title: A neurocomputational analysis of the sound-induced flash illusion.
abstract: Perception of the external world is based on the integration of inputs from different sensory modalities. Recent experimental findings suggest that this phenomenon is present in lower-level cortical areas at early processing stages. The mechanisms underlying these early processes and the organization of the underlying circuitries are still a matter of debate. Here, we investigate audiovisual interactions by means of a simple neural network consisting of two layers of visual and auditory neurons. We suggest that the spatial and temporal aspects of audio-visual illusions can be explained within this simple framework, based on two main assumptions: auditory and visual neurons communicate via excitatory synapses; and spatio-temporal receptive fields are different in the two modalities, auditory processing exhibiting a higher temporal resolution, while visual processing a higher spatial acuity. With these assumptions, the model is able: i) to simulate the sound-induced flash fission illusion; ii) to reproduce psychometric curves assuming a random variability in some parameters; iii) to account for other audio-visual illusions, such as the sound-induced flash fusion and the ventriloquism illusions; and iv) to predict that visual and auditory stimuli are combined optimally in multisensory integration. In sum, the proposed model provides a unifying summary of spatio-temporal audio-visual interactions, being able to both account for a wide set of empirical findings, and be a framework for future experiments. In perspective, it may be used to understand the neural basis of Bayesian audio-visual inference.
authors: Department of Electrical, Electronic and Information Engineering, University of Bologna, Bologna, Italy. Electronic address: cristiano.cuppini@unibo.it.
authors: Cristiano
authors: C
authors: Cuppini
authors: Department of Electrical, Electronic and Information Engineering, University of Bologna, Bologna, Italy. Electronic address: elisa.magosso@unibo.it.
authors: Elisa
authors: E
authors: Magosso
authors: Department of Psychology, University of Milano-Bicocca, Milan, Italy; IRCCS Istituto Auxologico Italiano, Milan, Italy. Electronic address: nadia.bolognini@unimib.it.
authors: Nadia
authors: N
authors: Bolognini
authors: Department of Psychology, University of Milano-Bicocca, Milan, Italy; IRCCS Istituto Auxologico Italiano, Milan, Italy. Electronic address: giuseppe.vallar@unimib.it.
authors: Giuseppe
authors: G
authors: Vallar
authors: Department of Electrical, Electronic and Information Engineering, University of Bologna, Bologna, Italy. Electronic address: mauro.ursino@unibo.it.
authors: Mauro
authors: M
authors: Ursino
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D001303:Auditory Cortex / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D003198:Computer Simulation; D003463:Cues; D006801:Humans; D007088:Illusions / Q000502:physiology*; D008959:Models, Neurological; D009415:Nerve Net / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology; D014793:Visual Cortex / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
keywords: Multisensory integration; Neural network modeling; Sound-induced flash illusion; Spatial processing; Temporal processing; Visual–auditory illusions