XB-ART-53159Elife. January 1, 2017; 6
A cellular mechanism for inverse effectiveness in multisensory integration.
To build a coherent view of the external world, an organism needs to integrate multiple types of sensory information from different sources, a process known as multisensory integration (MSI). Previously, we showed that the temporal dependence of MSI in the optic tectum of Xenopus laevis tadpoles is mediated by the network dynamics of the recruitment of local inhibition by sensory input (Felch et al., 2016). This was one of the first cellular-level mechanisms described for MSI. Here, we expand this cellular level view of MSI by focusing on the principle of inverse effectiveness, another central feature of MSI stating that the amount of multisensory enhancement observed inversely depends on the size of unisensory responses. We show that non-linear summation of crossmodal synaptic responses, mediated by NMDA-type glutamate receptor (NMDARs) activation, form the cellular basis for inverse effectiveness, both at the cellular and behavioral levels.
PubMed ID: 28315524
PMC ID: PMC5375642
Article link: Elife.
Grant support: T32 EY018080 NEI NIH HHS , F31 NS093790 NINDS NIH HHS
Article Images: [+] show captions
|Figure 2. Inverse effectiveness is not dependent on inhibition.(A) Maximum unisensory responses in spike output plotted against MSIn in Stage 49 tadpoles in control (n = 40, cells) conditions and with GABA-R blocker (n = 22; picrotoxin). Despite the apparent boost in MSI for the picrotoxin group across all response sizes, the decay trend for inverse effectiveness remains intact and similar to the control group. Curves represent a single exponential decay fit using the least-squares method.DOI: http://dx.doi.org/10.7554/eLife.25392.00410.7554/eLife.25392.005Figure 2—source data 1. Data for Figure 2.Excel sheet contains raw data points used to generate figure.DOI: http://dx.doi.org/10.7554/eLife.25392.005|