r Human Brain Mapping 35:1111–1128 (2014) r Uncertainty in Visual and Auditory Series is Coded by Modality-General and Modality-Specific Neural Systems

r r Abstract: Coding for the degree of disorder in a temporally unfolding sensory input allows for opti-mized encoding of these inputs via information compression and predictive processing. Prior neuroi-maging work has examined sensitivity to statistical regularities within single sensory modalities and has associated this function with the hippocampus, anterior cingulate, and lateral temporal cortex. Here we investigated to what extent sensitivity to input disorder, quantified by Markov entropy, is subserved by modality-general or modality-specific neural systems when participants are not required to monitor the input. Participants were presented with rapid (3.3 Hz) auditory and visual series vary-ing over four levels of entropy, while monitoring an infrequently changing fixation cross. For visual se-ries, sensitivity to the magnitude of disorder was found in early visual cortex, the anterior cingulate, and the intraparietal sulcus. For auditory series, sensitivity was found in inferior frontal, lateral tempo-ral, and supplementary motor regions implicated in speech perception and sequencing. Ventral premo-tor and central cingulate cortices were identified as possible candidates for modality-general uncertainty processing, exhibiting marginal sensitivity to disorder in both modalities. The right tempo-ral pole differentiated the highest and lowest levels of disorder in both modalities, but did not show general sensitivity to the parametric manipulation of disorder. Our results indicate that neural sensitiv-ity to input disorder relies largely on modality-specific systems embedded in extended sensory corti-ces, though uncertainty-related processing in frontal regions may be driven by both input modalities