Case Affective and Somatosensory Experience Lab

CASE Lab is affiliated with the Center for Brain Mechanisms of Pain and Health at UC San Diego. We use cognitive and affective neuroscience methods to understand how we experience touch as pleasant or painful. Pain arises from a combination of sensory input (from A-delta and C-nociceptive fibers) and top-down modulation by cognitive factors (such as mood and expectation). So far, one dedicated afferent sensory pathway has been identified for pleasant touch: slow stroking such as grooming and caress activates C-tactile fibers, which induce pleasant affect. We have used transcranial magnetic stimulation (TMS), fMRI, and psychophysical testing to identify the brain areas causally involved in perceiving the affective components of C-tactile touch. Using pharmacologic blockade of opioid receptors by naloxone, we have demonstrated a role for endogenous opioids in modulating perception of C-tactile touch. We have also applied similar techniques to characterize the pathways involved in affective perception of pressure, as found in hugs and massage. Our current research examines the modulatory effects of affective touch and pressure on perception of acute and chronic pain.