Symposium: Deviance-detection across modalities
Thursday, Sep 10, 2015
Processing of nociceptive deviant input in the brain: is there a real pre-attentive nociceptive-related mismatch response?
Psychology, Sapienza University of Rome, Rome, Italy
The mismatch negativity (MMN) has been advocated as a tool for assessing abnormal brain function in a large number of clinical conditions, except that for chronic pain conditions. To date, as a matter of fact, there is no evidence of MMN elicited by nociceptive stimuli. Given the current quest for objective neural markers of pain sensitivity, it is surprising that a pre-attentive electrophysiological index of brain activity associated with potentially noxious sensory events has not been investigated yet. In this talk I will illustrate experimental results showing event-related potentials (ERPs) linked to the process of deviance detection and standard formation of nociceptive stimuli as compared to other sensory stimuli. In a first study we show that the nociceptive MMN is topographically similar to the somatosensory MMN while differing in latency and possibly in functional organization of their generators. In a second study we attempted to improve the separation of ERPs elicited by different sensory stimuli in the context of a cross-modal design. By combining the topographical segmentation analysis with cluster-based statistical testing we were able to identify the neural activity associated with deviance detection and standard formation in the auditory, non-nociceptive somatosensory, and nociceptive modalities. Findings from both studies converge in showing that the manipulation of attention in a MMN paradigm is crucial to discriminate the effect of automatic change detection mechanisms from the modulatory effect of attention, particularly for nociceptive processing.
I will discuss methodological and theoretical aspect that currently prevent the robust identification of a purported nociceptive MMN.