Modeling the Minimal Newborn's Intersubjective Mind: the Visuotopic-Somatotopic Alignment Hypothesis in the Superior Colliculus

International audienceThe question whether newborns possess inborn social skills is a long debate in developmental psychology. Fetal behavioral and anatomical observations show evidences for the control of eye movements and facial behaviors during the third trimester of pregnancy whereas specific sub-cortical areas, like the superior colliculus (SC) and the striatum appear to be functionally mature to support these behaviors. These observations suggest that the newborn is potentially mature for developing minimal social skills. In this manuscript, we propose that the mechanism of sensory alignment observed in SC is particularly important for enabling the social skills observed at birth such as facial preference and facial mimicry. In a computational simulation of the maturing superior colliculus connected to a simulated facial tissue of a fetus, we model how the incoming tactile information is used to direct visual attention toward faces. We suggest that the unisensory superficial visual layer (eye-centered) in SC and the deep somatopic layer (face-centered) in SC are combined into an intermediate layer for visuo-tactile integration and that multimodal alignment in this third layer allows newborns to detect faces and to mimic. After the learning stage through hebbian reinforcement learning, we show that the intermediate layer develop visuo-tactile sensory alignment. We observe emergent properties of the global network such as sensitivity to he orientation of face-like patterns and detection of facial expressions