Psychology U4 AOS1 Revision

Psychological construct

a concept that is built to describe a specific psychological activity, or a pattern of activity, that is believed to occur/exist but cannot be directly observed.

Consciousness

our awareness of something either internal or external to yourself. It includes our awareness of all objects and events in the external world, and our sensations, mental experiences and our own existence at any given time.

Immediate conscious experience

Includes things that we are currently aware of

2 categories of consciousness

Normal waking consciousness (NWC) and altered states of consciousness (ASC)

Normal waking consciousness (NWC)

a maintained sense of time and place, where we spend 2/3 of our day

Altered states of consciousness (ASC)

different processing of internal and external stimuli to NWC. ASC can be induced (meditation, hypnosis, ingestion of drugs or alcohol) or naturally occurring (sleep, daydreaming, dreaming in sleep)

Levels of ASC

• Daydreaming

• Meditative state

• Hypnotized

• Sleep

• Anaesthetized

• Coma

Levels of NWC

• Sustained attention

• Normal wakefulness

Ways to measure sleep

• electroencephalograph (EEG)

• electromyograph (EMG)

• electro-oculargraph (EOG)

• sleep diaries

• video monitoring

electroencephalograph (EEG)

A device that detects, amplifies and records general patterns of electrical activity of the brain over a period of time. Small electrodes are attached to the scalp, and each detects and receives signals from many thousands of neurons that are activated near it. Based on the frequency and amplitude of brain waves, scientists can determine what stage of sleep a person is in.

Frequency

the number of brain waves per second. A pattern of high frequency brain wave activity is faster and has more brain waves per unit of time, and vice versa.

Amplitude

The intensity of brain waves, usually measured in microvolts, and can be visually judged by the height of the peaks and troughs of the waves. High-amplitude brain waves have bigger peaks and troughs, and vice versa.

beta brain wave pattern

Fastest of all the waves. High frequency and low amplitude, present during alertness and intensive mental activity during NWC and REM sleep

Alpha brain wave pattern

Present when we are awake and alert but mentally and physically relaxed and internally focused. Mostly originate in the occipital lobe. If relaxation is disturbed then they abruptly stop. Medium to high frequency and low amplitude.

Theta brain wave pattern

most commonly produced when one is very drowsy (just before sleep, light sleep, or just before waking). Medium frequency and low amplitude.

Delta waves

associated with deep, dreamless sleep or unconsciousness, appearing in NREM 3. Low frequency and high amplitude. Slowest brain wave pattern.

Advantages of EEGs

• non-invasive

• identifies stages of sleep

• measures level of alertness/consciousness

• determines abnormal brain activity

Limitations of EEGs

• Lack of inner brain neural activity can be measured

• Lack of detailed info

• Strength of brain waves is altered when travelling through the skull to electrodes

EMG (Electromyograph)

records the strength of electrical activity occurring in muscles, indicating muscle movement and tension during sleep. Lower awareness, more relaxed muscles. Muscles can also spasm in light sleep and hypnic jerks occur in deep sleep.

EOG (Electro-oculargraph)

electrodes are attached to the face surrounding the eyes, and produce results in line graphs. Have immense value in distinguishing REN from NREM.

Sleep diaries

self-monitoring of qualitative data regarding sleep, and can be influenced by biases

Video monitoring

filming behaviours when falling asleep and first waking, generally in a sleep study session.

Biological rhythms

naturally occuring physiological functions and various psychological functions that follow a set pattern of period changed. Eg core body temp, blood pressure, blood sugar level, hunger, digestive secretions, secretion of hormones, menstrual cycle and sleep-wake cycle.

Biological clock

innate timing mechanism that regulated the cycle of biological rhythm

Circadian rhythm

The physiological, psychological or behavioural changes that occur as part of a 24 hour cycle

Ultradian rhythm

a biological rhythm that involves psychological, physiological or behavioural changes that occur as part of a cycle that is shorter than 24 hours. This can include hunger, NREM, REM, alertness, activity of neurotransmitters and secretion of certain hormones.

Endogenous cues

internal cues for circadian rhythms

Exogenous cues

external cues for circadian rhythms

suprachiasmatic nucleus

considered the master biological clock that regulates timing and activity of the sleep-wake cycle, located in the hypothalamus

Melatonin

a hormone involved with initiating the sleep-wake cycle that makes us feel drowsy.

Sleep episode

a period of sleeping

REM sleep/paradoxical sleep

Rapid eye movement sleep. 20-25% of total sleep, including spontaneous bursts of actual REM. Fast and irregular heart and respiratory rate with shallow breathing. body and brain are internally active but externally relaxed purpose of paralysis remains on clear. most woken during REM report dreaming.

NREM sleep

non-rapid eye movement sleep

hypnogram

sleep graph, which tracks REM and NREM sleep periods throughout a typical sleep episode

sleep onset

the period of time from being awake to asleep

sleep latency

the time it takes to fall asleep

NREM1 (stage 1)

when sleep begins. decreased arousal and hypnic jerks with some eye rolling. Usually only 5mins/4-5% of total sleep time

Hypnic jerks

the feeling of falling then jerking awake

NREM2 (stage 2)

a light sleep which gradually becomes deeper. heart and respiratory rate slows down with decreased muscle tension, eye movement stops. during first half people didn’t feel asleep and in second half they would only be alerted by loud noise. 50% of sleep episode.

NREM3 (stage 3)

deep sleep. heart rate and respiratory rate are at their lowest, with muscles relaxed and no eye movement. Brain waves are at their slowest frequency and it is difficult to be awoken. About 20-40mins of the first sleep cycle in an episode, then decreases/disappears. 10-15% of sleep episode.

Dreaming

usually occurs in REM sleep, and is less story-like in NREM. Has beta brain waves in REM but theta and delta in NREM.

Primary sleep disorder

a persistent sleep disorder that cannot be attributed to another condition, whether mental, physical or another sleep disorder

Secondary sleep disorder

a bi-product of another condition or use of a substance. To fix this, the underlying cause is treated.

Partial sleep deprivation

not sleeping as long or as often as you should be. can be over a short or long period of time, can be voluntary or involuntary

Sleep debt

an accumulated amount of sleep loss from insufficient sleep

ABC model of Sleep deprivation

measuring the affects of partial sleep deprivation in affective, behavioural and cognitive areas.

Affective (ABC)

Emotional component. Lack of sleep can lead to amplified emotional responses, and inability to process emotional information, regulate and judge responses and facial expressions. This links specifically to loss of REM sleep.

Sleep inertia

a temporary period of reduced alertness and performance impairment immediately after waking. Awakening in REM and NREM3 produces greater sleep inertia, which can lead to microsleeps

Microsleep

1-15 second sleep.

Behavioural (ABC)

effects can include impaired control or regulation of behaviour, higher inattentiveness, lower social skills, higher injury rates, and reduced motor coordination, speed and accuracy.

Cognitive (ABC)

effects including difficulty making decision, missing important details, lack of situational awareness, limited STM processing, lower verbal reasoning, and lower performance on spatial tasks.

17 hours of sleep deprivation =

= a BAC of 0.05

24 hours of sleep deprivation =

= a BAC of 0.10

Circadian rhythm sleep disorders

a group of sleep disorders involving sleep disturbance primarily due to the mismatch between an individuals current and desired/required sleep-wake schedule

Types of circadian rhythm sleep disorders

DSPS, ASPS, Shift worker disorder

Delayed sleep phase syndrome (DSPS)

the natural tendency of the individual to go to bed late and sleep later into the next day. This means they experience sleep onset insomnia, difficulty waking at the desired time and excessive sleepiness. A delay in a major sleep episode in relation to the desired time or what is considered convention time. Common in adolescents

Advanced sleep phase syndrome (ASPS)

the persistent disturbance of sleep-wake cycle characterized by advance of the major sleep episode to earlier than desired or conventional time. When people consistently go to bed and wake up early. Leads to persistent sleep deprivation, daytime sleepiness and trouble in all ABC areas. Present in 1% of people, usually older adults.

Shift worker disorder

occurs as a result of work shifts being regularly scheduled during the usual sleep period.

Bright light therapy/phototherapy

A treatment for circadian rhythm disorders. involves timed exposure to intense amount of light for 20-30mins. Aims to shift a person’s sleep-wake cycle to the desired time by resetting the SCN. ASPS should use in early in the night and DSPS early in the morning.

REM Rebound

more REM due to sleep debt, sometimes in excessive amounts

Sleep in infants/newborns

Sleep onset at any time of day, due to no circadian rhythm. about 50% REM sleep, irregular sleep episodes between 30MIN-4HRS long. 16 hours a day on average

Sleep in children

Less REM than newborns (20-25%), around half of NREM is NREM3, deeper than adults. Onset occurs in the evening with 8-13 hours. The younger you are the more sleep you get

Sleep in adolescents

NREM3 progressively declines (by 40% since childhood) and REM decreases (still 20-25%) but can remain with consistent bedtimes. Tend to push 2 hours past sleep onset. around 9 hours total

Sleep in adults

8hrs decreasing to 6. 20-25% REM and gradual loss of NREM3 at 2% per decade. Sleep onset in the evening, usually 7-8 hours

Sleep hygiene/habits

behaviours and environmental factors that can be adjusted for a good night sleep and waking feeling rested. Practices can be appropriate or inappropriate for good sleep.

Entrainment

When the SCN adjusts due to a zeitgeber

Zeitgebers

Environmental time cues used by the SCN

DARE

Detects, amplifies and records electrical activity

Sleep in elderly

Sleep onset is slightly fragmented (naps and early nights). 20-23% REM and an average of 6-7 hours sleep