Statistical analysis of neuronal population codes for encoding acute pain

To date most pain studies have focused on spinal cord or peripheral pathways. However, a complete understanding of pain mechanisms requires the study of neocortex. Using an animal model of acute pain, we investigate neural codes for pain at both single-cell and population levels. We propose a statistical framework, rooted in state space analysis, for analyzing neural ensembles recorded from the rat primary somatosensory cortex (S1) and anterior cingulate cortex (ACC) during a laser pain stimulation protocol. The state space analysis allows us to uncover a latent state process that drives the observed ensemble spike activity, and to further detect the "neuronal threshold" for pain on a single or multiple-trial basis.