ways of investigating the brain Flashcards
spatial resolution
level of accuracy in identify the axact location of brain structure in space (where it happened)
temporal resoultion
level of acuracy in identifying the exxact lcoation of brain structure in time (when it happened)
FMRI
detects changes in blood oxygenation due to neural activity in specific brain parts
when brain more active, requires more oxygen , due to demand oxygenated blood is directed towards the area which is active
known as the haemodynamic response
produces 3d acitvity maps
which shows where blood is flowing and where is most concentrated
adv and dis of FRMI scans
good spatial resoultion. pictires we recive are clear of how functions are localised
strightforward to use
virtually risk free
dis-expensive and can only capture good picture if person is completely still
measure blood flwo therefore not looking at nrueons in brain, gives lesss sepcific insight into neural activity of brain
EEG
measures electical aciity
electrodes are attached to individuals scalp using sjull cap
acan recording reprent brain wave patterns
often used as diagnostic tool for abnormilities such as elipespy
adv of EEG
very useful in diagnostic of psychological conditions e.g eplepsy
high temporal resoultion as it can detect brain acitvity within a millisecond
dis of EEG
poor spatial resoultion as cannot pinpoint exact locationn of neural activity
signals can also be missed
ERP
more specific EEG recordings by eliminating all extraenous neural acivity and taking a statisticsal averge of activity relevent to task being performed
adv of ERP
more spefic
has good temporal resoultion which means clear understanding of time at whcih happened
dis of ERP
bakground noise and extrenous variables must be elimited which is not always easy to achieve
Post mortems
looking at persons brain after death
those subject are often those with rare disorders ir experinced unusual deficits in their lifetime
areas of damage are assessed after death
adv of post mortems
provided foundaition for the understanding of processes in the brain
e.g karl wernicke and paul broca both relied on this to establish links betweeen the brain, behaviour and language
dis of post mortems
ethical issues as in formed conset is not always given before persons death
e.g HM was unable to give his consent but they did the reserach still anyway after his death
what is a biological rythmn
distinct patterns of changes in body activity that conform to cyclyical time periods
can be influenced by internal body coacks (endogenous pacemakers) or external changes to enviroment (exogenous zeitegbers)
circaidan rythem
type of biological rythem which operates on a 24 hour scheldule
regulates bodily processes e.g sleep/wake cycle and core body temp
cicadian clock
regulates core bood temp, urine production
most important hormone affected by ciracdian clock is melotonin, produced in pineal gland chemically causes drowsiness and lowers body temp
cortisol produced in adrenal gland used to form glucose sugar
located in SCN (suprachiastic nucleus) in hypothalamus of brain
SCN-contains thousands of neuorns
has responsibility of sending signals to other parts of brain to regualte sleep, wake cycle and body temp andd more
core body temp
core temp- usualy reaches its minimum around 4:30-5:00 am in the morning for adults
melatonin-abesnt during daytime hours
begins to be produced around 8-9 at night and stops 7-8 in morning
sleepiness-deepest tendancy to sleepiness ccurs in middle of night around 2-3 am along with shorter shallower preiod of sleepiness around 12 hours after, around 2-3pm in afternoon
adv of sleep wake cycle
application to shift work
lead to desynchronisation of circadian rythmns abd can lead to psychological effects
research shown that night shift workers fuffer conenration at 6 am, increasing likekihood of accidents and they are also 3 times more likely to suffer from heart disease as a refuly from stress adjusting to sleep/wake cycle
shows it is intollerant to any major alternations to sleep and wake cyeles through processes such as shift work or jet lag
adv of sleep wake cycle
support from cave study
micheal siffre spent two months in caves of southern alps deprived of sunlight and sound, determining circaidan rythems remained between 24-25 hours
assumed that only natural light has an influenve on biological rythmns,
mean may lack valdiity
what are infradian rythms
biological rythem with a frequency of less then one cycle in 24 hours
what are ultradian rythms
biological rythemn with frequency of more than 1 cycle in 24 hours
examples of infradian rythms
Menstual cycle-governed by monthly changes in homrone levels within femaless, whcih govern ovulation
Seasonal affective disorder(sad)-depressive disorder with pattern of onset wich varie every season