Sleep & circadian rhythms 1

Question 1

State the functions of sleep (3)

Answer 1

Energy conservation (better not to deplete resources when dark), restoration and recovery of body systems (supports immune system), memory consolidation (forget unimportant)

Question 2

Define sleep deprivation

Answer 2

Deprivation associated with emotional intelligence reduction, less self-confidence and social skills

Question 3

Describe neuroimaging of emotional processing

Answer 3

More amygdala activation after sleep deprivation, less coupling of activation of the amygdala and prefrontal cortex. More negative emotionality, less prefrontal control of emotional processing

Question 4

Name the effects of sleep deprivation (4)

Answer 4

Working memory and attention, school grades, impulsive control/emotional regulation, regulation of hormonal systems related to weight gain

Question 5

Describe REM sleep

Answer 5

Muscles paralysed by the pons, 100 mins per night, more vivid, emotional and negative dreams

Question 6

Explain light sleep and deep sleep

Answer 6

Light sleep - not restoring, relatively strong muscle tone. Deep sleep - very restoring, relatively low muscle tone

Question 7

What is the 2 process model of sleep regulation?

Answer 7

Sleep pressure (process S) and circadian process (process C). Malfunction of 1 increases risk for psychological disorder.

Question 8

The circadian process (C) is…

Answer 8

Oscillating means swinging between sleep promoting/preventing. 7-9pm difficult to sleep, 2-4 easy to sleep. Regulates timing of sleep

Question 9

Describe the role of Zeitgebers

Answer 9

Sets clock according to 24hr rhythm of outside world. Synchronisation of peripheral bodily clocks

Question 10

How does light affect the SCN?

Answer 10

Retina absorbs light, has direct connection to SCN. When light is administered close to core body minimum, strong effect on circadian rhythm. Retina cells only react to 460nm

Question 11

State the 4 factors that affect body clock

Answer 11

Light (timing, intensity, duration, wavelength), exogenous melatonin, physical sports/activity, social activity, nutrition

Question 12

Describe the problem that can arise from disruption of circadian rhythm

Answer 12

Delayed sleep phase syndrome, falling asleep between 2-10am. Mood problems, prevalence = 0.2-10%, occurs during adolescence

Question 13

Describe the suprachiasmatic nucleus (SCN)

Answer 13

Modulation of circadian rhythms, endocrine function. Cognitive performances, emotional states. Sends info to pineal gland, secretion of melatonin, important in synchronisation

Question 14

Explain the pattern of melatonin over the day

Answer 14

Rises in evening, increases when sleeping. At highest when body temperature falls. Difficult to sleep when melatonin is low

Question 15

Name a treatment for disruption to the circadian rhythm

Answer 15

Bright light therapy in morning, exogenous melatonin in evening. Very effective and efficient treatment of the syndrome