Vladimir Y Vildavski

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Lateral occipital cortical areas are involved in the perception of objects, but it is not clear how these areas interact with first tier visual areas. Using synthetic images portraying a simple texture-defined figure and an electrophysiological paradigm that allows us to monitor cortical responses to figure and background regions separately, we found(More)
Discontinuities in feature maps serve as important cues for the location of object boundaries. Here we used multi-input nonlinear analysis methods and EEG source imaging to assess the role of several different boundary cues in visual scene segmentation. Synthetic figure/ground displays portraying a circular figure region were defined solely by differences(More)
We analyzed the coherence of electroencephalographic (EEG) signals recorded symmetrically from the two hemispheres, while subjects (n = 9) were viewing visual stimuli. Considering the many common features of the callosal connectivity in mammals, we expected that, as in our animal studies, interhemispheric coherence (ICoh) would increase only with bilateral(More)
Vision researchers rely on visual display technology for the presentation of stimuli to human and nonhuman observers. Verifying that the desired and displayed visual patterns match along dimensions such as luminance, spectrum, and spatial and temporal frequency is an essential part of developing controlled experiments. With cathode-ray tubes (CRTs) becoming(More)
Symmetry is a highly salient feature of animals, plants, and the constructed environment. Although the perceptual phenomenology of symmetry processing is well understood, little is known about the underlying neural mechanisms. Here we use visual evoked potentials to measure the time course of neural events associated with the extraction of symmetry in(More)
Visual evoked potentials were recorded during presentation of a single stimulus that generated bi-stable perceptual alternation between two diVerent three-dimensional percepts. One interpretation (asymmetric) changed depth structure from Xat to corrugated in depth and the other (symmetric) had the appearance of a Xat surface translating laterally behind a(More)
Glass patterns are moirés created from a sparse random-dot field paired with its spatially shifted copy. Because discrimination of these patterns is not based on local features, they have been used extensively to study global integration processes. Here, we investigated whether 4- to 5.5-month-old infants are sensitive to the global structure of Glass(More)
Glass patterns are a type of moiré created when a random-dot field is overlaid with a rotated, translated or dilated copy. The overall form of the moiré cannot be detected using local processing mechanisms, and because of this, Glass patterns are useful probes of global form processing. Here, we use event-related potentials to show that certain global(More)
Volterra analysis and its variants have long been prominent among methods for modeling multi-input non-linear systems. The product of Volterra analysis, the Volterra kernels, are particularly suited to quantifying intra- and inter-input interactions. They are also readily interpretable, which means that they can be related directly to physical behaviors,(More)
Heterogeneity of the posterior alpha rhythm (AR) is a widely assumed but rarely tested phenomenon. We decomposed the posterior AR in the cortical source space with a 3-way PARAFAC technique, taking into account the spatial, frequency, and temporal aspects of mid-density EEG. We found a multicomponent AR structure in 90% of a group of 29 healthy adults. The(More)
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