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Today in class we began discussing the functional mechanisms of individual neurons. We also touched upon the idea that our perception of the world is limited to signals for which we have receptors. We can perceive signals which come to us in the form of light waves, sound waves (via vibration), chemicals, and tactile stimulation. We are unable to perceive such things as electrical or magnetic fields, and many visual/auditory/chemical signals that are outside our range.

This fact has many interesting implications. The one that occured to me has to do with what it is that makes humans different from other animals. I fully subscribe to the idea that there might be nothing that makes us substantially different, but while thinking about sensory perception I had a few ideas. At first I was a little indignant, why do we think of ourselves as so superior? Birds have a more complete experience of the world than we do, we cant even sense magnetic fields. But, as Prof Grobstein pointed out, we created the compass. We also came up with radar, sonar, and infrared goggles. Through our technology we have been able to compensate for our inadequacies, and expand on our abilities. Maybe one day we will be able to genetically alter humans so that we develop neurons responsive to magnetic fields, biologically aquiring the senses we lack.

The idea that we can expand upon our sensory capacities is not unrealistic. This is due to our neural plasticity, the ability of our neurons to change, and neural networks to take on new functions. Many blind people, both those blind from birth and those who lost their sight at an early age, are able to use echolocation to navigate their environment. These individuals are able to perceive aspects of their environment by observing how an emitted sound is altered as it bounces off of objects. Through the use of PET scans and fMRI's it has been shown that the visual cortex is active during this activity. This shows that the area of the brain typically responsible for visual processing is involved in auditory processing in these individuals. The visual cortex is also active when a blind individual reads braille.

The ability of our brain to change through experience and learning means that we are not so constrained by our biology. Neural plasticity is responsible for everything we do. Without it, if our brains were static, we could not learn or remember. Possibly we would not have any concept of self, any ability to integrate ideas. Everything would be in one ear and out the other