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ion channel

a group of proteins forming a channel that spans a cell membrane, allowing the passage of ions between the extracellular environment and the cytoplasm of the cell. Ion channels are selective; allow passage of ions of a particular chemical nature, size, or electrostatic charge; and may be ungated (i.e., always open) or gated, opening and closing in response to chemical, electrical, or mechanical signals (see ligand-gated ion channel; voltage-gated ion channel). Ion channels are important in the transmission of neural signals between neurons at a synapse. The opening of sodium channels in the membrane of a postsynaptic neuron permits an influx of sodium ions (Na+) into the neuron, which produces an excitatory postsynaptic potential. The opening of potassium channels or chloride channels allows potassium ions (K+) to leave the postsynaptic neuron or chloride ions (Cl) to enter it, either of which produces an inhibitory postsynaptic potential. See also calcium channel.

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Psychology term of the day

January 23rd 2025

negative recency

negative recency

in recalling a list of items, the tendency to recall fewer of the final items of the list than the middle and early items. Negative recency contrasts with the enhanced recall of final items seen in the recency effect. Also called negative recency effect