Lecture 7: biota model

Question 1

What are the different stages of sleep and how are they characterized?

Answer 1

Wake: no large oscillations - a lot of noise
Light Sleep: oscillations slow dow, can see sleep spindles in certain areas of the cortex
Slow wave sleep: High amplitude oscillations (large neuronal firing all at once) - more of this early in the night
REM sleep: paradoxically, looks the same as in wake - pons = huge electrical potentials which cause the eye movement - more of this in the morning

Question 2

What do we know about reactivation of memories in rats?

Answer 2

Place cells are reactivated in high frequency in the hippocampus - they occur in the trough of the spindles which can be measured at the cortex

Question 3

How do we know what reactivation happens in humans?

Answer 3

Peigneaux et al (2004): MRI
Ps = video game where they have to move around a maze and are given tasks. The better they know the maze, the better they do at the tasks
Scan during the task: know what areas are activated
Then sleep in a scanner and compared to those who did a NON spatial memory task

Results:
The spatial task group - strong activation in the hippocampus
This activation, predicted the improvements participants made in the maze task (more activation = better behavioural improvements)

Question 4

IOTA part of the BIOTA model

Answer 4

IOTA: throughout NREM sleep, lots of experiences are converging together and those which has crossed over in the replications form stronger connections that are less likely to be downscaled during SWS
= convergent thinking whereby lots of experiences are morphed into one

Question 5

What does BIOTA stand for

Answer 5

broader information overlap to abstract

Question 6

What kind of thinking does the Biota part describe?

Answer 6

Divergent, outside the box thinking

e.g RAT task, distant primes (making links between distant concepts) and analogies

Question 7

What happens during REM sleep?

Answer 7

BIOTA:

• strongly inhibited connection to the hippocampus
• cortex, therefore, is functioning on its own and the hippocampus does not tell it which parts of memory to activate together
• Pons = activations in the cortex at random which illuminate memories completed unrelated to the concept
• High levels of acetylcholine: needed for plasticity

Question 8

What is the outcome of everything that occurs in REM sleep?

Answer 8

Pons, no hippocampus and acetylcholine = connections that would not be associated now can, and therefore if there is overlap, there is the potential for plasticity to occur

• need to happen more than once over multiple sleeps t make a large enough impact to detect

Question 9

What is targeted memory reactivation?

Answer 9

We can control when things get reactivated
Reactivation can be triggered by associated cues during sleep
Show 2 diff pic each with an associated sound - ask ppts to remember location
During sleep play 1 of the sounds
Ps are better at remembering the location of the pic when the sound has been played
= not only does playing associated cues reactivate the memory in the brain BUT it also improves the memory - behavioral benefits

Question 10

What is the resuly of TMR?

Answer 10

• results: can last up to 10 days, leads to structural changes in the brain and functional activity changes

Question 11

How does TMR relate to creativity?

Answer 11

Some studies show that TMR can boost activity: problem-solving associated with sound, play sound - reactivated in sleep = huge benefits
Linking task = benefits

But also evidence against this

Question 12

What did Stickgold et al study?

Answer 12

Ppts had to play 7 hours of tetris over 3 days
Ps = amnesics (no declarative memory- hippocampus), novice and experts
P’s went to sleep and were woken up during REM and asked what they were imagining

Question 13

Stickgold et als results

Answer 13

Amnesic = minimal improvements over the time
BUT, did report Tetris imagery (same % as non amnesics), no report of thoughts

Novice= large improvements over the time
Tetris imagery
Thoughts without imagery

Experts = no sig improvement
Tetris imagery
Thoughts without imagery

Question 14

Stickgolds conclusions:

Answer 14

lack of hippocampal activity involved in replaying images: especially true in REM sleep: explains why REM sleep dreams can be so bizarre and lack anything from what we have experienced in the world

Question 15

What was Cai et al study aim?

Answer 15

Examined the role of REM on creative problem solving with the RAT

Used a nap paradigm to d this to ensure circadian rhythms did not impact

Question 16

Study design of Cai et al

Answer 16

3 different groups: Nap - REM and NREM and quiet rest
Manipulated peoples exposure before the sleep / rest stage: repeated exposure (looked at role of incubation - 9am then 5pm), no exposure or primed (to test whether stimulation of unrelated nodes by another source can improve creative (divergent thinking))
Subjects were first tested on the RAT at 9am and then retested at 5pm

Question 17

Cai et al study results

Answer 17

Repeated exposure: no difference between nap groups: all improved = incubation period - offline time, improves ppts ability to make connections

Primed = In contrast to the incubation results, subjects that had REM sleep displayed a significant improvement above NREM sleep and quiet rest groups

Question 17

What happened in the primed condition?

Answer 17

After the morning RAT, subjects completed a set of analogies (e.g., CHIPS: SALTY; CANDY: S) in which half of the answers (e.g., SWEET) were also the answers to the afternoon RAT items (e.g., HEART, SIXTEEN, COOKIES; answer: SWEET).

Question 18

Cai et al study conclusions:

Answer 18

1. the passafe of time (incubation period) improves problem solving for previously exposed item
2. sleep enhances creative problem solving fr items that were primed before sleep, but this was only true for naps that included REM sleep
3. REM sleep improvements in creative problem-solving are not the result of selective improvements in memory
4. General problem solving abilities were not improved in wake or sleep conditions