Thursday, March 31, 2011

Nobel Prizes and Synapses

What do Nobel prizes and synapses have in common?

In order for us to move, feel and think, neurons in our brain relay messages to one another. When neurons "chat" among themselves, their means of communication relies on both electricity and chemistry.

Once incoming stimuli of a specific type reach a threshold point, a 270 mph electrical impulse “fires” and is transmitted down the axon of a neuron, the elongated portion of the nerve cell.

The chemical component of this informational exchange occurs by means of over 70 neurotransmitters (brain chemicals) and neuromodulators. Once the electrical impulse reaches the end of the axon, a tiny pocket of chemicals bursts releasing neurotransmitters (the “chemical couriers”), which travel across the synapse, a microscopic gap separating two theoretically “connected” neurons. The “apse” in synapse means binding, and “syn” meaning together.

Synapses in reality are contiguous rather than continuous contact points between the message-sending or pre-synaptic neuron and the post-synaptic or message-receiving neuron.

As neurotransmitters cross the synaptic gap they lock into receptor sites on the post-synaptic neuron (the next neuron on a neural pathway) and convey their chemical message only if their molecular properties fit the precise configuration of the receptor sites on the post-synaptic neuron. Over one quadrillion (1,000 trillion) synaptic connections can be established inside the human brain. Each neuron can make 15,000 to 200,000 connections with other brain cells.

Creating new synapses and delivering the appropriate types and quantities of neurotransmitters in these chemical communications, is the foundation of the event we generically call learning.

Although synaptic transmission is just one aspect of how the brain functions, three Nobel prizes have been awarded (to Arvid Carlsson, Paul Greengard, and Eric Kandel) for their research on this single portion of our complex brain transactions.

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