A neural model of sensory interactions in young neurotypical and ASD children

The brain at birth is characterized by a default state of competition among the senses [1], and integrative abilities are acquired only later in life, based on experience. Recently, Crosse and colleagues [2] in a bisensory reaction time task, with auditory (A) and visual (V) stimuli, presented alone or together (AV), in a random sequence, showed that children's reaction times (RTs) to congruent AV stimuli did not differ significantly from unisensory RTs, but differences emerged between ASD and neurotypical (NT) subjects. In this work, we implemented a neurocomputational model to simulate the RTs and analyse the behavioural responses of ASD children (6-7 years of age) and their NT counterpart. The model suggests that the comparable RTs found in unisensory and multisensory conditions could be interpreted by the default competition among the senses; this default state can be implemented via mutual inhibition between primary sensory areas; and the shift toward the classical multisensory facilitation, observed in adults, is the result of the inhibitory cross-modal connections becoming excitatory after an extended multisensory experience. Moreover, model results suggest that differences between ASD and NT children are due to a stronger cross-modal inhibition in 6-7 year-old ASD children. Finally, this neurocomputational model allowed investigation of the temporal profile of interactions among stimuli of different sensory modalities. These findings link the perceptual framework delineated by several empirical results to a plausible neural implementation.