Search our Database of Scientific Publications and Authors

I’m looking for a

    Details and Download Full Text PDF:
    Sources of top-down control in visual search.

    J Cogn Neurosci 2009 Nov;21(11):2100-13
    INB-3 AG Kognitive Neurologie, Research Centre Jülich, Germany.
    Endogenous control of visual search can influence search guidance at the level of a supradimensional topographic saliency map [Wolfe, J. M. Guided Search 2.0: A revised model of visual search. Psychonomic Bulletin & Review, 1, 202-238, 1994], and modulate nonspatial mechanisms coding saliency in dimension-specific input modules [Müller, H. J., Reimann, B., & Krummenacher, J. Visual search for singleton feature targets across dimensions: Stimulus- and expectancy-driven effects in dimensional weighting. Journal of Experimental Psychology: Human Perception and Performance, 29, 1021-1035, 2003]. The current experiment used fMRI to dissociate these mechanisms in a singleton feature search task in which the likely target dimension (color or orientation) was semantically precued and target saliency in each dimension was varied parametrically. BOLD signal increases associated with increased demands for top-down guidance were observed within the fronto-parietal attention network and in the right anterior middle frontal gyrus. Decreasing requirements for top-down control led to BOLD signal increases in medial anterior prefrontal cortex, consistent with a gating mechanism in favor of stimulus-related processing [Burgess, P. W., Dumontheil, I., & Gilbert, S. J. The gateway hypothesis of rostral prefrontal cortex (area 10) function. Trends in Cognitive Sciences, 11, 290-298, 2007]. Another network of brain areas consisting of left lateral fronto-polar cortex, the left supramarginal gyrus, and the cerebellum, as well as a bilateral network consisting of the posterior orbital gyrus, the inferior frontal gyrus, and the pre-SMA were associated with top-down dimensional (re-) orienting. These data argue in favor of distinct endogenous control systems for visuospatial and dimension-based attentional processing. Finally, cue validity modulated saliency processing in the left temporo-parietal junction (TPJ), pointing to a crucial role of the left TPJ in integrating an endogenous dimension-based attention set with bottom-up saliency signals.
    PDF Download - Full Text Link
    ( Please be advised that this article is hosted on an external website not affiliated with PubFacts.com)
    Source Status
    http://dx.doi.org/10.1162/jocn.2008.21173DOI ListingPossible

    Similar Publications

    The neural correlates of attention orienting in visuospatial working memory for detecting feature and conjunction changes.
    Brain Res 2007 Jan 14;1130(1):146-57. Epub 2006 Dec 14.
    Department of Psychology, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei, Taiwan 106.
    The neural mechanisms of attentional orienting in visuospatial working memory for change detection were investigated. A spatial cue was provided with the onset time manipulated to allow more effective top-down control with an early cue than with a late cue. The change type was also manipulated so that accurate detection depended on color or the binding of color and location. Read More
    Brain structures involved in visual search in the presence and absence of color singletons.
    J Cogn Neurosci 2010 Apr;22(4):761-74
    Vrije Universiteit, Amsterdam, Netherlands.
    It is still debated to what degree top-down and bottom-up driven attentional control processes are subserved by shared or by separate mechanisms. Interactions between these attentional control forms were investigated using a rapid event-related fMRI design, using an attentional search task. Following a prestimulus mask, target stimuli (consisting of a letter C or a mirror image of the C, enclosed in a diamond outline) were presented either at one unique location among three nontarget items (consisting of a random letter, enclosed in a circle outline; 50% probability), or at all four possible target locations (also 50% probability). Read More
    Top-down controlled visual dimension weighting: an event-related fMRI study.
    Cereb Cortex 2002 Mar;12(3):318-28
    Department of Experimental Psychology, University of Leipzig, Leipzig, Germany.
    Target detection in visual singleton feature search is slowed when consecutive targets are defined in different visual dimensions. Behavioral data provide evidence that attentional weight needs to be shifted between dimension-specific processing modules. We found similar dimension-specific change effects in a conjunction search task, in which observers searched for an odd-one-out target defined by a unique combination of size and color or, respectively, size and motion direction. Read More
    Cerebral correlates of alerting, orienting and reorienting of visuospatial attention: an event-related fMRI study.
    Neuroimage 2004 Jan;21(1):318-28
    Institute of Medicine, Research Centre Jülich, 52425, Jülich, Germany.
    The identification of brain systems contributing to different aspects of visuospatial attention is of both clinical and theoretical interest. Cued target detection tasks provide a simple means to dissociate attentional subcomponents, such as alerting, orienting or reorienting of attention. Event-related functional magnetic resonance imaging (fMRI) was used to study neural correlates of these distinct attentional processes. Read More