25th October 2023

Arousal

Awareness and consciousness

Consciousness and awareness are often erroneously used as synonyms, partly due to both having varying levels. Awareness is a relative concept often described as a state of cognisance of oneself and one’s environment. Consciousness is an objectively measured state in which one is awake and aware.

Full consciousness is a state of optimal waking awareness, and reduced consciousness can be produced by physiological or pathological processes, i.e. sleep or a head injury. Full consciousness is when a person can perceive and interact with the external world appropriately; altered states of consciousness are when a person’s sense perceptions or ability to respond to external stimuli are diminished. Consciousness can be measured via the Glasgow coma scale, which scores motor, verbal, and eye responsiveness to stimulus. Consciousness is only a small part of neural and psychological activity. Many brain activities are unconscious, i.e. visual analysis of depth perception or reflex motor activity, or regulation of hormones and biorhythms.

Unconscious processes are now understood to underlie many cognitive functions previously thought to be fully conscious processes. The unconscious processing of emotional information has long been a critical part of psychoanalytic psychology but is now a concept also endorsed by cognitive neuroscience, as functional imaging studies have established that the right hemisphere subcortical pathway is implicated in emotional processing.

Arousal, attention, and alertness

Arousal, attention, and alertness are overlapping constructs.

Arousal in psychology is defined as the sensation of being alert and awake. Arousal can be mental, emotional, or physical. The reticular activating system (RAS) regulates arousal and is within the brain stem. Arousal theory states that many factors influence arousal, including food, neurotransmitter levels, emotions, and the physical environment. Optimal levels of arousal aid human behaviour, but less than optimal levels (too much or too little) hinder us. Yerkes-Dodson law encapsulates this by stating that an optimal level of stress corresponds to an optimal level of performance.

Attention can be defined as a state of consciousness in which a person can attend to a stimulus and varies in its timespan or breadth. Attention is a vital part of memory, cognitive health and learning knowledge. Some key terms when describing attention are:

• Selective attention – Being able to attend to a specific stimulus despite distractions.
• Divided attention – Attending to different stimuli at the same time.
• Executive attention – Being able to regulate oneself to focus on the task.
• Sustained attention (Attention span) – Being able to attend to an individual stimulus over a prolonged period.

Sleep

Sleep is vitally important to physical and mental health. Although some aspects of how and why we sleep are still poorly understood, there is an understanding that sleep occurs in a cyclical phase, and there are two main types of sleep. REM (Rapid eye movement) sleep and NREM (Non-rapid eye movement) sleep. NREM sleep can be further divided into four distinct stages lasting for roughly 90 to 120 minutes, each with different EEG patterns described below.

REM sleep is characterised by skeletal muscle paralysis, increased neural activity and blood flow, rapid eye movements with closed eyelids, and dreaming. REM sleep typically starts 90 minutes after you fall asleep, with each REM cycle getting longer and longer, initially lasting 10 minutes, with the final REM of a night lasting an hour. The brain is highly active throughout REM sleep, with increased demands for glucose and blood flow.

ECG recording in NREM sleep stages

Hypnagogic stage or W stage – Initially, beta waves are seen, but as individuals become more drowsy, alpha waves start to predominate.

Stage 1 – Light sleep – Starts with a reduction of alpha waves being replaced by theta waves.

Stage 2 – Moderately deep sleep – Sleep spindles seen on EEG. Sleep spindles play an essential role in memory consolidation.

Stage 3 – Deep sleep – Delta waves replace sleep spindles: blood pressure, heart rate, and body temperature drop. Profoundly deep sleep in which the body repairs and strengthens the immune system, also the stage when sleepwalking happens.

Dreams

The phenomenon of dreaming and understanding the purpose of dreams is an area of ongoing psychological and neuroscientific enquiry. Sigmund Freud made a name for himself by proposing ideas around dreams being caused by unconscious thoughts or repressed desires and that they are a valuable way of connecting the conscious and unconscious mind. Freud called the apparent content of dreams ‘manifest content’ and the repressed desires ‘latent content’. Many modern psychotherapeutic theories build on early psychoanalyst’s work by endorsing the notion that dreams carry meaningful content linked to emotional processing and touch on unresolved conflicts of waking life.

Francis Crick argued that dreams constitute ‘reverse learning’ or a period of debugging of neural networks wherein extraneous information was evaluated and then consolidated or forgotten.

Jonathan Winson argued that biological and psychological explanations for dreaming could be combined by considering dreams as part of the memory or information processing that constitutes the unconscious mind. He also stated that dreams could be regarded as a type of ‘overnight therapy’ whereby upsetting memories or emotions were processed, and resultantly, the brain could be in better neurochemical balance by diminishing neurotransmitters associated with the stress of unresolved psychological conflicts.

Parasomnias and other sleep-wake disorders

Parasomnias are a group of sleep disorders characterised by abnormal motor or behavioural events that occur during sleep transitions. Parasomnias can occur during NREM or REM sleep and are more common in children than adults. Parasomnias are associated with neurological or neurodevelopmental disorders but can also be idiopathic or associated with psychiatric illness. In children, NREM parasomnias occur more frequently than REM parasomnias.

Sleepwalking is an example of parasomnia that causes ambulatory behaviour during stage three sleep. Most childhood parasomnias are benign and remit with age. However, adult parasomnias tend to be more challenging to manage.

Some key parasomnias with regards to the Paper A exam are:

• Somnambulance – Also known as sleepwalking, this can occur during stage 3 sleep. The affected person may mobilise independently whilst remaining in NREM sleep. Whilst not inherently dangerous, a risk can be presented from accidental injury.
• Night terrors – Abrupt terror and partial arousal from NREM sleep. High levels of autonomic arousal, e.g., racing heart, excessive sweating, gasping shallow breaths. Often difficult to reassure in the moment and may not remember the event in the morning.

Other sleep-wake disorders

• Nightmare disorder – Recurrent unpleasant dreams that result in abrupt waking from REM sleep with associated anxiety. However, the affected person is rapidly orientated to and reassured by their surroundings and will often remember the event in the morning.
• Insomnia – Perceived difficulty in initiating or maintaining sleep despite adequate opportunity. It can be short-term (Several times a week for less than three months) or chronic (Several times a week for more than three months.)

Narcolepsy – Complex condition increasingly managed by specialist neurology services, but defined for our purposes as daily periods of irrepressible need to sleep. Often associated with abnormal REM sleep architecture on monitoring, as well as a frequent correlation with hypothalamic dysfunction.

Biorhythms and sleep deprivation

The most well-known biological rhythm is the circadian rhythm. The pineal gland regulates the circadian rhythm. Melatonin is secreted by the pineal gland in a biological rhythm, which runs as a feedback loop dependent on how much light stimulation the retinal cells receive (daytime release is low, peak is the middle of the night). Artificial light at night can diminish melatonin secretion, as can supplementation with synthetic melatonin, and this can disrupt the circadian rhythm and produce sleep deprivation and consequent ill health.

Sleep is critical for the proper function of a multitude of bodily systems. Therefore, deficiencies in sleep quality or adequate duration of sleep are termed sleep deprivation. Sleep deprivation can occur due to extrinsic reasons (shift work), psychiatric illness (PTSD nightmares), or physical illness (sleep apnoea).

Sleep deprivation is known to increase vulnerability to physical and psychological distress and has been evidenced to cause abnormal:

• Hormone secretion.
• Metabolic activity.
• Sympathetic nervous system functioning.
• Memory and cognition problems.

Sleep deprivation has been evidenced to exacerbate illnesses such as hypertension, coronary artery disease, metabolic syndrome, IBD, peptic ulceration, depression, anxiety and T2DM, as well as ongoing research linking sleep deprivation with carcinogenesis. Although the evidence between poor physical health and poor sleep is emerging, the relationship is undoubtedly felt to be bi-directional.

Hypnosis and suggestibility

Freud used hypnotherapy in his clinical practice and, similarly to Milton Erickson, believed hypnotherapy was a means to communicate with the unconscious mind. Later, psychologists like Nicholas Spanos thought patients could receive hypnotic prompts via the conscious mind. Hypnotherapy still has some clinical use in disorders such as anxiety, smoking cessation and trauma. It involves the induction of an altered state of consciousness whereby people detach from solely external attention to look inside themselves. Hypnotic states are felt to increase susceptibility to suggestion, and this suggestibility is what is used to treat illness.

Ernest Hilgard wrote about the ‘domain of suggestion’ in his article ‘The Domain of Hypnosis’ and identified that the propensity of a patient to be hypnotised and respond to hypnotic commands correlated with how likely a person is to respond to placebo treatments, be misled by false information (including memories), and experience illusionary phenomena.

Hypnotic ‘suggestibility’ or ‘susceptibility’ refers to the degree to which a person readily responds to hypnotism.

The role theory states that hypnotised people are fulfilling a sociopsychological role and respond to external expectations when they demonstrate behavioural responses rather than any true communication with the unconscious mind.

Meditation

Reaching an altered state of consciousness through meditation is an ancient ritual which is amassing a growing body of evidence as a psychotherapeutic technique. Meditation has been shown to affect neural pathways between the prefrontal cortex and amygdala, serving to improve the processing of emotional responses.

Meditation has been shown to increase alpha and theta waveforms on EEG testing and is increasingly demonstrating quantifiable results as a treatment for PTSD.

Meditation uses introspection to create a sense of control/calm. For example, mindfulness meditation can focus on the sense of self, or in PTSD, the focus can be on accessing and ultimately addressing painful memories. Meditation emphasises being in the present moment and can strengthen a patient’s ability to avoid ruminating about anxieties (a disease of the future) or distressing experiences of grief (a disease of the past.)

References

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• Richard Gross Hachette 2020. Psychology: The Science of Mind and Behaviour 8th Edition.
• Tryon Warren. 2014. Cognitive Neuroscience and Psychotherapy :Network Principles for a Unified Theory. Elsevier.
• Bandy, C, Dillbeck, M., Sezibera, V., Taljaard, L., de Reuck, J., Wilks, M., Shapiro, D., Peycke, R. 2019. Psychological Reports. Reduction of PTSD in South African University Students Using Transcendental Meditation Practice.
• Kang SS, Erbes CR, Lamberty GJ, Thuras P, Sponheim SR, Polusny MA, Moran AC, Van Voorhis AC, Lim KO. 2018. Transcendental meditation for veterans with post-traumatic stress disorder. Psychol Trauma. Nov;10(6):675-680.
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• Luthar SS, Cicchetti D, Becker B. 2000. The construct of resilience: a critical evaluation and guidelines for future work. Child Dev; 71(3):543-62.