Final answer:
Post stroke thalamic pain syndrome typically causes pain on the side of the body opposite to the affected part of the thalamus, due to the contralateral processing of sensory information in the brain.
Step-by-step explanation:
Post stroke thalamic pain syndrome typically results in pain on the contralateral side of the body to the part of the thalamus that has been affected by the stroke. The thalamus is a relay station for sensory information, including pain, temperature, touch, and proprioceptive sensations. Following a stroke, when part of the thalamus is damaged, it can cause abnormal processing of sensory signals, leading to pain and sensory abnormalities on the side of the body opposite to the lesion.
In the scenario where a patient has a paralyzed leg and acknowledges painful stimuli, but not fine touch or proprioceptive sensations, this can be linked to different pathways. The dorsal column pathway, which carries information about fine touch and proprioception, ascends ipsilateral to the source of sensation and would be damaged on the same side as the paralyzed leg. The spinothalamic pathway, which carries information about pain and temperature, decussates, or crosses over, immediately upon entering the spinal cord and then ascends on the opposite side of the body (contralateral) relative to the source of the sensation. This decussation explains why, despite a lesion on one side of the spinal cord or brain, a person experiences sensory deficits on the opposite side of the body.