Biopsych investigation the brain, biological rhythms

Non-invasive techniques

fMRI, EEG, ERPs

Invasive techniques

post mortem studies

What is an fMRI

used to examine structure and function of the brain during tasks. more active areas of the brain have more oxygen therefore more blood flow - how it works.

What is an MRI

uses magnets to pick up the iron in the haemoglobin in the blood, can be used for lie detection

What is an EEG

used for monitoring electrical activity in the brain, electrodes are placed on the scalp to detect small electrical charges resulting from the activity of millions of neuron’s. detect stages of sleep

What are ERPs

measure electrical activity in the brain that results from specific stimuli. inconsistent brain activity is filtered out to leave only the ERPs

What are post mortem studies

examines structural damage to the brain after death to establish what damage leads to certain deficits, usually done on patients who have rare deficits in mental processes/behvaiour

What are biological rhythms

cyclical changes in the way that biological systems have evolved because the environment in which organisms live has cyclic changes, day/night, summer/winter etc…

What are circadian rhythms

cycles that occur every 24 hours (sleep cycle, body temp)

What are infradian rhythms

cycles that occur less than once every 24 hours (menstrual cycle)

What are ultradian rhythms

cycles that occur more than once every 24 hours (sleep stages/digesetion)

What are endogenous pacemakers

the boys internal clock that regulates many of our biological rhythms

What are exogenous zeitgebers

external changes in the environment

What is the superchiasmatic nucleus

tiny bundle of nerves located in the hypothalamus, vital for maintaining CR, when SCN receives into of light the eyes it passes info to Pineal glad

What is the pineal gland

responsible for melatonin secretion

What is entrainment

the synchronisation of internal biological clock rhythms to external time cues, such as natural dark-light cues

Role of light

receptors in the SCN are sensitive to changes in light levels and use this to synchronise body organs, light resets internal biological clock each day keeping a 24hr cycle

Social cues

social stimuli such as mealtimes and social activities may also have a role as zietgebers

Stages 1&2 of sleep cycle

Light sleep; someone can be easily woken, brain waves become slower and more rhythmic

Stages 3&4 of sleep cycle

Deep sleep; difficult to wake someone, slow waves with greater amplitude

Stage 5 of sleep cycle

REM sleep; body is paralysed, brain activity increases where brain appears almost awake (eye movement), correlated with dreaming

Daytime cycle BRAC

Brain reslt-actitivy cycle.

What is SAD

seasonal variation in moods in humans, becoming depressed during winter months, can be treated with light therapy