SLEEP AND DREAMS…

Dr MARIETA ANCA-HERSCHKOVITSCHDr MARIETA ANCA-HERSCHKOVITSCHNeurological Department –Wolfson M C Neurological Department –Wolfson M C

Sleep• Sleep is a behavior AND

an altered state of consciousness

• We spend about a third of our lives in sleep.

Sleep

Theories of Sleep

• Sleep is an active state that is critical for our physical, mental, and emotional well-being.

• Sleep is also important for optimal cognitive functioning,and sleep disruption results in functional impairment. Insomnia is the most common sleep disorder in psychiatry.

• At any given time, 50% of adults are affected with 1 or more sleep problems such as difficulty in falling or staying asleep, in staying awake, or in adhering to a consistent sleep/wake schedule.

• Repair/Restoration – Sleep allows for recuperation from physical, emotional,

and intellectual fatigue• Survival Value

– Sleep evolved to conserve energy and protect our ancestors from predators

Why Sleep?

Repair and Restoration Theory

– sleep enables the body and brain to repair itself after working hard all day

– going without sleep causes people to be irritable, dizzy, and to have hallucinations and impaired concentration

– sleep-deprived rats’ bodies work harder– BUT, how much we sleep does not depend on how

much we worked that day

Evolutionary Theory- we evolved to sleep so that we would conserve energy when we were least efficient

- during sleep body temperature decreases

- predicts that species will sleep different amounts depending on how much they must look for food and watch for predators

Why Sleep?

Circadian Rhythms: Sleep

Circadian Rhythms (9.1)• endogenous cycles• role of the suprachiasmatic nucleus• setting/resetting biological clocks

Sleep (9.2)

• why sleep?• stages of sleep

Dreaming (9.3)• why dream?

Suprachiasmatic Nucleus (SCN)

SCN - main control centerfor sleep and temperaturecircadian rhythms

Light

• retinal ganglion cells send direct projections to the SCN• this provides information about light to the SCN• light can also alter blood-borne factors• SCN is highly vascularized

Melatonin

• secreted from the pineal gland• increased levels of melatonin make you sleepy• melatonin can act on receptors in the SCN to phase-advance the biological clock

What Resets the Clock?

Sleep: Stages

REM Sleep

• REM: rapid-eye movement• lots of brain activity - EEG shows low voltage fast waves• postural muscles are most relaxed during REM sleep• loose associative thinking • PGO waves - start in the pons geniculate nucleus of

thalamus occipital cortex

REM Sleep

• neurons within the pons send inhibitory messages to the spinal cord during REM sleep

• this message inhibits

motor neurons that project to large muscles

• REM sleep is still observed after damage to the pons

• but, no inhibition of muscle neurons…

Basal ganglia efferents to the PPN involved in the control of REM and muscular atonia. (A) Schematic model for the basal ganglia control of REM sleep B) Experimental diagram for examination of the involvement of a nigrotegmental projection in the control of REM and muscular atonia. (C) (a) Stimulation of the PPN induced REM and muscular atonia. (b) Conditioning stimulation of the lateral part of the SNr diminished the PPN-effects. (c) Conditioning stimuli applied to the mid part of the SNr did not block REM but blocked the muscular atonia (REM without atonia).

“Sometimes,a cigar is just a cigar.”

- Freud, on themeaning of dreams

A.K.A. Psychoanalytic theory: Dreams represent disguised symbols of repressed desires and anxieties Manifest Content: symbols used to disguise true meaning of dreamLatent Content: true unconscious meaning of a dream

Wish Fulfillment –

Freud’s DreamTheory…

Why Dream?

Activation-Synthesis Hypothesis• dreams begin with episodic bursts of spontaneous activity in the Pons (PGO waves)

• these PGO waves partially activate certain regions of the cortex

• this haphazard input is combined with previous (waking) input

• cortex “synthesizes” a story to make sense of all the input it is receiving

The emerging concepts of sleep neurophysiology are consistent with the cholinergic-aminergic imbalance hypothesis of mood disorders>> depression is associated with an increased ratio of central cholinergic to aminergic neurotransmission. The characteristic sleep abnormalities of depression may reflect a relative predominance of cholinergic activity.

Sleep Disorders

• Dyssomnias

• Parasomnias

• Medical-Psychiatric

• Proposed

Dyssomnias

• Disorder of insomnia or excessive sleepiness

• Three subdivisions:– Intrinsic – Extrinsic– Circadian rhythm disorders

ICSD Dyssomnias

ICSD Parasomnias

ICSD Med/Psych Disorders

ICSD Proposed Sleep Disorders

Sleep and the Immune System

Sleep deprivation is correlated with a significant reduction in cellular immunityCan cause reductions in NK cells, T-cells, and monocyte functionProblems tend to diminish following recovery sleep

Sleep and the Immune System

Widows, whose sleep had been significantly disturbed, a decrease in the number of killer cells and a weakened immune system occurred

(Stapleton, 2001)

In lab rats, total sleep deprivation for four weeks can cause death by infection (Stapleton, 2001)

Sleep and the Immune System

Men who received just four hours of sleep a night for four straight nights after receiving a flu shot produced half the antibodies as the control group (Weintraub, 2004)

Sleep and the Cardiovascular System

Sleep deprivation increases concentrations of cytokines in the bodyAlso increases levels of C-reactive proteins, which can cause low-grade inflammation

This inflammation can damage the inner walls of the arteries, leading to possible stroke or heart disease

Blood pressure and heart rate are higher following sleep deprived nights

(Voelker, 1999)Men who work 60+ hours a week are twice as likely to have a heart attack as men who work 40 hours or less (Heart Disease Weekly, 2002)

Men who sleep 5 hours or less a night have twice as many heart attacks as men who sleep 8 hours or more

Sleep and the Cardiovascular System

A significant link has been found between exhaustion and coronary heart disease

(Cole et. al, 1999)Women who have less than 5 hours of sleep have a 30% increased risk of developing coronary heart diseaseSleep deprivation increases risk of heart disease in women

(Josefson, 2003)

Sleep Deprivation and Diabetes

• Chronic sleep deprivation leads to insulin resistance

• This resistance can result in high blood glucose concentrations, leading to diabetes

• Men who sleep 4 hours a night for 6 straight nights lose 30% of their ability to respond to insulin --> diabetes

MS and Sleep • MS causes sleep fragmentation in terms of abnormal

sleep pattern • Fatigue in MS could be explained also by disruption

of sleep microstructure, poor subjective sleep quality and depression.

• There are both central and peripheral mechanisms in fatigue.• The most common autonomic symptoms in MS are disorders of

micturition, impotence, sudomotor and gastrointestinal disturbances, orthostatic intolerance as well as sleep disorders.

• The combination of fatigue and depression with sleep disorders (insomnia, restless legs syndrome) is common in MS (decreased activity of the serotoninergic and noradrenergic systems).

• Sleep disturbance is common in MS and is associated with treatable symptoms, including pain and nocturia.

• Sleep problems frequently might include initial insomnia (anxiety and pain/discomfort, in 42%), middle insomnia(nocturia,in 53% with daytime fatigue ) and terminal insomnia in 58%.

“Regarding every disease now incurable we may entertain the hope that our powerlessness may not be permanent, and that we, or those who come after us , may be able to speak in very different terms “

W.R.Gowers , 1879