The Impact of Prior Experience With Cross-Modal Stimulation on Activation of Bipolar and Multipolar Neurons in the Intermediate Layer of Rat Superior Colliculus

Multisensory integration (MI) is the process in which information from multiple sensory modalities converges on single neurons. When a rat orients toward a cross-modal, light and sound, stimulus, neurons in the superior colliculus (SC) integrate the information. Most cells conducting MI are multipolar, and the rat intermediate SC (intSC), which contains bi- and multipolar neurons, plays a crucial role in MI. This study examined bi- and multipolar neuron activation in the intSC evoked by cross-modal or modality specific sensory stimulation as well as the role of prior cross-modal experience on the density of neurons activated by cross-modal stimulation within the region. More activated neurons were found in the intSC of cross-modal stimulated brains than in modality specific stimulated brains, and tissue from rats with cross-modal stimulation experience prior to stimulation to evoke activity had more activated neurons than rats that did not have prior experience with cross-modal stimulation. The results suggest that neurons of the rat intSC processes information from cross-modal stimuli, and prior experience with sensory input from multiple modalities may influence the neuronal response in the rat intSC when presented with cross-modal stimulation.