biosychopathology - p2 Flashcards
what are the 4 ways of studying the brain?
Post-Mortem
fMRI
EEG
ERP
studying the brain: post-mortem (3)
- technique involving analysis of person’s brain after death
- individual is likely to have a rare disorder/or mental deficits
- damaged areas are examined after death to establish cause of damage - may involve comparison of neurotypical brain to clarify difference
studying the brain: fMRI (3)
- detects changes in blood oxygenation/flow that occurs due to neural activity in certain parts of the brain
- when a brain area is more active - consumes more 02 to meet increased demand - blood flow directed to this area (haemoglobin response)
- produces 3D images (activation map) showing which parts are involved in a particular mental process
studying the brain: EEG (3)
- measures electrical activity in brain via electrodes that are fixed to the skull using a cap
- scan recording patterns that are generated from neuron action - providing an overall account for brain activity
- often used by clinicians as diagnostic tool for unusual arrhythmic patterns of activity which may indicate neurological abnormalities e.g epilesy
studying the brain: ERP (Event-Related Potentials) (3)
- teases and isolates neural responses associated with specific tasks (more finely tuned than EEG data)
- statistical averaging technique - extraneous activity from EEG filtered out, leaving only specific task responses
- ERP - types of brainwaves that are triggered by particular tasks/cognitive responses e.g attention
what is a biological rhythm?
distinct patterns of changes in body activity that conform to cyclical time periods, influenced by internal and external body clocks
what is a circadian rhythm?
biological rhythm, subject to a 24 hour cycle, that regulates a number of body processes like the sleep/wake cycle and changes in core body temperatures
what is an internal body clock?
biological changes= endogenous pacemaker
what is an external body clock?
environmental changes= exogenous zeitgebers
what is an ultradian rhythm?
rhythm that occurs many times during the day, frequency of more than one cycle in 24 hours
what is an infradian rhythm?
rhythm that takes longer than a day to complete, frequency of less than one cycle in 24 hours
what are examples of a circadian rhythm?
sleep/wake cycle, core body temperature
how is the sleep wake cycle affected?
by daylight- tend to feel sleepy at night and awake during the day
have an internal pacemaker- biological clock= suprachiasmatic nucleus, lies above optic chiasm which proides information from the eye about light
light can reset the suprachiasmatic nucleus
what happened in the case study of Siffre?
caveman who spent several extended periods underground to see the effect of his own biological rhythms, deprived of exposure to natural light and sound but had adequate food and drink, resurfaced in mid September 1962 and thought it was August, biological rhythm settled to just beyond 25 hours but continued to sleep and wake on a regular schedule
what happened in Aschoff and Wever’s study?
participants spent four weeks in a WW2 bunker deprived of natural light
all but one participants displayed a circadian rhythm between 24 and 25 hours
what are the conclusions from research into the sleep wake cycle?
natural sleep/wake cycle slightly longer than 24 hours but entrained by exogenous zeitgebers associated with our 24 hour day
what happened in Folkard et al’s study?
studied a group of 12 people in a cave for 3 weeks
went to bed when the clock said 11.45pm and rose when it said 7.45am
researchers gradually speeded up the clock so a ‘24 hour day’ only lasted 22 hours
only one of the participants could adjust to the new regime
what type of rhythm is the menstrual cycle?
infradian rhythm
what happens in the menstrual cycle?
monthly changes in hormone levels that regulate ovulation
typically lasts between 24 and 35 days
rising level of oestrogen causes ovulation
after ovulation, progsterone prepares the body for pregnancy
what did Stern and McClintock’s research show?
29 women with a history of irregular periods
pheromones were gathered from 9 of the women at different stages of their menstrual cycles via a cotton pad in their armpit
pads worn for at least 8 hours
pads were treated with alcohol and frozen to be rubbed on the upper lip of the participants
68% of women experienced changes to their cycle of their ‘odour donor’
suggests that although the menstrual cycle is endogenous it may be influenced by exogenous factors
what is seasonal affective disorder?
mental disorder that occurs seasonally, main symptoms are low mood, lack of activity and interest in life
what type of rhythm is seasonal affective disorder?
circadian rhythm
what do psychologists suggest is the cause of SAD?
hormone melatonin
pineal gland secretes melatonin until dawn when there is an increase in light
during winter, lack of light in the morning means this continues for longer
knock on effect on serotonin production
what type of rhythm is the sleep cycle?
ultradian rhythm
how many stages of sleep are there?
5
how long does a cycle of sleep last?
approximately 90 minutes
what happens in stage 1/2 of sleep?
light sleep where a person may easily be woken
brainwaves become slower and more rhythmic at the beginning of sleep (alpha waves) and these become slower as sleep becomes deeper (theta waves)
what happens in stage 3/4 of sleep?
delta waves are slower and have a greater amplitude than earlier waves
slow wave sleep, hard to wake someone
what happens in stage 5 of sleep?
REM
body paralysed but brain activity resembles that of someone who is awake
rapid eye movement occurs
when dreaming occurs
what is an endogenous pacemaker?
internal body clock that regulates our biological rhythms
what is an exogenous pacemaker?
external cues that entrain our biological rhythms
what is the suprachiasmatic nucleus?
bundle of nerve cells that is located in the hypothalamus, is a primary endogenous pacemaker which influences circadian rhythms
how does the suprachiasmatic nucleus process light?
receives information about light from the eyes, which has been processed by the visual area in the occipital lobe, and is relayed to the SCN via the optic chiasm between hemispheres
SCN processes info and triggers different rates of release of melatonin from the pineal gland
increased melotonin decreases serotonin levels
