A computational study of multisensory maturation in the superior colliculus (SC)

Multisensory neurons in cat SC exhibit signiWcant postnatal maturation. The Wrst multisensory neurons to appear have large receptive Welds (RFs) and cannot integrate information across sensory modalities. During the Wrst several months of postnatal life RFs contract, responses become more robust and neurons develop the capacity for multisensory integration. Recent data suggest that these changes depend on both sensory experience and active inputs from association cortex. Here, we extend a computational model we developed (Cuppini et al. in Front Integr Neurosci 22: 4–6, 2010) using a limited set of biologically realistic assumptions to describe how this maturational process might take place. The model assumes that during early life, cortical-SC synapses are present but not active and that responses are driven by non-cortical inputs with very large RFs. Sensory experience is modeled by a “training phase” in which the network is repeatedly exposed to modality-speciWc and cross-modal stimuli at diVerent locations. Cortical-SC synaptic weights are modified during this period as a result of Hebbian rules of potentiation and depression. The result is that RFs are reduced in size and neurons become capable of responding in adultlike fashion to modality-speciWc and cross-modal stimuli