SAC #5 U4 Annotated Folio

EEG (electroencephalogram)

it detects, amplifies and records the electrical activity of the brain via a series of electrodes attached to the scalp

frequency

it is the rate of brain waves measured in Hertz (Hz). a pattern of high frequency brain waves is faster and has more brain waves per unit of time

amplitude

it is the size of the peaks and troughs of the waves from a baseline of zero activity. high amplitude brain wave activity has higher peaks and troughs.

beta waves

they are fast and have high frequency but they are small peaks and troughs and thus has low amplitude. they are typically associated with normal waking consciousness, when we are alert, attentive to external stimuli and we are doing intensive mental activity.

alpha waves

they have high frequency but are slower than beta waves, and have low amplitude but the peaks and troughs are higher than beta waves. they are typically associated with a relaxed, calm, internally focused, wakeful state, with our eyes closed, such as daydreaming or early stages of sleep.

theta waves

they have medium frequency which is slower than beta and alpha waves and they have a mixture of high and low amplitude waves. they are typically associated with drowsiness, falling asleep, awakening from sleep, creative activities and when in a meditative state, but also when we are drunk

delta waves

they are the slowest and have the lowest frequency. however they have the biggest peaks and troughs and thus the highest amplitude. they are typically associated with the deepest stage of sleep, that is stage 3 and 4 of NREM, as well as a highly meditative state.

effects of stimulants on brain wave activity

they increase the frequency and decrease amplitude of brain waves, resulting in increased beta waves and a decrease in alpha, theta and delta waves in comparison to a normal waking consciousness.

effects of depressants on brain wave activity

they decrease frequency and increase amplitude of brain waves, resulting in a decrease in beta wave activity and an increase in alpha, theta or delta waves compared to a normal waking consciousness

brain wave activity during REM

there is higher frequency and lower amplitude beta like brain waves

brain wave activity during stage 1 NREM

EEG patterns are characterised by rhythmical alpha brain waves and some irregular theta waves

brain wave activity during stage 2 NREM

EEG readings are predominately theta waves with some alpha waves

brain wave activity during stage 3 NREM

on an EEG, delta waves start to appear. more than 50% of the brain waves are theta waves, with 20-50% of the waves being delta waves

brain wave activity during stage 4 NREM

more than 50% of this stage is characterised by delta waves on an EEG

consciousness

the level of awareness of our thoughts, feelings and perceptions and our own existence at any given moment

normal waking consciousness (NWC)

a state that is organised, clear and meaningful, and the individual is awake and aware of their thoughts, feelings and perceptions and they have heightened awareness of internal and external environments

altered state of consciousness (ASC)

a state which is distinctly different from normal waking consciousness in terms of level of awareness and experience

selective attention

it involves choosing and attending to a specific stimulus to the exclusion of others that we choose to ignore. for example the cocktail effect, where you may be at a party and despite being totally involved in one conversation, you can switch your attention to another conversation after hearing your name

divided attention

it involves the ability to distribute attention and undertake two or more activities simultaneously. for example using a stationary bike at the gym which is an automatic procedural memory and at the same time, watching TV which also generally requires little conscious effort

level of awareness during an ASC

level of awareness of internal state and external environment is generally diminished

level of awareness during a NWC

the level of awareness is relatively heightened as we are awake and typically aware of our internal state and the external environment and we have a relatively sound sense of self, reality and time

content limitations during a NWC

content is more limited, and our thoughts tend to be more logical and organised and certain stimuli is repressed

content limitations during an ASC

content is less restricted and less limited and so we are prone to more bizarre and unrealistic or creative thoughts

controlled processes during a NWC

we can competently complete a task that requires a high level of conscious awareness and at times we can complete an automatic process simultaneously

controlled processes during an ASC

it can impair our ability to complete a controlled process more than an automatic process

automatic processes during a NWC

we can competently complete a task that requires minimal conscious awareness and mental effort and we can complete multiple automatic processes at once

automatic processes during an ASC

it can impair our ability to complete a task that requires minimal conscious awareness and mental effort

perceptual distortions during a NWC

we can make clear and rational sense of sensory input

perceptual distortions during an ASC

ASCs such as daydreams or alcohol induced states can reduce our perceptions or dull individuals to an extent that some sensations are not experienced at all. however some stimulant drugs can enhance our perception and make us more receptive to external stimuli

cognitive distortions during a NWC

our thoughts are rational, clear and organised and we can store new memories and readily access memories from LTM when required

cognitive distortions during an ASC

it can cause distorted, illogical thoughts and can impair decision making and problem solving. it can also affect our ability to store new memories or retrieve existing memories

emotional awareness during a NWC

we can monitor our emotions and we generally exhibit predictable emotional reactions to events.

emotional awareness during an ASC

we are more likely to have reduced emotional awareness and less control over our emotions. we may feel emotionless or produce unpredictable emotional responses

self-control during a NWC

we can monitor and control our behaviour as well as maintaining coordination of movements

self-control during an ASC

generally self-control is reduced and we have a reduction in our coordination and inhibitions. however hypnosis may help us to gain greater self-control over addictions

time orientation during a NWC

time is perceived relatively accurately and we can shift our attention from past to present to future

time orientation during an ASC

our time orientation is reduced and we perceive time less accurately

distinguish between a NWC vs an ASC

a NWC is a state of consciousness characterised by clear and organised alertness to internal and external stimuli. an ASC is a state of consciousness characteristically different from NWC in terms of alertness, sensation and perception

distinguish between selective attention vs divided attention

selective attention involves choosing and attending to a specific stimulus to the exclusion of others. divided attention involves the ability to distribute attention and undertake two or more activities simultaneously

distinguish between an EEG, an EOG and an EMG

an EEG detects amplifies and records electrical activity in the brain. an EOG detects amplifies and records electrical activity of the eye muscles that control eye movement. an EMG detects amplifies and records electrical activity of the muscles

distinguish between controlled vs automatic processes

we cannot simultaneously complete multiple controlled processes, we have to complete them one at a time. whereas we can simultaneously complete multiple automatic processes as they require minimal conscious awareness and mental effort

distinguish between a stimulant vs a depressant

stimulants increase central nervous system activity and thus they increase the level of alertness. depressants decrease central nervous system activity and thus they reduce the level of alertness

distinguish between a circadian rhythm vs an ultradian rhythm

a circadian rhythm is a biological rhythm involving changes in physiological and behaviour processes that spans over 24 hours. an ultradian is a recurrent biological cycle that is repeated during a 24 hour period.

Distinguish between exogenous zeitgebers vs endogenous pacers

exogenous zeitgebers are cues that are external to the body that regulate our sleep-wake cycle such as light-dark. endogenous pacers are internal cues that regulate our sleep-wake cycle such as melatonin levels

distinguish between stage 1 and stage 2 NREM

stage 1 is where sleep onset typically starts and it's the lightest stage of sleep, where we have low arousal threshold. in general brain waves are alpha waves as well as some theta waves. stage 2 is a light stage and we can easily be woken. we spend more time in it than any other stage. brain waves are predominately theta waves with some alpha waves

distinguish between stage 3 and stage 4 NREM

stage 3 is the start of deep sleep and it's known as slow wave sleep as on a EEG more than 50% of the brain waves are theta waves with the rest being delta waves. stage 4 is the deepest stage of sleep, and if woken we experience sleep inertia. more than 50% of this stage is characterised by delta brain waves on an EEG.

distinguish between REM and NREM

REM has 1 stage, NREM has 4 stages. For an adult 20-25% of sleep is REM and 75-80% is NREM. In REM we have high frequency waves and in NREM there is relatively lower frequency brain waves. you cannot move in REM due to cataplexy but you are able to move in NREM. nightmares occur in REM whereas night terrors occur in NREM.

sleep cycles in terms of REM and NREM

from adolescence onwards we tend to only have deep sleep during the first two sleep cycles early in the night. the duration of each REM period increases with each cycle, and they occur closer together.

sleep cycles of young children

they sleep for 11 to 13 hours. Roughly half their NREM sleep is comprised of deep sleep. some children tend to skip the first REM episode.

sleep cycles of adolescents

they require 8.5-9.5 hours per night. deep sleep generally occurs in the first 2-3 cycles. 20-25% of their sleep is REM sleep. they don't typically skip the first REM. They experience a delayed sleep onset by 1-2 hours

sleep cycles of adults

They require around 8 hours sleep per night. 20-25% of their sleep is REM sleep. They may skip stage 1 of NREM sleep as the enter periods of REM sleep. they may experience brief periods of waking

sleep cycles of elderly

they average around 6-7 hours per night. Their NREM sleep is typically lighter and mostly stage 2, they experience very little, possibly no stages 3 and 4 NREM sleep and have frequent waking and thus their sleep tends to be more fragmented. they still have just under 20% REM sleep

compare one night of full sleep deprivation vs a legal BAC in terms of cognition

a full night of sleep deprivation will have a more significant impact on cognition than a legal BAC, as a lack of sleep will result in more illogical thought processes and difficulty with decision making in comparison to a legal BAC of 0.049 or less

compare one night of full sleep deprivation vs a legal BAC in terms of concentration

sleep deprivation will diminish the attention span, making it more difficult to concentrate and use selective attention compared to a legal BAC

compare one night of full sleep deprivation vs a legal BAC in terms of mood

sleep deprivation negatively impacts mood and generally makes the individual more moody and irritable. Alcohol can enhance mood and generally increases our confidence but it can sometimes negatively impact mood.

compare one night of full sleep deprivation vs a legal BAC in terms of recovery

recovery from a full night of sleep deprivation may take a couple of nights of full sleep to recover the sleep debt. recovery from a legal BAC will only take a few hours for the alcohol to be removed from bodily systems

distinguish between sleep deprivation vs blood alcohol concentrations

there will be similar effects on cognition and concentration for an individual who has not slept for 24 hours and someone with an illegal BAC of 0.1. The effects would also be similar for a driver with a BAC of 0.05 and a person who has been awake for 17 hours.

distinguish between a controlled process vs selective attention

controlled processes are serial and so usually you can only perform one task involving controlled processes at a time. whereas in selective attention, your attention can be focused on one thing but you are still capable of reacting to other stimuli.