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How can calcium channels affect habituation in Aplysia californica?

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neuroplasticity The fundamental cell of the nervous system is the neuron. Neurons in a human brain are shown here.

In the context of neuroplasticity, habituation in the marine snail Aplysia californica is characterized by a decline in the strength of the gill-withdrawal reflex following repeated tactile stimulation.12

At the cellular level, this process is linked to changes in synaptic efficacy. Specifically, habituation can be caused by the closing of calcium channels in the presynaptic terminals of sensory neurons. This reduction in the activity of calcium channels decreases the influx of calcium into these terminals, which subsequently leads to a decrease in the amount of neurotransmitter release into the synaptic cleft.2

As a result, the excitatory postsynaptic potential generated in the motor neurons is reduced, eventually becoming too small to trigger the action potentials required to cause the gill to withdraw. This mechanism demonstrates how synaptic changes serve as a fundamental basis for simple forms of learning.12