College aantekeningen
Notes college 1
- Vak
- Instelling
Notes of college 1 about EEG and ERP
[Meer zien]Voorbeeld 2 van de 5 pagina's
Voorbeeld 2 van de 5 pagina's
In winkelwagen
In winkelwagen
Verkoper
Volgen
Veravdl
Voorbeeld van de inhoud
Lecture 1 – Introduction to EEG & ERPEEG measures the difference in electrical potential between 2 points on your scalp. Electrode
on the mastoid bone because a reference location is needed. Mastoid bone is a decent neutral
reference with little brain activity, but quite close to the other sensors in the cap. Difference
between voltage measured at each sensor in the cap and reference electrode(s).
Here you see the difference in electrical potential between sensor and reference location.
Scale in micro volts (really tiny differences in electrical potential).
Peaks: eye activity blinks. Eyes are magnets. These are picked up by EEG.
Other peaks are muscle activity and not the brain. Because muscles are also driven by
electrical signals. When participant sits relaxed in the chair, the EEG will look cleaner. Blood
circulation is also seen in EEG.
Rythms in the brain
Delta: in adults in slow-wave sleep. Also seen normally in babies.
Theta: seen when very relaxed or meditation.
Alpha: emerges when eyes closed and in relaxed state.
Beta: associated with movement (across motor cortex) and active thinking.
Gamma: coordination between neurons?
Summary 1
EEG measures the difference of electric potential
Between: one or more electrodes placed on the scalp.
Versus: one or more reference electrodes placed on a “neutral” reference location.
EEG records mostly sources of interference:
Eye movement and blinks
Muscle movements
Heart beats
Any nearby electromagnetic activity
EEG also records brain activity:
Some rhythmic activity can be seen by “eyeballing” the EEG (used in hospitals)
Many types of activity only revealed by data analysis (cognitive science). For
example: Event Related Potentials (ERPs)
, Event Related Potential Analysis
Everytime the card you picked shows up, you get a little spike in your EEG signal P300
potential. We can detect this potential. You can’t see this with eyeballing, so we need data
analysis.
Frequency filters
Lowpass filter: will only keep waves who are slower than the given threshold. For example:
only keep waves slower than 2hz.
Highpass filter: will only keep waves who are faster than the threshold.
Bandpass filter: frequency range. E.g. 2-10hz.
Epochs: snippets of EEG. Cut-out seconds of EEG data.
For all the cards epochs were selected. To isolate the data is to create an average Event-
Related Potential = average. The brain activity unrelated to it will be different every time a
card is shown. These differences over time will level out because sometimes negative and
sometimes positive = 0. Only retain the portion of signal which is consistently the same every
time we present the stimulus.
Comparing ERP’s
Baseline period: time leading up to presentation of the stimulus. Some start positive and some
negative. Baseline correction: all of the stimuli need to start on 0.
P300 effect: by choosing one of the playing cards we split the game into 2 groups. The chosen
card versus the other cards. We no longer distinguish between the other cards.
ERP component naming scheme
P = positive
N = negative
Number indicates: milliseconds after onset or peak number.
Communication flow:
Axon of one neuron is connected to dendrite of another neuron. Neurotransmitters are
released, which are ionic charged particles. They are received by receptors on dendrites. This
is how communication flows. If we have enough neurons firing at the same time, in the same
direction all the electrical charges add up and then we can measure in the order of micro volts
a little tiny potential difference.
Dit zijn jouw voordelen als je samenvattingen koopt bij Stuvia:
Bewezen kwaliteit door reviews
Studenten hebben al meer dan 850.000 samenvattingen beoordeeld. Zo weet jij zeker dat je de beste keuze maakt!
In een paar klikken geregeld
Geen gedoe — betaal gewoon eenmalig met iDeal, creditcard of je Stuvia-tegoed en je bent klaar. Geen abonnement nodig.
Direct to-the-point
Studenten maken samenvattingen voor studenten. Dat betekent: actuele inhoud waar jij écht wat aan hebt. Geen overbodige details!
Veelgestelde vragen
Wat krijg ik als ik dit document koop?
Je krijgt een PDF, die direct beschikbaar is na je aankoop. Het gekochte document is altijd, overal en oneindig toegankelijk via je profiel.
Tevredenheidsgarantie: hoe werkt dat?
Onze tevredenheidsgarantie zorgt ervoor dat je altijd een studiedocument vindt dat goed bij je past. Je vult een formulier in en onze klantenservice regelt de rest.
Van wie koop ik deze samenvatting?
Stuvia is een marktplaats, je koop dit document dus niet van ons, maar van verkoper Veravdl. Stuvia faciliteert de betaling aan de verkoper.
Zit ik meteen vast aan een abonnement?
Nee, je koopt alleen deze samenvatting voor $3.51. Je zit daarna nergens aan vast.
Is Stuvia te vertrouwen?
4,6 sterren op Google & Trustpilot (+1000 reviews)
Afgelopen 30 dagen zijn er 72056 samenvattingen verkocht
Opgericht in 2010, al 15 jaar dé plek om samenvattingen te kopen
Laatst bekeken door jou
Overig ·
L'amore magazine
College aantekeningen ·
chapter 1
Overig ·
Copy work
Samenvatting ·
GIT EXAMINATION
Overig ·
socrates carpio
Overig ·
No presencial 9
