Psychiatry: basic sciences
Neurophysiology
Neurophysiology is how nerve cells and brain networks work electrically: signalling, sleep, brain rhythms and the stress response. Psychiatrists use it to understand EEGs, seizures, sleep problems and how treatments like ECT act.
Depth by stage, Pre-U → Consultant (details)
What is it?
Neurophysiology explains how the nervous system works rather than how it looks. It covers the resting membrane potential, the action potential, synaptic transmission, and how millions of neurones combine into rhythms that can be recorded on an EEG.
It also covers bodily systems controlled by the brain that matter greatly in mental health: the sleep–wake cycle, the body clock, appetite, sexual function and the hormonal stress response (the hypothalamic–pituitary–adrenal axis).
Medical students learn the general principles in physiology. Psychiatry trainees revisit them in more depth for the basic sciences examinations, with a focus on brain function relevant to mental illness.
Why does a psychiatrist need it?
Psychiatrists regularly order or interpret EEGs, assess patients with epilepsy, manage sleep disturbance and give ECT, which works by producing a controlled seizure. Knowing the physiology of sleep and the stress response also helps explain why mood and anxiety disorders affect sleep, appetite and the body, and why some medicines cause sedation or lower the seizure threshold.
What level is expected at each stage?
Scale: 1. Aware → 2. Understands → 3. Applies → 4. Masters / Teaches. What the levels mean.
- Pre-UAwareUnderstands the nerve impulse and reflexes at school-biology level.
- Pre-clinicalUnderstandsExplains action potentials, synapses and neuroendocrine control and passes physiology exams on them.
- ClinicalUnderstandsRecognises when EEG or nerve studies are used and what basic findings mean.
- HousemanshipUnderstandsApplies knowledge when managing seizures, sedation and electrolyte problems on the wards.
- Medical officerUnderstandsUnderstands why psychotropics affect seizure threshold and sleep, and when to request an EEG.
- Psych traineeAppliesCan explain EEG rhythms, sleep architecture, the stress axis and the physiology of ECT at exam level.
- Specialist / consultantAppliesUses neurophysiology confidently in neuropsychiatric, sleep and ECT practice and teaches it.
What are the key topics?
Neurone and synapse
- Resting membrane potential and ion channels
- Action potential generation and conduction; myelination
- Chemical synapse: release, receptors, reuptake, breakdown
- Excitatory and inhibitory postsynaptic potentials
- Ionotropic versus metabotropic receptors
- Synaptic plasticity: long-term potentiation and depression as a basis of learning
Electroencephalography (EEG)
- How the EEG is recorded and what it measures
- Normal rhythms: alpha, beta, theta, delta
- EEG changes with drowsiness, sleep, age and medication
- Epileptiform activity and its limitations in diagnosis
- EEG in delirium, encephalopathy and non-convulsive status
- Evoked potentials (brief awareness)
Sleep and circadian rhythms
- Sleep stages (NREM 1–3 and REM) and sleep architecture across the night
- The suprachiasmatic nucleus, melatonin and the body clock
- Changes in sleep in depression, mania and ageing
- Effects of alcohol, hypnotics and antidepressants on sleep
- Polysomnography basics
Neuroendocrine systems
- Hypothalamic–pituitary–adrenal axis and cortisol in stress and depression
- Thyroid axis and its link with mood
- Prolactin regulation by dopamine; antipsychotic-related hyperprolactinaemia
- Appetite and satiety signals
- Sex hormones and mood across the life course
Autonomic nervous system and arousal
- Sympathetic and parasympathetic control
- Physiology of fear and panic symptoms
- Pain pathways and modulation
- Physiology of the seizure induced in ECT
How is it learned and assessed?
- Physiology lectures and practicals in the pre-clinical years; MCQ and short-answer exams
- EEG and sleep study exposure during neurology and psychiatry postings
- Basic science teaching in psychiatry training; examined in MMed Psychiatry Part I and MRCPsych Paper A
- Hands-on learning during ECT sessions and neuropsychiatry case discussions
Typical textbooks and resources
- Guyton and Hall Textbook of Medical Physiology — Hall; standard physiology text
- Ganong's Review of Medical Physiology — Barrett and colleagues; concise review
- Principles of Neural Science — Kandel and colleagues; in-depth neuroscience reference
- Lishman's Organic Psychiatry — David and colleagues; clinical neurophysiology in psychiatric context
Titles are widely used examples; editions change. Use university libraries or legitimate purchases.
Common questions
Why would a psychiatrist order an EEG?
Mainly to look for epilepsy, delirium or another brain disturbance that can mimic or worsen a psychiatric illness. A normal EEG does not rule epilepsy out, so it is always read alongside the clinical picture.
How is stress linked to the body?
Stress activates the hypothalamic–pituitary–adrenal axis and the sympathetic nervous system, raising cortisol and adrenaline. Long-term overactivity of this system is linked to sleep problems, depression and physical ill health, which is why psychiatrists study it.