So this is the belief in 'good' neurons. Is it helpful in more than memory neurons? full article at the link.
http://www.scientificamerican.com/article.cfm?id=keeping-up-with-the-neurons
Neurons, or nerve cells, each have a pair of projections—the axon and
the dendrite, which transmit and receive impulses, respectively. The
dendrite, a treelike structure, has several branches dotted with
hundreds synaptic receiving terminals called "spines," each connected to
the axons of scores of other neurons. When one of these spines receives
stimulation (through the synapse it creates with another cell's axonal
projection), the spine expands into the synapse, strengthening the link
between its neuron and the other cell. This process of enhanced
communication through a synapse is called long-term potentiation (LTP) and is thought to be the basis of learning.
Previous attempts to identify this process were stymied by inexact
methods. Researchers primarily used electrical impulses, which do not
allow for good spatial observation. Svoboda and study co-author
Christopher Harvey, a graduate student in Svoboda's lab, used a more
precise technique. They attached a light-absorbing chemical group to the
neurotransmitter glutamate (an excitatory chemical messenger in the
brain) at a particular synapse in a slice of a rat's hippocampus, the
brain region responsible for short-term memory. When they trained a
laser on the glutamate, it was freed from its light-absorbing molecular
captor and thereby able to resume its function; it went to the dendritic
spine in the synapse, allowing ions to enter the cell and an electrical
signal to be generated.
As a result of this stimulation, the spine stretched farther into the
synapse. Researchers did not find any evidence that neighboring spines
had also expanded, but they did find that it took less stimulation—only
20 percent of the original prodding—to prompt any of the 20 spines
within 10 microns (around four ten-thousandths of an inch) to undergo
LTP. This effect appeared to last for five to 10 minutes, the scientists
report.
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