| Adaptation |
Characteristics of an organism that has survival value or increases reproductive potential. |
| Electroencephalogram |
Graph revealing the electrical activity of the brain. |
| Endogenous pacemaker |
Internal clocks controlling biological rhythms. |
| Exogenous zeitgeber |
External cues (German; 'time-givers') moderating the activity of the endogenous pacemakers. |
| Free-running |
Increased period of a bodily rhythm due to the removal of environmental cues. |
| Hypothalamus |
Part of the forebrain with a role in motivation, Homeostasis and emotional response. |
| Latent content |
Hidden meaning of dreams. |
| Lucid dreaming |
Ability to control events in a dream. |
| Manifest content |
Symbolic version of the true meaning of a dream. |
| Melatonin |
Hormone regulating many circadian and circannual rhythms. |
| Neurotransmitter |
Chemical messenger that crosses a synapse between a neurone and another cell. |
| Paradoxical sleep |
Intense brain activity accompanied by paralysis during sleep (REM sleep). |
| Pheromones |
Chemical messengers produced by one organism and having an effect on another. |
| Photoperiod |
Duration of daylight in a 24 hour period. |
| Pineal gland |
Gland located in the forebrain responsible for melatonin production. |
| Psychodynamic approach |
Pioneered by Freud, focusing on the conflicts within a individual's psyche that motivate behaviour. |
| REM rebound |
'Catching up' on lost REM sleep. |
| REM starvation |
Deprivation of REM sleep. |
| Seasonal Affective Disorder (SAD) |
Depression brought about by the onset of shortening days in autumn/winter. |
| Serotonin |
Neurotransmitter with many roles in the brain, including the precursor to the hormone melatonin. |
| Sleep deprivation |
Method of investigating the function of sleep by keeping participants awake. |
| Suprachiasmatic nucleus |
Located in the hypothalamus; the site if the biological clock. |
