Neuroanatomy and Neurophysiology
Structural Map
Build a mental atlas: cerebral lobes (frontal - motor, executive, Broca; parietal - somatosensory; temporal - auditory, Wernicke; occipital - vision), the cerebellum (coordination, balance), and the brainstem (midbrain, pons, medulla - cranial nerve nuclei and vital centers). The diencephalon includes the thalamus (sensory relay) and hypothalamus (autonomic and endocrine regulation). The limbic system (hippocampus, amygdala) governs memory and emotion.
Know the descending motor pathway: upper motor neurons originate in the cortex, travel through the internal capsule, decussate in the medulla (corticospinal tract), and synapse on lower motor neurons in the anterior horn. This explains why a cortical lesion causes contralateral deficits while a spinal or peripheral lesion causes ipsilateral ones. Ascending sensory pathways - dorsal columns (vibration, proprioception) and spinothalamic tract (pain, temperature) - cross at different levels, a frequent exam distinction.
Cerebrospinal fluid is produced by the choroid plexus in the lateral, third, and fourth ventricles and flows through the foramina of Monro, aqueduct of Sylvius, and foramina of Luschka and Magendie to the subarachnoid space, where it is reabsorbed by arachnoid villi. The circle of Willis provides collateral circulation.
Traps
Stems mix up Broca (expressive) and Wernicke (receptive) aphasia, or ask which tract carries pain (spinothalamic, not dorsal columns). Remember the corticospinal tract decussates in the medulla - a favorite question.
Rule of Thumb
"Cortex crosses, cord and nerve do not." Lesions above the decussation produce contralateral signs; below it, ipsilateral signs.