In
neuroscience,
synaptic plasticity is the ability of
synapses to
strengthen or weaken over time, in response to increases or decreases in their activity. Plastic change also results from the alteration of the number of
neurotransmitter receptors located on a synapse. There are several underlying mechanisms that cooperate to achieve synaptic plasticity, including changes in the quantity of
neurotransmitters released into a synapse and changes in how effectively cells respond to those neurotransmitters. Synaptic plasticity in both
excitatory and
inhibitory synapses has been found to be dependent upon
postsynaptic calcium release. Since
memories are postulated to be represented by vastly interconnected networks of synapses in the
brain, synaptic plasticity is one of the important neurochemical foundations of
learning and
memory (
see Hebbian theory).