Our environment is comprised of numerous dynamic sensory cues that are constantly changing in complex ways across the dimensions of both space and time. The role of the nervous system is to resolve the inherent ambiguities that result from these competing stimulus complexes in order to create veridical percepts. To accomplish this task, the brain has to correctly identify whether multiple sensory energies belong to a single event or several discrete events. Specific brain structures, including the midbrain superior colliculus (SC) and the cortex of the anterior ectosylvan sulcus (AES), have evolved to integrate multiple unisensory signals in order to resolve these uncertainties (i.e., multisensory integration). Prior work has established that the spatial location of stimuli is an important determinant of multisensory interactions. More recently, spatial receptive field (SRF) analyses of multisensory AES neurons has revealed strikingly heterogeneous receptive field architectures under both unisensory and multisensory conditions. The current study sought to extend this line of investigation to the superior colliculus (SC), and compare SRF architecture in these two multisensory structures. Multisensory SC neurons were isolated via standard extracellular single unit recording methods. Unisensory and multisensory SRFs were derived and compared to one another, to several predictive models, and between brain structures. In general, the unisensory and multisensory SRFs for individual SC neurons had a similar spatial organization (although gains could be dramatically different). In contrast, AES SRFs are frequently markedly different between both the unisensory and multisensory conditions. In addition, whereas cortical (i.e., AES) multisensory neurons are typically characterized by a single area of maximal response (i.e., hot spot), SC multisensory neurons ranged from having a similar singular architecture to having multiple hot spots. Despite these differences in SRF organization, the spatial heterogeneity of SRFs in both AES and SC dictated the final product of the resultant multisensory interactions, in that response efficacy was inversely related to multisensory interactive magnitude. These results suggest a universal multisensory coding concept in which receptive field architecture is a key factor, and which highlights the dynamic interplay between space and effectiveness in shaping the final neural product.