Question: I have read that learning happens when synapses between neurons are created - I appreciate this is fairly simplistic, but how close to reality is it? (Do we know?)
learning certainly involves synapses… but it’s not about creating synapses.
Synapses describe the space between neurons (nerve cells) and neurons communicate with each other by passing chemicals through the synaptic space (as the nerve cells don’t actually touch each other)…
learning involves altering the connections between neurons so that the neurons communicate more quickly and efficiently with each other… so learning alters the synapses (rather than creating them)
The neurophysiology is reasonably well established and there are good computational models of neural learning – so we have some knowledge… but there is an awful lot more that we don’t understand about human learning!
Learning occurs when synapses are altered, engaging new circuits in the brain. This involves both strengthening some synapses, perhaps diminishing the strength of others and creating new or eliminating old synapses. Altering synaptic strength is called synaptic plasticity. Creating and eliminating synapses are collectively called structural synaptic plasticity. These structural changes are thought to occur as a second level event after synaptic plasticity has already occurred. Sometimes all of these are condensed and talked about simply as synaptic strengthening, which is not totally accurate.
At each synapse, the nerve terminal spits out a chemical neurotransmitter that travels across the small adjoining space to the dendrite of the next neuron where it is tasted by special protein receptors. For a synapse to become stronger, more neurotransmitter must be released or more receptors must be present or both. A series of biochemical events triggered by the protein receptors can result in new protein synthesis for these receptors and if necessary, for all the proteins needed to build new synapses. As neuroscientists, we have a large body of knowledge surrounding the molecules involved in all aspects of synaptic plasticity. While we are still investigating the function and regulation of many of the proteins involved in synaptic plasticity and structural synaptic plasticity, the basic outline provided here is sound.
Comments
dubin001 commented on :
Learning occurs when synapses are altered, engaging new circuits in the brain. This involves both strengthening some synapses, perhaps diminishing the strength of others and creating new or eliminating old synapses. Altering synaptic strength is called synaptic plasticity. Creating and eliminating synapses are collectively called structural synaptic plasticity. These structural changes are thought to occur as a second level event after synaptic plasticity has already occurred. Sometimes all of these are condensed and talked about simply as synaptic strengthening, which is not totally accurate.
At each synapse, the nerve terminal spits out a chemical neurotransmitter that travels across the small adjoining space to the dendrite of the next neuron where it is tasted by special protein receptors. For a synapse to become stronger, more neurotransmitter must be released or more receptors must be present or both. A series of biochemical events triggered by the protein receptors can result in new protein synthesis for these receptors and if necessary, for all the proteins needed to build new synapses. As neuroscientists, we have a large body of knowledge surrounding the molecules involved in all aspects of synaptic plasticity. While we are still investigating the function and regulation of many of the proteins involved in synaptic plasticity and structural synaptic plasticity, the basic outline provided here is sound.
Jan
dubin001 commented on :
A simplified cartoon explaining synaptic plasticity can be found at
http://brainu.org/movies
Jan