sleep

Question 1

what is a circadian rhythm?

Answer 1

24hr cycle in physiological process of living beings; internally generated & externally moderated

Question 2

3 main measures of sleep

Answer 2

EEG, EOG,EMG

Question 3

4 stages of sleep

Answer 3

stage 1: low voltage high frequency
by stage 4: voltage increase but frequency decrease
IS A CYCLE so people travel through them repeatedly

Question 4

alpha waves

Answer 4

weaker bursts of eeg waves

Question 5

delta waves

Answer 5

largest and slowest

Question 6

REM sleep

what increases?

Answer 6

o2 consumption, cerebral firing & blood flow
Muscle contraction
Range of ANS functions i.e. blood pressure

Question 7

REM and dreaming arguments

Answer 7

FOR: Desseilles et al. 2001 (80% of awakenings during REM can report dream)
BUT:
- Mcnamara et al 2010 (review of REM & dreams)
- Siegel 2011 “ (ALSO says about REM & health/memory)
- Oudiette et al 2012 (antidepressants reduce REM but not dreaming)
- Solms, (1997) lesions can affect dreams but not REM

Question 8

Hobson & Mcarley 1989 theory

Answer 8

activation synthesis theory:

• various waves activate regions (pons)
• cerebral cortex tries to make sense
• we dont act out our dreams bc of muscle atonia

Question 9

Recoperation theories of sleep

Answer 9

• awake disrupts homestasis
• need sleep to restore
• also conserves energy: smaller animals sleep more
• BUT isnt affected by sport

Question 10

Ecological Niche

Answer 10

we’ve adapted this way to avoid preds at night time (Siegel 2009)

Question 11

memory consolidation: FOR (4)

SWS: NREM

Answer 11

Dikelmann & born (2010): sleep helps remember material
NREM: seems to aid consolidation: ESP DECLARATIVE MEMORY (facts) Marshal et al. 2006
REM: “ REM may aid consolidation of NON DEC memory (unconscious)
4) PATTERNS of neuro activity occur during SWS; brain rehearsing? (Dikelmann & born 2010) & (Euston et al 2007)

Question 12

memory consolidation: AGAINST

Answer 12

No correlation between species and time spent asleep and learning capacity - we sleep less than some species but are more intelligent (Siegel, 2001)
NO correlation between time in REM sleep and !) (Borrow et al 1980)

Question 13

what is the problem with interpreting results from sleep deprivation studies?

Answer 13

May be confoudning variables i.e. stress is often the cause of sleep loss - reason for seeing what we are seeing?

Question 14

Sleep deprivation & humans

Answer 14

Durmer & Dinges (2005) - moderate deprivation -moderate effects

Question 15

deprivation on complex cognition

Answer 15

less consistent results - seems that a substantial amount of deprivation is needed for a consistent disruption (Drummond et al 2004) (alexander & home, 2006)

Question 16

ONLY SOME COG FUNCTIONS ARE SUSCEPTIBLE

Answer 16

executive functioning: creative thinking > logical deduction (Nilsson et al 2005)

Question 17

Rechtshaffen & Bergmann (1995)

Answer 17

sleep deprivation on animals: carousel

Question 18

Limitations with

Rechtshaffen & Bergmann (1995)

Answer 18

• humans and rats have been kept awake longer than that before w.out dying
  Siegel (2009) & Rial et al. (2007)
• it is prob stress that killing them: all have enlarged adrenal gland (HPA axis)

Question 19

REM sleep & deprivation: 2 main effects

Answer 19

1) REM rebound - more REM in following few nights (Brunner et al, 1990)
2) more deprivation the more likely REM will occur (i.e. frequency)
~~ REM must be separate from SWS

Question 20

Sleep recovery

Answer 20

SWS sleep becomes more efficient DOESNT INCREASE SLEEP ( Elmenhorst et al 2008)

Question 21

Evidence in support of the efficient SWS

Answer 21

• waking ppts in REM doesnt interfere with their performance during the day but SWS interruption does (Nykamp et al. 1998)
• if sleep time is reduced, then time in SWS stays the same but REM time decreases

Question 22

reticular formation WHAT

Answer 22

In the brain stem (in the little bulge at front)

intricate network of neurons extending from spinal cord to thalamus

Question 23

reticular formation & sleep

Answer 23

Bremer 1936: severed cat brains
disconnect forebrain & sensory input coming in
Cutting the forebrain off - contin sleep
cutting lower than Pons - no effect
~~~ reticular formation affects wakefulness

Question 24

Sleep nuclei

Answer 24

reticular REM:controls REM sleep
each site (nuclei) –> controls a particular characteristic of REM sleep
TOGETHER THEY MAKE UP REM SLEEP when all activated

Question 25

2 main elements of a biological clock

Answer 25

1) FREE RUNNING: maintains own cycle & doesnt need input from external cues - not totally in line with outside world tho
2) ENTRAINMENT: we can train our bio clock to be in synchro with an external stimulus

Question 26

name for a stimulus that trains our biological clock

Answer 26

Zeitgeber

Question 27

where is the biological clock

Answer 27

suprachiasmatic nucleus (tiny pair of neuron clusters in the hypothamalmus

Question 28

lesions to this area cause disruption to circadian cycles i.e. sleep - waking cycle - EVIDENCE

Answer 28

1) Ralph & menaker (1990) hamster experiment

2) the nuclei displays cycles that are entrained by light /dark cycle

Question 29

suprachaismatic nucleus may not be the only biological clock though - evidence (3)

Answer 29

1) bilateral lesions can leave SOME circadian rhythms unaffected
2) bilateral SCN lesions dont elimainate ability of all enviro stimuli to entrain circadian rhythms (i.e. can be others that are entrained)
3) other tissue cells display free running circadian rhythms when maintained in tissue culture

Question 30

neural mechanisms of environment

~ how does light/dark entrain the sleep wake cycle

Answer 30

Morin & allen (2006):
~ cutting optic tracts BEFORE chaism - eliminates pathway (after, DOES NOT)
1) Retinohypothalamic tracts leave the chaism & project to the SCN (biological clock)
2) this pathway leads to pineal gland (& other areas)
3) pineal gland secretes MELATONIN

Question 31

Melatonin

Answer 31

If light is present: melatonin secretion is inhibited

if darkness: melatonin is released –> melatonin involved with decrease in temp –> leading to sleep?