Methods in cognitive neuroscience I Flashcards
what is cognition?
the mental aciton or process of acquiring knowledge and understanding through thought, experience, and the senses
what is cognitive science?
study of mental processes involved in cognitive processes in computational terms
what is cognitive neuto?
extension of cognitive science, aimed at discovering the neural substrates that support the various cognitive processes
what are the 7 levels of NS organisaiton
CNS systems maps networks neurons synapses molecules
what are marrs three levels of analysis
computational -> algorithmic -> implementaiton
what is the computaitonal level
identify the problem and decompose into main constitutes
what is the algorithmic level
specifies formal procedure to perform task
what is implementation level
how to solve the problem
what is an example used to represent marrs levels? and what questions are asked at each level
median
problem: what is the median of these numbers
computational: how can i find the median? steps: sorting , counting, finding 50% mark
algorithmic: writing computer programme using specify algorithms to achieve sorting
implementation: running the programme on a computer
what is the doctrine of independence?
address given problem at given level independent of implementation
what is determinism?
scientific reduction- wholes are nothing but their parts
describe determinism
philosophical belief that all current and future events and actions can be predicted ina dvance- if all parameters are known
what are two examples of determinism
chaos theory: idea that system and future state depends on itial parameters chosen
quantum theory: heisenbergs uncertainty principle
what is emergence
wholes are more than the sums of their parts
what is an emergent property
purely physical system composed exclusively of bits of matter, when it reaches a certain degree of complexity, can begin to exhibit genuinely novel properties not possessed by simpler constitutes
what are two examples of when emergence can occur in neuro?
sleep and consciousness
what is an example of an emergent proprty
heart muscle - lots of cells with different functions but do not work unless all put together
what is multiple realizability
functional system properties can in pronciple be instatiated by indefintely many distinct physical structures
what is the functionalist theory of mind
what makes something a mental state of a particular type does not essentially depend on its intrinsic material constituations, but rather on the way it functions in the system to which it belongs
what are three examples of multiple realizability
musical notes sound different on different instruments
octopus consciousness- we cannot know as their brains are different to ours
plato in a cave- flame reflections
what are two important considerations of neuroimaging techniques?
spatial and temporal resolution
what is the oldest data collection method?
lesion studies for suggesting localisation of function
what are three examples of lesion studies?
phinease gage
brocas patient ‘tan’
patient HM
what are three different methods for lesion studies?
physical lesions
pharmological lesions- inject poison into brain
reversible lesions- colling, TMS
what are the advantages of lesion studies?2
can provide info about function of specific region
natures experiments
what are three disadvantages of lesion studies?
how precise/specific lesions are
how to interpret the effects
recovery process- plasticity
what is TMS
transcranial magnetic stimulation and is a technique for inducing virtual lesions or temporarily exciting neurons
what is the main principle of TMS?
rapidly changing magnetic fields -> induction of electrical current
what is the process of TMS?
coil placed near head and very brief, large current ran through brain
what does TMS lead to and cause?
leads to induction of strong transient magnetic field and this induces current in neurons in the brain
causes activation, inhibition or stimulation
what can tMS be used for?
to distinguish between models
what are the advantages of TMS? 4
study healthy participants
inexpensive
good temporal resolution
controlled stimulation
what are 6 disadvantages of TMS?
noisy low spatial resolution small risk to enduce epilepsy effects mood local pain and headache burns on scalp
what is tDCS
transcranial direct current stimulation- shows that electrical stimulation can change cortical excitability
what are the two mechanisms of tDCS
cathodal stimulation
anodal stimulation
what is cathodal stimulation
negative
hyperpolarisation of neuronal membranes-> decrease in firing rate and excitability
what is anodal stimulation
depolarisation of neuronal membranes-> increase in firing rate and excitability
what are the short term and long term effects of tDCS
mins- polarisation effects on the neuronal membranes
hours- modulation of NMDA receptor strength or changes in transmembrane proteins
describe tDCS motor cortex stimulation
the MEP amplitude increased with anodal and decreased with cathodal current stimulation
what is MEP
motor evoked potential
what is the ADM muscle and what is it related to
abductor digit minimi and DC stimulation via tDCS
what are three advantages of tDCS
study healthy participants
inexpensive
controlled neuromodulation
what are 4 disadvantages of tDCS
considered safe under 20 mins
low spatial resolution
not used in participants on certain meds
local itchy and mild headaches
what are two less/non-invasive imaging techniques
haemodynamic and electromagnetic
what are three haemodynamic techniques
Positron emmission topography (PET)
functional magnetic resonance imaging (fMRI)
optical imaging NIRS
what are two electromagentic imaging techniques
electroenchephalography (EEG)
magnetoencephalography (MEG)
how do PET scans work?
inject/inhaled radioactive material
when in bloodstream it goes to areas of brain that use it
oxygen and glucose common as they accumulate
the isotopes emit positrons
these collide with electrons and emmit two photons in opposite directions
where does radioactive material accumulate in brain
in areas with increased metabolism
what are three advantages of PET scan
used to measure metabolism and blood flow
used in humans in conjunction with behavioural studies
used within psychopharmacological studies
what are four disadvantages of PET scans
very expensive
poor temporal resolution
only moderate spatial resolution
invasive procedures
what is an MRI for
anatomy, one scan for brain structures
what is an fMRI for
brain function
what is a BOLD signal
blood exygentaiton level dependent response
indirect measure of neural response - increased blood flow represents increased neural activity
