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Axon terminals (also called terminal boutons, synaptic boutons, end-feet, or presynaptic terminals) are distal terminations of the branches of an axon. An axon, also called a nerve fiber, is a long, slender projection of a nerve cell that conducts electrical impulses called action potentials away from the neuron's cell body to transmit those ...
Some of these mechanisms rely on changes in both the presynaptic and postsynaptic neurons, resulting in a prolonged modification of the synaptic potential. [7] The strength of changes in synaptic potentials across multiple synapses must be properly regulated. Otherwise, the activity across the entire neural circuit would become uncontrollable. [8]
Postsynaptic potentials occur when the presynaptic neuron releases neurotransmitters into the synaptic cleft. These neurotransmitters bind to receptors on the postsynaptic terminal, which may be a neuron , or a muscle cell in the case of a neuromuscular junction . [ 1 ]
where ′ is the firing times of neuron j (i.e., its spike train); () describes the time course of the spike and the spike after-potential for neuron i; and and (′) describe the amplitude and time course of an excitatory or inhibitory postsynaptic potential (PSP) caused by the spike ′ of the presynaptic neuron j.
The presynaptic axon terminal, or synaptic bouton, is a specialized area within the axon of the presynaptic cell that contains neurotransmitters enclosed in small membrane-bound spheres called synaptic vesicles (as well as a number of other supporting structures and organelles, such as mitochondria and endoplasmic reticulum).
Neurotransmission (Latin: transmissio "passage, crossing" from transmittere "send, let through") is the process by which signaling molecules called neurotransmitters are released by the axon terminal of a neuron (the presynaptic neuron), and bind to and react with the receptors on the dendrites of another neuron (the postsynaptic neuron) a ...
This depolarizing current reaches the presynaptic terminal, and the membrane depolarization that it causes there initiates the opening of voltage-gated calcium channels present on the presynaptic membrane. There is high concentration of calcium in the synaptic cleft between the two participating neurons (presynaptic and postsynaptic). This ...
The amount of attenuation of the signal is due to the membrane resistance of the presynaptic and postsynaptic neurons. Long-term changes can be seen in electrical synapses. For example, changes in electrical synapses in the retina are seen during light and dark adaptations of the retina. [16]