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Primary visual coding can be characterized by the receptive field (RF) properties of single neurons. Subject of this paper is our search for a global,second coding step beyond the RF-concept that links related features in a visual scene. In recent models of visual coding, oscillatory activities have been proposed to constitute such linking signals. We(More)
We adapted to the neocortex of waking monkeys a method for multiple microelectrode recording devised by Reitboeck. A sliding platform allows micropositioning of 7 electrodes independently, in 2 microns steps. Microelectrodes are quartz glass filaments (80 microns o.d.) with central metal cores (30 microns) of tungsten-platinum alloy. Filaments are drawn in(More)
Until recently, no known physiological mechanism could explain the transient linking of local visual features into global coherent percepts. The authors have found such principles at a 'computational stage' of preattentive processing in the cat's primary visual cortex. The results show that stimulus-evoked oscillations of local processing units,(More)
Methods for the fabrication of tungsten-glass and platinum-rhodium-quartz fiber microelectrodes and of fiber pipettes are described and the electrical and mechanical properties of fiber electrodes are discussed. These properties (minimal tissue damage, good single unit isolation and temporal stability) make them particularly suited for multielectrode(More)
The performance of technical and biological vision systems crucially relies on powerful processing capabilities. Robust object recognition must be based on representations of segmented object candidates which are kept stable and sparse despite the highly variable nature of the environment. Here, we propose a network of pulse-coding neurons based on(More)
The mapping of retinal space onto the striate cortex of some mammals can be approximated by a log-polar function. It has been proposed that this mapping is of functional importance for scale-and rotation-invariant pattern recognition in the visual system. An exact log-polar transform converts centered scaling and rotation into translations. A subsequent(More)