w2 neural time series analysis

Question 1

neural time series

Answer 1

recordings of ongoing brain activity

any data that we can represent over time: EEG, fMRI, a spike train (spike is 1, otherwise 0)

has sampling rate

in contrast to CT scan, structural MRI - they take a static image

Question 2

neural time series: spatial and temporal resolution

Answer 2

Question 3

amount of potassium and related voltage at rest

Answer 3

Question 4

voltages of the resting potential

Answer 4

Question 5

from action potentials to electrical fields in the brain

Answer 5

Question 6

local field potential

Answer 6

if you measure the input like from the one neuron recording, but from multiple neurons

the way to measure the combined activity of hundreds of neural cells

Question 7

electrical fields in the brain

Answer 7

all alligned in the same way, all active at the same time - field can be measured on the skull, because they are all just beneath the skull

collective activity of all the dipoles is building up into an electrical current that can activate the electrode

Question 8

what’s the important information that one could extract from the EEG recordings?

Answer 8

dominant frequencies

particular oscillation, in this case around 11 Hz, is dominant in the signal

Question 9

how to interpret Hz?

Answer 9

times per second

Question 10

what does 11 Hz means with relation to seconds?

Answer 10

11 times per second

so every 1/11 = 0.09 second it happens

Question 11

1 kHz in Hz and in seconds

Answer 11

1000 Hz

something happens 1000 times per second, so every 1/1000 = 0.001 second

Question 12

benefits of EEG

Answer 12

Question 13

drawbacks of EEG

Answer 13

Question 14

EEG studies design for cognitive science

Answer 14

EEG measurement should be complemented with behavioral task (behavioral measurement) that will guide into the interpretation of the results

Examples of behavioral tasks: accuracy rate (how big is the percentage of correct responses), reaction times (the easier something is - the faster somebody can answer to that. We know this from the previous research. And this would help to interpret the EEG measurements).

Question 15

what are the letters?

Answer 15

they are not the lobes, but the surface distribution

First letter: Anterior frontal, Frontal, Central, Central Parietal, Parietal, Occipital

Second character: z for zero, it’s in the middle, even for the right side, odd for the left side

Question 16

what measures saccades?

Answer 16

EOGH – electrooculography horizontal

Question 17

what measures blinks?

Answer 17

EOGV - electrooculography vertical

Question 18

what does the reference electrode do?

Answer 18

our skin and our bones conduct electricity. We want to deduct this minimum conducted by the skin and by the bones from the brain activity measurements. Reference electrode could be anywhere, but most of the time on mastoids because those have both the skin and the bone. Some people do on the ear lobe, some - on the nose.

Question 19

source separation

Answer 19

many overlapping sources of EEG signal - how to reconstruct the sources? - you create different conditions, and the only thing that is different - that thing is not the noise for sure

Question 20

what are the solutions?

Answer 20