This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
The inability to perceive the texture & shape an object occurs in a lesion of 
Select and explain. 
A. Lateral spino-thalamic tract, B. Nucleus gracilis, C. Spino reticular tract, D. Nucleus cuneatus
D: Nucleus cuneatus
Answer: D: Nucleus cuneatus 
Explanation: Though both nucleus cuneatus & nucleus gracilis are correct, since it is a single answer question, the best answer would be tractus cuneatus, as we commonly use hands to recognize size and shape of objects, more than the foot.
Somatosensory cortex lesion- proprioception and tactile sensations are lost while pain and temperature sensations are preserved.
Tractus cuneatus- formed by fasciculus cuneatus (spinal cord) and nucleus cuneatus (medulla). Pass through the lateral portion of the dorsal column. Carries sensations of the dorsal column- proprioception and tactile sensations from upper part of the body.
Tractus gracilis- formed by fasciculus gracilis (spinal cord) and nucleus gracilis (medulla). Pass through the medial portion of the dorsal column. Carries sensations of the dorsal column- proprioception and tactile sensations from the lower part of the body.