PSY1003 WEEK 3 PART 1 Flashcards
what are CAT/CT scans
computerised tomography
computer-assisted x-ray rotated over head, sometimes including constrast agents
produces horizontal slices put together to from 3D image showing structural abnormality
what is MRI
magnetic fields cause Hprotons to align in same orientation
pass radio frequency wave through head, protons relax and emit electromagnetic energy, picked up by MRI
different tissue types produce different signals
what are positives of using MRI
high resolution images from using radio-frequency waves from H atoms emitting when aligning with a magnetic field
high spatial resolution, 3D
what is diffusion tensor imaging
magnet-based, identifies pathways of water molecule diffusion,
provides image of major tracts (axon bundles) has become major focus of current research
what are contrast x-rays
inject substance absorbing x-rays less or more than surrounding tissue, heightens contrast
eg:- cerebral antiography is infusion of radio-opaque dye into cerebral artery to visualise cerebral circulatory system
explain fMRI
neurons cannot store fuel so need constant supply, blood carries O2 and glucose to active parts showing BOLD response/haemodynamic response
oxygenated blood has magnetic properties influencing radio-frequency waves emitted by H atoms in MRI
what is BOLD
blood-oxygen-level-dependent signal
what is hyper-remia
blood carries glucose and oxygen to active brain parts
what are advantages of fMRI
nothing injected, provides structural and functional info
high spatial resolution
3D
what are disadvantages of fMRI
poor temporal resolution
2-3 seconds to measure BOLD signal
what is EEG (electroencephalography)
electrode net to record electrical activity and reflect sum of electrical events (AP, post-synaptic potential, skin and muscle electrical signals)
what are advantages of EEG
high temporal resolution (instant signal detection),
direct reflection of neuronal activity,
cost less than fMRI
produces ‘wave-picture’ so in epilepsy shows characteristic change when epileptic fits about to happen
what are disadvantages of EEG
poor spatial localization due to scalp recording and better to determine when not where cognitive process occur
what are ERP’s (event-related-potentials)
ERP’s are background waves from EEG responses to stimuli
ppt listen to sound many times, average brain waves for when sound occureed to remove background activity and find brain region relating directly to sound
study sensory-evoked potentials
state 3 psychophysiological methods of studying brain
EEG. ERP, MEG
what are sensory-evoked potentials
change in cortical EEG signals elicited by momentary presentation of sensory stimuli
what is MEG (magnetoencephalography)
measure magnetic field change on scalp produced by changes in neural activity patterns
what is PET (positron-emission tomography)
radio-activity based and shows activity
inject FDG into carotid artery, taken up by active cells but not metabolised so accumulate in active neuron, showing levels of radioactivity in horizontal brain levels
give one main weakness of what PET can produce
not specific brain picture, just radioactivity map so how it actually maps onto brain structure has to be estimated - use MRI alongside also
what can PET be useful in
identifying interesting molecule distributions by injecting ligands to bind to molecules
give some psychophysiological measures of ANS activity
skin conductance - electrodermal activity (skin conductance level (SCL) and skin conductance response (SCR))
cardiovascular activity - HR BP
give some psychophysiological measures of SNS activity
muscle tension - EMG (electromyography)
eye movement - EOG (electrooculograhy)
what is intracellular recording
insert electrode into soma and record moment-by-moment membrane potential fluctuation
what is extracellular recording
microelectrode in extracellular fluid next to neuron recording electrical disturbances from neuron fire
in multiple-unit recording use larger tip to pick up signals from many neurons and integrate to show total number of recorded AP per time unit
name 2 methods of stimulating neuron
electrical and optogenetic
outline electrical neuron stimulation
use stimulating electrode in brain tissue
outline optogenetic neuron stimulation
change neuron to make it light sensitive
activate via shining a light
what are opsins
light sensitive proteins causing a neural light switch
light sensitive ion channel
inserting opsin gene into neuron allows hyperpolarisation/depolarisation from lights
what is TMS
transcranial magnetic stimulation to turn of cortex using magnetic fields created by a coil
measure disruptive effect on cognition and behaviour
major issues on safety
what is tDCS
transcranial direct current stimulation
stimulate cortex area through electrodes on scalp to temporarily increase brain area activity while assessing cognitions, behaviour
what is GFP
green fluroescent protein - exhibit green in blue lights, mostly in neuroscience researching
give some lesion methods
aspiration lesions (suction off cortex tissue)
radio-frequency lesions (targeted high frequency current)
knife cut sectioning to eliminate nerve/tract conduction
reversible lesions through cooling target areas or injecting anestheti
