TY - JOUR
T1 - Multimodality in the superior colliculus
T2 - An information theoretic analysis
AU - Patton, Paul
AU - Belkacem-Boussaid, Kamel
AU - Anastasio, Thomas J.
N1 - Funding Information:
We thank Prakash Ishwar, Pierre Moulin, Jesse Reichler, and Liudmila Yafremava for helpful discussions and for comments on the manuscript prior to submission. This work was supported by NSF grants IBN 92-21823 and IBN 00-80789, and a grant from the Critical Research Initiatives of the State of Illinois, all to T.J.A.
PY - 2002
Y1 - 2002
N2 - 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.
AB - 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.
KW - Bayes' rule
KW - Information theory
KW - Multisensory integration
KW - Probability theory
KW - Superior colliculus
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U2 - 10.1016/S0926-6410(02)00057-5
DO - 10.1016/S0926-6410(02)00057-5
M3 - Article
C2 - 12063126
AN - SCOPUS:0036596637
SN - 0926-6410
VL - 14
SP - 10
EP - 19
JO - Cognitive Brain Research
JF - Cognitive Brain Research
IS - 1
ER -