Physiology, MBBS Second Year. This chapter is split into 8 topics and has
277 practice questions. The topics covered are listed below, followed by
10 free sample questions from the chapter.
Topics in this chapter
Motor cortex areas (primary, premotor, supplementary)38 questions
Specialized motor areas & mirror neurons25 questions
Sample questions: Cortical and Brain Stem Control of Motor Function
10 sample questions with the correct answer and an explanation. Try to answer each one before reading the explanation.
Q1. Which sequence describes premotor coordination of a movement?
A. Basal ganglia form the image → M1 executes
B. M1 forms an image → premotor executes directly
C. Most anterior part forms a motor image → posterior premotor cortex excites sequential muscle actions via direct impulses to M1 or via basal ganglia and thalamus(correct answer)
D. Thalamus forms the image → cerebellum executes
Answer: C.The most anterior part of the premotor area forms a motor image of the movement; the posterior premotor cortex then excites the sequential muscle actions, either by direct impulses to M1 or via the basal ganglia and thalamus back to M1.
Q2. The supplementary motor area provides:
A. Speech production
B. Sensory feedback for touch
C. Background motor control for finer movements of the arms and hands managed by the premotor area and M1(correct answer)
D. Only eye movements
Answer: C.The SMA works with the premotor area to provide body-wide attitudinal and fixation movements, and provides background motor control for the finer arm/hand movements managed by the premotor area and primary motor cortex.
Q3. Which statement correctly contrasts M1, premotor and supplementary areas?
A. M1 — direct control of precise voluntary movement; premotor — coordinates complex multi-joint movement; SMA — bilateral movements and postural/positioning support(correct answer)
B. M1 — postural control
C. Premotor — direct finger control
D. SMA — speech production
Answer: A.M1 directly controls voluntary precise movements, the premotor cortex coordinates complex multi-joint movements and prepares the body, and the SMA controls bilateral movements and supports posture/positioning for fine motor control.
Q4. Which statement about the motor cortex map is TRUE?
A. Body parts are represented somatotopically, roughly inverted along the cortex(correct answer)
B. Face is represented in the longitudinal fissure
C. The map is random
D. The trunk occupies the largest area
Answer: A.The primary motor cortex has a somatotopic map with face/mouth near the sylvian fissure, arm/hand in the midportion, trunk near the apex and leg/foot dipping into the longitudinal fissure — an inverted representation.
Q5. The ventral corticospinal tract:
A. Carries ipsilateral fibres that eventually cross in the neck or upper thoracic region, controlling bilateral postural movements(correct answer)
B. Terminates in the cerebellum
C. Carries only crossed fibres
D. Originates in the basal ganglia
Answer: A.The ventral corticospinal tract contains the few fibres that do not cross in the medulla; they pass ipsilaterally and eventually cross in the neck/upper thoracic region, controlling bilateral postural movements under the supplementary motor cortex.
Q6. Which statement about cerebellopetal tracts is TRUE?
A. They carry signals from the cerebellum to the cortex
B. They carry only pain signals
C. They bypass the cerebellum
D. They carry information from cortex, olive, vestibular apparatus and reticular formation to the cerebellum(correct answer)
Answer: D.Cerebellopetal (to-cerebellum) tracts include the corticopontocerebellar, olivocerebellar, vestibulocerebellar and reticulocerebellar tracts, bringing movement, learning, balance and integrative information to the cerebellum.
Q7. The positive feedback role of muscle spindles in motor control is:
A. Spindles have no feedback role
B. If spindle fibres stretch more than the skeletal muscle, feedback enhances contraction to match the spindle's stretch(correct answer)
C. Spindle stretch inhibits contraction
D. Spindles control skin compression
Answer: B.When spindle fibres are stretched more than the surrounding skeletal muscle, feedback to the motor cortex enhances contraction so that the muscle shortens to match the spindle's stretch — a positive feedback mechanism.
Q8. Spasticity after motor cortex lesions arises because:
A. Nonpyramidal pathways that normally inhibit vestibular and reticular brain stem nuclei are damaged, causing disinhibition and excessive spastic tone(correct answer)
B. The cerebellum is removed
C. The cortex overexcites the cord
D. Muscle spindles are destroyed
Answer: A.Nonpyramidal pathways normally inhibit the vestibular and reticular brainstem nuclei; cortical lesions damaging adjacent areas (e.g., basal ganglia) disinhibit these nuclei, producing excessive spastic muscle tone.
Q9. A lesion blocks corticospinal input to the medullary reticular nuclei. What is the expected effect?
A. Loss of medullary inhibition leads to pontine overactivity and increased extensor (spastic) tone(correct answer)
B. Loss of vision
C. Loss of sensation
D. Flaccid paralysis
Answer: A.Because corticospinal (and rubrospinal) input normally drives the inhibitory medullary reticular nuclei, blocking it leaves the excitatory pontine system unopposed, increasing extensor tone — the mechanism of decerebrate rigidity.
Q10. Which subconscious stereotyped movements are controlled by the brain stem?
A. Only breathing
B. Only posture
C. Eating, drinking, sneezing, coughing, vomiting and scratching(correct answer)
D. Only eye movements
Answer: C.The brain stem controls subconscious stereotyped movements such as eating, drinking, sneezing, coughing, vomiting, scratching and responses to leg pressure; these are integrated even in severe brain injury (e.g., anencephaly).