Multisensory integration in the superior colliculus: a neural network model.
Neurons in the superior colliculus (SC) are known to integrate stimuli of different modalities (e.g., visual and auditory) following specific properties. In this work, we present a mathematical model of the integrative response of SC neurons, in order to suggest a possible physiological mechanism underlying multisensory integration in SC. The model includes three distinct neural areas: two unimodal areas (auditory and visual) are devoted to a topological representation of external stimuli, and communicate via synaptic connections with a third downstream area (in the SC) responsible for multisensory integration. The present simulations show that the model, with a single set of parameters, can mimic various responses to different combinations of external stimuli including the inverse effectiveness, both in terms of multisensory enhancement and contrast, the existence of within- and cross-modality suppression between spatially disparate stimuli, a reduction of network settling time in response to cross-modal stimuli compared with individual stimuli. The model suggests that non-linearities in neural responses and synaptic (excitatory and inhibitory) connections can explain several aspects of multisensory integration.
Ursino
Mauro
M
Department of Electronics, Computer Science and Systems, University of Bologna, Bologna, Italy. mauro.ursino@unibo.it
Cuppini
Cristiano
C
Magosso
Elisa
E
Serino
Andrea
A
di Pellegrino
Giuseppe
G
D000161:Acoustic Stimulation; D000465:Algorithms; D003198:Computer Simulation; D005246:Feedback; D016571:Neural Networks, Computer; D009474:Neurons / Q000502:physiology*; D010465:Perception / Q000502:physiology*; D010775:Photic Stimulation; D013477:Superior Colliculi / Q000166:cytology / Q000502:physiology*; D013569:Synapses / Q000502:physiology; D009435:Synaptic Transmission; D013997:Time Factors