How do neurons use electrical activity to transmit information? Flashcards
back propagation
Reverse movement of an action potential into the dendritic field of a neuron; postulated to play a role in plastic changes that underlie learning.
concentration gradient
Differences in concentration of a substance among regions of a container that allow the substance to diffuse from an area of higher concentration to an area of lower concentration.
microelectrode
A microscopic insulated wire or a salt-water-filled glass tube of which the uninsulated tip is used to stimulate or record from neurons.
graded potential
Small voltage fluctuation in the cell membrane restricted to the vicinity on the axon where ion concentrations change to cause a brief increase (hyperpolarization) or decrease (depolarization) in electrical charge across the cell membrane.
depolarization
Decrease in electrical charge across a membrane, usually due to the inward flow of sodium ions.
nerve impulse
Propagation of an action potential on the membrane of an axon.
voltage gradient
Difference in charge between two regions that allows a flow of current if the two regions are connected.
voltage-sensitive channel
Gated protein channel that opens or closes only at specific membrane voltages.
voltmeter
Device that measures the flow and the strength of electrical voltage by recording the difference in electrical potential between two bodies.
end plate
On a muscle, the receptor-ion complex that is activated by the release of the neurotransmitter acetylcholine from the terminal of a motor neuron.
resting potential
Electrical charge across the cell membrane in the absence of stimulation; a store of potential energy produced by a greater negative charge on the intracellular side relative to the extracellular side.
hyperpolarization
Increase in electrical charge across a membrane, usually due to the inward flow of chloride or sodium ions or the outward flow of potassium ions.
oscilloscope
Device that serves as a sensitive voltmeter by registering the flow of electrons to measure voltage.
saltatory conduction
Propagation of an action potential at successive nodes of Ranvier; saltatory means ‘jumping’ or ‘dancing.’
temporal summation
Graded potentials that occur at approximately the same time on a membrane are summed.
absolutely refractory
Refers to the state of an axon in the repolarizing period during which a new action potential cannot be elicited (with some exceptions), because gate 2 of sodium channels, which is not voltage sensitive, is closed.
optogenetics
Transgenic technique that combines genetics and light to control targeted cells in living tissue.
diffusion
Movement of ions from an area of higher concentration to an area of lower concentration through random motion.
threshold potential
Voltage on a neural membrane at which an action potential is triggered by the opening of Na+ and K+ voltage-sensitive channels; about 250 millivolts relative to extracellular surround.
transmitter-sensitive channel
Receptor complex that has both a receptor site for a chemical and a pore through which ions can flow.
relatively refractory
Refers to the state of an axon in the later phase of an action potential during which increased electrical current is required to produce another action potential; a phase during which potassium channels are still open.
excitatory postsynaptic potential (EPSP)
Brief depolarization of a neuron membrane in response to stimulation, making the neuron more likely to produce an action potential.
electroencephalogram (EEG)
Graph that records electrical activity through the skull or from the brain and represents graded potentials of many neurons.
electrical stimulation
Passage of an electrical current from the uninsulated tip of an electrode through tissue, resulting in changes in the electrical activity of the tissue.
stretch-sensitive channel
Ion channel on a tactile sensory neuron that activates in response to stretching of the membrane, initiating a nerve impulse.
action potential
Large, brief reversal in the polarity of an axon.
node of Ranvier
The part of an axon that is not covered by myelin.
inhibitory postsynaptic potential (IPSP)
Brief hyperpolarization of a neuron membrane in response to stimulation, making the neuron less likely to produce an action potential.
autoimmune disease
Illness resulting from the loss of the immune system’s ability to discriminate between foreign pathogens in the body and the body itself.
spatial summation
Graded potentials that occur at approximately the same location and time on a membrane are summed.
