 Dr. Apkarian's early work with primate electrophysiology established that thalamic neurons can be physiologically characterized based on morphology and projections to the cortex, which led to the discovery that the thalamus dynamically encodes nociceptive stimuli in response to features of sensory stimuli.In the 1990s, his research transitioned to human brain imaging-based investigations of pain qualia and neural mechanisms underlying chronic pain.Dr.