Lesion localization · Neuroanatomy
Brain Regions & Functions MCQ
Cortical lobes, basal ganglia, limbic system, brainstem, cerebellum, and vascular territories, with the lesion patterns that show up most often on the INBDE. 25 board-style MCQs plus 12 INBDE patient cases.
25 practice MCQsQuick-reference tableMnemonics + clinical pearlsFull distractor explanations
High-yield review
Concept summary and clinical relevance.
Quick-reference structure first, then detailed coverage. Mnemonics in amber, clinical pearls in blue.
Brain regions are best learned by what they do, and what shows up clinically when they're damaged. Lesion-based reasoning is what the INBDE tests: aphasia patterns, hemineglect, hemianopia, Parkinson's, and the vascular territories of MCA/ACA/PCA strokes.
Cortical lobes: function & classic lesions
| Lobe | Key functions | Classic lesion |
|---|---|---|
| Frontal | Voluntary movement (precentral gyrus); executive (prefrontal); motor speech (Broca's, dominant) | Broca's aphasia: effortful, “broken” speech with intact comprehension |
| Parietal | Somatosensation (postcentral gyrus); calculation/praxis (dominant); spatial attention (non-dominant) | Hemineglect (non-dominant lesion); 2-point discrimination loss |
| Temporal | Auditory cortex; language comprehension (Wernicke's, dominant); memory (hippocampus); emotion (amygdala) | Wernicke's aphasia: fluent nonsense, poor comprehension; hippocampal lesion → no new memories |
| Occipital | Primary visual cortex | Contralateral homonymous hemianopia (often with macular sparing) |
Brainstem cranial nerve nuclei
| Brainstem level | CN nuclei | Clinical correlation |
|---|---|---|
| Midbrain | CN III, IV | Pupillary reflexes; eye movements |
| Pons | CN V (motor for mastication), VI, VII, VIII | Trigeminal motor + facial expression + balance |
| Medulla | CN IX, X, XI, XII; respiratory & cardiac centers | Loss of respiratory drive = medullary lesion |
Vascular territories: strokes you must recognize
| Artery | Territory | Classic deficit |
|---|---|---|
| MCA (dominant) | Lateral cortex: face & arm motor/sensory + language | Aphasia + face/arm hemiparesis |
| MCA (non-dominant) | Same region, opposite hemisphere | Hemineglect + face/arm hemiparesis |
| ACA | Medial cortex (leg motor/sensory area) | Contralateral leg weakness; abulia |
| PCA | Occipital lobe; thalamus | Contralateral homonymous hemianopia |
Clinical pearl, Aphasia in 30 seconds
If speech is fluent but the words don't make sense → Wernicke's (temporal). If speech is halting and effortful but the patient understands you → Broca's (frontal). If repetition specifically is impaired → conduction aphasia (arcuate fasciculus). “Wernicke's wonders, Broca's broken.”
Clinical pearl, Why dental students need neuroanatomy
Patients with prior strokes, Parkinson's, or dementia are common in the dental chair. Recognizing facial droop, dysarthria, or hemineglect during a routine visit can flag a new event. And drug interactions (e.g., levodopa with epinephrine, anticonvulsants) directly affect anesthetic choices.
Mnemonic, Brainstem CN nuclei
“3–4 mid, 5–8 pons, 9–12 medulla.” Cranial nerves III & IV in midbrain; V, VI, VII, VIII in pons; IX, X, XI, XII in medulla.
Mnemonic, Hypothalamus
“THE PASt”: Temperature, Hormones, Eating, Parasympathetic/Sympathetic, Arousal, Sleep. The hypothalamus regulates all of these.
Cerebral lobes
- Frontal: precentral gyrus = primary motor cortex (voluntary movement, contralateral). Prefrontal cortex = executive function (planning, judgment, impulse control). Broca's area (dominant) = motor speech.
- Parietal: postcentral gyrus = primary somatosensory cortex (touch, pain, temperature, proprioception). Non-dominant parietal = spatial attention; lesion → hemineglect.
- Temporal: primary auditory cortex; Wernicke's area (dominant) = language comprehension; hippocampus = memory consolidation; amygdala = fear/emotion.
- Occipital: primary visual cortex; lesion → contralateral homonymous hemianopia.
Deep gray systems
- Basal ganglia (caudate, putamen, globus pallidus, subthalamic nucleus, substantia nigra): smooth voluntary movement.
- Parkinson's = substantia nigra dopaminergic loss → bradykinesia, rigidity, resting tremor.
- Huntington's = caudate atrophy → chorea.
- Hemiballismus = subthalamic nucleus lesion → flinging movements.
Diencephalon
- Thalamus: relay station for all sensory information except smell.
- Hypothalamus: homeostasis (temperature, hunger, thirst, sleep, autonomics) and endocrine control via the pituitary.
Cerebellum
- Compares motor plan to actual movement → coordination and balance.
- Vermis lesion: wide-based, “drunk” gait.
- Hemisphere lesion: ipsilateral intention tremor and dysmetria.
- Flocculonodular lobe: balance and eye movements.
CSF & ventricles
- Produced by the choroid plexus in the ventricles.
- Flow: lateral ventricles → foramen of Monro → 3rd → aqueduct of Sylvius → 4th → foramina of Luschka/Magendie → subarachnoid space → arachnoid granulations → venous sinuses.
- Obstructive hydrocephalus: blocked flow (e.g., aqueduct stenosis).
- Communicating hydrocephalus: impaired absorption at arachnoid villi.
Core Recall Check
25 board-style MCQs.
Active recall is the highest-yield study method. Pick an answer, check it, and read why every distractor is wrong.
0 of 25 answered · 0 correct
Keys: A-E or 1-5, Enter to check
- Question 1EasyThe precentral gyrus corresponds to which functional area of the brain?
- Question 2EasyLesion to Broca's area produces which deficit?
- Question 3EasyWhich lesion causes fluent but meaningless speech with poor comprehension?
- Question 4EasyWhich structure consolidates short-term memory into long-term memory?
- Question 5ModerateHuntington's disease results from degeneration of which basal ganglia component?
- Question 6EasyWhich sensory modality bypasses the thalamus?
- Question 7ModerateWhich brainstem structure contains nuclei for cranial nerves III and IV?
- Question 8EasyFailure of respiratory drive localizes to which structure?
- Question 9EasyWhich structure produces cerebrospinal fluid?
- Question 10ModerateA stroke in the left middle cerebral artery (MCA) of a right-handed patient is most likely to cause:
- Question 11ModerateWhich artery supplies most of the motor and sensory cortex for the legs?
- Question 12EasyThe postcentral gyrus is the primary cortex for which function?
- Question 13ModerateA patient ignores food on the left side of the plate and fails to dress the left side of the body. Where is the lesion?
- Question 14ModerateAn isolated lesion of the right occipital lobe produces:
- Question 15ModerateA 68-year-old shows resting tremor, bradykinesia, and rigidity. Degeneration of which structure is responsible?
- Question 16HardSudden, violent flinging movements of one arm (hemiballismus) result from a lesion of which structure?
- Question 17ModerateA patient has a wide-based, staggering “drunken” gait but normal limb coordination on finger-to-nose testing. Where is the lesion?
- Question 18ModerateA lesion of the right cerebellar hemisphere causes intention tremor and dysmetria on which side?
- Question 19EasyWhich structure is the principal regulator of body temperature, hunger, thirst, and circadian rhythm?
- Question 20ModerateCerebrospinal fluid flows from the lateral ventricles into the third ventricle through the:
- Question 21ModerateCSF is returned to the venous circulation primarily through the:
- Question 22EasyWhich structure is most responsible for processing fear and assigning emotional significance to stimuli?
- Question 23ModerateAfter a frontal injury, a previously polite patient becomes impulsive, profane, and shows poor judgment. The lesion most likely involves the:
- Question 24HardA patient has fluent speech and intact comprehension but cannot repeat a spoken phrase. Which structure is damaged?
- Question 25ModerateVisual information relays through which thalamic nucleus before reaching the occipital cortex?
Clinical Reasoning Cases
INBDE patient cases.
12 ADA INBDE-format patient cases on brain regions. Each case is a shared patient box plus linked questions with full distractor explanations.
INBDE Patient Cases
Brain Regions INBDE Patient Cases →
12 patient cases · 60 linked questions
Open cases →
Author
Dr. Isaac Sun, DDS
Founder, KYT Dental Services. These MCQs are reviewed by a practicing clinician and offered as an educational reference for dental students.
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