AREAL HETEROGENEITY OF BIMODAL NEURONS
M. Alex Meredith, Leslie P Keniston, Brian L Allman
Poster
Time: 2009-06-29 11:00 AM – 12:30 PM
Last modified: 2009-06-04
Abstract
Bimodal neurons have long been regarded as the basic unit of multisensory processing. Largely from studies of the superior colliculus (SC), bimodal neurons have been shown to integrate information from different sensory modalities. Also, features of the evoking stimuli influence the level of interaction achieved in all bimodal neurons, but different bimodal neurons exhibit different ranges of integrative capacity, or functional modes. Given that bimodal neurons also occur in cortex, it has been assumed (and questioned) that cortical neurons integrate multisensory information in the manner identified in the SC. Using the same methodology as in investigations of the SC, the present study examined the range of multisensory integration observed in bimodal neurons from 3 different feline cortical areas: Anterior Ectosylvian Sulcus (AES), Rostral Suprasylvian Sulcus (RSS), and the Posterolateral Lateral Suprasylvian area (PLLS). Both statistical and summative criteria for integration were used to define multisensory interactions. Unlike the SC, each cortical area revealed that less than 50% of the bimodal neurons generated statistically significant levels of integration, and even fewer (<20%) showed summative responses. In particular, bimodal neurons in RSS and PLLS were highly non-integrative. These results indicate that the multisensory properties of the SC and cortex are dissimilar and that the integrative capacity of a specific region is likely to be determined by the integrative range of its constituent neurons.