Neuropsychology of Action
(PI: Angela Sirigu,Caroline Emily)
The members of our team have a strong background in psychology, neuropsychology, molecular biology, informatics and engineering. We study behavior and brain functions using several techniques (fMRI, EEG, TMS, PET‐scan, central [cortical] and peripheral [vagal] stimulation, Light‐sheet Microscopy). During the last five years our research has been oriented towards two main axes:
- The organization of the human sensorimotor system and its relation to consciousness
- Evolution, cognition and brain bases of social behavior: its implications for autism.
The organisation of the human sensorimotor system and its relation to consciousness
Regarding the first axis, in collaboration with Desmurget’s team, we found hand/mouth motor synergies (and not only single joint muscles responses) after stimulation of the primary motor cortex, which we believe can be considered a sort of motor priors related to the ability of human newborns to accurately produce coordinated hand/mouth movements, despite the immaturity of their motor system (Desmurget… & Sirigu, PNAS, 2014). Interestingly, we previously found that cortical stimulation of the inferior parietal lobe doesn’t triggers movements and yet patients report awareness and intention to move without explicitly moving (Desmurget… & Sirigu, Science 2009). If activity of inferior parietal regions produces illusory movements, artificially triggered activity in a specific sector of superior areas 7, inhibits an initiated motor plan (Desmurget… & Sirigu, Current Biology 2018) suggesting a functional specialization for motor intention and sensory prediction within parietal areas.
Finally, we investigated awareness from the perspective of translational neuroscience by looking at how consciousness can be repaired in patients lying in vegetative states and the role of parietal cortex in this recovery. By using vagus nerve stimulation we showed in a single case improved behavioral responsiveness and enhanced brain connectivity patterns in the parietal cortex, a region which appeared a major player in guiding the expansion of neural activity across others brain areas (PhD thesis of Martina Corazzol; Corazzol et al, Current Biology, 2017). All of these studies were possible thanks to the work of Nathalie Richard (CNRS Research Engineer in our team) who has done an amazing work on image analysis and reconstruction of stimulation sites and on modelling patients’ tumoral areas. Moreover, Nathalie has modeled brain connectivity patterns found after cortical stimulation in the domain of fiber track diffusion methods, thus strengthening our findings obtained in the surgery room.
Evolution, cognition and brain bases of social behavior: its implications for autism
Regarding the second axis, several studies have been completed with the aim of looking at the meaning of human sociality and how this has evolved across primates ‘societies. With Alice Gomez (young research professor at Lyon 1), Manuela Costa (PhD) and Guillaume Lio (postdoc) and in collaboration with JR Duhamel’s team, in a recent published study, we investigated whether the ability to form first impression of trustworthiness is specific to humans (PhD study of Manuela Costa; Costa et al, Nature Communications, 2018). We found that macaque monkeys like humans, display preferential attention to trustworthiness‐associated facial cues when looking at computer‐generated human faces, therefore suggesting the presence of common mechanisms among primates for first impression of trust. In a follow up collaborative study with the Psychology department at SCNU in Guangzhou we looked at the effect of culture in trust formation. Using a reversal correlation paradigm where subjects spontaneously selected a trust face from noise, we found that the eyes and specifically, the sclera/iris contrast, is a universal cue for building a representation of trust regardless of cultural identity (Mo et al, submitted). These questions have been also addressed in the context of rare genetic disorders like William syndrome in collaboration with Demily/Franck’s team (Gomez et al, under revision).