More than 90 percent of individuals diagnosed with autism spectrum disorder (ASD) exhibit sensory alterations, with 60 percent displaying altered tactile sensitivity. Sensory challenges are detectable in infants as young as six months who are later diagnosed with ASD, and altered sensory responses are so common that they can serve as an early predictor for autism^1,2. Given the critical importance of gentle affective touch for social bonding early in development, differences in tactile processing may contribute to certain aspects of ASD-related social phenotypes. Thus, elucidating the causes of somatosensory alterations is imperative for understanding the etiology of ASD and its presentation.

The midbrain superior colliculus has been proposed as a brain area of interest that may underlie sensory alterations; yet to date, studies of tactile sensitivity in the superior colliculus associated with ASD are notably absent. Here, Kate Hong’s lab proposes to determine whether altered function in the superior colliculus underlies tactile differences in genetic mouse models of ASD.

Hong and colleagues plan to directly test the hypothesis that aberrant neural responses in the superior colliculus mediate the two main characteristics of tactile differences observed in ASD: (i) hyper- or hyposensitivity to tactile stimuli and (ii) a decreased ability to habituate to repeated stimuli. Using well-established mouse models of ASD (e.g., fmr1 knockout mice, known to show hypersensitivity to tactile inputs^{3, 4, 5}), the team plans to combine whisker-mediated tactile behavior and multi-area electrophysiology recordings to determine psychophysical and neurometric performance in wildtype and mutant mice. Furthermore, simultaneous recordings in the primary somatosensory cortex (S1) and superior colliculus will enable Hong’s lab to determine the relative contributions of cortical and subcortical somatosensory processing during tactile behavior.

The proposed pilot studies will serve as a launching point for investigating the mechanisms that control tactile sensation and adaptation in the superior colliculus. The findings will help guide future work on the role of the superior colliculus during development and function in the etiology of sensory differences that accompany ASD.

1. Turner-Brown L.M. et al. Autism 17, 527–540 (2013) PubMed
2. Baranek G.T. et al. Dev. Psychopathol. 25, 307–320 (2013) PubMed
3. Schaffler M.D. et al. Curr. Psychiatry Rep. 21, (2019) PubMed
4. He C.X. et al. J. Neurosci. 37, 6475–6487 (2017) PubMed
5. Orefice L.L. et al. Cell 178, 867-886.e24 (2019) PubMed