// Sleep and memory Flashcards
1
Q
The sleep effect
A
Jenkins 1924
Learning followed by sleep leads to better recall than learning followed by wake
2
Q
Theories for how sleep aids memory
A
- Interference, decay and consolidation
- ASE model
- System consolidation
- Replaying memories
- Replaying schemata
- Insight
- Memory triage
- Time between recall and learning
- Sleep duration
3
Q
Interference, decay and consolidation
A
Ekstrand 1977
Interference
- behavioural - simplest theory
- fewer events interfere with the memory during sleep
Decay
- Happens slower during sleep
Consolidation
- aided by lack of interference and decay
- sleep actively improves memory
4
Q
ASE model
A
Walker 2005
How memories become long-term during sleep
- acquisition - memory can be recalled in the short-term
- stabilisation - lack of interference over time
- enhancement - interconnection of the memory with others in the LTM
Points 2 & 3 are consolidation
5
Q
System consolidation
A
Diekelman 2010
- fast rate learning - temporary store
- slow rate learning - long-term store
- memories gained in slow rate learning are strengthened over time
- reactivation and consolidation during SWS avoids interference and altered synapses during REM
- integrates memories into LTM store
- promotes extraction of repeating features to form schemata
- evidence for reactivation - cues present in learning and sleep = stronger consolidation
- Lee 2002 - rat place cells in hippocampus that fire when learning a maze also fire during SWS - replaying the memory. Mixed up during REM - triggers abstraction (form schemata)
6
Q
Replaying schemata
A
Lewis
- schemata are replayed during sleep, not single memories
- abstraction = extraction of repeating features to create an abstract gist for all similar situations (schemata)
- DRM Paradigm = more likely to form false memories during sleep bc gist is processed rather than specific details
7
Q
Insight
A
Wagner 2004
- calculate final number in a series
- complex but can be done simply once insight into the method is gained
- more likely to gain insight after sleep
8
Q
Memory triage
A
Stickgold 2013
- Selective processing of valuable info
- Told after learning they’ll be tested on certain lists/get monetary rewards for remembering certain lists = higher consolidation of these lists
- Rijn 2017 – triage for personal, non-reward-related valuable info
- Learn 14 welsh words
- Cued recall – given welsh, asked for English
- Better recall after sleep
- Better recall for those who value the Welsh language more
9
Q
Time between learning and recall
A
Stickgold 2001
Experiment 1
- visual discrimination task
- test after 2, 5, 11 hrs - little difference
- test after 9, 13, 22 hrs including 7hrs sleep - improved performance
Experiment 2
- test on same day as learning = no improvement
- more night sleep = more improvement but little difference after 4th night
- no improvement if no sleep on first night - initial night’s sleep is the beneficial part!
- improvement related to SWS in first quarter and REM in last quarter of sleep
10
Q
Sleep duration
A
Tucker 2009
- 3.5hr naps and 7.5hr sleep improves declarative and motor memory
- longer stage 2 improves procedural task speed
- intelligence correlates with test performance on both tasks but not with sleep-related changes
- intelligence doesn’t influence sleep’s effect on memory
11
Q
NREM is more important for memory
A
Ekstrand 1977
Retention better after SWS than after REM, worse after wakefulness
12
Q
REM is more important for memory
summary
A
- General memory
- Emotional memory
- Visual memory
- Procedural memory
- Cognitive flexibility
- REM augmentation
- Dreams and memory
- Flexible processing
- Neurochemical balance
13
Q
REM and general memory
A
Fishbein 1970
- REM deprivation leads to fragile memory
- Others argued it’s the stress of REM deprivation
- Oniani 1987 – woke animals gently from REM, no fragile memories
Tilly 1978
- REM deprivation –> poorer story recall than N3 deprivation
- Less deterioration of recall accuracy following REM recovery than N3 recovery
14
Q
REM and emotional memory
A
Wagner 2001
- Learn emotional or neutral short story
- Enhanced memory for emotional texts after REM compared to SWS
- Goes beyond behavioural theory – two sleep types giving different results
Walker 2009
- Seen in the 80s, people with PTSD are more likely to have sleep apnoea
- Explained that people with sleep apnoea are less able to process trauma during sleep bc of disruption so are more likely to go on to develop PTSD
- Suggests similar for mood and anxiety disorders
15
Q
REM and visual memory
A
Karni 1994
- Visual discrimination task – identify whether rotated dashes are aligned horizontally or vertically
- REM sleep only –> improved performance
- SWS only –> poorer performance
- Regular sleep –> improved performance
