So, the other day my sweetie turns to me and asks if
plasticity means changeable in neuroscience jargon. Being a little foolish, I said, "Yes, but ... . " Here's the "but."
Neuroplasticity (variously referred to as brain plasticity or cortical plasticity) refers to the changes that occur in the organization of the brain as a result of experience. A surprising consequence of brain plasticity is that the location of a given function can move to another location in the brain as a consequence of training or brain damage. One of my colleagues has shown the types of rearrangement that can be achieved relatively rapidly in the brain due to trauma, including amputation. One of the people who has studied the "phantom limb" phenomenon in humans (as a result of amputations) is V.S. Ramachandran at UCSD and the Salk Institute.
When a cellular neurobiologist refers to plasticity, however, he or she is often referring the changes at a single synapse. For instance, some signaling molecules cause the number of vesicles of transmitter that are released in response to a single action potential to increase or decrease. When all that extra neurotransmitter reach the postsynaptic neuron, they activate a greater number of ligand-gated ion channels and, therefore, there is a bigger response.
So, plasticity on the micro and macro levels both play a part in learning, memory, and adaptation within the nervous system.
That's it for today. Tune in tomorrow for something else new.
