psych- chapter 6

Consciousness

The level of awareness an individual has of their thoughts, feelings, perceptions and existence.

Psychological Construct

An agreed-upon description of a phenomenon that cannot be directly observed or measured, e.g., consciousness.

consciousness can be divided into two types:

• Normal Waking Consciousness (NWC)

• A state in which a person is awake, alert and aware of internal and external stimuli.

Altered State of Consciousness (ASC)

altered state of consciousness is a type of consciousness that is distinclty different from normal waking consciousness in terms of quality of experience and levels of awareness.

Naturally Occurring ASC

An altered state that occurs without deliberate intervention, such as sleep or day-dreaming.

Induced Altered State of consciousness

A type of altered state of consciousness that occurs due to a purposeful action or aid.

Consciousness Continuum

The consciousness continuum is a visual representation of the different states of consciousness that progress from lower levels of awareness to higher levels of awareness

Sleep (psychological construct)

A regular, naturally occurring ASC involving reduced awareness and disengagement from internal and external stimuli.

Characteristics of sleep include:

• a reduced ability to control behaviour

• a reduction in the control we have over thoughts, for example, we lack control over what we dream about

• less accurate understanding of the passage of time

• perceptual and cognitive distortions.

Sleep is divided into two different types of sleep.

• Rapid Eye Movement (REM) Sleep

REM (rapid eye movement) sleep is a type of sleep characterised by rapid eye movement, high levels of brain activity, and low levels of physical activity. Specifically, REM sleep involves low levels of somatic nervous system activity, meaning there are low levels of movement in this stage.

characteristics of REM:'

• • The sleeper is considered to have a highly active brain and a less active body during REM sleep.

• The sleeper is virtually paralysed during REM sleep, meaning that most muscle movement is not possible.

• REM is a relatively light stage of sleep; despite the muscle paralysis, the brain is active and sleepers can be woken fairly easily.

• Vivid dreaming tends to occur during REM sleep. The sleeper frequently recalls dreams when woken during REM sleep.

• REM sleep makes up approximately 20–25% of a sleep episode for most age groups.

• The amount of time spent in REM sleep increases as the sleep episode progresses, with the largest amount of REM in the sleep cycle occurring immediately before waking.

• Early in the night, REM sleep may only last a few minutes, but later during the night, it can last up to an hour.

Non-Rapid Eye Movement (NREM) Sleep

Sleep characterised by no rapid eye movement; subdivided into Stages 1–3 with progressively deeper sleep.

-characteristics of NREM include:

• The sleeper is considered to have a less active brain than normal waking consciousness.

• As opposed to REM sleep, physical movement is possible in NREM sleep, therefore the body is said to be ‘more active’ in this stage of sleep. However, movement tends to decrease as NREM stages progress.

• Muscle movement is possible for the sleeper during NREM sleep.

• Dreams can occur in NREM sleep but they are often non-vivid (as opposed to REM sleep).

• The sleeper does not frequently recall dreams when woken during NREM sleep.

• The amount of time spent in NREM sleep is highest during the first half of a sleep episode.

• NREM sleep makes up approximately 75–80% of a sleep episode.

• NREM sleep tends to become shorter with each sleep cycle.

• NREM sleep is subdivided into three stages. These are explored in table 3.

The three stages of NREM sleep

• NREM stage 1 When moving into stage 1 of NREM sleep, the sleeper transitions from being awake into a light sleep. This transition is signified by the experience of the hypnagogic state, in which some people experience feelings of floating or falling, or a sudden jerk (referred to as a hypnic jerk). In this stage, the sleeper loses awareness of themselves and their surroundings but is still aware of faint sounds in the environment. The sleeper can be easily woken in stage 1.

• In stage 2 of NREM sleep, the sleeper is still in a relatively light sleep. Individuals spend the majority of their time asleep in NREM stage 2. In this stage, the sleeper is considered ‘truly’ asleep, due to the types of brain waves occurring. Brain waves are explored in the next lesson.

• In stage 3 of NREM sleep, the sleeper is in a deep stage of sleep. It is difficult to wake the sleeper in this stage of NREM. If the sleeper is woken during this stage they are likely to feel drowsy and disoriented. During this stage, sleepwalking and sleep talking are most likely to occur.

Sleep Episode

The full duration of time spent asleep, from sleep onset to final awakening.

Sleep Cycle

Sleep cycle is an approximately 90-minute-period that repeats during a sleep episode in which an individual progresses through stages of REM and NREM sleep

Hypnogram

A graph that plots the progression of sleep stages across a sleep episode.

Frequency and amplitude

• Brain waves vary in frequency (rate) and amplitude (height)

• Frequency is the number of brian waves that occur per second.

• Amplitude is the intensity and height of the brain waves.

Electroencephalograph (EEG)

• EEGs, EMGs, and EOGs are considered to be objective (FACTS) physiological measures. This means that they provide reliable, unbiased, quantitative data that can indicate someone’s state of consciousness. However, they do not provide qualitative detail about the personal experience of sleep, such as an individual’s thoughts or feelings. Additionally, changes in physiological responses may be due to factors other than a change in consciousness, thus the findings may lack validity at times

Is a device that detects, amplifies and records the electrical activity of the brain.

The frequency and amplitude in EEG is likely to show:

• higher frequency and lower amplitude in REM sleep.

• high frequency and low amplitude in NREM sleep stage 1 (transitioning from wakefulness to sleep), but lower frequency and higher amplitude than normal-waking consciousness.

• medium frequency and medium amplitude in NREM sleep stage 2 (light sleep).

• ower frequency and higher amplitude in NREM sleep stage 3 (deep sleep).

Electromyograph (EMG)

Device that detects, amplifies and records electrical activity of body’s muscles.

Electro-oculograph (EOG)

Device that detects, amplifies and records electrical activity of muscles responsible for eye movements.

Sleep Diary

• sleep diaries and video monitoring are considered to be subjective (opinion) measures. This means that information is provided by an individual and is related to their personal experiences. In this way, subjective measures do not provide a direct observation and the accuracy and reliability of such measures can be limited due to their subjective nature. It is important to note that subjective measures can provide both qualitative and quantitative data.

is a record containing a self-reported description from an individual about thier sleeping periods including an estimated time spent sleeping and judgements they might have about the quality and nature of sleep.

It is commonly used to track sleep patterns and identify potential issues.

-Some of the information that can be recorded by an individual in a sleep diary include:

• the duration of sleep

• the quality of sleep • thoughts and feelings before going to sleep thoughts and feelings after waking up

• behaviours before going to sleep

• behaviours after waking up

• the number of times sleep was disrupted.

Video Monitoring

Use of audio-visual recording to observe and analyse a person’s behaviour while sleeping.

• Video monitoring is particularly useful for individuals with sleep disorders, as their behaviours during sleep can be observed. Video monitoring can also be used in conjunction with physiological measures to give validity to a phenomenon. For example, a spike in an EMG recording could correspond to bodily movement in the bed, which would be validated with video monitoring. The interpretation of video monitoring is subjective

Biological Rhythm

• There are two different types of biological rhythms that are related to our sleep-wake patterns: circadian and ultradian rhythms.

are repeated biological processes that are regulated by internal mechanism. e.g. circadian or ultradian rhythms.

Circadian Rhythm

is a biological and behavioural changes that occur as part of a cycle that lasts around 24 hours. e.g.. sleep wake cycle.

Sleep-Wake Cycle

24-hour-cycle that is made up of time spent sleeping and time spent awake and alert.

• Therefore, the sleep-wake cycle is a circadian rhythm because it involves biological changes that occur over a 24-hour period as individuals are transitioning from sleep to wakefulness.

Ultradian Rhythm

is a biological and behavioural changes that occur in a cycle that lats less than 24 hours.

• A sleep cycle is therefore an example of an ultradian rhythm. This is because sleep cycles involve changes in physiological activity that repeat in a cyclic manner in less than 24 hours

Suprachiasmatic Nucleus (SCN)

is an area of the hypothalamus that is responsible for regulating an individual’s sleep-wake cycle.

Cluster of neurons in the hypothalamus acting as the body’s master clock, regulating circadian rhythms.

How does the SCN regulate the sleep-wake cycle?

The SCN receives information from both external and internal cues to help modulate the circadian rhythm.

• External cues involve information from the environment, such as the presence or absence of light.

• Internal cues involve information that originates within the body (such as the expression and suppression of particular genes, known as clock genes).

Pineal Gland

is a gland in the brain that is responsible for the production and release of melotonin.

Melatonin

a hormone released by the pineal gland typically at night-time to induce sleep as part of the sleepwake cycle

• The body produces melatonin naturally and usually in adequate amounts. At the onset of darkness in the evening, levels of melatonin start to rise (Grivas & Savvidou, 2007). At around 8 to 9pm, melatonin levels should reach a level that starts to induce a sense of calmness, which promotes sleepiness, leading to an individual naturally wanting to induce sleep at around 10 to 11pm. Melatonin peaks between 2 and 4am, when individuals are typically in the deepest sleep, before gradually declining over the night and before waking in the morning. Melatonin does not directly induce sleep, but rather promotes a state of calm and relaxation to help make it easier to fall asleep. Once melatonin is produced and released, it travels to all areas of the body via the bloodstream.

The following steps summarise the process of the SCN regulating the sleep-wake cycle at night-time:

1. The SCN receives external cues. The SCN also receives internal cues.

2. After receiving both internal and external cues, the SCN sends neural messages (signals) to the pineal gland to produce and release melatonin.

3. The pineal gland releases melatonin into the bloodstream, which promotes feelings of calm and relaxation, therefore promoting sleep.

Cortisol

Hormone released by the adrenal cortex that is responsible for increasing alertness and maintaining heightned arousal.

→elevates alertness and arousal, peaking in the early morning.

Clock Genes

Genes whose expression and suppression follow a 24-hour negative-feedback loop to regulate circadian rhythms.

Delayed Sleep Phase (Disorder)

Circadian rhythm shift common in adolescence causing later sleep onset and wake times.

Advanced Sleep Phase Syndrome

Circadian shift in older adults leading to earlier sleepiness in the evening and earlier awakening.

Sleep Hygiene

Behavioural and environmental practices designed to promote consistent, restorative sleep.

Sleep Spindle

Brief burst of high-frequency brain waves in Stage 2 NREM, indicating ‘true’ sleep.

Hypnagogic State

Transition phase from wakefulness to sleep often involving sensory anomalies like floating or falling sensations.

Hypnic Jerk

Sudden, involuntary muscle twitch that can occur during Stage 1 NREM sleep.

Sleep Demand / Requirement

The amount of sleep necessary for healthy functioning, varying across the lifespan.