deep sleep

the stage of the sleep cycle in which arousal thresholds are highest and consciousness is taken to be least likely. In electroencephalography, deep sleep is commonly defined by a predominance of slow, high-amplitude waveforms. See delta wave; slow-wave sleep.

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Psychology term of the day

January 3rd 2025

ring chromosome 18

a congenital chromosomal disorder characterized by microcephaly, ear and eye abnormalities, and mild to severe cognitive impairment. The condition is not hereditary but due to breakage of the arms of chromosome 18, which fuse to form one or more rings of varying sizes.