This indicates that a lower GMD in the IC correlates with lower dichotic–diotic dissonance difference values. Such a role of the IC would be in line with previous findings, demonstrating that the IC may be responsible for the encoding of dissonance at a subcortical level when peripheral processing is minimised (McKinney et al., 2001; Bidelman & Krishnan, 2009). Evidence has been provided that the internal frequency organisation of the central nucleus of the IC might contribute to the generation of the critical-band behavior of its neurons (Schreiner & Langner, 1997). The majority of these

neurons have been classified as binaural unit types (Brückner & Rübsamen, 1995; Kuwada Ku-0059436 price et al., 1997) well suited to account for bihemispheric integration of the auditory pathway

signal. According to the VBM formalism, an increased apparent GMD can result from either a greater total volume of gray matter, or a reduced density of myelinated axons within INCB024360 order the gray matter. Given that one might expect an enhanced functionality to arise from either an increase in myelination or an increase in the total number of available neurons, it is more probable that the observed increase in GMD is due to an increase in myelination of axons within the gray matter. The structural findings provide strong evidence for a role of the IC in binaural integration of dichotically presented dissonance. In accordance with a study indicating that neural mechanisms presumably originating from the IC show preferential encoding of consonant musical relationships (Bidelman & Krishnan, 2009), this corroborates a key role of the IC in consonance/dissonance representation in humans. This is functionally in line with single-unit recordings from the IC of Dial-anesthetised cats where the degree of dissonance was well

represented in the average response of IC neurons (McKinney et al., 2001). This also suggests that general cochlear and peripheral neural mechanisms that have been shown to mediate sensory consonance/dissonance in the cat auditory nerve (Bidelman & Heinz, 2011) are complemented by at least another prominent processing stage in the IC in consonance/dissonance representation. The finding of an increased (un)pleasantness experience when listening to Ribonucleotide reductase dichotically presented musical excerpts and an increased GMD in the left pulvinar had not been hypothesised. However, its possible role in the binaural integration of dichotically presented dissonance is substantiated by research indicating that the pulvinar may be crucial in modifying attention towards auditory input including music at the earliest stages of cortical processing (LaBerge, 1995). Such a role of the pulvinar in auditory attention is further supported by evidence that showed that its lesion has been associated with auditory neglect (Hugdahl et al., 1991).