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

Abstract

The 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) 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 have a sensitivity to configuration of eyes and mouth. We show that the visual and tactile maps align through a Hebbian learning stage and and strengthen their synaptic links from each other into the intermediate layer. It results that the global network produces some emergent properties such as sensitivity toward the spatial configuration of face-like patterns and the detection of eyes and mouth movement.

The Human Fetus Preferentially Engages with Face-like Visual Stimuli

“…For example, only light from the red (or long wave) end of the spectrum penetrates maternal tissue. Despite this, the results are consistent with a model of fetal visual preferences [8], whereby the largest differential response was for a negative polarity stimulus set with white dots on a black background when contrasted with other stimuli, including black dots on a white background. It should also be noted that the results of the present study do not imply that the fetus can respond to faces presented externally under everyday circumstances.…”

“…An exploration of capacities at this stage of development could greatly inform our understanding of visual preferences, as models of development feature different assumptions related to the underlying development of visual systems. For example, even though the results of the present study are compatible with superior colliculus activity [8], the same cannot be said for a proposed ''gravity bias'' for visual stimuli, which has been previously proposed [30].…”

“…Based on a prior computational model of the fetal visual system during the third trimester [8], we propose that the fetus will produce more head turning to the upright contrasted with the inverted stimuli, in a manner consistent with postnatal studies.…”

Spatio-Temporal Tolerance of Visuo-Tactile Illusions in Artificial Skin by Recurrent Neural Network with Spike-Timing-Dependent Plasticity

“…The learning of visuo-tactile integration is rapid in the neural networks, which is in line with previous observations and models in favor of an acquisition at an early stage of somatotopic and visuo-tactile body maps3233343536. Experiments with infants as old as 6 months show their sensitivity to small temporal delays for self-body registration and for self-other differentiation78.…”

Exploiting the gain-modulation mechanism in parieto-motor neurons: Application to visuomotor transformations and embodied simulation

“…We hypothesized that an automatic mimicry system is maturing at the fetal stage possibly in the superior colliculus (SC) forming the ground for the cortical circuits to organize the MNS (Pitti, Kuniyoshi, Quoy, & Gaussier, 2013b). At a first stage, we proposed that the topological alignment in SC across the modalities enables the automatic social responses of the newborns like facial preference and facial mimicry.…”