Search results
Results from the WOW.Com Content Network
Synaptic potential refers to the potential difference across the postsynaptic membrane that results from the action of neurotransmitters at a neuronal synapse. [1] In other words, it is the “incoming” signal that a neuron receives. There are two forms of synaptic potential: excitatory and inhibitory.
These electrical signals may be excitatory or inhibitory, and, if the total of excitatory influences exceeds that of the inhibitory influences, the neuron will generate a new action potential at its axon hillock, thus transmitting the information to yet another cell. [1] This phenomenon is known as an excitatory postsynaptic potential (EPSP).
Multiple inhibitory inputs combine and deepen hyperpolarization of the membrane (more negative). If the cell is receiving both inhibitory and excitatory postsynaptic potentials, they can cancel each other out, or one can be stronger than the other, and the membrane potential will change by the difference between them.
Inhibitory synapse: Diminishes the probability of depolarization in postsynaptic neurons and the initiation of an action potential. An influx of Na+ driven by excitatory neurotransmitters opens cation channels, depolarizing the postsynaptic membrane toward the action potential threshold.
The size of the neuron can also affect the inhibitory postsynaptic potential. Simple temporal summation of postsynaptic potentials occurs in smaller neurons, whereas in larger neurons larger numbers of synapses and ionotropic receptors as well as a longer distance from the synapse to the soma enables the prolongation of interactions between neurons.
The postsynaptic neuron may receive inputs from many additional neurons, both excitatory and inhibitory. The excitatory and inhibitory influences are summed, and if the net effect is inhibitory, the neuron will be less likely to "fire" (i.e., generate an action potential), and if the net effect is excitatory, the neuron will be more likely to fire.
A neuroeffector junction is a site where a motor neuron releases a neurotransmitter to affect a target—non-neuronal—cell. This junction functions like a synapse.However, unlike most neurons, somatic efferent motor neurons innervate skeletal muscle, and are always excitatory.
In general, the result is excitatory in the case of depolarizing currents, and inhibitory in the case of hyperpolarizing currents. Whether a synapse is excitatory or inhibitory depends on what type(s) of ion channel conduct the postsynaptic current(s), which in turn is a function of the type of receptors and neurotransmitter employed at the ...