This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous System, Subject name: Physiology
Most sensory information reaches the cortex after first being processed by the: 
Select and explain. 
A. Basal ganglia, B. Brain stem, C. Thalamus, D. Cerebellum
C: Thalamus
Answer: C: Thalamus 
Explanation: (C) Thalamus > There is a major input from the anterolateral systems into the mesencephalic reticular formation. Thus, sensory input activates the reticular activating system, which in turn maintains the cortex in the alert state.