PSYC550Biological Bases of

BehaviorSleep and Sex

A Physiological and Behavioral

Description of Sleep• alpha activity

– Smooth electrical activity of 8-12 Hz recorded from the brain; generally associated with a state of relaxation.

• beta activity– Irregular electrical activity of 13-30 Hz recorded from

the brain; generally associated with a state of arousal.• theta activity

– EEG activity of 3.5-7.5 Hz that occurs intermittently during early stages of slow-wave sleep and REM sleep.

• delta activity– Regular synchronous electrical activity of less than 4

Hz recorded from the brain; occurs during the deepest stages of slow-wave sleep.

SWS vs REM• NREM (SWS in stages 3 and 4)

– Alpha, delta, and theta activity– Light, even respiration– Lowered BP– Muscle control is present– Difficult to arouse (especially from stage 4)

• REM– Asynchronized beta– Increased respiration and BP– REM– PGO waves– Spinal paralysis– Dreams– Sexual arousal

A Physiological and Behavioral

Description of Sleep• REM sleep

– A period of desynchronized EEG activity during sleep, at which time dreaming, rapid eye movements, and muscular paralysis occur; also called paradoxical sleep.

• non-REM sleep– All stages of sleep except REM sleep.

• slow-wave sleep– Non-REM sleep, characterized by synchronized EEG

activity during its deeper stages.• basic rest-activity cycle

– A 90-minute cycle (in humans) of waxing and waning alertness, controlled by a biological clock in the caudal brain stem; controls cycles in REM sleep and slow-wave sleep.

Neurotransmitters involved in Sleep

• Serotonin– In raphe and pons– Increased in SWS, decreased in REM

• Dopamine– Decreased in REM

• Norepinephrine– Decreased in REM

• Acetylcholine– Greatly increased in REM

I get 8 hours of sleep each night, without

fail.

Stro

ngly A

gree

Agre

e

Dis

agre

e

Stro

ngly D

isag

ree

25% 25%25%25%1. Strongly Agree2. Agree3. Disagree4. Strongly

Disagree

Disorders of Sleep• insomnia

– Discuss sleep hygiene

• drug dependency insomnia– An insomnia caused by the side effects of ever-increasing

doses of sleeping medications.• sleep apnea

– Cessation of breathing while sleeping.• narcolepsy

– A sleep disorder characterized by periods of irresistible sleep, attacks of cataplexy, sleep paralysis, and hypnagogic hallucinations.

• sleep attack– A symptom of narcolepsy; an irresistible urge to sleep

during the day, after which the person awakens feeling refreshed.

People with narcolepsy collapse into sleep from total alertness without

warning.

Stro

ngly A

gree

Agre

e

Dis

agre

e

Stro

ngly D

isag

ree

25% 25%25%25%1. Strongly Agree2. Agree3. Disagree4. Strongly

Disagree

1010

http://www.youtube.com/watch?v=tOAvWbspeSQ&feature=related

Narcolepsy• cataplexy

– A symptom of narcolepsy; complete paralysis that occurs during waking.

• sleep paralysis– A symptom of narcolepsy; paralysis occurring just

before a person falls asleep.• hypnagogic hallucination

– A symptom of narcolepsy; vivid dreams that occur just before a person falls asleep; accompanied by sleep paralysis.

• hypocretin– A peptide, also known as orexin, produced by

neurons whose cell bodies are located in the hypothalamus; their destruction causes narcolepsy.

Disorders of Sleep

• REM sleep behavior disorder– A neurological disorder in which the

person does not become paralyzed during REM sleep and thus acts out dreams.

• Night terrors vs nightmares• Somnambulism• Somniloquy• Enuresis• Bruxism

Why do we sleep?

For r

esto

ratio

n

To c

onsolid

ate

mem

ory

To re

mai

n saf

e fro

m ..

.

To le

arn to

rela

x

25% 25%25%25%1. For restoration2. To consolidate

memory3. To remain safe

from predators4. To learn to

relax

1010

Why Do We Sleep?• sleep-related eating disorder

– A disorder in which the person leaves his or her bed and seeks out and eats food while sleepwalking, usually without a memory for the episode the next day.

• fatal familial insomnia– A fatal inherited disorder characterized by

progressive insomnia.• rebound phenomenon

– The increased frequency or intensity of a phenomenon after it has been temporarily suppressed; for example, the increase in REM sleep seen after a period of REM sleep deprivation.

• adaptive response to danger

Physiological Mechanisms of Sleep

and Waking• locus coeruleus

– A dark-colored group of noradrenergic cell bodies located in the pons near the rostral end of the floor of the fourth ventricle; involved in arousal and vigilance.

• raphe nucleus– A group of nuclei located in the reticular formation of the

medulla, pons, and midbrain, situated along the midline, contains serotonergic neurons.

• tuberomammillary nucleus (TMN)– A nucleus in the ventral posterior hypothalamus, just rostral

to the mammillary bodies; contains histaminergic neurons involved in cortical activation and behavioral arousal.

• ventrolateral proptic area (VLPA)– A group of GABAergic neurons in the preoptic area whose

activity suppresses alertness and behavioral arousal and promotes sleep.

Physiological Mechanisms of Sleep

and Waking• PGO wave

– Bursts of phasic electrical activity in the pons, followed by activity in the lateral geniculate nucleus and visual cortex, a characteristic of REM sleep.

• medial pontine reticular formation (MPRF)– A region that contains neurons involved in

the initiation of REM sleep; activated by acetylcholinergic neurons of the peribrachial area.

Physiological Mechanisms of

Sleep and Waking• magnocellular nucleus

– A nucleus in the medulla; involved in the muscular paralysis that accompanies REM sleep.

Biological Clocks• circadian rhythm

– A daily rhythmical change in behavior or physiological process.

• zeitgebers– A stimulus (usually the light of dawn) that resets the

biological clock that is responsible for circadian rhythms.• suprachiasmatic nucleus (SCN)

– A nucleus situated atop the optic chiasm. It contains a biological clock that is responsible for organizing many of the body’s circadian rhythms.

• melanopsin– A photopigment present in ganglion cells in the retina

whose axons transmit information to the SCN, the thalamus, and the olivary pretectal nucleus.

Biological Clocks

• pineal gland– A gland attached to the dorsal tectum;

produces melatonin and plats a role in circadian and seasonal rhythms.

• melatonin– A hormone secreted during the night by

the pineal body; plays a role in circadian and seasonal rhythms.

Sexual Development

• sry– The gene on the Y chromosome that instructs the

undifferentiated fetal gonads to become testes.• organizational effect (of hormone)

– The permanent effect of a hormone on tissue differentiation and development.

• activational effect (of hormone)– The effect of a hormone that occurs in the fully

developed organism; may depend on the organism’s prior exposure to the organizational effects of hormones.

Sexual Development

• defeminizing effect– An effect of a hormone present early in development that

reduces or prevents the later development of anatomical or behavioral characteristics typical of females.

• androgen– A male sex steroid hormone; stimulates the development of

the Wolffian system. Testosterone is the principal mammalian androgen.

• masculinizing effect– An effect of a hormone present early in development that

promotes the later development of anatomical or behavioral characteristics of males.

• testosterone– The principal androgen found in males.

AIS• androgen insensitivity

syndrome– A condition caused by

a congenital lack of functioning androgen receptors; in a person with XY sex chromosomes, causes the development of a female with testes but no internal sex organs.

Sexual Development

• Turner’s syndrome– The presence of only one sex chromosome

(an X chromosome); characterized by lack of ovaries but otherwise normal female sex organs and genitalia.

Sexual Development

• follicule-stimulating hormone (FSH)– The hormone of the anterior pituitary gland that causes

development of an ovarian follicle and the maturation of an ovum.

• luteinizing hormone (LH)– A hormone of the anterior pituitary gland that causes

ovulation and development of the ovarian into a corpus luteum.

• estradiol– The principal estrogen of many mammals, including

humans.• estrogen

– A class of sex hormones that cause maturation of the female genitalia, growth of breast tissue, and development of other physical features characteristic of females.

Copyright © Allyn & Bacon 2007

Hormonal Control of Sexual Behavior

• oxytocin: The big “O”– A hormone secreted by the posterior pituitary gland;

causes contraction of the smooth muscle of the milk ducts, the uterus, and the male ejaculatory system; also serves as a neurotransmitter in the brain.

• prolactin– A hormone of the anterior pituitary gland, necessary

for production of milk; has an inhibitory effect on male sexual behavior.

• lordosis– A spinal reflex seen in many four-legged animals;

arching of the back in response to approach of a male or to touching the flanks, which elevates the hindquarters.

Hormonal Control of Sexual Behavior

• pheromone– A chemical released by one animal that affects the behavior

or physiology of another animal; usually smelled or tasted.• Lee-Boot effect

– The slowing and eventual cessation of estrous cycles in groups of female animals that are housed together; caused by a pheromone in the animals’ urine; first observed in mice.

• Whitten effect– The synchronization of the menstrual or estrous cycles of a

group of females, which occurs in the presence of a pheromone in a male’s urine.

Hormonal Control of Sexual Behavior

• Vandenbergh effect– The early onset of puberty seen in female animals that are

housed with males; caused by a pheromone in the male’s urine; first observed in mice.

• Bruce effect– Termination of pregnancy caused by the odor of a

pheromone in the urine of a male other than the one that impregnated the female; first identified in mice.

• vomeronasal organ (VNO)– A sensory organ that detects the presence of certain

chemicals, especially when a liquid is actively sniffed; mediates the effects of some pheromones.

• accessory olfactory bulb– A neural structure located in the main olfactory bulb that

receives information from the vomeronasal organ.

Hormonal Control of Sexual Behavior

• medial nucleus of the amygdala– A nucleus that receives olfactory

information from the olfactory bulb and accessory olfactory bulb; involved in the effects of odors and pheromones on reproductive behavior.

• congenital adrenal hyperplasia (CAH)– A condition characterized by hypersecretion

of androgens by the adrenal cortex; in females, causes masculinization of the external genitalia.

Copyright © Allyn & Bacon 2007

Copyright © Allyn & Bacon 2007

Copyright © Allyn & Bacon 2007

Neural Control of Sexual Behavior

• medial preoptic area (MPA)– An area of cell bodies just rostral to the

hypothalamus; plays an essential role in male sexual behavior.

• sexually dimorphic nucleus– A nucleus in the preoptic area that is much larger

in males than in females; first observed in rats; plays a role in male sexual behavior.

• periaqueductal gray matter (PAG)– The region of the midbrain that surrounds the

cerebral aqueduct; plays an essential role in various species-typical behaviors, including female sexual behaviors.

Neural Control of Sexual Behavior

• ventromedial nucleus of the hypothalamus (MH)– A large nucleus of the hypothalamus

located near the wall of the third ventricle; plays an essential role in female sexual behaviors.

The neural structure most involved in female reproductive behavior

is:

Gone

afte

r the

hon...

The

Med

ial P

reoptic

...

The

Ventro

med

ial H

...

The

Hippoca

mpu

s (..

.

25% 25%25%25%1. Gone after the honeymoon

2. The Medial Preoptic Area (MPA)

3. The Ventromedial Hypothalamus (VMH)

4. The Hippocampus (HPC)

1010

During paradoxical sleep, you will expect an increase in the

neurotransmitter:

Ser

otonin

Nore

pinep

hrine

Dopam

ine

Ace

tylc

holine

25% 25%25%25%1. Serotonin2. Norepinephrine3. Dopamine4. Acetylcholine

1010