7 Sleep

Question 1

What are the general changes in sleep pattern across a lifetime?

Answer 1

REM sleep gradually decrease in percentage. NREM gradually decreases too.

Question 2

Reasons why some think sleep is unnecessary?

Answer 2

Orca mother and baby don’t sleep for the first several weeks after birth - ensures baby is safe and learning to breathe with needed

Question 3

When trying to catch up on lost sleep, what are the differences between Slow Wave Sleep (SWS) and Rapid Eye Movement?

Answer 3

You go into REM sleep faster and skip on SWS From lecture slide:”rebound of REM is greater than that of SWS”

Question 4

Does sleep promote LTM formation?

Answer 4

Diekelmann and Born (2000) have shown that the brain (cortex +hippocampus) rehearses recent events during sleep. Their experiment on human experiments tested for memory performance on a certain task. Whilst learning the task participants were exposed to a specific odour. After learning, participants were allowed to sleep. Some participants were exposed to an odour during sleep and others were just exposed to air as a neutral stimuli. Participants were then given an interference task to ensure they were not rehearsing the previous task. Participants were tested again. Those exposed to the scent during sleep performed better than those not. This effect was only seen in participants exposed during SWS. Interpretation: memory consolidation may occur during SWS. Odour being paired at this time may have provided a stronger cue for that memory making it more active during that state, which has then lead to increased results in memory performance

Question 5

What is sleep for?

Answer 5

• restoration
• consolidation
• conservation

Question 6

What are the stages of sleep?

What are the characteristics of these stages?

Answer 6

NREM stages:

1. Theta waves, slow
2. k complexes + spindles, slow - people often say they’re awake
3. & 4. slower delta waves. Sleep walking + talking occur here + vague dreams. Hard to wake up during this phase

REM:

• High freq activity in brain, similar to awake. Muscle inhibition + elaborate narrative dreams

Question 7

How does the brain regulate sleep?

Answer 7

There are two interracting systems that mutually inhibit each other.

The Ascending Arousal Pathway (AAP) vs. the activity of the Ventrolateral Preoptic Area (vlPOA).

AAP consists of structures that release neurotransmitters that keep us awake.

• Locus Coerulus -> NE
• Raphne Nuclei -> seratonin (immediate activation when woke)
• Tuberomammilary nucleus -> histamine
• Tegmentum -> ACh
• Lateral Hypothalamus -> Orexin (increases the release of above transmitters)

vlPOA makes use of the chemicals GABA and Adenosine.
The activity of GABAnergive neurons in the hypothalamus supress alertness and behavioral arousal (AAP), promoting sleep.