Show Reference: "The role of anterior ectosylvian cortex in cross-modality orientation and approach behavior"

The role of anterior ectosylvian cortex in cross-modality orientation and approach behavior. Experimental Brain Research, Vol. 112, No. 1. (November 1996), pp. 1-10 by Lee K. Wilkinson, M. Alex Meredith, Barry E. Stein
    abstract = {Physiological and behavioral studies in cat have shown that corticotectal influences play important roles in the information-processing capabilities of superior colliculus ({SC}) neurons. While corticotectal inputs from the anterior ectosylvian sulcus ({AES}) play a comparatively small role in the unimodal responses of {SC} neurons, they are particularly important in rendering these neurons capable of integrating information from different sensory modalities (e.g., visual and auditory). The present experiments examined the behavioral consequences of depriving {SC} neurons of {AES} inputs, and thereby compromising their ability to integrate visual and auditory information. Selective deactivation of a variety of other cortical areas (posterolateral lateral suprasylvian cortex, {PLLS}; primary auditory cortex, {AI}; or primary visual cortex, 17/18) served as controls. Cats were trained in a perimetry device to ignore a brief, low-intensity auditory stimulus but to orient toward and approach a nearthreshold visual stimulus (a light-emitting diode, {LED}) to obtain food. The {LED} was presented at different eccentricities either alone (unimodal) or combined with the auditory stimulus (multisensory). Subsequent deactivation of the {AES}, with focal injections of a local anesthetic, had no effect on responses to unimodal cues regardless of their location. However, it profoundly, though reversibly, altered orientation and approach to multisensory stimuli in contralateral space. The characteristic enhancement of these responses observed when an auditory cue was presented in spatial correspondence with the visual stimulus was significantly degraded. Similarly, the inhibitory effect of a spatially disparate auditory cue was significantly ameliorated. The observed effects were specific to {AES} deactivation, as similar effects were not obtained with deactivation of {PLLS}, {AI} or 17/18, or saline injections into the {AES}. These observations are consistent with postulates that specific cortical-midbrain interactions are essential for the synthesis of multisensory information in the {SC}, and for the orientation and localization behaviors that depend on this synthesis.},
    author = {Wilkinson, Lee K. and Meredith, M. Alex and Stein, Barry E.},
    citeulike-article-id = {13377433},
    citeulike-linkout-0 = {},
    citeulike-linkout-1 = {},
    issn = {0014-4819},
    journal = {Experimental Brain Research},
    keywords = {aes, behaviour, biology, motor, orienting},
    month = nov,
    number = {1},
    pages = {1--10},
    pmid = {8951401},
    posted-at = {2014-09-29 13:47:01},
    priority = {2},
    title = {The role of anterior ectosylvian cortex in cross-modality orientation and approach behavior},
    url = {},
    volume = {112},
    year = {1996}

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Irrelevant auditory stimuli can dramatically improve or degrade orientation performance in visual orientation tasks:

In Wilkinson et al.'s experiments, cats' performance in orienting towards near-threshold, medial visual stimuli was much improved by irrelevant auditory stimuli close to the visual stimuli and drastically degraded by irrelevant auditory stimuli far from the visual stimuli.

If visual stimuli were further to the edge of the visual field, then lateral auditory stimuli improved their detection rate even if they were disparate.

Chemical deactivation of AES degrades both the improvement and the degradation of performance in orienting towards visual due to auditory stimuli.

Deactivation of AES and rLS leads to a complete lack of cross-modal enhancement while leaving intact the ability of multi-sensory SC neurons to respond to uni-sensory input and even to add input from different sensory modalities.