ways of studying brain Flashcards
fMRI (Functional Magnetic Resonance Imaging)
-detects blood flow
-large magnets to detect oxygenised blood and show deoxygenised blood
- areas that are active, need more blood flow, =oxygenised blood + non active= deoxygenised
fmri evaluation
strengths
-Good spatial resolution of 1mm. Precisely identifying active brain regions and patterns of activation over time
-non invasive
-produces a moving picture
fmri evaluation
weaknesses
-expensive machine
–patients have to stay still
-normally small sample size
-poor temporal resolution: 1-4 secs
-causation: dont provide direct measure of neural activity, cant conclude wether area is associated w particular function
EEG (Electroencephalogram)
-electrodes placed on scalp
-there are 22-34 electrodes placed on scalp but can be 2-100 placed to record the brain activity
-activity is displayed in brain waves
-amplitude shows the brain intensity and the frequency shows the speed of activation
EEG + erp evaluation
strengths
-none invasive; dont use radition/ risk free
-cheaper + more available
-temporal resolution: every millisec so in real time
EEG + erp evaluation
weakness
-TR CP: uncomfortable so unrepresentitve findings
-spatial resolution: only detect in superficial areas so cant detect deep in brain
-Some cognitive process can not be studied using ERP as they are unable to be presented multiple times
ERP (Event-related Potential)
-ame apparatus and technique as EEG
-record when there is activity in reaction to a stimulus
-provides data using statistical averaging
-waveform’s peaks and dips show when cognitive processes happen in relation to when the stimulus is presented
ERP + EEGS differences
-ERPS; stimulus is presented to a participant + they looks for activity related to that stimulus where as eeg r continuous measure of electrical brain activity
ERP+ EEG similarities
-same equipment: electrodes attached to the scalp
Post Mortem Dissection
-examine and dissect brains of individuals who suffered from trauma/mental illness + compare with someone who had a neurotypical brain
-discovered brocas area
-broca had an epileptic patient, he stopped speaking.
-after death he did a PMD n found a lesion on the left temporal lobe- named broca area
-Broca’s aphasia is used today for patients who display problems producing speech
Post Mortem Dissection
strengths
-indivual is dead so unharmed
-can see deeper areas of brain others cannot
-fundamental in development of understanding of brain+ functions eg localisation
-detailed examination of anatomical + neurochemical aspects
post mortem support
iverson
-high concentration of dopamine in limbic system of patients w schizoprenia; promoted researcher into looking at neural correlates of this disorder
Post Mortem Dissection
weakness
-causation:defecit displayed in life time might not be related to defecit in brain
-extraneous factors: meds they take, age,
-No brain activity can be measured as the research is conducted on a dead person
-Brains could have been affected by the cause of death, effecting the results
-ethical issues; informed consesnt
Brain scanning
CAT (Computerised Axial Tomography)
uses an x-ray beam to produce a picture of the brain that shows the physiology of the brain, this is not a moving picture, but can show lesions on the brain
Brain scanning
PET (Position Emission Tomography)
involves injecting the patient with a radioactive glucose to produce a moving picture of the brain. The glucose goes to the seas of the brain with the most activity and so this is able to be picked up in the scan
