Basic Neurosciences and Behavioural Sciences
What this domain tests
The Basic Neurosciences and Behavioural Sciences domain asks you to connect brain structure and neurotransmitter systems to bedside psychiatric signs, and to use behavioural-science models - learning theory, attachment, genetics - to explain illness and treatment choice.
Core rules and concepts
- Dopamine pathways: mesolimbic (positive symptoms), mesocortical (negative and cognitive symptoms), nigrostriatal (extrapyramidal effects), tuberoinfundibular (prolactinaemia).
- Transmitters: glutamate NMDA hypofunction (ketamine psychosis model); GABA-A as the benzodiazepine site; noradrenaline from the locus coeruleus; acetylcholine from the nucleus basalis of Meynert, which degenerates earliest in Alzheimer disease.
- Circuits: dorsolateral prefrontal cortex for working memory; orbitofrontal and ventromedial cortex for impulse control and social behaviour; amygdala for fear conditioning; hippocampus for declarative memory; Papez circuit for emotion and memory.
- Behavioural models: classical conditioning (Pavlov), operant conditioning (Skinner), learned helplessness (Seligman) as a depression model, and Bowlby/Ainsworth attachment styles - secure, avoidant, ambivalent, disorganised.
- Genetics: twin-study heritability and gene–environment interaction; never genetic determinism.
Worked example
A man with bilateral amygdala damage cannot acquire conditioned fear and cannot recognise fear in faces, yet he describes the day of his accident in detail. The amygdala is required for fear learning and fear-face recognition; episodic memory depends on the intact hippocampus. The exam point is the dissociation between the two systems, not the lesion name.
Traps that cost marks
- Crediting all antipsychotic action to D2 blockade while ignoring 5-HT2A and glutamate.
- Swapping amygdala and hippocampus in memory items.
- Reading "heritability 80%" as "80% of this patient's illness is genetic".
- Confusing negative reinforcement (removing a stimulus) with punishment (adding one).