# Show Reference: "Multimodality in the superior colliculus: an information theoretic analysis"

Multimodality in the superior colliculus: an information theoretic analysis Cognitive Brain Research, Vol. 14, No. 1. (June 2002), pp. 10-19 by Paul Patton, Kamel Belkacem-Boussaid, Thomas J. Anastasio
@article{patton-et-al-2002,
abstract = {The deep superior colliculus ({DSC}) integrates multisensory input and triggers an orienting movement toward the source of stimulation (target). It would seem reasonable to suppose that input of an additional modality should always increase the amount of information received by a {DSC} neuron concerning a target. However, of all {DSC} neurons studied, only about one half in the cat and one-quarter in the monkey were multimodal. The rest received only unimodal input. Multimodal {DSC} neurons show the properties of multisensory enhancement, in which the neural response to an input of one modality is augmented by input of another modality, and of inverse effectiveness, in which weaker unimodal responses produce a higher percentage enhancement. Previously, we demonstrated that these properties are consistent with the hypothesis that {DSC} neurons use Bayes' rule to compute the posterior probability that a target is present given their stochastic sensory inputs. Here we use an information theoretic analysis of our Bayesian model to show that input of an additional modality may indeed increase target information, but only if input received from the initial modality does not completely reduce uncertainty concerning the presence of a target. Unimodal {DSC} neurons may be those whose unimodal input fully reduces target uncertainty and therefore have no need for input of another modality.},
address = {Beckman Institute, University of Illinois at Urbana/Champaign, Urbana, IL 61801, USA.},
author = {Patton, Paul and Belkacem-Boussaid, Kamel and Anastasio, Thomas J.},
issn = {0926-6410},
journal = {Cognitive Brain Research},
keywords = {information\_theory, model, sc},
month = jun,
number = {1},
pages = {10--19},
pmid = {12063126},
posted-at = {2014-02-03 17:24:22},
priority = {2},
title = {Multimodality in the superior colliculus: an information theoretic analysis},
url = {http://view.ncbi.nlm.nih.gov/pubmed/12063126},
volume = {14},
year = {2002}
}


In Anastasio et al.'s model of multi-sensory integration in the SC, an SC neuron is connected to one neuron from each modality whose spiking behavior is a (Poisson) probabilistic function of whether there is a target in that modality or not.

Their single SC neuron then computes the posterior probability of there being a target given its inputs (evidence) and the prior.