Are the processes reflected by late and ultra-late laser evoked potentials specific of nociception?

Publisher Summary This chapter reviews different hypotheses and their consequences regarding the functional significance of both late and ultra-late laser-evoked brain potentials (LEPs). An alternate hypothesis is presented, challenging the nociceptive specificity that is often ascribed to LEPs. Activation of Aδ- and C-fiber nociceptors produces a sensation of first pain and second pain without necessarily evoking late and ultra-late LEP responses. This observation indicates that the processes underlying LEPs may not be directly related to the perception of nociceptive input. Occurrence and amplitude of LEPs seem strongly conditioned by the salience of the evoking afferent input, suggesting that LEPs reflect processes related to mechanisms of involuntary attentional capture. The morphological, topographical, and behavioral similarities between N2 and P2 LEP components and the late endogenous vertex potentials that can be evoked by any kind of sensory stimulation suggests that these “vertex” components reflect nonspecific processes common to all sensory modalities.