electroencephalography Flashcards

1
Q

MEG

A

doesnt touch head

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

EEG

A

on scalp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

ECoG

A

above/below dura mater

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

MEA

A

pia mater
- To find the origin of epilepsy so the tissue can be removed
- Very invasive
- High spatial and temporal resolution (low noise)
* Unfiltered by skull and scalp
- Allow measurement of high gamma activity >70Hz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

SEEG

A

cortex
- Needles (about 10) into brain
- Less invasive than ECoG due to soft electrodes that push brain tissue to the side
- Can be used to do task to record high quality brain activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what does EEG measure and which technique measures something else

A

EEG does not measure action potentials only MEA does
- The rest measure local field potentials  accumulation of many individual action potentials
* IPSP
* EPSP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

fMRI

A
  • fMRI measure changes in blood flow in brain areas due to neuro-activity (NVU - neurovascular coupling)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

frequency domains

A
  • Spectral power decreases with increasing frequency
  • 1Hz –> strong frontal activity (eye movement)
  • 10Hz –> occipital alpha activity
  • 60Hz –> power line noise (USA)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

EEG-rhythms

A
  • Neuronal oscillations = rhythmic or repetitive neuronal activity
  • Synchronization of larger cortical areas lead to oscillatory activity
  • Examples:
  • Alpha rhythm: occurs in absence of sensory stimuli
    o Occipital regions  8/13Hz
  • Mu rhythm: suppressed during motor and imagination activity
    o Sensorimotor regions  8/13Hz
  • Gamma rhythm: cognitive activity
    o Various regions  >60Hz
  • Theta rhythm: hippocampal activity during memory formation
  • These frequency bands are strongly person and author dependent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

EEG topography

A
  • Bad spatial resolution
  • Still helpful to find out spatial patterns
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

event-related potentials

A
  • An Event-Related Potential (ERP) is the brain’s electrical response shortly after an event
  • Mostly measured by EEG and MEG
  • Typically triggered by an external sensory stimulus
  • Can be internal stimulus (e.g. associated with the execution of a motor, cognitive, or psychophysiological task)
  • ERPs can provide information about brain function (clinical use)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

ERP complex

A
  • ERPs are composed of several ERP components
  • Parts of the waveform called positive (P) or negative (N) according to their polarity
    o Warning: Sometimes negative is upwards!!
  • Followed by a number indicating
    o Component’s ordinal position in the waveform (e.g., P1, N1, P2, N2, P3)
    o Latency in milliseconds (e.g., N100, N170, P300)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

parameters ERP

A
  • Important parameters of ERP components
  • Peak amplitude in μV (often normalized to 200ms pre-stimulus interval)
  • Peak latency in ms
  • Mean amplitude of an ERP component (intervals more robust than peak)
  • Electrode location (spatial focus)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

clinical use EEG

A

epilepsy diagnosis (spatial)
sleep disorders –> sleep staging
brain tumours
brain damage
stroke

How well did you know this?
1
Not at all
2
3
4
5
Perfectly