Simon D. Neitzel

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Receptive fields (RFs) of cortical sensory neurons increase in size along consecutive processing stages. When multiple stimuli are present in a large visual RF, a neuron typically responds to an attended stimulus as if only that stimulus were present. However, the mechanism by which a neuron selectively responds to a subset of its inputs while discarding(More)
For processing and segmenting visual scenes, the brain is required to combine a multitude of features and sensory channels. It is neither known if these complex tasks involve optimal integration of information, nor according to which objectives computations might be performed. Here, we investigate if optimal inference can explain contour integration in(More)
Selective attention causes visual cortical neurons to act as if only one of multiple stimuli are within their receptive fields. This suggests that attention employs a, yet unknown, neuronal gating mechanism for transmitting only the information that is relevant for the current behavioral context. We introduce an experimental paradigm to causally investigate(More)
Human contour integration performance decreases [1,2] with eccentricity, though less so for contours with good gestalt properties [3]. However, the cause is still not well understood. On the one hand, there is reduced visual acuity in the periphery due to cortical magnification. The same area of the visual field is mapped to a larger area of cortical(More)
Coherent oscillations and synchronous activity are suggested to play an important role in selective processing and dynamic routing of information across the primary visual cortical areas. In this contribution we show that phase coherency between distant recording sites allows to distinguish almost perfectly between two attentional states in a behavioral(More)
Contour integration is believed to be an important step in human image processing and object recognition, and has been shown to be performed very efficiently by the visual system. However, its neuronal mechanisms are still not well understood. Most contour integration models propose lateral connections between distant orientation columns of similar(More)
Contour integration is a dynamical process which links oriented, local elements into the percept of a coherent contour. Detailed psychophysical studies have described the basic properties of this process. In particular, studies on a contourdetection paradigm where subjects have to find a continuous path of Gabor elements embedded in a background of randomly(More)
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