EEG Flashcards
1
Q
What does EEG stand for?
A
ElectroEncephaloGraphy
2
Q
What is the function of EEG? And how do they work?
A
- The recording/measurement of the brain’s electrical activity, usually across the scalp.
- EEG measures extracellular ionic currents.
- EEG measures the voltage fluctuations resulting from ionic current which flows within the neurons of the brain.
- 1- Ions of like charge repel each other, and when many ions are pushed out of many neurons at the same time, they can push their neighbors, who push their neighbors, and so on, in a wave.
- 2- When the wave of ions reaches the electrodes on the scalp, they can push or pull electrons on the metal on the electrodes
3
Q
Event-related potentials (ERPs)
A
- Refer to averaged EEG responses that are time-locked to more complex processing of stimuli
- Uses the measurement of EEG
- Can shows us your minds process and electric changes before/when/after you see specific picture/things (stimuli)
- However, the key difference is that a stimulus is presented to a participant
4
Q
Evoked potentials (EP)
A
- involves averaging the EEG activity time-locked to multiple instances of the presentation of a stimulus of some sort (visual, somatosensory, or auditory)
5
Q
What does EEG activity reflect?
A
- EEG activity reflects the summation of the synchronous activity of thousands or millions of neurons that have similar spatial orientation.
- If the cells do not have similar spatial orientation, their ions do not line up and create waves to be detected.
- Currents that are tangential to the scalp are not picked up by the EEG
6
Q
Pyramidal Neurons
A
thought to produce the most EEG signal because they are well-aligned and fire together
7
Q
What are the shortcomings of EEG?
A
This is why EEG’s not perfect:
- You can’t measure from deep areas
- It doesn’t reflect the whole brain activity:
- EPSP and IPSP will cancel each other out but the fact that they existed will not be detecte
- We can detect deep layers at times, but not at a high special resolution
8
Q
Oscillations in EEG
A
- waves=summed activity of a specific region=how any times were neurons in this region active
- The EEG voltage recorded on the scalp often produce a pattern with a stable rhythm or frequency.
- Patterns of oscillations have characteristic frequency ranges, and spatial distributions across the scalp, and are associated with different states of brain functioning (e.g., waking and the various sleep stages).
- Oscillations represent synchronized activity over a network of neurons
- Most of the cerebral signal observed in the scalp EEG falls in the range of 1–20 Hz
9
Q
Herz
A
- cycles per second.
- Each peak is summed electrical activity [of many action potentials and positive ions] how many times per second (not a direct measurement of action potential)
10
Q
Delta
A
- the frequency range up to 4 Hz.
- tends to be the highest in amplitude and the slowest waves.
- It is seen normally in adults in slow wave sleep
11
Q
Theta
A
- 4-7hz
- Found in young children, drowsiness, and meditation
12
Q
Alpha
A
- 8-12 Hz
- Relaxed or reflecting, eyes closed
13
Q
Beta
A
- 12-30
- Working, active, busy, anxious, thinking
14
Q
Gamma
A
- 30-100 Hz
- binding of different populations of neurons together into a network for the purpose of carrying out a certain cognitive or motor function
15
Q
Applications of EEG
A
- Monitoring Sleep
- Detecting and Mapping Epilepsy
- Hearing testing
- Studying Cognition and Emotion
