When ionotropic receptors are activated, certain ion species such as Na to enter the postsynaptic neuron, which depolarizes the postsynaptic membrane.If more of the same type of postsynaptic receptors are activated, then more Na will enter the postsynaptic membrane and depolarize cell.Once bounded with Ca2 , the vesicles dock and fuse with the presynaptic membrane, and release neurotransmitters into the synaptic cleft by a process known as exocytosis.
An action potential can be divided into several sequential phases: threshold, rising phase, falling phase, undershoot phase, and recovery.
Following several local graded depolarizations of the membrane potential, the threshold of excitation is reached, voltage-gated sodium channels are activated, which leads to an influx of Na ions.
Several techniques such as intracellular recording, patch-clamp, and voltage-clamp technique, pharmacology, confocal imaging, molecular biology, two photon laser scanning microscopy and Ca2 imaging have been used to study activity at the cellular level.
Cellular neuroscience examines the various types of neurons, the functions of different neurons, the influence of neurons upon each other, how neurons work together.
Plastic change often 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.
Moreover, the distinctions based on function between neurons and other cells such as cardiac and muscle cells are not helpful.
Thus, the fundamental difference between a neuron and a nonneuronal cell is a matter of degree.
Neurons are cells that are specialized to receive, propagate, and transmit electrochemical impulses.
In the human brain alone, there are over eighty billion neurons.
Some neurons such as photoreceptor cells, for example, do not have myelinated axons that conduct action potentials.