Ultrafast novelty detection in the human auditory system
Grimm, S., Costa-Faidella, C., Slabu, L., and Escera, C.
Cognitive Neuroscience Research Group, Department of Psychiatry and Clinical Psychobiology, Faculty of Psychology, University of Barcelona, Spain
Novelty detection is a critical brain function allowing for prompt adaptive behavior to potentially relevant new events. We here report a correlate of auditory novelty detection in the human evoked potential (EP) at a latency of about 40ms post-stimulus onset measured as a stronger Nb response to rarely presented sounds compared to frequent ones. A further controlled block confirmed these effects as not reflecting responses of less-refractory neural populations responding to low probability sounds but to their status of regularity-violating events. These responses preceded the well characterized evoked potential correlate of novelty detection known as the mismatch negativity (MMN). The resemblance in latency and eventual origin of these responses allows speculation about these early markers of novelty detection to be a human correlate of novelty neurons' activity as reported in animal studies. Our findings strongly supports the idea of a multi-stage comparison processes serving novelty detection in the auditory system.