Research methods in biopsych Flashcards
what is a CAT scan?
many x-rays of brain
how do CT scans work?
dye injected
what is a limitation of CAT and CT scans?
exposure to radiation
what are MRIs?
powerful magnetic field , using magnetic probabilities of hydrogen in the body
How do MRIs work?
Radiofrequency pulse flips hydrogen atoms out of alignment which emits energy a detector ray around the patient’s head detects this which forms an image of the brain, different tissues or substances emit energy at a different speed.
limitation of MRI?
❌ patient can’t move
What is an EEG? purpose?
- EEG - records electrical activity of neurons, electrodes on the scalp
Records spontaneous activity
What is an ERP?
instant recording of brain activity on the millisecond-scale
limitation of ERP?
❌spatial resolution is poor
what is a MEG?
similar to EEG, records magnetic fields generated by electrical activity of neurons (helmet)
What is a PET scan? purpose?
records the emission of radioactivity from injected chemicals , chemical accumulates in certain brain areas - detectors build up a 3D picture of activity in the brain
limitation of PET scan?
❌radioactive substance, low temporal resolution , expensive
what is a fMRI? how does it work?
same basic principles as MRI , based on haemoglobin
stronger signals emitted from the hydrogen atoms in brain areas with more haemoglobin with oxygen (BOLD response)
What are micro-electrode recordings ?
- thin electrode inserted into the brain
only for animals in research but can be for adults in neurological surgeries , great temporal and spatial resolution
limitation of micro electrode recordings?
❌invasive
what is double dissociation (brain damage) ?
Link between brain area and function suggestive of localisation of function but not proof , find two patients with mirror deficits , then those functions must be independent systems
what is a lesion?
intentional damage to a selected brain area in lab animals only. sham lesions are used as a control comparison.
what is an ablation?
complete removal of a brain area
What is transcranial magnetic stimulation? (TMS)
= temporarily inactivates the neurons below the magnet
= certain cognitions and behaviour can be studied with brain regions areas inactive and active
How does electromyogram (EMG) measure muscle tension (psychophysiological activity) ?
- electrodes taped to the surface of the skin
- eyes and skin and muscles
- uses moisture on skin
- skin conductance - the ability of skin to conduct electricity
- cardiovascular activity
What is a closed head injury?
Sharp blow to the head
diaschisis ?
decreased activity of surviving neurons after damage to other neurons
collateral sprouts (axon sprouting) definition?
axons that are formed to take over the vacant synapses - can encourage and inhibit recovery depending on what area of the brain is damaged
denervation supersensitivity?
remaining synapses become more responsive more easily stimulated
phantom limb?
a continuing sensation of an amputated body part
deafferented limb definition ?
a limb that has lost its sensory input
what are the two classifications of strokes?
haemorrhagic (less common and usually fatal)
or ischemic
How are strokes treated?
- a drug called tissue plasminogen activator breaks up blood clots, giving stroke patients better survival prospects
- cooling the brain can alleviate strokes as well as cannabinoids
give 3 factors that limit axon regeneration after stroke trauma
- cut in nervous system causes scar barrier (blocking regrowth)
- neurons on either side of the cut pull apart
- glia cells that react to CNS damage which releases chemicals that inhibit axon growth
= protein bridges are built to combat this
