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
[{'content': 'The inability to perceive the texture & shape an object occurs in a lesion of \nSelect and explain. \nA. Lateral spino-thalamic tract, B. Nucleus gracilis, C. Spino reticular tract, D. Nucleus cuneatus', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Though both nucleus cuneatus\xa0& 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.\nSomatosensory cortex lesion- proprioception and tactile sensations are lost while pain and temperature sensations are preserved.\nTractus 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.\nTractus 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.', 'role': 'assistant'}]