neutral point

the single wavelength of visible light that appears uncolored (white or gray) to a person with dichromatism (someone with only two cone photopigments, rather than three). The specific wavelength of the neutral point varies according to which photopigment is missing. Those with normal color vision (trichromatism) and three cone photopigments have no neutral point.

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Psychology term of the day

September 8th 2024

NMDA receptor

a type of glutamate receptor that binds NMDA as well as glutamate. NMDA receptors are coupled to ligand-gated ion channels and are also voltage-sensitive, which enables them to participate in a variety of information-processing operations at synapses where glutamate is the neurotransmitter. The drugs of abuse ketamine and PCP are antagonists at NMDA receptors, preventing the influx of calcium ions at calcium channels, which may cause the hallucinogenic effects of these drugs. Excessive flow of calcium ions into the presynaptic neuron via the NMDA receptor is thought to contribute to glutamate toxicity. A hypothesis on the etiology of schizophrenia involves dysfunction of the NMDA glutamate receptor (see glutamate hypothesis). Compare AMPA receptor.