Atypical Neural Response to Biological Motion in Children with ASD: A Preliminary Functional Near Infrared Spectroscopy Analysis

Background:

Attentional bias towards biological motion (BM) is an evolutionarily-preserved early-developing skill considered a fundamental process of neurocognition (Krakowski, 2014). It is likely that perceptual sensitivities underlying preferences for social and biological information impact and underpin developmental trajectories of social cognition skill acquisition, an area of primary deficits in individuals with ASD. Recognition of and preference for BM is found to be impaired in ASD (e.g. Kaiser et al. 2009, 2010, Annaz et al. 2012), with oxytocin and social inclusion modulating perceptual and neurophysiological response to BM in typical individuals (Keri and Benedek 2009, Perry et al. 2010, Bolling et al. 2014). Bolling et al. (2014), in a dual fMRI-fNIRS (functional Near Infrared Spectroscopy) study of 12 healthy typically developing (TD) adults demonstrated that fNIRS can reliably measure brain responses to BM. However, there are few reported studies of BM using fNIRS in young children with ASD.

Objectives:

To explore the use of fNIRS to examine hemodynamic response differences in TD children and children with ASD as they viewed emotion-modulated BM stimuli.

Methods:

8-year-old children with ASD (n=40) and TD (n=25) sat in front of a computer monitor while wearing a cap embedded with optodes (Gowerlabs NTS) covering prefrontal cortex (PFC) and superior temporal sulcus (STS) areas. Emotional BM clips (fear, anger, joy, neutral) were presented alongside rotating control point light displays (PLDs). Changes in oxygenated hemoglobin (Oxy-Hb) during stimuli observation were analyzed by applying motion artifact removal, band pass filtering (0.010hz-0.50hz) and General Linear Modeling (for short separation and drift correction). Long distance channels were removed to reduce artifactual and noisy signal.

Results:

a) Trial-based analysis: using the median of the 90th percentile concentration from valid trials in each channel, statistical analyses revealed the following: 1) Biomotion: Between-group differences in Oxy-Hb (t-test, α=0.05) over the angular right gyrus and deOxy-Hb(α=0.05) over frontal_middle_left, frontal_inferior_triangularis_left, and angular_left areas. 2) Rotation: Only weakly significant differences (α=0.1) were observed between TD and ASD participants with Oxy-Hb over frontal_supramarginal_left, frontal_middle_left, and parietal_inferior_right and with deOxy-Hb over frontal_supramarginal_left.

b) Functional-Connectivity: the analysis of functional connectivity with 0.65 cross correlation cutoff indicated higher PFC connectivity in TD compared to ASD in Oxy-Hb, with TD participants demonstrating both inter- and intra-hemispheric connectivity in frontal regions both in rotation and biomotion stimuli. TD participants demonstrated higher level of intra-connectivity with the rotation paradigm compared to biomotion while a similar level of inter-connectivity in frontal regions was observed in this group in both biomotion and rotation paradigms. No intra-connectivity was observed in middle and posterior regions with either biological motion or rotation in either group.

Conclusions:

While analyses are ongoing, preliminary results suggest that between-group differences are evident in brain areas associated with biological motion perception in typical individuals and noted in previous research to be atypically activated in children with ASD. Functional connectivity results suggest that responses of children with ASD to biological motion are less expansively organized across brain regions than TD children, who demonstrated a wider breadth of activity and connectivity across the frontal areas.