Authors:

Finn Joshi

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About Paper:

Virtual reality (VR) allows precise control over sensory inputs in experiments. Traditional mouse VR experiments rely mainly on visual stimuli. Using the Miniature Rodent Stereo Illumination VR mouse goggles (iMRSIV), looming objects, used to simulate overhead predation, elicited defensive freezing behaviors. However, real-life threats are often multisensory and include tactile stimuli that may alter defensive responses. In this study, we compared mouse defense behavior when exposed to a brief tactile air puff vs. visual looming stimuli. Mice received headplates for head fixation to the iMRSIV system. Before exposure to stimuli, naive mice (n=5) were trained to run for water rewards within a linear VR track. Each mouse experienced a loom-only (2 s overhead looming object), air puff-only (0.25 s puff above the nose), and a combined loom+puff trial (randomized order). Running speed was aligned to stimulus onset and quantified within a 0-3 s response window. Across first exposures, tactile and multisensory stimuli produced faster reactions than loom-only. Latency to minimum speed (mean + SD) was 0.833 + 0.606 s for loom-only (n=4), compared with 0.400 + 0.041 s for puff-only (n=5) and 0.353 + 0.122 s for loom+puff (n=5). Deceleration was also stronger with air puff and combined, with mean slopes of velocity of -100.246 cm/s? (loom), -138.067 cm/s? (air), and -141.024 cm/s? (loom+puff). Freezing time (speed < 2.0 cm/s for 20.5 s) increased from 1.258 + 0.551 s (loom) to 1.880 + 0.866 s (air) and 1.767 + 0.496 s (loom+puff). These results support the hypothesis that adding a tactile stimulus can enhance the ethological relevance of mouse VR, providing a potential framework for neuronal measurement of multisensory threat processing.

Source:

Northwestern University

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Co-authors:

Finn Joshi