A synaptic potential exists at the INPUT of a neuron (dendrite), and an action potential occurs at the OUTPUT of a neuron (axon). (from OldGuy)
(from Ilantoren:) A synaptic potential is the result of many excitatory post synaptic potentials (epsp) each one caused by the synaptic vesicles released by the pre-synaptic terminus. If there are enough of these epsp then the responses will summate and depolarize the post-synaptic membrane at the axon hillock enough to fire an action potential.
A synapse and an action potential have a flip-flopping cause and effect relationship, in that an action potential in a presynaptic neuron initiates a release of neurotransmitters across a synapse, which can then subsequently potentially trigger an action potential in the axon of the postsynaptic neuron, which would then cause release of neurotransmitters across a following synapse.
Called an interspike interval
The resting and action potentials depend on the balance of charges of the area outside the neuron and inside the neuron. A resting potential is when the neuron is more negatively (approximately -70mv) charged than the area outside the neuron. The action potential occurs when sodium ions rush into the neuron, causing the polarity to be reversed. When there is no difference in charge between the area inside the neuron and the area outside the neuron, no action potentials can be started by that neuron.
Local Potentials: Ligand regulated, may be depolarizing or hyperpolarizing, reversible, local, decremental Action Potentials: Voltage regulated, begins with depolarization, irreversible, self-propagating, nondecremental.
Action potentials also known as spikes, differ from graded potentials in that they do not diminish in strength as they travel through the neuron.
initial segment
a periodic production of action potentials even without synaptic input
In general, action potentials that reach the synaptic knobs cause a neurotransmitter to be released into the synaptic cleft. The arrival of the action potential opens voltage-sensitive calcium channels in the presynaptic membrane.
Axons conduct the nerve impulses, or action potentials, to the axon terminals and the synaptic cleft.
A hyperpolarizing graded potential makes the cell more negative, typically caused by an influx of chloride ions or efflux of potassium ions. In contrast, a depolarizing graded potential makes the cell less negative, often due to an influx of sodium ions or calcium ions. Both types of potentials play a role in generating action potentials in neurons.
Synapses occur between two neurons. Electrical activitiy in the pre-synaptic neuron influences the post-synaptic neuron. There are two types of synapses in the body: Electrical and chemical. Electrical synapses occur in pre and post synaptic neurons that are joined via gap junctions. Currents from action potentials flow across the junction through channels called connexons. This current will depolarize the membrane of the post synaptic neuron to threshold, which will continue the action potential in the cell. Electrical synapses are fast and bidirectional. However, they are mainly found in cardiac and smooth muscles, and not in the mammalian nervous system.Chemical synapses use neurotransmitters. Depolarization occurs in the pre-synaptic neuron and calcium ions rush in. The calcium ions activate neurotransmitter release into the synaptic cleft. The neurotransmitters reach the post-synaptic neuron and cause action potentials to develop.Note: this can go into much more detail
Called an interspike interval
It is a difference in charge supplied by ion position. In resting potential the tendency is for the inside of the cell membrane to have a negative ionic charge, while the outside of the membrane has a positive charge. The change, back and forth in these two charge potentials is the conduction of charge down the neuron and is called the action potential.
John H. Byrne has written: 'An introduction to membrane transport and bioelectricity' -- subject(s): Action potentials (Electrophysiology), Biological transport, Cell Membrane, Electrophysiology, Membrane Potentials, Physiology, Synaptic Transmission 'Learning and Memory'
The resting and action potentials depend on the balance of charges of the area outside the neuron and inside the neuron. A resting potential is when the neuron is more negatively (approximately -70mv) charged than the area outside the neuron. The action potential occurs when sodium ions rush into the neuron, causing the polarity to be reversed. When there is no difference in charge between the area inside the neuron and the area outside the neuron, no action potentials can be started by that neuron.
action potentials are non-decremental and do not get weaker with distance.
A neuromodulator modifies or makes more or less efficient the synaptic action of a neurotransmitter. Whereas a neurotransmitters work as chemicals released from terminal vesicles into synaptic clefts to receptors depolarizing the next neuron and initiates an electrical charge.
The FREQUENCY of action potentials that are conducted into the central nervous system serves as the code for the strength of the stimulus. This frequency code is needed because the amplitude of action potentials is constatnt (all or none). Acting through changes in action potential frequency, tonic receptors thus provide information about the relative intensity of a stimulus.