The novel somatosensory nose-poke adapted paradigm (SNAP) is an effective tool to assess differences in tactile sensory preferences in autistic-like mice

Abstract

One of the most prevalent deficits in autism spectrum disorder (ASD) are sensitivities to sensory stimuli. Despite the prevalence of sensory deficits in autism, there are few paradigms capable of easily assessing sensory behaviors in ASD-like mouse models. We addressed this need by creating the Somatosensory Nose-poke Adapted Paradigm (SNAP), which consists of an elevated platform with 6 holes in the center, half of which are lined with sandpaper and half are smooth, requiring mice to use their whiskers to sense the texture. The SNAP paradigm assesses tactile sensory preferences as well as stereotypy, anxiety, and locomotion. We used two wildtype (neurotypical) mouse strains, C57BL/6J (C57) inbred and CD-1 outbred mice, and two ASD mouse models, BTBR (a model of idiopathic ASD) and Cntnap2^-/- mice (a model of syndromic ASD). We found that both ASD models produced more nose pokes into the rough condition than the smooth condition, suggesting an increased preference for complex tactile stimulation when compared to the neurotypical groups, wherein no differences were observed. Furthermore, we found increased stereotypy and time spent in the center, suggestive of decreased anxiety, only for BTBR mice compared to the other mouse strains. Overall, SNAP is an easy to implement task to assess the degree of preference for complex tactile stimulation in ASD mouse models that can be further modified to exclude possible confounding effects of novelty or anxiety on the sensory preferences.

Significance Statement

Despite sensory deficits occurring in 90% of individuals with ASD, there are few behavioral sensory tasks available. To address this need, we developed a tactile sensory task, called the Somatosensory Nose-poke Adapted Paradigm (SNAP) that harnesses innate behavior, is easy to implement, and is not memory dependent. We assessed two neurotypical mouse strains: C57 and CD-1 mice, and two ASD mouse models: BTBR and Cntnap2^-/- mice. Both ASD models displayed preferences for rough textures and inter-strain differences in stereotypy, anxiety, and locomotion. SNAP is thus an easy to implement test to assess differences in tactile sensory preferences in ASD mouse models.