📝 Step 5 — KMU Past Papers & Exam Learning
This section contains KMU-style past paper questions designed to strengthen conceptual understanding. Focus on understanding explanations rather than memorizing answers.
🎯 How to Study KMU Past Papers
- Read the question carefully.
- Think about the answer before looking.
- Read the explanation slowly.
- Understand the reasoning behind the correct answer.
- Revise difficult questions again.
MCQ 1
Question:
A lesion involving the basal ganglia produces abnormal movement but no primary loss of muscle power. Which explanation best accounts for this finding?
Options:
Basal ganglia form the lower motor neuron pathway
Basal ganglia directly innervate skeletal muscles
Basal ganglia modulate motor cortex through thalamus
Basal ganglia carry conscious proprioceptive signals
Basal ganglia transmit corticospinal fibers to the cord
Correct Answer:
Basal ganglia modulate motor cortex through thalamus
Explanation:
Basal ganglia regulate movement indirectly through basal ganglia–thalamocortical loops. Their lesions disturb motor control rather than directly causing paralysis.
MCQ 2
Question:
In a coronal section of brain, the internal capsule separates the lentiform nucleus from which medial structures?
Options:
Putamen and claustrum
Amygdala and hippocampus
Red nucleus and substantia nigra
Subthalamic nucleus and midbrain
Caudate nucleus and thalamus
Correct Answer:
Caudate nucleus and thalamus
Explanation:
The internal capsule lies between the caudate nucleus and thalamus medially and the lentiform nucleus laterally.
MCQ 3
Question:
A student identifies a C-shaped grey matter structure following the curvature of the lateral ventricle. Which structure is being described?
Options:
Putamen
Caudate nucleus
Globus pallidus
Subthalamic nucleus
Substantia nigra
Correct Answer:
Caudate nucleus
Explanation:
The caudate nucleus is C-shaped and closely follows the lateral ventricle through its head, body, and tail.
MCQ 4
Question:
A vascular lesion damages the lentiform nucleus and adjacent descending fibers. Which combination of findings is most likely?
Options:
Pure sensory loss with visual field defect
Cerebellar ataxia with intention tremor
Memory loss with olfactory disturbance
Movement disorder with contralateral weakness
Hearing loss with facial paralysis
Correct Answer:
Movement disorder with contralateral weakness
Explanation:
The lentiform nucleus is related to basal ganglia motor control, while the nearby internal capsule contains corticospinal fibers.
MCQ 5
Question:
Which arrangement correctly represents a functional flow through the main basal ganglia motor loop?
Options:
Cortex → striatum → pallidum → thalamus → cortex
Thalamus → cerebellum → cortex → putamen → cord
Cortex → red nucleus → spinal cord → thalamus → cortex
Striatum → cortex → thalamus → cerebellum → pallidum
Putamen → hippocampus → thalamus → cortex → cord
Correct Answer:
Cortex → striatum → pallidum → thalamus → cortex
Explanation:
The basal ganglia function through closed loops linking cerebral cortex, striatum, pallidal output, thalamus, and cortex.
MCQ 6
Question:
A patient has difficulty initiating movement but can generate normal force once the movement begins. Which circuit dysfunction best explains this?
Options:
Damage to posterior column pathway
Failure of neuromuscular transmission
Impaired basal ganglia motor selection
Loss of primary sensory cortex input
Interruption of lateral spinothalamic tract
Correct Answer:
Impaired basal ganglia motor selection
Explanation:
Basal ganglia help initiate and select appropriate motor programs. Their dysfunction affects movement initiation more than muscle strength.
MCQ 7
Question:
A patient with Parkinsonism has reduced arm swing while walking. Which basal ganglia function is most directly impaired?
Options:
Conscious vibration sense
Voluntary pain withdrawal
Pupillary light reflex
Cerebellar error correction
Automatic associated movement
Correct Answer:
Automatic associated movement
Explanation:
Basal ganglia regulate automatic associated movements such as arm swing during walking, which are reduced in Parkinsonism.
MCQ 8
Question:
Which effect occurs when the direct pathway becomes active during a desired movement?
Options:
Thalamic inhibition increases
Thalamic drive to cortex increases
Subthalamic output to cortex increases
Corticospinal fibers are directly blocked
Cerebellar output to thalamus decreases
Correct Answer:
Thalamic drive to cortex increases
Explanation:
The direct pathway inhibits GPi, reducing its inhibition of the thalamus. This disinhibits the thalamus and facilitates cortical motor activity.
MCQ 9
Question:
In the indirect pathway, inhibition of globus pallidus externa leads to which next major effect?
Options:
Reduced activity of subthalamic nucleus
Increased dopamine release from midbrain
Direct excitation of spinal motor neurons
Increased activity of subthalamic nucleus
Suppression of primary sensory cortex
Correct Answer:
Increased activity of subthalamic nucleus
Explanation:
GPe normally inhibits the subthalamic nucleus. When GPe is inhibited, the subthalamic nucleus becomes more active.
MCQ 10
Question:
Which pathway relationship best explains why dopamine facilitates movement?
Options:
It enhances the direct pathway and reduces the indirect pathway
It blocks the direct pathway and activates the indirect pathway
It stimulates the thalamus and inhibits the motor cortex
It suppresses the putamen and excites the internal capsule
It activates cerebellum and inhibits the vestibular nuclei
Correct Answer:
It enhances the direct pathway and reduces the indirect pathway
Explanation:
Dopamine stimulates D1-mediated direct pathway activity and reduces D2-mediated indirect pathway activity, producing a net pro-movement effect.
MCQ 11
Question:
A lesion in the subthalamic nucleus produces violent flinging movements. Which mechanism best explains this clinical sign?
Options:
Reduced output from motor cortex
Excessive inhibition of thalamus
Loss of corticospinal tract fibers
Excess dopamine release from putamen
Reduced excitatory drive to GPi
Correct Answer:
Reduced excitatory drive to GPi
Explanation:
The subthalamic nucleus excites GPi. Its lesion reduces GPi activity, decreases thalamic inhibition, and allows excessive movements.
MCQ 12
Question:
A person learns a skilled repeated motor task such as writing. Which basal ganglia circuit is most involved in smooth execution of this learned pattern?
Options:
Caudate-prefrontal circuit
Limbic-amygdaloid circuit
Putamen motor circuit
Red nucleus reflex circuit
Hippocampal memory circuit
Correct Answer:
Putamen motor circuit
Explanation:
The putamen circuit is linked with learned motor patterns, automatic motor programs, and smooth skilled movements.
MCQ 13
Question:
A patient can move individual muscles but has poor organization of a goal-directed sequence. Which circuit is most likely involved?
Options:
Vestibulospinal circuit
Caudate circuit
Rubrospinal circuit
Spinocerebellar circuit
Reticulospinal circuit
Correct Answer:
Caudate circuit
Explanation:
The caudate circuit connects association cortex with basal ganglia and helps plan, organize, and sequence goal-directed movement.
MCQ 14
Question:
Which feature best differentiates the caudate circuit from the putamen circuit?
Options:
It directly supplies lower motor neurons
It carries pain and temperature signals
It controls primary muscle contraction
It links cognitive planning with action
It forms the main auditory reflex loop
Correct Answer:
It links cognitive planning with action
Explanation:
The caudate circuit is more related to cognitive motor planning, while the putamen circuit is more related to learned motor execution.
MCQ 15
Question:
Which midbrain nucleus contains neuromelanin-rich neurons that influence striatal motor circuits?
Options:
Substantia nigra pars compacta
Red nucleus
Inferior colliculus
Oculomotor nucleus
Substantia nigra pars reticulata
Correct Answer:
Substantia nigra pars compacta
Explanation:
Substantia nigra pars compacta contains dopaminergic, neuromelanin-rich neurons projecting to the striatum.
MCQ 16
Question:
Which statement best describes substantia nigra pars reticulata?
Options:
It supplies dopamine to the striatum
It forms the main sensory relay nucleus
It functions as an output nucleus
It produces cerebrospinal fluid
It connects hippocampus with amygdala
Correct Answer:
It functions as an output nucleus
Explanation:
Substantia nigra pars reticulata acts like GPi and contributes to basal ganglia output pathways.
MCQ 17
Question:
A lesion in the tegmentum of midbrain affects a motor nucleus receiving cerebellar input through the superior cerebellar peduncle. Which nucleus is involved?
Options:
Caudate nucleus
Putamen
Globus pallidus
Subthalamic nucleus
Red nucleus
Correct Answer:
Red nucleus
Explanation:
The red nucleus lies in the midbrain tegmentum and receives cerebellar input, contributing to extrapyramidal motor coordination.
MCQ 18
Question:
A patient has rigidity and slowness of movement after degeneration of nigrostriatal neurons. Which thalamic change is expected?
Options:
Increased thalamic excitation of cortex
Reduced thalamic excitation of cortex
Complete sensory relay failure
Direct thalamic activation of spinal cord
Loss of thalamic connection with cerebellum
Correct Answer:
Reduced thalamic excitation of cortex
Explanation:
Dopamine loss increases GPi inhibitory output to the thalamus, reducing thalamocortical motor facilitation.
MCQ 19
Question:
Which clinical feature best reflects failure of basal ganglia suppression of unwanted motor activity?
Options:
Flaccid paralysis
Loss of pain sensation
Complete aphasia
Choreiform movement
Loss of tendon reflexes
Correct Answer:
Choreiform movement
Explanation:
Chorea represents excessive, irregular, involuntary movement due to failure of normal basal ganglia inhibitory control.
MCQ 20
Question:
A student compares pyramidal and basal ganglia lesions. Which finding favors basal ganglia involvement?
Options:
Normal strength with abnormal involuntary movement
Loss of all sensory modalities below lesion
Lower motor neuron wasting in one limb
Complete loss of voluntary contraction
Dermatomal pain and temperature loss
Correct Answer:
Normal strength with abnormal involuntary movement
Explanation:
Basal ganglia lesions disturb movement quality, tone, and automatic movements, while primary muscle strength may remain relatively preserved.
📌 Important Exam Strategy
KMU examinations often test integrated understanding rather than isolated facts. Focus on linking anatomy, embryology, histology, and clinical concepts when reviewing questions.
✅ Revision Tip
If you can explain the reason behind the correct answer without looking at notes, your concept is strong.