States of conciseness

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Consciousness

awareness of internal and external stimuli such as feelings of hunger and pain or detection of light

A biological rhythm

 an internal cycle of biological activity including:
-Fluctuation of body temperature.

-An individual's menstrual cycle.

-Levels of alertness.

Circadian rhythm

– biological rhythm that occurs over approximately 24 hours.

-Generated by the suprachiasmatic nucleus (SCN)

-The sleep-wake cycle, one of our main circadian rhythms, is linked to our environment's natural light-dark cycle.

What controls our biological rhythms

The hypothalamus is responsible for maintaining homeostasis, the tendency to maintain a balance, or optimal level, within a biological system.

THE SUPRACHIASMATIC NUCLEUS (SCN)

Located in the hypothalamus, serves as the brain’s clock mechanism.

The clock sets itself with light information received through projections from the retina, allowing it to synchronize with the outside world.

Sleep

a state marked by relatively low physical activity and a reduced sense of awareness.

Sleep is associated with the secretion and regulation of many hormones including

-Melatonin

-Follicle stimulating hormone

-Luteinizing hormone

-Growth hormone.

brain areas involved in sleep

thalamus

hypothalamus

scn

pons

spitutuary glads

Adaptive Function (Evolutionary Hypotheses)

Sleep is essential to restore resources that are expended during the day.

-Sleep is an adaptive response to predatory risks, which increase in darkness.

There is little evidence to support these explanations.

Cognitive Function

Focuses on sleep's importance for cognitive function and memory formation.

-Research shows that sleep deprivation results in disruptions in cognition and memory deficits.

- These impairments become more severe as the amount of sleep deprivation increases.

-Slow-wave sleep appears to be essential for effective memory formation.

Brainwaves during sleep 

Alpha – relatively low frequency, relatively high amplitude, synchronized.

Theta – low frequency, low amplitude. 

Delta – low frequency, high amplitude, desynchronized.

Amplitude

range of the waves 

Frequency -

how often they occur 

stage 1 of sleep

occurs between wakefulness and sleep , respiration and heartbeat slow down , muscle tension and body temp decrease ( alpha waves )

stage 2 of sleep

body goes into deep relaxation , (theta waves ), characterized by the appearance of both sleep spindles and k complexes

sleep spindles 

rapid bursts of high frequency brain waves 

k complexes

very high amplitude pattern of brain activity

stages 3 and 4

slow wave sleep, delta waves , respiration and heart rate slow even more

Rapid eye movement ( REM

• Rapid eye movement 

• Paralysis of voluntary muscles 

• Dreams 

• Brain waves are similar to those seen during wakefulnes

PARASOMNIA

 involve unwanted motor behavior/experiences throughout the sleep cycle.

what is SIDS 

Sudden infant death syndrome 

Cataplexy

loss of muscle tone while awake or in some cases complete paralysis of the voluntary muscles.

(DSM-5 definition)

Substance use disorder is a compulsive pattern of drug use despite negative consequences

Physiological dependence

 involves changes in normal bodily functions and withdrawal upon cessation of use.

Psychological dependence

emotional need for the drug.

Depressants

drugs that suppress the central nervous system activity. Usually GABA agonists have a quieting effect on the brain.

Work by binding to GABA receptors which makes the neuron less likely to fire.

GABA receptors

Neural activities decrease with Gaba ↑

Stimulants

– Increase overall levels of neural activity.