Vestibular stimulation and primitive reflex integration may drive multisensory processing: putative principles for a Targeted sensorimotor therapy (TSMT)

Abstract

Background: At birth the vestibular system is fully mature, and primitive reflexes are functional whilst higher order sensory processing is yet to develop in the full-term neonate. Sequential motor development driven by primitive survival reflexes sets the appropriate framework for development of sensory processing including multisensory processing and sensorimotor integration.Results and conclusions: The current paper lays out a putative theoretical framework to account for the role vestibular stimulation may have driving multisensory and sensorimotor integration. Accordingly, vestibular stimulation, by activating the parieto-insular vestibular cortex, and/or the posterior parietal cortex may provide the cortical input for multisensory neurons in the superior colliculus that is needed for multisensory processing. Furthermore, we propose that primitive survival reflex-driven motor development, by inducing change of reference frames, may shape the receptive field of multisensory neurons. This, by leading to lack of spatial contingency between formally contingent stimuli, may cause degradation of prior motor responses, hence lead to integration of reflexes. Integration of primitive survival reflexes is mandatory prerequisite for cortically controlled motor responses to emerge. Additionally, we offer a testable hypothesis explaining the beneficial effect of sensory integration therapies regarding attentional processes. Key concepts of a sensorimotor integration therapy (e.g. targeted sensorimotor therapy (TSMT)) are also put into a neurological context. TSMT utilizes specific tools and instruments. It is administered in 8-weeks long successive treatment regimes, each gradually increasing vestibular and postural stimulation, so sensory-motor integration is facilitated, primitive reflexes are inhibited, and muscle strength is increased. Empirically TSMT is indicated for various diseases. Theoretical foundations of this sensorimotor therapy are discussed.