Psychology
Consciousness
Awareness of the environment, ones own existence, sensations, thoughts
States of Consciousness Distinctive or discrete patterns in the function of consciousness
Biological Rhythms
Endogenous cycles
Bio Rhythms: endogenous rhythms are systematic changes in the brain’s function that are vastly internal brain mechanisms. One of the things that does alter conscious states are actually these bio rhythms.
1. Circadian 24hr. cycle. Sleep, temperature
2. Infradian Less often that 24hrs. E.g., migration in animals, Fertility cycle
3. Ultradian More frequent than 24hrs. Stomach contractions, hunger, performance, alertness, daydreaming, within sleep cycle
Circadian cycle / rhythm Sleep-wake cycle. In free running experiments averaged 25hrs.
Controlled by a tear drop shaped area in the hypothalamus called The Suprachiasmatic Nucleus (SCN)
All other clocks take their cue from SCN. The SCN itself is kept in synch with day-night patterns by a hormone ‘Melatonin’ secreted by the Pineal gland. Insomnia is correlated with and has been treated with low Melatonin levels • Way to test these cycles: Free running experiments. Here you very carefully remove people from the natural environmental stimuli. You take them to a building where everything is independent of the environment. There is not external stimuli – nothing to signal what time it is – eg day light and sound etc. The experiment showed that the endogenous cycle of sleeping is actually internal and lasts 25 hours. • There are time keeping mechanisms within the brain. It is a tear-brain shaped area within the hypothalamus, it is called Supachiasmatic Nucleus called the SCN. There are a series of neurons which stimulate themselves in a cycle and after a number of cycle they shoot of signals to other parts of the brain. Amongst other place, the SCN tells inhibitory signals to the base of the brain which tells it when to shut down. •
Awareness of the environment, ones own existence, sensations, thoughts
States of Consciousness Distinctive or discrete patterns in the function of consciousness
Biological Rhythms
Endogenous cycles
Bio Rhythms: endogenous rhythms are systematic changes in the brain’s function that are vastly internal brain mechanisms. One of the things that does alter conscious states are actually these bio rhythms.
1. Circadian 24hr. cycle. Sleep, temperature
2. Infradian Less often that 24hrs. E.g., migration in animals, Fertility cycle
3. Ultradian More frequent than 24hrs. Stomach contractions, hunger, performance, alertness, daydreaming, within sleep cycle
Circadian cycle / rhythm Sleep-wake cycle. In free running experiments averaged 25hrs.
Controlled by a tear drop shaped area in the hypothalamus called The Suprachiasmatic Nucleus (SCN)
All other clocks take their cue from SCN. The SCN itself is kept in synch with day-night patterns by a hormone ‘Melatonin’ secreted by the Pineal gland. Insomnia is correlated with and has been treated with low Melatonin levels • Way to test these cycles: Free running experiments. Here you very carefully remove people from the natural environmental stimuli. You take them to a building where everything is independent of the environment. There is not external stimuli – nothing to signal what time it is – eg day light and sound etc. The experiment showed that the endogenous cycle of sleeping is actually internal and lasts 25 hours. • There are time keeping mechanisms within the brain. It is a tear-brain shaped area within the hypothalamus, it is called Supachiasmatic Nucleus called the SCN. There are a series of neurons which stimulate themselves in a cycle and after a number of cycle they shoot of signals to other parts of the brain. Amongst other place, the SCN tells inhibitory signals to the base of the brain which tells it when to shut down. •