The role of the human auditory middle latency response in auditory novelty detection

invariance, which displays an invariance as complex as the hypercomplex or the pattern invariance, would be tracked at latencies as early as the latencies of the MLR. A complex invariance, where none of the standard stimuli are identical, but all are the same regarding at least one feature, has, to author’s knowledge, not been tested neither. In the third study of the present thesis the multi‐feature paradigm was applied (Althen et al., in preparation). In this paradigm, three types of deviants were presented, so that there was a certain variation in the stimuli which formed the standard trace. The results showed that frequency‐intensity double deviants elicited a significant enhancement of the Nb and Pb wave of the MLR compared to the MLR to standard stimuli. Also a study by Leung and colleagues (2012), who applied the original version of the multi‐feature paradigm, suggests that frequency deviants elicit an enhanced Nb wave. In this paradigm, every second stimulus was a deviant, and four types of deviants were presented. That is, the standard trace was highly variable. The outcome of these two studies, point to a toleration of feature variation in the standard trace at the level of the MLR. Nevertheless, it would be interesting to record the MLR to stimuli of a complex invariance in a future study, in order to examine the exact extent of this tolerance for variance in the standard trace. In the third study of the present thesis the MLR to frequency‐intensity double deviants was tested (Althen et al., in preparation). Double deviants elicited an enhancement of two MLR waves, the Nb and the Pb wave. It has been shown in several precedent studies that deviance in frequency triggers an enhancement of the Nb wave (see above). An additional enhancement of the magnetic Pb wave has also been reported by Recasens and colleagues (submitted). Moreover, in the second study of the present thesis higher amplitudes of the Pb wave were observed in response to frequency