Wednesday, May 17, 2006

Your Brain is not a Computer – Part 1

There are many people who believe that the brain processes information in a fashion similar to that of a computer. This idea is based on the simplest function of brain cells involving the chemical synapses of the neurons. In this model, information is transmitted linearly from a pre-synaptic neuron to the post-synaptic membrane. Pre-synaptic neurotransmitters are released, bind to receptor proteins on the post-synaptic membrane, and open ion channels causing a change in the potential of the post-synaptic cell.

Some believe that by merely copying the exact architecture of the brain onto silicon transistors, a person’s personality could eventually be artificially recreated. What they fail to take into account is the process of neuromodulation and neural plasticity.

Although the primary structure of the neural network is genetic, neurons undergo changes in function and organization even in the adult. This reality underlies things like long-term memory and learning that are both important components of the personality.

A neuron is not a static unit but is instead, temporally dynamic. Its receptor milieu may change in response to changes in the frequency of stimulation. Hormones, particularly the reproductive hormones, also have an important influence on the responsiveness of neurons and the brain as a whole. For instance, the feed back systems of the hypothalamus are also related to behavioral states.

Just recreating the neural framework of the brain will not reflect the variability of the neuron. In fact, I would argue that merely duplicating the neural architecture of the brain would yield nothing more than an automaton with the functional capacity of a human ant. You will need another whole different set of algorithms.

-Just a peasant

Photo of the human brain (cephalic portion of the nervous system) from the National Institute of Mental Health