Biological Bases of Behavior
What you must know
This domain links nervous system structure to behavior. Be able to describe neurons (dendrites receive, axons transmit, myelin speeds conduction, terminal buttons release neurotransmitters across the synapse). Know excitatory vs. inhibitory signals and that a neuron fires when threshold is reached (all-or-none). Distinguish agonists (mimic or enhance a neurotransmitter) from antagonists (block it). Map the nervous system: central (brain, spinal cord) vs. peripheral, with the peripheral split into somatic (voluntary skeletal muscle) and autonomic (involuntary), and autonomic split into sympathetic (arousal, fight-or-flight) and parasympathetic (calming, restoration).
Brain regions: medulla (breathing, heart rate), pons (bridge, sleep), cerebellum (balance, motor coordination), reticular formation (arousal), thalamus (sensory relay), hypothalamus (temperature, hunger, endocrine control), amygdala (fear, emotional salience), hippocampus (memory consolidation), and the cerebral cortex with its four lobes (frontal: planning, motor, Broca's area; parietal: somatosensory; temporal: hearing, Wernicke's area; occipital: vision). Know hemispheric specialization and split-brain findings.
Traps
Questions swap Broca's (production, frontal) and Wernicke's (comprehension, temporal). They confuse the thalamus (relay) with the hypothalamus (regulation). They call the sympathetic system "calming." They treat a neurotransmitter as good or bad rather than context-dependent. They assume brain regions work alone, when questions test localization vs. distributed processing.
Worked example
A patient speaks fluently but cannot understand language. Rule of thumb: comprehension = Wernicke's (temporal); production = Broca's (frontal). Fluent but nonsensical output points to Wernicke's.
Rule of thumb
When a question names a structure, ask what function it serves, then match the behavior in the stem to that function.