Crossmodal integration improves sensory 3 detection thresholds in

27 During the last two decades ferrets (Mustela putorius) have been established as a highly 28 efficient animal model in different fields in neuroscience. Here we asked whether ferrets 29 integrate sensory information according to the same principles established for other species. 30 Since only few methods and protocols are available for behaving ferrets we developed a 31 head-free, body-restrained approach allowing a standardized stimulation position and the 32 utilization of the ferret’s natural response behavior. We established a behavioral paradigm to 33 test audiovisual integration in the ferret. Animals had to detect a brief auditory and/or visual 34 stimulus presented either left or right from their midline. We first determined detection 35 thresholds for auditory amplitude and visual contrast. In a second step, we combined both 36 modalities and compared psychometric fits and the reaction times between all conditions. We 37 employed Maximum Likelihood Estimation (MLE) to model bimodal psychometric curves and 38 to investigate whether ferrets integrate modalities in an optimal manner. Furthermore, to test 39 for a redundant signal effect we pooled the reaction times of all animals to calculate a race 40 model. We observed that bimodal detection thresholds were reduced and reaction times 41 were faster in the bimodal compared to unimodal conditions. The race model and MLE 42 modeling showed that ferrets integrate modalities in a statistically optimal fashion. Taken 43 together, the data indicate that principles of multisensory integration previously demonstrated 44 in other species also apply to crossmodal processing in the ferret. 45 46 not peer-reviewed) is the author/funder. All rights reserved. No reuse allowed without permission. The copyright holder for this preprint (which was . http://dx.doi.org/10.1101/014407 doi: bioRxiv preprint first posted online Jan. 26, 2015;