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
Brain scanning
MRI (Magnetic Resonance Imaging
records the energy produced by molecules of water once the magnetic field is reduced, it is a still picture produced
Brain scanning
fMRI (Functional Magnetic Resonance Imaging)
works in a similar way to MRI’s, however, instead of measuring energy emitted from water, it measures the energy released by haemoglobin and is a moving picture.
