Sleep, Arousal And Biological Rythms Flashcards
What does the Yerkes-Dodson law state?
Although we can record physiological measures if arousal, it has also been used by psychologists as an explanatory theoretical concept to explain the effects of arousing manipulations in behaviour. The Yerkes-Dodson law states that there is an inverted-U shaped relationship between arousal and the level of performance.
What do Psychophysiologists do?
Psychophysiologists study human subjects, recording physicians activity using electrodes attached to the body surface. Many of these measures , such as heart-rate and sweat gland activity, are related to physiological arousal, while the EEG records cortical arousal.
What does the brainstem reticular formation contain?
The brainstem reticular formation contains centres controlling cortical arousal and sleep.
What biological rhythms occur in plants and throughout the animal kingdom?
Circadian rhythms repeat themselves every 24 hours, infradian have a cycle length greater than 24 hours, and ultradian less than 24 hours.
How is the human sleep-waking cycle controlled?
The human sleep-waking cycle is controlled by a mixture of naturally occurring (endogenous) pacemakers in the brain , and external cues (zeitgebers) such as light. The endogenous mechanisms include the pineal gland and the supra-chiasmatic nucleus of the hypothalamus.
Why can Jet travel and shift work affect us?
Because the involve dislocation between the endogenous pacemakers and external cues.
What is paradoxical sleep?
Paradoxical sleep, or phase of REM , occurring every 90 minutes or so, and is associated with an aroused EEG, rapid eye movements, and the reporting of dreams.
How have EEG recordings been used to investigate sleep ?
EEG recordings have been used to identify stages of sleep, ranging from drowsiness to deep sleep as EEG waves become larger and slower.
What is the function of sleep?
There are many hypotheses about the functions of sleep. Many sleep deprivation studies have been done, showing severe effects in animals and less dramatic effects in humans, but but pointing to any single function of sleep.
Ecological studies show that sleep patterns can be related to lifestyle, body size, metabolic rate, and evolutionary status. What does Horne suggest?
Horne suggests that species differences in these variables means that it is possible looking for a single and general function of sleep across all species.
A popular hypothesis has been that REM sleep is related to brain recovery processes, and slow-wave sleep to bodily recovery. What does Hornes propose?
Horne proposes that in humans both are dedicated to brain recovery , with relaxed wakefulness coping with body-tissue repair.
What has Jouvet shown?
Jouvet has shown that the brain mechanisms of sleep include the locus coeruleus and raphe nuclei of the brainstem reticular formation, which seems to be involved in REM sleep and slow-wave sleep respectively.
What did Jouvet demostrate?
Jouvet demonstrated that REM is associated with the neurotransmitter noradrenaline, and slow-wave sleep with serotonin. Drugs affecting these transmitters can alter sleep patterns.
What is the precise function of sleep-inducing chemicals?
Chemicals have been isolated from the blood of sleeping or sleep-deprived animals, and have been shown to produce sleep when given to other animals. The precise function of these sleep-inducing chemicals has yet to be identified.
What kind of state is sleep?
Rather than being a passive state, sleep is actively imposed on the brain by sleep-inducing or hypogenic centres; these coordinate information from endogenous pacemakers, reticular arousal centres, external cues and other sensory input.
