Development of multisensory integration: Transforming sensory input into motor output

Abstract

By pooling and integrating signals from different sensory channels, specialized populations of ''multisensory'' neurons not only help to maximize the brain's ability to detect and identify external events, but also help to initiate reactions to them. Although multisensory neurons are found in many areas of the brain, those in the midbrain (i.e., superior colliculus, SC) have been studied most extensively and have served as a model for understanding some of the neural operating principles of multisensory integration, as well as the impact of these processes on overt attentive and orientation behaviors. However, this capability is not hard-wired at birth. Very young SC neurons are responsive only to unimodal inputs; it is not until many days later that some of them begin to respond to inputs from more than a single sensory modality, and even then they are not yet capable of integrating these inputs to produce the synthesized multisensory signals that characterize the normal adult. The most significant occurrence to precede this maturational change is the appearance of influences from association regions of the neocortex. These influences appear abruptly on any given individual neuron, but because different neurons are targeted at different times during development, it takes many weeks before the mature complement of such neurons is achieved. It is likely that the maturational timing of the interplay between the cortex and SC determines not only the kinds of multisensory information that can be integrated in SC neurons, but the kinds of multisensory behaviors that SC neurons are able to mediate at different stages of development.1999 Wiley-Liss, Inc.

Superior sensation: superior colliculus participation in rat vibrissa system

“…The superior colliculus has long been studied as a center for visual sensory and motor responses [1-3], and is involved in orienting attention [4-6] and multimodal processing [7-10]. The functions of the colliculus have been characterized principally in relation to vision and eye movements, whereas its role in other sensorimotor transformations has received less attention.…”

Laminar profile of visual response properties in ferret superior colliculus

“…The visual system is the predominant sensory modality in the SC, with sensory and motor maps spatially aligned to retinal coordinates (Stein et al 1999). The sources of afferent pathways innervating superficial and deep layers reflect the functional dichotomy within the SC, with superficial layers being innervated predominantly by retinal and early visual cortical projections, and deeper layers receiving higher visual and motor cortical projections (Harting et al 1992;Manger et al 2010;Zhang and Hoffmann 1993).…”

A Computational Analysis of Neural Mechanisms Underlying the Maturation of Multisensory Speech Integration in Neurotypical Children and Those on the Autism Spectrum

“…Multisensory experience during the developmental period is fundamental for the acquisition of multisensory integrative abilities (Stein et al, 1999 , 2014 ; Bahrick and Lickliter, 2000 ; Pons et al, 2009 ; Lewkowicz, 2014 ; Rowland et al, 2014 ; Xu et al, 2015 ). The same is correct also for this network.…”