What you'll learn
Biological Bases of Behavior examines how the nervous system, brain, and hormones shape behaviour and mental processes — a core, heavily tested AP Psychology unit.
The neuron
The neuron is the basic unit of the nervous system. A signal travels as an electrical action potential down the axon, then crosses the synapse chemically via neurotransmitters. The myelin sheath insulates the axon and speeds transmission.
Key neurotransmitters
- Dopamine — reward, movement.
- Serotonin — mood, sleep.
- Acetylcholine — muscle action, memory.
- GABA — inhibitory (calming); glutamate — excitatory.
The brain
- Cerebellum — balance and coordinated movement.
- Amygdala — emotion, especially fear.
- Hippocampus — forming new explicit memories.
- Hypothalamus — drives (hunger, thirst), links to the endocrine system.
- Cerebral cortex — higher thought; lobes (frontal = planning, occipital = vision, etc.).
- Left hemisphere typically handles language; the brain shows plasticity (it can reorganise).
Nervous system divisions
- Central (brain + spinal cord) and peripheral.
- Peripheral splits into somatic (voluntary muscles) and autonomic (involuntary).
- Autonomic splits into sympathetic (fight-or-flight arousal) and parasympathetic (rest-and-digest).
Endocrine system
Glands release hormones into the bloodstream — slower but longer-lasting than neural signals. The pituitary is the "master gland," directed by the hypothalamus; the adrenal glands release adrenaline in stress.
Exam tips
- Know neurotransmitter functions and the effect of damage to specific brain regions.
- Distinguish sympathetic vs parasympathetic responses.
- Be ready to apply terms to scenarios (the AP exam loves application questions).
Common mistakes
- Confusing the endocrine (hormones) with the nervous (neurotransmitters) system.
- Mixing up sympathetic and parasympathetic.
- Forgetting the hippocampus is for forming new memories, not storing all of them.