PSY1003 WEEK 3 PART 1

Question 1

what are CAT/CT scans

Answer 1

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

Question 2

what is MRI

Answer 2

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

Question 3

what are positives of using MRI

Answer 3

high resolution images from using radio-frequency waves from H atoms emitting when aligning with a magnetic field
high spatial resolution, 3D

Question 4

what is diffusion tensor imaging

Answer 4

magnet-based, identifies pathways of water molecule diffusion,
provides image of major tracts (axon bundles) has become major focus of current research

Question 5

what are contrast x-rays

Answer 5

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

Question 6

explain fMRI

Answer 6

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

Question 7

what is BOLD

Answer 7

blood-oxygen-level-dependent signal

Question 8

what is hyper-remia

Answer 8

blood carries glucose and oxygen to active brain parts

Question 9

what are advantages of fMRI

Answer 9

nothing injected, provides structural and functional info
high spatial resolution
3D

Question 10

what are disadvantages of fMRI

Answer 10

poor temporal resolution
2-3 seconds to measure BOLD signal

Question 11

what is EEG (electroencephalography)

Answer 11

electrode net to record electrical activity and reflect sum of electrical events (AP, post-synaptic potential, skin and muscle electrical signals)

Question 12

what are advantages of EEG

Answer 12

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

Question 13

what are disadvantages of EEG

Answer 13

poor spatial localization due to scalp recording and better to determine when not where cognitive process occur

Question 14

what are ERP’s (event-related-potentials)

Answer 14

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

Question 15

state 3 psychophysiological methods of studying brain

Answer 15

EEG. ERP, MEG

Question 16

what are sensory-evoked potentials

Answer 16

change in cortical EEG signals elicited by momentary presentation of sensory stimuli

Question 17

what is MEG (magnetoencephalography)

Answer 17

measure magnetic field change on scalp produced by changes in neural activity patterns

Question 18

what is PET (positron-emission tomography)

Answer 18

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

Question 19

give one main weakness of what PET can produce

Answer 19

not specific brain picture, just radioactivity map so how it actually maps onto brain structure has to be estimated - use MRI alongside also

Question 20

what can PET be useful in

Answer 20

identifying interesting molecule distributions by injecting ligands to bind to molecules

Question 21

give some psychophysiological measures of ANS activity

Answer 21

skin conductance - electrodermal activity (skin conductance level (SCL) and skin conductance response (SCR))
cardiovascular activity - HR BP

Question 22

give some psychophysiological measures of SNS activity

Answer 22

muscle tension - EMG (electromyography)
eye movement - EOG (electrooculograhy)

Question 23

what is intracellular recording

Answer 23

insert electrode into soma and record moment-by-moment membrane potential fluctuation

Question 24

what is extracellular recording

Answer 24

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

Question 25

name 2 methods of stimulating neuron

Answer 25

electrical and optogenetic

Question 26

outline electrical neuron stimulation

Answer 26

use stimulating electrode in brain tissue

Question 27

outline optogenetic neuron stimulation

Answer 27

change neuron to make it light sensitive
activate via shining a light

Question 28

what are opsins

Answer 28

light sensitive proteins causing a neural light switch
light sensitive ion channel
inserting opsin gene into neuron allows hyperpolarisation/depolarisation from lights

Question 29

what is TMS

Answer 29

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

Question 30

what is tDCS

Answer 30

transcranial direct current stimulation
stimulate cortex area through electrodes on scalp to temporarily increase brain area activity while assessing cognitions, behaviour

Question 31

what is GFP

Answer 31

green fluroescent protein - exhibit green in blue lights, mostly in neuroscience researching

Question 32

give some lesion methods

Answer 32

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