Eating, Biological Rhythms, Sleep and Dreaming

nightmare

A REM dream with frightening content.

Delta waves

A brain waveform having 1 to 4 cycles per second that occurs during stages 3 and 4 of NREM sleep.

gamma band activity (when youre in a band and playing an instrament you need sensory input in order to play properly)

A brain waveform having more than 30 cycles per second, associated with the processing of sensory input.

K-complexes

A brief burst of brain activity consisting of single delta waves occurring during stage 2 NREM sleep.​

shift maladaptation syndrome

A condition resulting in health, personality, mood, and interpersonal problems resulting from sleep disruption due to shift work.

Zeitgeber ("time-giver").

A cue that an animal uses to synchronize internal clocks with the environment. Example: Light​ Availability of food ​ Body temperature ​ Sleep-related hormones ​ Physical activity​

Glycogen

A form of glucose stored for a short term in the liver and muscles. ​

Insulin

A pancreatic hormone used to convert Glucose to Glycogen. -released immediately following a meal.​ -Insulin levels lowest during long periods of fasting.​​ -Moves glucose into the blood.

It's not always bad to lose sleep

A paradoxical improvement in mood is observed in depressed patients after one night of REM sleep deprivation.

Insomnia (waking disorder)

A person has difficulty initiating or maintaining enough sleep to feel rested.​ Causes: multiple factors, including stress, anxiety, major depressive disorder, use of stimulant drugs, shift work or jet lag etc.​ -Treatment: Sedatives (such as benzodiazepine) speed up the onset of sleep by about 15 minutes and lengthen the night's sleep by perhaps a half hour (cost-benefit...) also Cognitive Behavioral Therapy (CBT).​ A common medication: zolpidem (Ambien) - GABA agonist. ​ Side effects: sleepwalking and binge eating or even driving while asleep.​

Hypopnea (hypo = not enoug, apnea= breathing)

A reduction in airflow during sleep.​ ​ The person experiences shallow breathing or a very low rate of breathing.​ ​ Often occurs in obese individuals who snore, indicating that airway obstructions might be the root of the problem. ​ ​ Losing weight or surgically correcting any obstructions in the airway can be helpful. ​

free-running circadian rhythms

A rhythm that is not synchronized to environmental time cues like for blind people.

Sleep Spindles:

A short burst of 12-14 cycle-per-second waves observed during NREM sleep.​

activation-synthesis theory (active dreams in your brain because neural activity occurs)

A theory suggesting that dream content reflects ongoing neural activity.

What makes us REM sleep?​

ACh from laterodorsal tegmental nucleus (LDT) / pedunculopontine nucleus (PPT) in the Pons increases cortical activity (so we dream). ​ LDT/PPT also stimulate medulla GABA and glycine neurons to inhibit spinal motor neurons (so we are paralyzed, except eye muscles, breathing, and muscles of the middle ear). MCH from Lateral Hypothalamus - opposite of orexin; REM> NREM> Wake.​

Biochemical Correlates of Sleep

Acetylcholine ​ Glutamate​ Adenosine ​ Melatonin​

Activation-Synthesis model (Hobson & McCarley: Freud was wrong. ​)

Activation: brain stem (pons) provides random, direct stimulation of forebrain​ Cerebral cortex attempts to synthesize the stimulation. ​ Dreams are not essentially meaningful.​

Default Mode Network (DMN) (waking behaviors) (default= autopilot =daydreaming)

Activity in the DMN is often associated with daydreaming = decreases when engaging in a conscious task such as problem-solving.​ -consists of: Medial prefrontal & parietal cortex. Lateral parietal & temporal cortex. -Unusual DMN activity could = neurodegenerative disorders

Jet Lag

Adjustment to jet lag requires about 1 day per time zone crossed.​ Airline crews traveling across time zones are subject to cognitive defects.​

Excess Weight

Belly fat plays a part in developing chronic, or long-lasting, inflammation in the body. Chronic inflammation can damage the body over time, without any signs or symptoms. Also contributes to insulin resistance, high blood pressure, imbalanced cholesterol, and cardiovascular disease (CVD).

Proteins

Can also be converted into glucose by the liver.​ Very dangerous.

Narcolepsy & Cataplexy

Cataplexy does not cause a loss of consciousness.​ Cataplexy is nearly always preceded by a strong emotional reaction or stress (also sex...). ​ Might also experience sleep paralysis (either precedes actual sleep or lingers once the person has awakened)​ Might also experience REM dreaming phenomena intrude into wakefulness: hypnogogic hallucinations (imagined sensations that seem very real. They occur as a person is falling asleep) or hypnopompic hallucinations (can seem real and are often frightening.) (upon awakening).​

Glucagon

Converts Glycogen back into Glucose.

Cortisol

Cortisol levels are related to blood pressure, heart rate, BMR​. Cortisol release is highest in the morning and drops during the day.​ -Stress-induced cortisol levels related to poor sleep quality.​

Glucose transporters

Cover the cell membrane and interact with insulin to bring glucose into the cell.

Ultradian rhythms: (ultra is more, so cycles that occur more than ones)

Cycles that occur several times per day​

Circadian rhythms:

Daily rhythms​

Pattern of Sleep ​in an Elderly Person​

Dramatic decline in stages 3 and 4: by age 60. By age 90 stages 3 and 4 have disappeared. completley.

Obesity Is Difficult to Treat

Drugs that modify the hypothalamic appetite system may be good in obesity treatment.​ ​-Example: arcuate nucleus of the hypothalamus -α-MSH agonists as appetite suppressants. ​ ​ Promising chemicals include modulation of leptin, AgRP, MCH.​

Thalamus: Gateway

During wakefulness and REM sleep, ACh depolarizes thalamic neurons to suppress spindles and slow waves and promote the transmission of single spikes that transmit desynchronized information to the cortex and drive cortical activity. -During wakefulness, monoamines strengthen this effect. ​

Polysomnography (poly is many so this shows different states of waking and sleeping.)

Electrical brain potentials can be used to classify levels of arousal and states of sleep.​

Hunger cues: External Signals

External Signals -Sights, smells, sounds of delicious food.​ -Time of day.​ -Other habits (e.g., must eat while watching TV). ​ -Social eating.​

Hunger decreases metabolic rate

Fat cells---- Arcuate Nucleus (AgRP​ NPY)--- Lateral​ Hypothalamus (Inhibitory​ Neuro-​transmission​)---- Pituitary​ Gland (TSH​ ACTH​). TSH and ACTH both increase metabolic rate. Suppressing them slows the body's use of energy. Meaning that nutrients received from food go to replenish the fat stores. As fat stores return to normal levels, more leptin is released, NPY and AgRP are less active, and the feeding cycle tapers off. ​

Dreams

Flying or falling could reflect unusual activation of the vestibular system.​ Sexual contents could reflect engorgement of the genitals with blood.​ Dreaming that unable to move, captured could reflect REM muscle paralysis.​

K-complexes in EEG

K-complexes also begin to appear in the stage 2 EEG recording. These waveforms are made up of single delta waves. Although K-complexes occur spontaneously, they are also seen in response to unexpected stimuli, such as loud noises. ​

Neural communication in the lateral hypothalamus

LH releases: -Melanin Concentrating Hormone (MCH), (a peptide neurotransmitter), used to communicate widely with the cortex: causing higher-order motivated feeding behaviors.​ -Orexin

Primary process mechanisms

Latent dream thoughts transformed into manifest dreams. A primitive form of thinking predominant in dreams

Adipose tissue

Lipids (fat), used for longer-term storage, are deposited in this tissue. Another energy source used when all the new and stored Glucose has already been used up.

Restricted food intake does promote longevity, perhaps due to:

Lower BMR.​ (the rate of energy expenditure at rest.) Less trophic factors promote cell growth.​ (helper molecules that allow a neuron to develop and maintain connections with its neighbors) nearly all of which are peptides or small proteins - that support the growth, survival, and differentiation of both developing and mature cells.​

Light can correct the ​ Molecular Clock in SCN cells

Melanopsin cells detect light and release glutamate in the SCN.​ ​Glutamate triggers the production of the Per protein, which shifts the clock and the animal's behavior.​

Diabetes Mellitus Type II

Middle age, insulin resistance. ​ -Gradual decline in amount of insulin produced, risk factor - obesity!! ​ -Bodies either don't make enough insulin or don't use insulin efficiently- a condition known as insulin resistance. ​ -Glucose from food circulates through the bloodstream without being absorbed or stored by the body's tissues. ​ -The cells are literally starving while high levels of glucose are excreted in the urine.​

Sleep Walking

More common in children than in adults (4 - 12 years).​ ​ During an episode lasts anywhere from a few seconds to 30 minutes. ​ ​ Body movements are typically uncoordinated and aimless (can lead to physical injury).​ Causes​: -Probably a NREM phenomenon - the paralysis accompanying REM makes walking during this stage unlikely. ​ -Episodes can be triggered by sleep deprivation, use of alcohol or other medications, stress, or fever.​

Shift Work (work sucks so less happy less seratonin)

More errors occur on evening and night shifts - even medicine and security work.​ Shift workers average 1.5 hours less sleep, and are more prone to sleep-related illnesses and psychological disorders; lower serotonin levels.​

NPY/AgRP neurons

NPY: neurons produce neuropeptide Y. AgRP: neurons produce agouti-related peptide. These neurons act on lateral hypothalamus and paraventricular nucleus of the hypothalamus to stimulate appetite and lower metabolism, promoting weight gain.​

Narcolepsy part 2

Narcolepsy results from disruptions in the synthesis of orexins (also known as hypocretins) or in their receptors. ​ Orexins:​ typically found in the cerebrospinal fluid of people without narcolepsy but are absent or greatly reduced in patients with the disorder.​ cells in the hypothalamus that normally secrete orexins are missing or damaged in the brains of patients with narcolepsy.​ Note: Narcoleptic dogs have a mutant gene for a orexin/hypocretin receptor.

Homeostasis and Emotion

Needs to be balanced. Emotion​ Motivation​ Reinforcement​ Arousal

Retinohypothalamic pathway

Retinal Ganglion Cells project to Superchiasmatic Nucleus (SCN)​. The RGCs are not connected to rods or cones.​ ​ Most contain melanopsin, a special photopigment; makes them sensitive to light.​

intrinsically photosensitive retinal ganglion cells (ipRGCs)

Retinal cells that do not process information about visual images, but rather provide light information to the suprachiasmatic nucleus through the release of melonopsin through the retnohypothalmic pathway.

suprachiasmatic nucleus (SCN) in sleeping

SCN neurons then relay these timing signals to the adjacent subparaventricular zone, using neuropeptides such as prokineticin 2 or transforming growth factor-α. This signal is then passed through the dorsomedial nucleus of the hypothalamus and on to brain regions that regulate sleep and wakefulness such as the LC, VLPO, and lateral hypothalamus.

Biological Rhythms​ include

Seasonal migrations​ Mating seasons​ Menstruation​

Seasonal Affective Disorder (SAD)​

Serotonin levels normally drop in late fall through winter - people with SAD may experience too much of a drop.​ Light therapy an effective treatment -uses lights of 2,500 lux (normal indoor light is about 100 lux, sunlight is about 10,000 lux).​

Delta waves in EEG

The largest, slowest (1 to 4 cycles per second), most synchronized brain waves. Both stage 3 and stage 4 feature delta wave activity, Stage 4 (about half) consists of delta waves. Awakening from stage 4 is difficult and disorienting. You might have received a phone call about an hour after going to sleep when you are likely to be in stage 4. If you hear the phone​ at all, it might take several seconds to locate the phone and wake up enough to have a decent conversation. ​

REM rebound

The increased amount of REM sleep following a period of REM deprivation.

Defending the Obese Weight

-Obese people have heavier fat cells than people of normal weight. -Surgically removed fat (liposuction) is quickly replaced.​ -Obesity may have delayed satiety messages to the brain.​ -Exposure to some viruses may influence obesity.​ -Genetics may account for differences in metabolism and set points.​

MC4 Receptor (in satiety)

When MC4 receptors are activated by aMSH, feeding is inhibited.​

MC4 Receptor

When MC4 receptors are blocked, feeding is initiated. AgRP acts as an antagonist at MC4 receptor sites in the lateral hypothalamus.

Putting us to sleep

-The preoptic area (POA) of the hypothalamus, which receives input from the anterior raphe nuclei, forms inhibitory feedback loops with waking pathways. -POA cells are often referred to as NREM-on cells because electrical stimulation of these cells produces immediate NREM sleep, and lesions result in insomnia.

lucid dreaming

Thoughtful dreaming; the dreamer is aware that he or she is dreaming and can manipulate the experience. Hypothesized to occur "when wake-like frontal lobe activation is associated with REM-like activity in posterior brain structures"

Beginning to Dream

Time of emergence of adult-type dream consciousness is debated: not before age 5 years and may be as late as age 8 years​

Slow-wave sleep (SWS)

can be divided into four stages and is characterized by slow-wave EEG activity.​

Alpha-MSH and CART

cause the pituitary gland to release TSH and ACTH, raising body metabolic rates. aMSH acts as an agonist at a special receptor site in the lateral hypothalamus.

VMH syndrome

characterized by large weight gains and picky eating habits

Rapid-eye-movement sleep (REM)

characterized by small amplitude, fast-EEG waves, no postural (posture) tension, and rapid eye movements.

Condensation

combining elements (people, objects, events)​

Circadian Rhythms

controlled by the suprachiasmatic nucleus (SCN), which is updated by light signals from the optic nerve. and in turn makes us fall asleep. SCN → subparaventricular zone → dorsomedial nucleus → the other sleep regions (efferent pathway to activate sleep)

Indirect incorporation:

dream of a leaky roof.

Direct incorporation

dream of being squirted by someone.​

NTTI REVONSUO (2000): ​ THREAT SIMULATION HYPOTHESIS​

dreaming is viewed as a way to simulate escape from threatening situation. ​

Pseudoinsomnia (pseudo = fake, feeling like youre awake when youre actually sleeping)

dreaming that you are awake. ​

Self-regulating

feedback mechanism

Binge eating

gorging with more food than is necessary to satisfy hunger.​

In the absence of cues

humans have a free-running period (The length of time it takes for an organism's endogenous rhythm to repeat) of ~25 hours; varies with age.​ Blind individuals and sailors serving on submarines may experience sleep problems.​

Anterior raphe nuclei (seratonin = awake)

manages sleep-waking cycles -- -These serotonergic nuclei communicate with the preoptic area and suprachiasmatic nucleus of the anterior hypothalamus as well as with the cerebral cortex. -less active during NREM, and silent during REM.

Bulimia

marked by periodic gorging and purging by vomiting or laxatives.​ -Average binge session involves 1500 calories of food.​ -More common than anorexia nervosa. -Some individuals experience both anorexia and bulimia.​ -Symptoms include fatigue, headaches, puffy cheeks, loss of dental enamel.​

Apnea-Hypopnea Index (AHI)

measures sleep apnea severity. The AHI is the sum of the number of apneas (pauses in breathing) plus the number of hypopneas (periods of shallow breathing) that occur, on average, each hour.​

Sleep Talking

-Typically occurs in lighter stages of sleep of both REM and NREM.​ -Diminishes with age.​ ​-Talking person is often responsive to external stimuli.​​

tuberomammillary nucleus (TMN)

-a small cluster of cells adjacent to the mammillary body at the base of the posterior hypothalamus. -Axons of the tuberomammillary nucleus project primarily to the cerebral cortex, thalamus, basal ganglia, basal forebrain, and hypothalamus. The projections to the cerebral cortex directly increase cortical activation and arousal, and projections to acetylcholinergic neurons of the basal forebrain and dorsal pons do so indirectly, by increasing the release of acetylcholine in the cerebral cortex.

Onset insomnia = (onset beggining of sleep)

occurs when a person is unable to go to sleep.​ Treatment: behavioral adjustments are usually helpful (Light pollution!).​

Synchronous activity

occurs when neurons are firing more in unison and characterizes deep stages of sleep.

Maintenance insomnia (cant maintain sleep)

occurs when sleep is frequently interrupted or early waking occur

Locus coeruleus (norepinephrine) (loco lots of energy the person is awake)

participates in diverse states of awareness. -the source of most of the norepinephrine in the brain. -relatively less active when a person is relaxed. -During NREM sleep it is quieter and is totally silent during REM.

Symbolization

possibility of universal symbols in dreams. Some of these were sexual in nature (e.g. guns, and swords representing the penis).​

Submersion tests

provide the most accurate measures of body fat.​

Electroencephalography (EEG):

records electrical activity in the brain​

Electro-oculography (EOG) (ocul = eye)

records eye movements

Electromyography (EMG) (my= like muscles)

records muscle activity​

Duodenal (intestines) glucoreceptors

sense sugars and inhibit eating. -These receptors are activated by Fats/proteins. -Once activated by fats they release cholecystokinin (CCK) promoting the release of insulin = contracts of the gallbladder, and initiating digestion.

Displacement

shifting emphasis from one element to another ​

Preoptic area of the anterior hypothalamus

sleep centre

SOLMS: NEUROPSYCHOLOGY OF DREAMING

solms found that the PTO junction (pareital-temporal-occipital) and the ventromedial deep frontal white matter cause complete loss of dreaming if damaged. Lesions to the latter cause complete cessation of dreaming - because of interruption in dopamine transmission which forms the interactions between the basal forebrain and limbic structures and many parts of the frontal cortex. Lesions to visual association cortex cause loss of visual imagery in dreams, but not lesions to primary visual cortex. Lesions in the DLPFC responsible for executive functioning, goal oriented behavior and self monitoring, had no effect on dreaming. Brainstem lesions: patients can still dream (without a pons)

Donor rhythms

tested using hamsters bred to have a 20 hour cycle, their SCN tissue was implanted in 24 hour hamsters - which affected their rhythms.​

TSH & ACTH

the release of NPY and AgRP in the lateral hypothalamus and PVN suppresses the release of two pituitary hormones, TSH and ACTH. Both increase metabolic rate, so suppressing them slows the body's use of energy therefore nutrients received during feeding are used to replenish the fat stores.

Genetic reality

there are 'morning people' & 'night people' (& also in-betweens).​ Most adolescents are temporarily "night-owls" - Drop in melatonin production at the onset of adolescence. ​

Adenosine

throughout the brain - is also related to sleep debt. Reminder: caffeine is an adenosine antagonist

Glucoreceptors

(NST) located in the medulla. A mechanism for signalling hunger. Has no BBB so glucoreceptors in the medulla are able to detect glucose levels in the blood. Receives input from taste system. Communicates with the hypothalamus

Censorship of conflicted wishes

(to prevent excessive anxiety that disturbs sleep); diminished, but present even during sleep. ​Dreams also contain 'day residues' (memory traces left by the events of the waking state).

Arcuate nucleus

-A cluster of neurons in the hypothalamus. -Associated with feeding. -Leptin and insulin communicate with neurons in this nucleus.

cholecystokinin (CCK)

-A gut hormone released due to consumption of fats. -Also acts as a central nervous system (CNS) neurochemical that signals satiety.

Two pathways originating in the reticular formation of the medulla are essential to waking:

-A ventral pathway proceeds from the medulla to the posterior hypothalamus and on to the basal forebrain. -A dorsal pathway projects to a group of cells in the midbrain reticular formation known as the cholinergic mesopontine nuclei, located at the junction of the pons and midbrain and uses acetylcholine (ACh) as their major neurotransmitter

Treatment of Eating Disorders

-Antidepressant medications appear effective in treating bulimia. -Cognitive-behavioral therapies, especially when body image is addressed.​ -Family therapy for adolescent anorexia.​ -Anorexia may require hospitalization. ​

The Effects of Damage and Lesions in the SCN (located in the anterior part of the hypothalamus)

-Cutting the optic tract deprives rats of the ability to see "consciously"- but the SCN still gets input from the Retino-hypothalamic pathway. -Without zeitgeber input about the time of day (e.g., in constant dim light), the SCN "drifts", but has a (25 hour) stable rhythm. ​ -When the SCN is lesioned - with natural light there are behavioral cues that act directly on other brain areas; without light - the rat's sleep-waking-activity patterns are completely disorganized.​

What causes eating disorders?

-In response to difficult life experiences. -Peer pressure regarding body image.​ -Common in cultures where it is bdesirable to be slim. ​ ​-Sometimes people with an eating disorder are depressed, and they may have obsessions (co-morbidity).​

Other obesity treatments include:

-Increasing the body's metabolic rate, with specific thyroid hormones (danger of increasing heart rate).​ -Inhibition of fat, by interfering with new fat tissue using angiogenesis inhibitors.​ ​-Reduced absorption of fat in digestion through medications.​ -Amphetamines (Ritalin...) to reduce appetite - not effective in the long-term and side effects.​

Acting out your dreams

-Normal REM paralysis is absent.​ -Usually begins after age 50.​ An inherited problem in most cases, but it can also result from brain damage, particularly in the pons:​ -Accompany or precede neurodegenerative diseases, especially Parkinson's disease. ​ -Treated with sedative medications, such as the benzodiazepines, or with melatonin.​ In cataplexy: we see the absence of normal REM paralysis when it is supposed to occur. ​

What puts us to sleep?

-Locus coeruleus (LC): Norepinephrine (NE) ​ -Dorsal and Medial raphe nuclei: Serotonin (5-HT) ​ -Tuberomammillary nucleus (TMN): -Histamine (HA)​ -Substantia nigra, Ventral tegmental area, and Ventral periaqueductal gray (SN/VTA/vPAG): Dopamine (DA)​ -ACh from the laterodorsal and pedunculopontine tegmental nuclei (LDT/PPT).​

What keeps us awake?

-Norepinephrine (NE)= Locus coeruleus (LC) -Serotonin (5-HT)= Dorsal and Medial raphe nuclei. ​ -Histamine (HA)​=Tuberomammillary nucleus (TMN): -Dopamine (DA)= ​Substantia nigra, Ventral tegmental area, and Ventral periaqueductal gray (SN/VTA/vPAG) Neurons in the laterodorsal and pedunculopontine tegmental nuclei (LDT/PPT) release ACh​ to excite neurons in the thalamus,​ hypothalamus, and brainstem.​ Neurons in basal forebrain (BF) cortical activation using ACh and GABA. ​

Restless Leg Syndrome (RLS)

-Occurs when one of a person's limbs, usually a leg, experiences a sensation of tingling and moves at regular intervals of 15, 30, or 45 seconds. ​ -Frequent in children and adults with ADHD - Both conditions are characterized by atypical dopamine function.​ Other medical conditions, such as kidney disease, pregnancy, and anemia, might be at fault.​ -Treatment generally consists of massage, the application of heat or cold, avoidance of caffeine, and, if necessary, medication.​

Infant sleep is characterized by

-Shorter sleep cycles​ -Half of the time sleeping is spent in REM. Newborn infants: Sleep 14 to 16 hours per day. -Half of sleeping time is in REM. Note: The more prematurely the child is born, the greater percentage of his or her sleep time is spent in REM. Processes during REM sleep are important for pruning and maintaining newly formed synapses

Hunger cues: Internal Signals

-Stomach contractions ("growling").​ -Blood glucose levels.​ -But diabetics feel hungry despite excess glucose.​

Obestatin (obesity you need a decrease in appetitie)

-encoded by same gene as ghrelin. -decreases appetite

NST

-receives information from glucoreceptors and taste receptors and participates in energy storage. -Disruption of this pathway = abnormal eating patterns. ​

PYY3-36

-secreted by cells in intestines.​ -Low levels before eating, rise rapidly after meal.​ -It also acts in opposition to ghrelin, acting as an appetite suppressor

sleep terrors

An NREM episode in which the individual is partially aroused, disoriented, frightened, and inconsolable.

PGO wave (P= pons to O= occipital lobe)

An electrical waveform observed during REM sleep, originating in the pons and traveling to the thalamus and occipital lobe. Each PGO wave is associated with an eye movement.

Daylight Savings Time Requires Adjustment, Too​

April shift is a phase advance. ​ analogous to eastward travel​ 7% increase in traffic accidents​ October shift is a phase delay. ​ analogous to westward travel​ 7% decrease in traffic accidents​

Levels of Fats also influence eating​

Arcuate nucleus of the hypothalamus is governed by these hormones: Leptin​ Insulin​ Ghrelin​ Obestatin​ PYY3-36​

Energy expenditure is adjusted in response to nutrition.

At the start of a diet (less nutrition), the basal metabolic rate (BMR) will fall - to prevent losing weight.​

Diabetes Mellitus Type I

Autoimmune attack on pancreas beta cells.​ Usually in children. -Glycogen doesn't form.​ -Glucose does not enter cells​. -Doesn't produce insulin. -Sweet urine​ -Thirst because of solute imbalance, fatigue, weight loss.

Biochemical Correlates of Waking​

Awake and asleep -Acetylcholine ​ (release by the pons and basal forebrain is associated with both waking and REM sleep) -Glutamate​ (in the frontal lobes is high during both waking and REM sleep.) Awake -Histamine​ (These neurons project widely throughout the forebrain.) -Serotonin​ (from the raphe nuclei). -Norepinephrine (from the locus coeruleus). -Norepinephrine​ (Adenosine specifically inhibits neurons releasing neurochemicals like norepinephrine.) -Cholinergic agonists, such as nicotine, produce a high level of mental alertness.

Cells releasing orexins are influenced by leptin levels:

High leptin = sufficient fat storage----> Orexin cells are inhibited = feeding is reduced. Low leptin = low fat storage-------> Orexin cells are active and are released = feeding is stimulated.

Orexin/Hypocretin

From neurons in the lateral and posterior hypothalamus​, sustains long periods of wakefulness​. -Orexins excite target neurons through the OX1 and OX2 receptors. Like most other wake-promoting neurons, orexin neurons fire mainly during wakefulness, especially during active exploration, and are silent during NREM and REM sleep. -Orexins directly excite neurons of the mesolimbic reward pathways, and orexin antagonists can reduce the motivation to seek drugs of abuse.

Leptin defects

Genetic defects in leptin production or sensitivity give a false (low) reporting of body fat, causing animals to overeat.​​​

Causes of Eating Disorders

Genetic factors - especially in anorexia. Twin studies suggest an inherited vulnerability.​ Elevated CART levels accompany anorexia.​ Patients with major depressive disorder, OCD and eating disorders show decreased levels of serotonin.​ Bingeing may involve addictive processes.​ cocaine- and amphetamine-regulated transcript peptide (CART).​

Narcolepsy

Go strait into REM sleep. ​ Sleep attacks usually last from 10 to 20 minutes (can continue up to 1 hour). ​ ​ In a sleep attack, attacks occurring approximately every two to three hours. ​

Feeding is inhibited. (process)

High leptin levels stimulate arcuate nucleus, which releases αMSH (via POMC) and CART.​ αMSH and CART stimulate the release of TSH and ACTH by the pituitary gland, raising metabolic rates.​ αMSH and CART initiate Sympathetic nervous system activity (brainstem & spinal cord).​ αMSH and CART inhibit synthesis of NPY and AgRP.​

Human Sleep Patterns

In a typical night of young adult sleep:​ Sleep time ranges from 7-8 hours​ -Half of the time sleeping is spent in stage 2 sleep. -Small portion of sleep is REM sleep​. -Cycles last 90-110 minutes -Cycles early in the night: More stage 3 and 4 SWS. Later cycles have: More REM sleep. We usually spend the last half hour of the night's sleep in REM we wake up knowing that we just dreamt.

Sleep spindles in EEG

In stage 1 Some theta wave activity now occurs, and heart rate and muscle tension begin to decrease. After 10 to 15 minutes, stage 1 gives way to stage 2 NREM, which accounts for about 50 percent of the night's entire sleep. Further reductions in heart rate and muscle tension occur. ​ The EEG shows sleep spindles that are generated by interactions between the thalamus and the cortex. ​Although spindles are prominent in stage 2, they do occur in other stages of NREM. After about 15 minutes in stage 2, we enter stage 3 and stage 4 NREM sleep.​ During these stages, body temperature, breathing, blood pressure, and heart rate are at very low levels due to the activity of the parasympathetic nervous system. Energy use by the brain drops to between 1 1 and 40 percent of that required by the waking brain and delta waves are used. Stage 4 has more delta waves than stage 3.

The Suprachiasmatic Nucleus (SCN) (S- super, C- clock, N)

Isolated SCN tissue maintains its circadian rhythms - therefore it's a self-timing clock (not dependent on zeitgebers)! ​ ​ The retinohypothalamic pathway provides information about light to the SCN.​

​ The SCN

Organs such as lungs and liver as well as muscles also have circadian rhythms, and may take cycles to adjust after a phase shift of 6 hours or more - SCN adjusts within 1-2 cycles, lungs & muscles 6, liver 16! - long term effects of jet lag. SCN entrained by light - other organs by feeding patterns - so travelers should move to new mealtimes in advance.​ ​ The SCN is active only during the day in both diurnal and nocturnal animals.

The Internal Protein Clock

Oscillations of gene activity and their protein production and degradation serves as the "ticking" of the internal clock.​ ​ Light may participate in the triggering of some of these protein fluctuations.​

How long does it take you to adjust? Daylight Savings Time

Patterns of function of lung and muscle tissue in rats needed ​ six light-dark cycles to adjust to a six-hour phase shift. ​ Liver cells required 16 cycles.​

Lactose Tolerance Correlates with Use of Dairy Products

People who became relatively dependent on milk products as a source of protein, are much more likely to be tolerant of lactose.

Type II diabetes (possible cause)

Possible cause: complex interactions in fat tissue draw immune cells to the area and trigger low-level chronic inflammation. This inflammation can contribute to the development of insulin resistance, In type 2 diabetes losing weight can reduce insulin resistance and prevent or delay type 2 diabetes.

Leptin

Produced by fat cells and are sent to the bloodstream. -High leptin levels: Might inhibit the Arcuate Nucleus of the Hypothalamus and inhibit NPY/AgRP neurons.​ -Low leptin levels: Activate the Arcuate Nucleus to release neuropeptide Y (NPY), agouti related peptide (AgRP) to communicate with the Lateral Hypothalamus and the Paraventricular Nucleus of the Hypothalamus which activate parasympathetic NS to initiate feeding.

Ghrelin

Produced primarily by the pancreas and the lining of the stomach and is sent into the bloodstream. Gherlin receptors have been found in the arcuate nucleus and the ventromedial hypothalamus. Ghrelin affects feeding by acting on brain circuits involved with memory and reward especially when food deprivation has been more severe. Levels of ghrelin rise during fasting & fall after a meal, except in obese subjects - they remain high.

Pancreas

Produces glucagon and insulin. These hormones regulate the body's supply of energy from glucose.​

JONATHAN WINSON (1985): EVOLUTIONARY MODEL

Proposed an evolutionary model, in which animals evolved the ability to integrate sensory experience with stored memories during REM sleep rather than while awake.​ ​ Dreaming, in this view, is just a window into the brain's processing of the day's events.​

Statistics for SIDS:

Rates are lower among children who are exclusively breastfed.​ - African American babies are twice as likely and Native American infants are three times as likely to die from SIDS. - Boys are at higher risk than girls. ​

Lateral hypothalamus

Rats with lesions in the LH would starve to death in the presence of food because they would not initiate eating! ​If rats with LH lesions were force-fed, they eventually began to initiate feeding on their own again. ​ ​ Electrical stimulation of the LH produces immediate feeding. ​

Sudden Infant Death Syndrome (SIDS)

Sleep apnea resulting from immature respiratory pacemaker systems or arousal mechanisms.​ Abnormalities in the serotonergic systems of the medulla. The most common cause of death in the first six months of life.

myoclonia (my= muscle)

Stage one is usually disturbed occasionally by a muscle jerk, usually in an arm or leg. This experience is often accompanied by a brief visual image, such as stumbling on the stairs or on a curb.

Orexin cells (hypocretin)

Stimulated by ghrelin -initiate feeding. -Neurons that release orexins project widely in the cerebral cortex as well as to the midbrain and pons. -Orexin plays an important role in narcolepsy. - Orexin is a peptide neurochemical produced in the LH.

areas in the brain activated in response to food cues, ect...

The orbitofrontal cortex & amygdala - reward value of food . The insula - taste of food The nucleus accumbens & dorsal striatum - motivation to eat. The lateral hypothalamus - rewarding responses to palatable food and drive food-seeking behaviors.

Glucose

The principal sugar used for energy.​

Gluconeogenesis

The process of converting fat to glucose and ketones, a form of fuel, by the liver.​

Glycolysis

The process of converting glycogen back into glucose when blood glucose levels drop.​

NIF

The retinohypothalamic pathway provides information about light to the SCN. from non image forming cells about light and dark outside during pigment (melanopsin).​

Obese

The state of being extremely overweight, that is 20 percent higher than typical.

Apnea

The total absence of airflow for a period of time during sleep.​ In apnea, breathing ceases for as long as a minute or two, resulting in reduced oxygen levels in the blood. The person awakens gasping for air.​ ​ Muscles in the chest and diaphragm may relax too much or pacemaker respiratory neurons in the brain stem may not signal properly. ​ Treatments include a removable tube in the throat or a CPAP (continuous positive airway pressure) machine, to prevent collapse of the airways.​

POMC/CART neurons

These neurons inhibit appetite and raise metabolism, promoting weight loss.​ POMC/CART neurons produce pro-opiomelanocortin (POMC→αMSH) and cocaine- and amphetamine-related transcript (CART)​ Related to the decrease of eating by amphetamines and Ritalin.​​

Dreaming during Non-REM sleep

Typically (but not always) more thought-like, fragmentary, and related to daily concerns than the vivid, hallucinatory, predominantly visual narratives commonly reported from REM sleep

VMH (Ventromedial Hypothalamus) lesions

VMH important for satiety. -Adjacent pathways are destroyed like fibers connecting the paraventricular nucleus (PVN) to the nucleus of the solitary tract (NST) in the brainstem. -VMH lesions also result in excess insulin production = chronically low-circulating glucose levels = constant hunger and feeding.​

NREM sleep pathways.

Ventrolateral preoptic area (VLPO) neurons are active during NREM sleep and reduce activity in the ascending arousal systems using GABA and galanin. A subset of VLPO neurons is also active during REM sleep. ​

Neural-Network Model (CRICK & MITCHISON (1983))

Views dreaming as a way for the brain to forget irrelevant and unnecessary information. Subsequent research on both development and learning has supported this model, as REM sleep influences the elimination and maintenance of newly formed synapses

Homeostasis Needs

Water, sugar, protein, fat, calcium, salt, other minerals, and oxygen. Optimal fluid and temperature balance. ​

BMI

a measure of body weight relative to height

Dynamic

a process of constant adjustment.

Sleep debt

accumulation of serotonin in ventrolateral preoptic nucleus of the hypothalamus, eventually deactivates the wakefulness circuits.​

Nocturnal (N for night)

animal active during the dark​

Diurnal (D for day)

animal active during the light​

De-synchronous brain activity

arises from the relatively independent action of many neurons and is correlated with alertness. ​

The pineal gland

in older adults begins to calcify and produce smaller amounts of melatonin= fewer hours of sleep.

The Basal Forebrain (anterior to the hypothalamus)

includes these structures: -medial septum (It plays a role in the generation of theta waves in the hippocampus.), -diagonal band of Broca (generation of theta waves in the hippocampus.), -substantia innominata, -magnocellular preoptic nucleus. Basal forebrain cholinergic neurons contain two major groups: -one localized in the medial septum (MS)/vertical diagonal band of Broca (vDB) -the other in the nucleus basalis magnocellularis (NBM). ​ Its GABA-ergic neurons promote wakefulness by inhibiting inhibitory neurons in other areas that otherwise would reduce activity. ​

Anorexia nervosa

individuals severely deprive themselves of food. -90% of patients are female, starts at mid-teens..​ -Disturbed body image.​ -Amenorrhea (absence of menstruation), -lanugo, increased sensitivity to cold, -yellowed skin, -cardiovascular and gastrointestinal problems are common. ​ -people with anorexia in particular do not always ask for treatment.​

Rimonabant (rimon blocks receptor reduce appetite)

is an anorectic anti-obesity drug that was first approved in Europe in 2006 but was withdrawn worldwide in 2008 due to serious psychiatric side effects; it was never approved in the United States

Growth hormone

is released during deep sleep.​

Melatonin

is released only at night (by the retina and the pineal gland).​​ 4 AM melatonin peak - hardest to stay awake.​ When Melanopsin is activated by the short wavelength component of light, it supresses Melatonin synthesis.

Bariatrics (its barbaric to cut somones stomach shorter.)

is the branch of medicine that deals with the causes, prevention, and treatment of obesity.​ (procedure includes shortening of the stomach.)

Entrainment (we are "trained" to change the rythm)

is the process of shifting the rhythm.​

phase shift

is the shift in activity pattern in response to a synchronizing stimulus, such as light or food.​ Phase shifts occur in nature in response to the seasonal change in daylight duration.

Latent dream thoughts:

unconscious conflicted instinctual, wishes originating in childhood; motive force for dream, an attempt at fulfillment of these wishes. ​