Is the posterior insula specifically involved in pain perception?

Liberati, Giulia [UCL]

Because lesions of the posterior insula and adjacent operculum can alter pain perception, and because electrical stimulation and epileptic seizures in this region can generate pain-related experiences, it is generally believed that the posterior insula plays a specific role in pain perception. Moreover, depth recordings in humans have shown that nociceptive stimulation elicits robust local field potentials (LFPs) in this region, often considered to reflect early stages of nociceptive processing specifically related to pain. However, the insula is involved in the processing of a wide range of non-nociceptive sensory inputs, and contributes to a large number of cognitive, affective, and homeostatic functions. The objective of this presentation is to revisit the role of the insula in pain perception, taking into account recent data acquired in our lab. Specifically, I will present results obtained using depth EEG recordings of the human insula, which demonstrate that nociceptive stimuli elicit LFPs at the same locations as non-nociceptive vibrotactile, auditory, and visual stimuli, thereby indicating that these responses are unspecific for pain. However, I will also show that nociceptive stimuli, but not non-nociceptive stimuli, elicit an increase in gamma-band oscillations (GBOs) within this region, possibly reflecting nociceptive-specific activity.