Sleeping and Biological Rhythms Flashcards
What happens electrically when a neuron fires?
Positive current flows into the dendrite leaving the extracellular fluid around dendrite slightly negative. The positive current then escapes at deeper parts of the neuron leading to slightly positive extracellular fluid there.
What do EEGs measure?
EEGs measure the change in voltage through thick layers of tissue
What role does synchronization play in EEG signals?
When neuron responses are synchronized, the EEG signals are much larger than if unsynchronized.
Beta activity
High frequencies with low amplitudes
EEG characteristics of a waking state
EEGs are desynchronized, with beta activity
What frequency are alpha rhythms?
8-13 Hz
EEG characteristics of Stage 1 sleep
Alpha rhythms appear during relaxation and sharp waves called vertex spikes appear during stage 1.
What frequency are sleep spindles?
12-14 Hz
K-complexes
Sharp negative EEG potential
EEG characteristics of Stage 2 sleep
Brief periods of sleep spindles and K complexes
Delta waves
The slowest type of EEG waves, with a frequency of 1 Hz
EEG characteristics of Stage 3 Sleep
Also know as slow wave sleep (SWS), it’s characterized by long and slow delta waves
EEG characteristics of REM sleep
EEG activity resembles waking activity despite deep muscle relaxation
What happens to REM sleep as the night goes on? (in a young adult)
REM sleep gets longer
What happens to SWS as the night goes on? (in a young adult)
We lose stage 3 sleep
Name two things that occur in the body during non-REM sleep
- Heart rate and respiration have a slow decline
- Brain temperature is decreased
- Cerebral blood flow is reduced
- Knee jerk reflex is normal
- Eye movements are infrequent, slow, and uncoordinated
- Thoughts are mostly vague with occasional dreams
- High growth hormone secretion
Name two things that occur during REM sleep.
- Heart rate and respiration are variable with high bursts
- Brain temperature is increased
- Cerebral blood flow is high
- Knee jerk reflex is suppressed
- Eye movements are rapid and coordinated
- Vivid dreams
- Low growth hormone secretion
How is sleep different in marine mammals?
One hemisphere is used for slow wave sleep and the other is used for REM sleep
How do sleep time and body size correlate?
In herbivores, the larger animals such as elephants sleep less while smaller ones like voles sleep more.
Carnivores sleep on average the same amount regardless of size
What does human sleep look like early in life?
We spend almost all the day sleeping, with half of it in REM sleep.
What does human sleep look like later in life?
We sleep about 8 hours a night with 20% of that spent in REM.
What does sleep look like in elderly people?
They wake up frequently, and have a severe reduction in slow wave sleep.
How did people perform on a memory retrieval test when exposed to an odor during SWS and testing?
People who did the test while re-exposed to the odor did better at recalling object locations.
What effects do anesthetics have on GABA receptors?
All anesthetics are some degree of agonist for GABA