Crossmodal integration improves sensory detection thresholds in the ferret

Abstract

During the last two decades ferrets (Mustela putorius) have been established as a highly efficient animal model in different fields in neuroscience. Here we asked whether ferrets integrate sensory information according to the same principles established for other species. Since only few methods and protocols are available for behaving ferrets we developed a head-free, body-restrained approach allowing a standardized stimulation position and the utilization of the ferret's natural response behavior. We established a behavioral paradigm to test audiovisual integration in the ferret. Animals had to detect a brief auditory and/or visual stimulus presented either left or right from their midline. We first determined detection thresholds for auditory amplitude and visual contrast. In a second step, we combined both modalities and compared psychometric fits and the reaction times between all conditions. We employed Maximum Likelihood Estimation (MLE) to model bimodal psychometric curves and to investigate whether ferrets integrate modalities in an optimal manner. Furthermore, to test for a redundant signal effect we pooled the reaction times of all animals to calculate a race model. We observed that bimodal detection thresholds were reduced and reaction times were faster in the bimodal compared to unimodal conditions. The race model and MLE modeling showed that ferrets integrate modalities in a statistically optimal fashion. Taken together, the data indicate that principles of multisensory integration previously demonstrated in other species also apply to crossmodal processing in the ferret.

Neural Correlates of Multisensory Detection Behavior: Comparison of Primary and Higher-Order Visual Cortex

“…When stimulus intensity is high, the need to perform multisensory integration to detect the stimulus is low, because the unisensory stimulus is easily perceivable; however, multisensory integration is still required to differentiate uni-from multisensory stimuli. During low-intensity stimulation, detection of sensory stimuli is more difficult, and integrating information from different modalities can help this process (Gleiss and Kayser, 2012;Hollensteiner et al, 2015). In line with this, we previously showed that the behavioral gain during multisensory detection is highest when the unisensory stimulus constituents are presented around their perceptual thresholds, but is largely absent when the stimulus intensities are higher (Meijer et al, 2017).…”

Development, organization and plasticity of auditory circuits: Lessons from a cherished colleague

“…Fortunately, it turned out that ferrets can be readily trained to carry out sensory tasks. This species is increasingly being used to study aspects of visual (Garipis & Hoffmann, ; Von Melchner, Pallas & Sur, ; Zhou, Yu, Sellers & Fröhlich, ) and multisensory behaviour (Hammond‐Kenny, Bajo, King & Nodal, ; Hollensteiner, Pieper, Engler, König & Engel, ), and has been employed extensively in a range of auditory detection, discrimination and localization tasks (reviewed by Fritz, Elhilali, David & Shamma, ; Nodal & King, ).…”

Behavioural benefits of multisensory processing in ferrets

“…Ferrets have been used extensively in physiological and anatomical studies of multisensory processing (e.g. King & Hutchings, 1987;King et al, 1988;King & Schnupp, 2000;Bizley et al, 2007;Bizley & King, 2008;Stitt et al, 2015), but only to a limited degree so far in behavioural experiments (Isaiah et al, 2014;Hollensteiner et al, 2015), despite the ease with which they can be trained to carry out localization and other sensory tasks. We have previously characterized sound localization behaviour in this species by measuring their head-orienting response following stimulus presentation and the subsequent locomotor response as the animals approach the perceived location of the sound source to receive a water reward (Nodal et al, 2008).…”