Dit is dé samenvatting van 'Cognitive Neuroscience' gegeven aan de faculteit sociale wetenschappen op de Universiteit Utrecht. Het is een erg volledige samenvatting van het vak en verschaft genoeg infromatie om het tentamen te halen. Desalniettemin bevat het veel informatie over onderwerperen die ...
Neuroscience and cogniton is a very good class that will teach you all about cognitve
functoning and the brain hhe lectures for the absolute basis for the uuestons asked in
the exa Making this su ary was y way of studying for both exa s and y fnal grade
was a 9 out of 10 I hope this su ary will help you obtain the sa e ark!
Methods of measurement in cognitie neuroscience
EEG
What does it easure?
EEG easures diferences in voltage across the scalp caused by post-䝬synaptc potentals
(PSP) hhese can be both excitatory and inhibitory EEG does not easure a single acton
potental bot a local feld potental: a su aton of actvity of any neurons EEG easures
Event related potentals (ERP) Because the signal around the scalp is best, it easures
ainly actvity in the gyri and the edges of the sulci
When is the easure ent good?
When (1) any neurons have the sa e align ent, in other words, there is a lot of aligned
actvity, and (2) the actvity is synchronieed, not individual acton potentals but fring at the
sa e t e EEG is good at easuring (3) actvity close to the scalp, because the scalp and
skull s ears out the signal, actvity close to the scalp is clearer than deeper actvity (4)
Electronic devices should be switched of because they can interfere with the data
1 Mass actvity
2 Synchronieed actvity
3 Close to the scalp
4 No noise sources
Electrode layouts
32 – 64 electrodes are enough to easure P100,
N200, P300 etc
P100 is P1, the frst positve response occuring at
around 100 s N2 is the second negatve
response occurring around 200 s
128 electrodes are enough for localieaton
Advantages: EEG vs MEG
MEG easures a agnetc feld, whereas EEG easures voltage potentals hherefore, MEG
is ore accurate and has better localieaton because of less distortons by the skull
EEG is cheaper and can easure ore neurons For both the spatal resoluton is OK
MEG can easure deeper area’s and area’s that point to the side of the skull instead of to
the top of the skull, which can be easured by EEG
When you are interested in efects over t e at a high te poral resoluton (e g p100)
In so e cases useful for the localieaton of neural loci
EEG Waves
Aroused = low a plitude, high freuuency = fast waves
Relaxed = high a plitude, low freuuency = slow waves
Here = freuuency per second
Ga a (32+he) and Beta (16+he) are waves during arousal
Alpha waves (8+he) are waves during relaxaton
hheta waves (4+he) are waves during sleep
Delta waves (4-䝬he) are waves during deep sleep
Co a waves are even less actve
Diferent freuuencies refect a diferent arousal state
Event-䝬related potentals
Find epochs (responses) around st ulus presentatons ERP are not very clear in a single
trial because of the background EEG waves Over 50 trials are needed to get a noise free
average of ERP ERP can be easured using the peaks and troughs (P100, N200, P300 etc)
after presentng a st ulus
hhese can be used to easure a plitudes and latencies of peaks and troughs, the a ount
and the t ing of actvity and the fne changes in potentals in response to st uli
Brain source localieaton
Multple electrodes, and looking at the diferences between the can help us localiee brain
source hhe potental sources can help ake a odel of dipoles
Su ary Workgroup EEG
Event Related Potentals easure post synaptc potentals surrounding dendrites hhese
potentals are created by actvaton of receptors on these dendrites In ERP, the extracellular
potentals can be picked up outside the scalp without signifcant t e delay hherefore, these
potentals can be tracked fro illisecond to illisecond, and thus have a very high
te poral resoluton
Magnetc Resonance I aging (MRI) relies on interactons of a agnetc feld with brain
tssue and easures the agnetc propertes of that tssue It allows the reconstructon of an
i age by recording any points in space
Structural / anato ical MRI
Structural MRI i ages tssue depending on agnetc propertes, for exa ple gray and white
atter It was nor ally designed to highlight diferences between gray and white which are
pretty clear in i ages, but it can also be used to analyee tssue changes in health and
disease ho allow us to look at a 3D odel of the brain instead of looking at slices, co puters
are used
Difusion hensor I aging (DhI)
DhI, so et es also called, difusion MRI, easures the directon of water ove ent by
co paring responses to agnetc felds in diferent directons hhen it co bines this
infor aton into neural fber bundles Following fbers allows us to ap connectons
between brain areas in health and disease
fMRI
fMRI easures how tssue agnetc interactons change over t e and exa ines changes in
blood fow and oxygenaton over t e hhis allows us to easure neural actvity changes
while subjects are exposed to a st ulus or task, and show us the part of the brain that is
actve during the perfor ance of this task
A diference between structural MRI and fMRI is that structural MRI i ages are a lot clearer
hhat’s because structural MRI shows contrast between diferent tssue types, with lots of
spatal detail fMRI is opt ieed to show the level of blood fow and oxygenaton fMRI does
have a te poral resoluton, for it can be easured every 2 seconds and give us an i age of
brain actvity over t e
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