Biological Psychlogy Methods Flashcards
What is the scientific method?
Process of sytmeatically collecting and evaluating evidence to test ideas, understnad a topic and answer questions
What was Phineas Gage (1823-1860) known for?
- Large rod passing through his skull and damaged his frontal lobe
What is ablation?
Removal of brain area
What is lesion?
Damage of a brain area
What was special case about the rod passing through Phineas Gage?
- Few people have damage confined to just one brain area
Why distinguishing lesional mania from primary bipolar disorder difficult?
No clear difference in presenting symptoms
What is used in distinguishing lesional mania from primary bipolar disorder?
Prognostic marker
Is EEG continuous?
Yes
What is an Event Related Potential?
A stimulus triggers a change in electrical activity in th ebrain
What can be an example of an event?
- Visual/auditory stimulus
- Execution of a cognitive function
- Motor response
What must be taken into consideration before recording using a EEG?
Background noise
ERPs are evoked by events. What does this mean?
Electrical responses are time-locked to the events
What is signal average?
Noise and electrical reponses not time-locked will cancel out
How to get an ERR?
1) Get an EEG signal containing repitions of the event (trials)
2) Get a time window around the event of interest
3) Cut EEG into segments aligned to event markers, then compute the average of all segments
4) ERP waveforms have peaks showing the neural activites
How can a ERP component be defined?
One of the component waves of the more complex ERP waveform
What does each electrode site on the ERP have
A waveform
How can waveforms be plotted?
Scalp map
Purpose of a waveform at one electrode site?
Informing which condition in stronger than others at twhat time at what locations
What is single cell recording?
Response of individual neuorns or a group (population) of neurons
WHat is the purpose of single cell/ group cell recording experiments?
Determine what experimental manipulations produce a consistent change in the response rate of an isolated cell or cell population
What does single cell and group cell recording enable to determine?
Determine if the patterns have a casual role in a certain type of information processing
What is intracellularly
Records single cells
What is extracellularly recording?
Records the activity of a small set of neurons
How can intracllular signal cell recording occur?
In brains that:
- Have been removed and sliced
- Anethetised subjects
- Behaving subjects that cannot move
What are the use of electrophysiological methods?
Identify the response characterisitcs of cells in the visual cortex
How is cell recording from a human brain done?
Intracranial electrodes is inserted to localise the abnormality in preparation of the surgical resection
What is used in intracrancial recording in humans?
Electrocorticography (ECoG)
What tasks are adminstered in electrocorticography
visual and auditory processing
visual and auditory language processing
short-term memory
motor functions
How are electrodes placed on the brain surfacE?
Epidurally or subdurally
What is bioelectromagnetism?
A discipline that examines the eletric, electromagnetic and magnetic phenomena which arise in biological tissues
What happens when electrons travel along a wire?
A magentic field is produced around the electron
What position is the magnetic field around the elecric current in a wire?
perpendicular
What is the Magnetoencephalography for?
Direct extrnal recording of magnetic fields created by electrical currents in the cortex
What is the role of Magnetoencephalography (MEG) in neuroimaging?
Neural correlates of cognitive and perceptual processes
Localise affected regions before surgery, detrmine regional and network functionality
Who pioneered the Magnetoencephalography (MEG)?
David Cohen in 1968
How does Magnetoencephalography (MEG) detect magnetic signal?
Current flow from cortical neurons in both sulci and gyri
What are the similarities between MEG and EEG?
Both measure the same underlying neural currents
What are the differences between MEG and EEG?
Provide better spatial resolution than EEG
What does MEG measure?
Changes in magnetic flux density outside of the head
What does EEG measure?
Differences in electric potential at the scalp
Where is the MEG kept?
Magentically shielded room
Why is the MEG preformed with a dewar?
Contains multiple sensor coils wich do not touch the patient’s head
What is SQUID?
Super conductin quantum interference device
What is the SQUID kept in?
Liquid helium - refrigerant (around -250 C)
What are OPMs?
Optically Pumped Magentometers - does not require cryogenic cooling
Advantages of MEG?
- Non Invasive
- Direct measurement of neuronal function
- High temporal resolution (ms or less)
- Better spatial reosltuion than EEG
- Easy to use clincally
- Quiet
- Provide a more natural enviornment (e.g subject sitting up)
Limitations of MEG?
- Expensive
- Lower spatial resolution
- Low sensitivity depth
WHhat are the precinciples of bioelectromagnetism
- Pass current through coil
- Create magnetic fiel d
- Magnetic field induces a secondary current to the neurons below the stimulation site (depolarisation)
Why is the coil shape in TMS instrumentation important?
Determines how focused the induced current is - hence also the targetd brain area
What does it mean if coils have a larger dimensions?
Create an electric field that penetrates deeper but less focal than that of smaller coils
What is the purpose of a figure 8 coil?
Focal point of stimulation lies a tthe intersection of the two loops
Is 1cm^2 in area
What is the purpose of a circular coil
Induces a nonfocal ring shaped electric field maxmium potnetially stimulating a swath of brain regions uner the coil perimeter
What are the TMS protocols and parameters online?
- Stimulation is applied while the participant is perofrming a task
- Low frequency stimulation (less than 1ms)
- Produce transietn stimulation effects that modfiy coritcal excitability short term
What are the TMS protocols and parameters offline?
- Stimulation is applied before the participants perform a task
- Reptitive stimulation over serveral minutes
- Results in longer aftereffects (e.g modulation of cortical excitability)
What is pulse intensity?
Strength of stimulation
What is pulse frequency?
How many pulses in a sec
What is ITI?
Intertrain interval
Advantages of TMS?
- Reversible lesions
- May establish causal link between brain activation and behaviour
- Therapeutic benefits
Disadvantages to TMS?
- Risks to subjects
- Unpleasant for subjects
- Only regions on cortical surfac can be stimulated
- Localisation uncertainity
- Stimulation level uncertainty
