TAMU BIOL 320 LAB PRACTICAL 1
EXAM 2025 QUESTIONS AND ANSWERS
LAB 1- PowerLab 1- Electroencephalography (EEG), Psychophysiology & Wii Lab - ANS
Electroencephalogram (EEG) - ANS - made by placing electrodes on scalp and connecting to
apparatus that measures electrical potential differences between various cortical areas
* recording of voltage changes in brain by use of electrodes placed along the scalp
Brain Waves - ANS - patterns of neuronal electrical activity in the brain
- categorized into general classes based on frequency at which voltage changes occur
-BW recorded by EEG are subthreshold potentials recorded from the cortex (not action
potentials in white matter)
Recording EEG - ANS -signals are small because recording electrodes are separated from the
brain's surface by scalp, skull, and layer cerebrospinal fluid
-Need specially designed amplifier like the BioAmplifier built into PowerLab
-Place 2 frontal electrodes on forehead and 3rd (ground) to mastoid process to reduce electrical
interference
Artifacts - ANS range of unwanted interfering influences
-electrical interference
origins of the EEG signals - ANS -EEG results from slow changes in membrane potentials of
cortical neurons especially:
EPSPs- excitatory postsynaptic potentials
Copyright ©2025 BRIGHTSTARS ALL RIGHTS RESERVED 1
,IPSPs- inhibitory postsynatpic potentials
-EEG reflects algebraic sum of the electrical potential changes occurring from large large
populations of cells
components of the EEG - ANS continuous train of peaks and troughs
-frequency
-amplitude
Frequency brain - ANS -expressed in hertz (Hz)
-number of peaks in one second
-1Hz means 1 peak each second
Amplitude brain - ANS -intensity of wave represented by how high peaks rise and how low
troughs dip
-reflect synchronous activity of individual neurons
-normally low amplitude in brain waves, except in sleep
Alpha Waves - ANS -Frequency= 8-13 Hz
-Amplitude= 30-50 uV
-regular and rhythmic, low-amplitude, synchronous waves
-indicate brain idling
-indicate calm, relaxed state of wakefulness
- seen when eyes closed and subject relaxed
- abolished by eye opening and mental effort (calculations, concentration)
-indicate degree of cortical activity
- > cortical activity= < alpha activity
-strongest occipital cortex and front cortex
Beta Waves - ANS - Frequency= 13-30 Hz
Copyright ©2025 BRIGHTSTARS ALL RIGHTS RESERVED 2
,-Amplitude= <20 uV
- rhythmic but not as regular as alpha, higher frequency
- occur when mentally alert and awake or concentrating on problem/visual stimulus
- absent/reduced in areas of cortical damage
-accentuated by sedative-hypntoic drugs like benzodiazepines and barbiturates
Theta waves - ANS - frequency= 4-7 Hz
-amplitude= <30 hz
- common in awake children
- uncommon in awake adults but may appear when concentrating
- normal during sleep of all ages
- frequency band 2 components:
1. Low-theta activity
2. high-theta activity
Low-theta activity - ANS -frequency= 4-5.45 hz
-correlated with decreased arousal and increased drowsiness
High-theta activity - ANS -Frequency= 6-7.45 Hz
- enhanced during tasks involving working memory
Delta Waves - ANS - Frequency= 0.5-4 Hz
-Amplitude= 100-200 uV
- high amplitude waves seen during sleep and when reticular activating system dampened
(anesthesia)
-indicate brain damage in awake adults
-dominant rhythm in sleep stages 3 and 4
- not seen in conscious adult
-highest amplitude of all EEG waves
Copyright ©2025 BRIGHTSTARS ALL RIGHTS RESERVED 3
, -artifacts caused by movements of the jaw and neck muscles produces waves in same
frequency
Gamma waves - ANS - frequency[ 30-50 Hz
-associated with higher mental activity (perception and consciousness)
-disappear under general anethesia
-reflect mental activity involved in integrating various aspects of an object , such as color, shape
and movement
-enhanced in buddhist monks during meditation
-absent in schizophrenics
Active/Inactive Brain - ANS Active= higher frequency, lower amplitude
Inactive= lower frequency, higher amplitude
Frequency of brain waves too high or too low= unconsciousness occurs - ANS Interference
with cerebral cortical functions
Flat EEG - ANS -absence of spontaneous brain waves
-clinical evidence of death
Consciousness - ANS - conscious perception of sensations, voluntary initiation and control of
movement, and higher mental processing (memory, logic, judgement)
-Defined as continuum that grades behavior in response to stimuli:
1. alertness (highest state)
2. drowsiness before sleep
3. stupor
4. coma (most depressed)
Copyright ©2025 BRIGHTSTARS ALL RIGHTS RESERVED 4
EXAM 2025 QUESTIONS AND ANSWERS
LAB 1- PowerLab 1- Electroencephalography (EEG), Psychophysiology & Wii Lab - ANS
Electroencephalogram (EEG) - ANS - made by placing electrodes on scalp and connecting to
apparatus that measures electrical potential differences between various cortical areas
* recording of voltage changes in brain by use of electrodes placed along the scalp
Brain Waves - ANS - patterns of neuronal electrical activity in the brain
- categorized into general classes based on frequency at which voltage changes occur
-BW recorded by EEG are subthreshold potentials recorded from the cortex (not action
potentials in white matter)
Recording EEG - ANS -signals are small because recording electrodes are separated from the
brain's surface by scalp, skull, and layer cerebrospinal fluid
-Need specially designed amplifier like the BioAmplifier built into PowerLab
-Place 2 frontal electrodes on forehead and 3rd (ground) to mastoid process to reduce electrical
interference
Artifacts - ANS range of unwanted interfering influences
-electrical interference
origins of the EEG signals - ANS -EEG results from slow changes in membrane potentials of
cortical neurons especially:
EPSPs- excitatory postsynaptic potentials
Copyright ©2025 BRIGHTSTARS ALL RIGHTS RESERVED 1
,IPSPs- inhibitory postsynatpic potentials
-EEG reflects algebraic sum of the electrical potential changes occurring from large large
populations of cells
components of the EEG - ANS continuous train of peaks and troughs
-frequency
-amplitude
Frequency brain - ANS -expressed in hertz (Hz)
-number of peaks in one second
-1Hz means 1 peak each second
Amplitude brain - ANS -intensity of wave represented by how high peaks rise and how low
troughs dip
-reflect synchronous activity of individual neurons
-normally low amplitude in brain waves, except in sleep
Alpha Waves - ANS -Frequency= 8-13 Hz
-Amplitude= 30-50 uV
-regular and rhythmic, low-amplitude, synchronous waves
-indicate brain idling
-indicate calm, relaxed state of wakefulness
- seen when eyes closed and subject relaxed
- abolished by eye opening and mental effort (calculations, concentration)
-indicate degree of cortical activity
- > cortical activity= < alpha activity
-strongest occipital cortex and front cortex
Beta Waves - ANS - Frequency= 13-30 Hz
Copyright ©2025 BRIGHTSTARS ALL RIGHTS RESERVED 2
,-Amplitude= <20 uV
- rhythmic but not as regular as alpha, higher frequency
- occur when mentally alert and awake or concentrating on problem/visual stimulus
- absent/reduced in areas of cortical damage
-accentuated by sedative-hypntoic drugs like benzodiazepines and barbiturates
Theta waves - ANS - frequency= 4-7 Hz
-amplitude= <30 hz
- common in awake children
- uncommon in awake adults but may appear when concentrating
- normal during sleep of all ages
- frequency band 2 components:
1. Low-theta activity
2. high-theta activity
Low-theta activity - ANS -frequency= 4-5.45 hz
-correlated with decreased arousal and increased drowsiness
High-theta activity - ANS -Frequency= 6-7.45 Hz
- enhanced during tasks involving working memory
Delta Waves - ANS - Frequency= 0.5-4 Hz
-Amplitude= 100-200 uV
- high amplitude waves seen during sleep and when reticular activating system dampened
(anesthesia)
-indicate brain damage in awake adults
-dominant rhythm in sleep stages 3 and 4
- not seen in conscious adult
-highest amplitude of all EEG waves
Copyright ©2025 BRIGHTSTARS ALL RIGHTS RESERVED 3
, -artifacts caused by movements of the jaw and neck muscles produces waves in same
frequency
Gamma waves - ANS - frequency[ 30-50 Hz
-associated with higher mental activity (perception and consciousness)
-disappear under general anethesia
-reflect mental activity involved in integrating various aspects of an object , such as color, shape
and movement
-enhanced in buddhist monks during meditation
-absent in schizophrenics
Active/Inactive Brain - ANS Active= higher frequency, lower amplitude
Inactive= lower frequency, higher amplitude
Frequency of brain waves too high or too low= unconsciousness occurs - ANS Interference
with cerebral cortical functions
Flat EEG - ANS -absence of spontaneous brain waves
-clinical evidence of death
Consciousness - ANS - conscious perception of sensations, voluntary initiation and control of
movement, and higher mental processing (memory, logic, judgement)
-Defined as continuum that grades behavior in response to stimuli:
1. alertness (highest state)
2. drowsiness before sleep
3. stupor
4. coma (most depressed)
Copyright ©2025 BRIGHTSTARS ALL RIGHTS RESERVED 4
