The model is then fed into computer software to obtain the predictions.
"We found that neural "code" or "language" of a brain cell could be changed by controlling the amount and timing of excitation and inhibition", says Dr. Bendor, in contrast to the strength of the sound.
In other words, how do we hear sound? An obvious assumption would be that, it is based on the strength of the sound- either high or low.
But besides the magnitude of sound levels, there are other mechanisms, which our brain employs to process the sound information and produce neural codes or patterns.
As discussed in this study, one mechanism is that the brain uses the "timing" information of the excitatory and inhibitory inputs in deciphering patterns within the sound.
A lot of evidence in the field of neuroscience shows that neural patterns of activity in the brain are critical in cognition, perception, memory etc. amongst others.
Given, that the brain consists of more than billion neurons, which make about a trillion connections, Dr. Bendor's study establishes simple principles for how the brain operates during complex behavior.
In future, Dr. Bendor says, "This work proposes an idea that controlling excitation and inhibition of a brain cell will determine the neural code it uses. We would like to test this using optogenetics, a technique where light can independently be used to excite or inhibit neural activity."
How our brain actually works is a complete mystery to date. Therefore, a study like this paves the way for artificial intelligence and other brain therapeutic procedures.
In short, the future sounds good!
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