Which of the following tracts is responsible for reflex movement of head and neck in response to visual stimuli:

Correct Answer: D

Rationale: Tectospinal tracts. The tectospinal tract, from the superior colliculus, coordinathead and neck reflexto visual stimuli (e.g., tracking). Choice A (rubrospinal) is for tone. Choice B (vestibulospinal) is for posture. Choice C (spinothalamic) is sensory. Thus, D correctly identifithe tectospinal role, making it correct.

Correct Answer: D

Rationale: Anterior limb of the internal capsule . Corticospinal fibers, part of the pyramidal tract, originate in the motor cortex and descend through specific white matter regions to the spinal cord for voluntary movement control. Choice A, Pyramid of medulla oblongata, is incorrect because corticospinal fibers pass through the medullary pyramids, where most decussate to form the lateral corticospinal tract. Choice B, Posterior limb of the internal capsule, is wrong as this is a key region where corticospinal fibers travel between the cortex and brainstem, carrying motor signals. Choice C, Cerebral peduncle of the midbrain, is also incorrect since corticospinal fibers traverse the middle three-fifths of the pedunclen route to the pons. However, Choice D, Anterior limb of the internal capsule, donot contain corticospinal fibers; it primarily carrifrontopontine fibers (to the pons) and thalamocortical fibers, not motor tracts, which are confined to the posterior limb. Thus, Anterior limb of the internal capsule is the region that donot include corticospinal fibers, making D the correct answer.

Correct Answer: C

Rationale: Fibers of corticospinal tract pass through the anterior limb of the internal capsule . Corticospinal fibers travel through the posterior limb of the internal capsule, not the anterior limb, which carrifrontopontine fibers. Choice A is correct; alpha motor neurons in the ventral horn receive corticospinal input for voluntary movement. Choice B is true; damage above the medullary decussation (e.g., cortex) causcontralateral paralysis due to crossed fibers. Choice D is accurate; corticospinal upper motor neurons originate in the cerebral cortex (precentral gyrus). Thus, C misplaccorticospinal fibers, making it the wrong statement and the correct answer.

Correct Answer: B

Rationale: In corticospinal tract hemisection of the right half of the spinal cord in the cervical region result in motor deficit in the left side of the body . This seems misaligned with standard anatomy: corticospinal fibers decussate in the medulla, so below this, a right cervical hemisection affects right-sided (ipsilateral) motor function. Above decussation, damage causcontralateral loss (making A wrong). Choice C is false (terminate in ventral horn). Choice D is incorrect (below decussation is ipsilateral). Assuming intent, B may reflect a higher lesions contralateral effect, but per options, its likely a miswording.

Correct Answer: B

Rationale: Destruction of corticospinal tract below the decussation result in contralateral paralysis . This is incorrect: below decussation, damage causipsilateral paralysis. Choice A is wrong (above is contralateral). Choice C is false (ventral horn). Choice D is incorrect (right hemisection is right deficit). Assuming intent, none match perfectly possible error.