Which structure is commonly involved in the perception of pain and touch sensations?

The pulvinar of the thalamus is integral to the perception of pain and touch sensations due to its role as a relay station in the sensory pathways. It processes and integrates sensory information from various parts of the body before sending it to the appropriate cortical areas for interpretation.

The thalamus, including the pulvinar, acts as a central hub that organizes sensory input, ensuring that the brain receives the necessary signals related to tactile and nociceptive stimuli. This function is crucial for a coherent perception of touch and pain, as it helps prioritize sensory information for further processing.

Other structures mentioned—such as the mammillary body, medial geniculate body, and red nucleus—do not primarily function in the somatosensory system. The mammillary body is primarily involved in memory processes, the medial geniculate body is focused on auditory information, and the red nucleus is associated with motor control. Thus, the pulvinar's specific involvement in sensory processing makes it the correct choice for this question.