Show Reference: "Evaluating the Operations Underlying Multisensory Integration in the Cat Superior Colliculus"

Evaluating the Operations Underlying Multisensory Integration in the Cat Superior Colliculus The Journal of Neuroscience, Vol. 25, No. 28. (13 July 2005), pp. 6499-6508, doi:10.1523/jneurosci.5095-04.2005 by Terrence R. Stanford, Stephan Quessy, Barry E. Stein
@article{stanford-et-al-2005,
    abstract = {It is well established that superior colliculus ({SC}) multisensory neurons integrate cues from different senses; however, the mechanisms responsible for producing multisensory responses are poorly understood. Previous studies have shown that spatially congruent cues from different modalities (e.g., auditory and visual) yield enhanced responses and that the greatest relative enhancements occur for combinations of the least effective modality-specific stimuli. Although these phenomena are well documented, little is known about the mechanisms that underlie them, because no study has systematically examined the operation that multisensory neurons perform on their modality-specific inputs. The goal of this study was to evaluate the computations that multisensory neurons perform in combining the influences of stimuli from two modalities. The extracellular activities of single neurons in the {SC} of the cat were recorded in response to visual, auditory, and bimodal visual-auditory stimulation. Each neuron was tested across a range of stimulus intensities and multisensory responses evaluated against the null hypothesis of simple summation of unisensory influences. We found that the multisensory response could be superadditive, additive, or subadditive but that the computation was strongly dictated by the efficacies of the modality-specific stimulus components. Superadditivity was most common within a restricted range of near-threshold stimulus efficacies, whereas for the majority of stimuli, response magnitudes were consistent with the linear summation of modality-specific influences. In addition to providing a constraint for developing models of multisensory integration, the relationship between response mode and stimulus efficacy emphasizes the importance of considering stimulus parameters when inducing or interpreting multisensory phenomena.},
    address = {Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA. Stanford@wfubmc.edu},
    author = {Stanford, Terrence R. and Quessy, Stephan and Stein, Barry E.},
    day = {13},
    doi = {10.1523/jneurosci.5095-04.2005},
    issn = {1529-2401},
    journal = {The Journal of Neuroscience},
    keywords = {biology, enhancement, multisensory-integration, sc, superadditivity},
    month = jul,
    number = {28},
    pages = {6499--6508},
    pmid = {16014711},
    posted-at = {2013-06-07 08:13:59},
    priority = {2},
    publisher = {Society for Neuroscience},
    title = {Evaluating the Operations Underlying Multisensory Integration in the Cat Superior Colliculus},
    url = {http://dx.doi.org/10.1523/jneurosci.5095-04.2005},
    volume = {25},
    year = {2005}
}

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Stanford et al. studied single-neuron responses to cross-modal stimuli in their receptive fields. In contrast to previous studies, they systematically tried out different combinations of levels of intensity levels in different modalities.

Neural responses in the sc to spatially and temporally coincident cross-sensory stimuli can be much stronger than responses to uni-sensory stimuli.

In fact, they can be much greater than the sum of the responses to either stimulus alone.

Stanford et al. state that superadditivity seems quite common in cases of multi-sensory enhancement.