Tools of Cog Neuro Flashcards
What three techniques are considered “perturbation approaches”
TMS, introducing exogenous neurotransmitter/drug and lesions
what assumptions are made when you use a perturbation approach
that the changes you induce cause changes to behavior (measured/dependent variable)
what are some limitations to natural lesions?
No way to measure temporal aspects, we assume other regions function normally, plastic brains may begin to recover behavior, assumes a mapping between anatomical regions and cognitive function
Pros/cons of experimental lesions?
PROS: can control site and size of lesion (replicability, and can make more relevant to hypothesis) CONS: animal training can be difficult/time consuming, some may have ethical concerns
what is TDCS, what is it used for, and what are the limitations?
passing current thru 2 electrodes placed on a surface of the scalp, used to interrupt function in areas between electrodes. Low spatial resolution, and cannot stimulate deep brain areas, mild seizure risk.
TMS?
Used a magnetic field to induce a current in the brain rather than directly stimulate it. Due to RHR, the 8 ring is the best way to get a localized current to stimulate
single stimulation versus repeated
single is good for mapping excitability, perception/motor areas, or determining temporal relationships by stimulating at different points in time. Rapid is good for getting at interactions of functional units in the brain, and can be used as a temporary lesion.
SINGLE and MULTI unit studies refer to
recording from a single or group of neurons. measures relationship between firing rate and external stimulus plasticity/learning/memory/perception
EEG measures
the potentials created by the brain, measured from the scalp
MEG measures
basically the same thing except instead of potentials it’s the associated magnetic field
Pros of EEG
high temporal resolution(ms), noninvasive,
cons of EEG
inverse problem, skull “smears” signal because current runs better over the skull than through it (low spatial resolution)
what is the inverse problem
assigning scalp activity to a source is susceptible to the fact that a pattern of scalp activity could be produced by many sources in the brain… it makes assumptions
what do you need for EEG to work
a large number of parallel, synchronous pyramidal neurons
MEG vs EEG?
EEG measures radial and tangential sources, it’s “smeared” signal whereas MEG is not (B field is unimpeded by tissue) both suffer from inverse problem but because MEG has only tangential sources it is simpler.
