Sensorimotor Control of Facial Expression in Autism

PROJECT SUMMARY
Facial expression is a complex sensorimotor behavior involving precise contraction of the facial muscles guided
by dynamic sensory and proprioceptive feedback. Atypical facial expressivity is a common characteristic of
autism that impairs interpersonal communication and hinders the recognition of discomfort and pain, leading to
the inadequate address of social and homeostatic needs for autistic individuals. Although these effects are
strongly tied to negative mental health outcomes in autism, including high comorbidity with anxiety and mood
disorders, the etiology of and appropriate treatment for atypical facial expression remain unknown.
While atypical facial expressivity in autism has long been assumed to reflect reduced social motivation or
differences in the experience of emotion, interventions focused on the development of social and emotional skills
are largely ineffective for improving atypical facial expressivity. Considering that i) facial expressions are a
sensorimotor behavior, ii) sensorimotor deficits are a core characteristic of autism, and iii) other facial
sensorimotor functions such as feeding and speech are disrupted in autism, it is likely that sensorimotor
differences contribute to atypical facial expression behavior and represent a potential therapeutic target.
However, to date there is very little published work investigating the sensorimotor basis of atypical facial
expression in autism, a gap which prevents the development of evidence-based interventions for this critical
communication barrier. I propose to address this gap by using neuroimaging, clinical, and behavioral data to
test the hypothesis that atypical facial expression in autism is associated with differences in functional
connectivity within the facial sensorimotor brain network. This work will illuminate the sensorimotor basis of
atypical facial expression in autism to inform the necessary development of targeted therapeutic approaches.
A major barrier to the study of facial sensorimotor network differences in autism is the lack of prerequisite work
characterizing the topology of this network in neurotypical individuals. Using extant functional magnetic
resonance imaging (fMRI) data collected by my laboratory, I will address this gap by applying a graph theoretical
approach to characterize connectivity between facial sensory and motor brain regions in a neurotypical sample
(Aim 1a). Then, I will utilize fMRI, clinical assessment data, and behavioral measures of facial expressivity
collected from a sample of autistic adults to test the hypothesis that functional connectivity in the facial
sensorimotor network is reduced in autistic individuals with atypical facial expressivity compared to neurotypical
controls (Aim 1b). Finally, I will replicate these analyses using an open-source dataset - the Autism Brain Imaging
Data Exchange - to assess if group differences in facial sensorimotor network connectivity are independently
observed across larger samples of autistic and neurotypical adults (Aim 2).
This work will interrogate the brain basis of a critical nonverbal communication barrier in autism to inform the
necessary development of evidence-based interventions and prevent social and psychiatric sequelae.

Grant Number: 5F30MH136677-02
NIH Institute/Center: NIH
Principal Investigator: Kimberly Bress