Christina Schmitz, PhD, Neuroscientist

I am a CNRS (National Center for Scientific Research) researcher, working in the Lyon Neuroscience Research Center (INSERM U1028, CNRS UMR5292, University Claude Bernard Lyon 1, FRANCE), in the DYCOG team.

I aim at using knowledge about the dynamics of a developing brain to understand its alteration in neurodevelopmental disorders, and vice-versa. My second goal is to uncover reliable markers of dysfunctions across the life span that might help developing rehabilitation. I am especially interested in Autism Spectrum Disorders, as they constitute a fascinating challenge of an alternative path to typical development.

The brain constantly makes predictions used to shape our perception, optimize motor control, and improve our understanding of social interactions. The goal of my research is to better understand the development of predictive mechanisms and their acquisition, in typical individuals and in autism. And the questions that are tackled in our group, through targeting different modalities, are all integrated into a general approach of atypical predictive mechanisms in autism.
Indeed, while for decades theories of ASD have mainly focused on the social symptoms, the “Bayesian brain” perspective conceptualizes ASD under a predictive coding framework and explains autistic cognition as the consequence of atypical perception and learning. The development of this line of research has emerged from a collaboration with Dr Jérémie Mattout, from the DYCOG team as well.

By varying the stable or unstable nature of the environment in a decision-making task, we pointed out that the difficulties people with ASD encounter in their social life might be enhanced by the unpredictability associated with the social world (Robic et al, 2014). We characterized the learning-style of individuals with ASD as being driven by a tendency to memorize lists of associations rather than extracting regularities to interpolate (Sapey-Triomphe et al, 2018). We also examined the sensory profiles of adults with ASD (Sapey-Triomphe et al, 2017) and pointed-out that atypical GABA modulation contributes to their tactile hypersensitivity (Sapey-Triomphe et al, 2019). Importantly, using models of behaviour perceptual learning and decision-making in a two-alternative forced choice tactile task, we were able to characterize some of the mechanisms underlying atypical perception in ASD, i.e. slower learning and a lack of adjustment of precision weights when facing new contexts (Sapey-Triomphe et al. in prep). We also investigated the neural correlates of such processes in adults with ASD (Sapey-Triomphe et al, in prep). In collaboration with Pr Laurent Mottron from Hôpital Rivière-des-Prairies (Montreal), we are now using a MEG auditory oddball paradigm to characterize implicit perceptual learning in ASD, by taking advantage of the fact that oddball sequences enable a fine control of the sensory context to probe perception under variable conditions of predictability and uncertainty. 

In the motor domain, predictive mechanisms can be explored through the study of Anticipatory Postural Adjustments (APAs), their development and their learning. During bimanual coordination, i.e. when manipulating with the dominant hand an object held by the postural hand, APAs are characterized by early changes in the contralateral postural muscles before the hand starts lifting the object. We use a bimanual load-lifting task that enables to measure the efficiency of APAs in terms of postural stabilization, together with the concomitant recording of EMG, EEG/MEG data. In adults, we found that a progressive shift towards an earlier onset of the postural flexor inhibition could constitute a neurophysiological marker of the on-line learning of new APAs (Barlaam et al, 2016). Using MEG, we recently evidenced that improved APAs efficiency with learning was associated with a decreased amplitude of the mu sensori-motor rhythm, along with a trial-to-trial update of the sensori-motor representation (Di Rienzo et al, 2019). We are now analyzing data acquired in children with typical development, as well as in children with ASD to study the oscillatory dynamics of the mu and beta rhythms to characterize the maturational state of the system in the period 8-12 years, as well as their alteration during the acquisition of new APAs. 

Because we are interested in the motor representation of social interactions, we developed a paradigm that enables to evaluate the correct understanding of social scenes depicted by moving human bodies in the form of point-lights (Centelles et al, 2011; 2013). Using fMRI, we evidenced that across childhood and adolescence, enhanced grasp of social cues involves brain maturational refinement through the increased recruitment of regions that are part of the mirror system and the social brain networks (Sapey-Triomphe et al, 2017). In adults with ASD, impaired ability to decipher body motion cues used for social understanding is reflected by lower frontal connectivity and aberrant striatal connectivity (Duret et al, in prep ). 

Predictive processes are grounded on the correct build-up and update of priors, or representations. At the basis of the build-up of sensori-motor, action and social interaction representations are the repetition of a gesture, the accumulation of experience, and the urge to interact with our environment. It has been hypothesized that the matching between an observed action and its associated representation contributes to action understanding, and that this perception/action coupling is impaired in ASD. Our hypothesis is that the integrity of this perception/action coupling is strongly dependent on motor experience feeding up a motor repertoire. In children with ASD (aged 2-17), we aim at setting reliable neurophysiological markers in a passive eye-tracking paradigm that will test the influence of motor experience, and evaluate training effects following early behavioural therapy such as the Early Start Denver Model. 

These talented persons are currently working in the team:
  • Quentin Guillon, post-doctoral researcher
  • Pauline Duret, PhD student (co-supervised with Pr Laurent Mottron, coll. with Dr Jérémie Mattout)
  • Nicole Clavaud, PhD student
  • Florence Brun, Master 2, voluntary internship
  • Lucie Gabard, Master 2 student
I have been lucky to have them as part of the "Autism team":
  • Sara Maghous, Master 2 student
  • Laurie-Anne Sapey-Triomphe, Mater 2 and PhD student (co-supervised with Dr Jérémie Mattout)
  • Fanny Barlaam, Master 2 and PhD student, and post-doctoral researcher
  • Jordan Alvès, Master 2 student
  • Anne Frénois, Master 2 student
  • Anaëlle Bain, Master 2 student
  • Judith Vergne, Research assistant
  • Franck Di Rienzo, post-doctoral researcher
  • Miiamaaria Kujala, post-doctoral researcher
  • Suzanne Robic, PhD student
  • Laurie Centelles, PhD student

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