Physiology, MBBS Second Year. This chapter is split into 10 topics and has
504 practice questions. The topics covered are listed below, followed by
10 free sample questions from the chapter.
Sample questions: The Eye III: Central Neurophysiology of Vision
10 sample questions with the correct answer and an explanation. Try to answer each one before reading the explanation.
Q1. Which statement correctly contrasts magnocellular and parvocellular pathways?
A. Both transmit colour equally
B. Magnocellular — large neurons, M cells, rapid conduction, black-and-white, poor point-to-point; parvocellular — small-medium neurons, P cells, colour, accurate spatial info(correct answer)
C. Magnocellular — colour; parvocellular — motion
D. Magnocellular has the most accurate point-to-point transmission
Answer: B.Magnocellular layers have large neurons, fast conduction and carry black-and-white motion/coarse detail with poor point-to-point fidelity; parvocellular layers have smaller neurons, moderate conduction, colour information and accurate spatial transmission.
Q2. Which visual fibres do NOT pass through the LGN on their way to older brain areas?
A. Parvocellular fibres
B. Magnocellular fibres
C. Geniculocalcarine fibres
D. Fibres to the hypothalamus, pretectal nuclei and superior colliculus(correct answer)
Answer: D.Besides the geniculocalcarine pathway to V1, visual fibres also pass directly to older areas — hypothalamus (suprachiasmatic nucleus), pretectal nuclei, superior colliculus and ventral LGN/basal regions — for non-conscious functions.
Q3. How do complex cells differ from simple cells?
A. Complex cells require exact line position
B. Complex cells detect colour only
C. Complex cells respond to movement and do not require the line to be in an exact position(correct answer)
D. Complex cells are inactive
Answer: C.Complex cells detect lines or edges of a specific orientation but, unlike simple cells, they respond to movement and do not require the line to be in an exact position — helping process motion and shapes over a broader area.
Q4. After removal of the primary visual cortex, some 'blind' patients can still:
A. Describe objects consciously
B. React subconsciously to light intensity, movement and gross patterns, turning eyes or head(correct answer)
C. Perceive colour normally
D. Read fine print
Answer: B.Even after cortical removal, patients may subconsciously react to changes in light intensity, movement and gross patterns (turning eyes/head, avoidance), mediated by pathways from the optic tracts to the superior colliculi and other dorsal visual system structures.
Q5. Assertion: Uniform illumination excites only a few neurons in V1. Reason: Equally stimulated adjacent receptors mutually inhibit each other.
A. Assertion is false but Reason is true
B. Both Assertion and Reason are true, and the Reason correctly explains the Assertion(correct answer)
C. Both are true, but the Reason does not explain the Assertion
D. Assertion is true but Reason is false
Answer: B.With even illumination, adjacent receptors inhibit one another, so the net excitation of cortical neurons is small; contrast borders break this mutual inhibition and strongly excite neurons — the basis of contrast detection.
Q6. Involuntary fixation movements are controlled by:
A. The spinal cord
B. Secondary visual areas in the occipital cortex(correct answer)
C. The cerebellum
D. The frontal lobe only
Answer: B.Once voluntary fixation is established, involuntary fixation movements (controlled by secondary visual areas in the occipital cortex) take over to maintain fusion and keep the eyes locked on target despite head or object motion.
Q7. Which sequence correctly describes the parasympathetic pathway to the eye?
A. Edinger-Westphal nucleus → oculomotor nerve → ciliary ganglion → short ciliary nerves → sphincter pupillae and ciliary muscle(correct answer)
B. Hypothalamus → CN IV → ciliary ganglion
C. Superior cervical ganglion → oculomotor nerve → eye
D. Pretectal nucleus → optic nerve → retina
Answer: A.Parasympathetic fibres arise in the Edinger-Westphal nucleus (midbrain), travel in CN III as preganglionic fibres to the ciliary ganglion (posterior orbit), and continue as short ciliary nerves to the sphincter pupillae (miosis) and ciliary muscle (accommodation).
Q8. Which sequence correctly describes the pupillary light reflex?
Answer: C.Light activates the retina; signals travel via the optic nerve to the pretectal nucleus, then to the Edinger-Westphal nucleus, whose parasympathetic fibres in CN III reach the ciliary ganglion and sphincter pupillae to constrict the pupil.
Q9. The Argyll Robertson pupil is characterised by:
A. Poor pupillary constriction to light but normal constriction during accommodation(correct answer)
B. Complete loss of all pupil reflexes
C. Normal light reflex but absent accommodation
D. Dilated pupil with ptosis
Answer: A.In the Argyll Robertson pupil (neurosyphilis/tabes dorsalis), midbrain damage — particularly in the pretectal area — abolishes the light reflex while accommodation constriction persists, since the accommodation pathway uses different neurons.
Q10. Which sequence correctly describes the sympathetic pathway to the eye?
A. Retina → optic nerve → superior cervical ganglion
B. Cerebellum → CN VI → orbit
C. Edinger-Westphal nucleus → CN III → ciliary ganglion
Answer: D.Sympathetic fibres descend from the posterior hypothalamus to the intermediolateral cell column (C8–T2), exit the ventral root at T1–T2, ascend the sympathetic chain to the superior cervical ganglion, and travel via the carotid plexus into the orbit.