Lab 4 Flashcards
1
Q
What does an EEG do?
A
measure electrical signals from the brain
2
Q
We weren’t measuring APs, but summated graded potentials in the brain called:
A
EPSPs and IPSPs
3
Q
How are waves differentiated?
A
- depending on their frequency (measured in Hz) and amplitude (measured in volts)
4
Q
What waves were we looking for in this lab?
A
alpha waves
5
Q
FFT
A
processing of signals
6
Q
What artifact did we see often during this experiment?
A
- 60 Hz artifact
- usually due to other electrical signals in the building
7
Q
Brain waves
A
synchronized activity of neurons in the brain
8
Q
What are EEG signals affected by?
A
- state of arousal of the cerebral cortex
- stimulation of the external environment
9
Q
Why are the voltage signals of the brain difficult to record?
A
- recording electrode is separated from the brains surface by the skull, the scalp, and CSF
10
Q
What does an EEG reflect?
A
- the algebraic sum of the electrical potential changes occurring from large pops of cells
11
Q
Alpha waves
A
- btwn 8-13 Hz
- amplitude of 30-50 microvolts
- seen when the eyes are closed and the volunteer is relaxed
- inversely proportional to the degree of cortical activation
- strongest over the occipital and frontal cortex
12
Q
Beta waves
A
- btwn 13-30 Hz
- amplitude of <20 microvolts
- alert and eyes open
- absent or reduced in areas of cortical damage and can be accentuated by sedative-hypnotic drugs
13
Q
Theta waves
A
- 4 and 8 Hz
- amplitude of <30 microvolts
- awake children but not adults
- normal during sleep of all ages
- 4-5.45 Hz correlated w/ decreased arousal and increased drowsiness
- 6-7.45 Hz enhanced during tasks involving working memory
14
Q
Delta waves
A
- 0.5 and 4 Hz
- amplitude of 100-200 microvolts
- dominant rhythm in sleep stages 3 and four
- not seen in conscious adults
- artifacts can be caused by jaw and neck muscle movement
15
Q
Gamma waves
A
- 30 and 50 Hz
- may be associated w/ higher mental activity like perception and consciousness
- mental activity involved in integration
