Second order neuron of Posterior spinocerebellar tract will enter cerebellum through:

Correct Answer: C

Rationale: Inferior cerebellar peduncle . The posterior spinocerebellar tracts second-order neurons, originating in Clarknucleus (dorsal nucleus), ascend ipsilaterally and enter the cerebellum via the inferior cerebellar peduncle, relaying unconscious proprioception from lower limbs. Choice A (superior cerebellar peduncle) is for efferent cerebellar output. Choice B (middle cerebellar peduncle) is for pontocerebellar fibers. Choice D (crus cerebri) is midbrain motor tracts. Thus, C accurately identifithe entry route, making it correct.

Correct Answer: B

Rationale: Gracile . The posterior (dorsal) horn contains sensory nuclei: nucleus dorsalis (Clarkes, A) for spinocerebellar tracts, nucleus proprius for touch, and substantia gelatinosa for pain/temperature. The gracile nucleus is in the medulla, not the spinal cords posterior horn, processing dorsal column input. Thus, B is the exception, making it correct.

Correct Answer: D

Rationale: Medullary reticulospinal tracts is tonically active . The medullary reticulospinal tract inhibits extensors and is not tonically active (pontine reticulospinal is). Choice A is true (vestibulospinal supports antigravity). Choice B is correct (pontine is uncrossed). Choice C is accurate (rubrospinal is lateral). Thus, D misattributtonic activity, making it the wrong statement and the correct answer.

Correct Answer: A

Rationale: Lesions of this area alone produce more severe paralysis than destruction of primary motor area , which is false. The premotor area plans movements (C, D), receiving inputs , but its lesion causapraxia, not severe paralysis (primary motor areas role). Choice A overstatits impact, making it the exception and the correct answer.

Correct Answer: D

Rationale: Pontine reticulospinal tract - spinal cord , which is incorrect. The pontine reticulospinal tract descends ipsilaterally, with no decussation. Choice A (corticospinal - medulla), B (spinothalamic - spinal cord), and C (rubrospinal - brainstem/midbrain) are correct. Thus, D misattributdecussation, making it the incorrect pair and the correct answer.