Sleep and EEG

Question 1

What is considered to be “the body’s cock”?

Answer 1

Suprachiasmic nucleus

Question 2

What genes/proteins are involved in setting the circadian rhythm?

Answer 2

Clock (CLK) and BMAL1 (increases at night) increase transcription of Period genes (Per1-3) and Cryptochrome genes (Cry1, 2). The protein products of Per and Cry will inhibit CLK and BMAL1. This occurs in the SCN.

Question 3

When do BMAL1/CLK genes activate?

CRY/Per?

Answer 3

Their activation rises during the night and peaks at morning.

CRY/Per peak just past morning. They are a little behind BMAL1/CLK.

Question 4

How do we make “day match day”?

Answer 4

Light/dark info binds to melanopsin receptors and travels to the hypothalamus (SCN) via the Retino-hypothalamic tract and causes release of glutamate (light).

Question 5

How is melatonin secretion regulated during the day and night?

Answer 5

During daytime, inputs from RHT to the SCN inhibit the pineal gland.

At night, the pineal gland is not inhibited and releases melatonin.

Question 6

Alpha waves characteristics:

When do they occur?

Where do they occur most?

What happens to them in sleep?

Answer 6

8-13 Hz
~50 uV

Occur during quiet wakefulness (thinking) with eyes closed.

Mostly over occipital region.

Disappear in sleep.

Question 7

What is the origin of alpha waves?

Answer 7

Requires connection between thalamus and cortex, forced by GABAergic neurons.

Question 8

Beta waves characteristics:

When do they occur?

Where do they occur most?

Answer 8

14-80 Hz
< 50 uV

During alert wakefulness with eyes open.

Frontal and parietal cortices.

Question 9

What is an alpha block?

Answer 9

With sensory input (eyes opening), alpha waves cease and beta waves begin. They will persist for as long as alert and when eyes close again, alpha waves will resume.

Question 10

What is the origin of beta waves?

Answer 10

Thought to be same as alpha

Question 11

Gamma waves characteristics:

When do they occur?

What might these waves require?

Answer 11

30-80 Hz

Occur when individual is focused on something, especially when planning a motor response.

Might require hippocampus.

Question 12

Theta waves characteristics:

When do they occur?

Answer 12

4-7 Hz
~100 uV

Normal in children, over parietal and frontal cortices.
In adults, may accompany frustration/disappointment.
Can also occur in sleep.

Question 13

What is the origin of Theta waves?

Answer 13

Unknown, but thought to require hippocampus to some degree

Question 14

Delta waves characteristics:

When do they occur?

Answer 14

< 3.5 Hz
~100-200 uV

Occur in deep sleep in adults.
Infants.

If they appear during wakefulness, it is a sign of “serious organic brain disease”.

Question 15

Delta waves do not require…

Answer 15

It does not require a connection from thalamus to cortex.

Question 16

Increased mental/neural activity is associated with…

Answer 16

Increased EEG activity

Question 17

What is the beta activity in infants?

Answer 17

Fast beta-like activity, but over occipital region there is slow 0.5-2.0 Hz activity.

Question 18

When does the adult alpha wave pattern begin to exist on EEG?

Answer 18

Activity in the occipital region gradually increases throughout childhood and appears during adolescence.

Question 19

What can decrease the frequency of the alpha rhythm?

Answer 19

Hypoglycemia
Low body temp
Low glucocorticoids
High CO2

**anything that reduces metabolism and leads to reduced neuronal activity

Question 20

Non-REM sleep stages:

Can dreams happen?

Answer 20

3 stages: N1, N2, N3 (deep)
-progressive slowing of EEG waves

Dreams can occur, but generally boring and re-hash the day’s events.

Question 21

REM sleep on EEG:

What kind of dreams?

Answer 21

Low amplitude, high freq.

Vivid dreams that are remembered.