Biological Psychology Terms - Chapter 8 Definitions

endogenous circadian rhythms

self-generated rhythm that lasts about a day

endogenous circannual rhythm

self-generated rhythm that lasts about a year

jet lag

a disruption of circadian rhythms due to crossing time zones

melatonin

hormone that influences both circadian and circannual rhythms

pineal gland

an endocrine gland located just posterior to the thalamus that releases the hormone melatonin

suprachiasmatic nucleus (SCN)

part of the hypothalamus; provides the main control of the circadian rhythms

zeitgeber

stimulus that resets the circadian rhythm

alpha waves

a steady series of brain waves at a frequency of 8 to 12 per second that are characteristic of relaxation

basal forebrain

area anterior and dorsal to the hypothalamus; includes cell clusters that promote wakefulness and sleep,

brain death

condition with no sign of brain activity and no response to any stimulus

coma

an extended period of unconsciousness with a low level of brain activity

insomnia

inadequate sleep

K-complex

a sharp brain wave associated with temporary inhibition of neuronal firing

locus coeruleus

a small structure in the pons that emits bursts of impulses in response to meaningful events, especially those that produce emotional arousal

minimally conscious state

condition of decreased brain activity with occasional, brief periods of purposeful actions and limited speech comprehension

narcolepsy

a condition characterized by frequent periods of sleepiness during the day

night terrors

experiences of intense anxiety from which a person awakens screaming in terror; more severe than a nightmare

non-REM (NREM) sleep

stages of sleep other than REM

orexin (or hypocretin)

neurotransmitter that increases wakefulness and arousal

paradoxical sleep

sleep that is deep in some ways and light in others

periodic limb movement disorder

a sleep disorder characterized by repeated involuntary movement of the legs and sometimes the arms

PGO waves

a distinctive pattern of high-amplitude electrical potentials that occur first in the pons, then in the lateral geniculate, and then in the occipital cortex

polysomnograph

a combination of EEG and eye-movement records

pontomesencephalon

part of the reticular formation that contributes to cortical arousal

rapid eye movement (REM) sleep

sleep stage with rapid eye movements, high brain activity, and relaxation of the large muscles

REM behavior disorder

a condition in which people move around vigorously during REM sleep

reticular formation

a structure that extends from the medulla into the forebrain; controls motor areas of the spinal cord and selectively increases arousal and attention in various forebrain areas

sleep apnea

impaired ability to breathe while sleeping

sleep spindle

12 to 14 Hz brain waves in bursts that last at least half a second

slow-wave sleep (SWS)

sleep occupied by slow, large-amplitude brain waves

unresponsive wakefulness syndrome

(coma) an extended period of unconsciousness with a low level of brain activity

activation-synthesis hypothesis

idea that a dream represents the brain's effort to make sense of sparse and distorted information

neurocognitive model

proposal that dreams represent thinking related to recent memories under conditions of reduced sensory input