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  • 1
    Electronic Resource
    Electronic Resource
    Methoden zum Vergleich des Leistungsvermögens biologischer und technischer Systeme (1972)
    Springer
    Biological cybernetics 10 (1972), S. 1-16 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Summary In this work the methods of the communication theory for binary detection, multiple detection and extraction are applied to biological systems. It is the objective of this investigation to compare the performance of optimal and biological systems in receiving signals superimposed by noise. The required mathematical relations and methods of measurements are derived. In the second part of this work pattern recognition experiments (multiple detection) at the human visual system with stationary and time variant patterns are described. The comparison of the performance between optimal and biological system shows that the human visual system acts in a suboptimal way. From some other detection experiments it can be concluded that the recognition process is describable by spatial cross-correlation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00288779
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  • 2
    Electronic Resource
    Electronic Resource
    Analysis of neuronal networks in the visual system of the cat using statistical signals (1976)
    Springer
    Biological cybernetics 22 (1976), S. 7-20 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract If the input signals of the visual system in the cat are statistical patterns in space and time, a complete system analysis can be carried out. What counts here as a system are the neuronal networks between retina and recording site. In the case of linearity, one obtains the temporal impulse response functions at every point in the receptive field with the aid of correlation methods. The measuring time is about one minute. Some aspects of the procedure are explained in terms of examples. The method of measurement also makes it possible to determine the characteristic function of the system in time and space between different recording sites within the cortex. It is possible to specialize the procedure for analysing the stationary space dependent behaviour of neuronal networks. The extension of the analysis procedure allows a concise, relatively simple description for nonlinear systems in which linear and nonlinear subsystems can be separated. Besides this, there are no restrictions concerning the kind of nonlinearity. A second paper will present the detailed experimental application of these methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00340228
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  • 3
    Electronic Resource
    Electronic Resource
    On the function of cell systems in area 18. Part I (1981)
    Springer
    Biological cybernetics 41 (1981), S. 47-57 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract Proceeding from previous studies on cells in area 18, neurophysiological experiments were carried out using combinations of deterministic and statistical stimuli. The evaluation of the results on the space, time and amplitude characteristics of the cells show that for nearly all cells in this area, pattern distorition and shift due to motion are eliminated by spatial asymmetry of the coupling and specific combinations of on-off systems. So, the extraction of features despite pattern movement is possible in area 18. The features are extracted in the low spatial frequency range.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01836126
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  • 4
    Electronic Resource
    Electronic Resource
    On the function of cell systems in area 18. Part II (1981)
    Springer
    Biological cybernetics 41 (1981), S. 59-69 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract In addition to the asymmetry of the spatial coupling and of the specific temporal combination of excitation and inhibition, the non-linearity is very pronounced in area 18. Taking the sequence of a linear operation and a stationary nonlinear characteristic as a model, the experimental findings can be systematized and a cell classification specified which departs from the customary ones. The hypercomplex cell system probably originates in recurrent inhibition and leads to differentiation of the patterns along their contour line. Problems of cell classification and of the type of parallelism in the visual cortex are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01836127
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  • 5
    Electronic Resource
    Electronic Resource
    On the analysis of the cat's pattern recognition system (1983)
    Springer
    Biological cybernetics 48 (1983), S. 115-124 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract The objective of the paper is to determine in abstract terms the algorithms used by the cat detecting simple patterns and to quantify the contributions of the visual areas 17, 18, 19 for this task. The data incorporated in the algorithm are collected from behavioral experiments where the animals had to distinguish between two patterns. The patterns were superimposed with gaussian noise and the detection probability was measured. The resulting model describes pattern recognition in two steps: first extraction of features and second classification. The test of the validity of the model system was to predict the outcome of similar experiments but with different patterns. With the help of the model it is possible to deccribe the effect of a lesion in parametric form. This in turn gives some hints about the functions of the visual areas 17, 18, 19 for the specific fask, tested in the experiments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00344395
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  • 6
    Electronic Resource
    Electronic Resource
    Self-organizing maps for visual feature representation based on natural binocular stimuli (2000)
    Springer
    Biological cybernetics 82 (2000), S. 97-110 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract. We model the stimulus-induced development of the topography of the primary visual cortex. The analysis uses a self-organizing Kohonen model based on high-dimensional coding. It allows us to obtain an arbitrary number of feature maps by defining different operators. Using natural binocular stimuli, we concentrate on discussing the orientation, ocular dominance, and disparity maps. We obtain orientation and ocular dominance maps that agree with essential aspects of biological findings. In contrast to orientation and ocular dominance, not much is known about the cortical representation of disparity. As a result of numerical simulations, we predict substructures of orientation and ocular dominance maps that correspond to disparity maps. In regions of constant orientation, we find a wide range of horizontal disparities to be represented. This points to geometrical relations between orientation, ocular dominance, and disparity maps that might be tested in experiments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00007968
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  • 7
    Electronic Resource
    Electronic Resource
    Dynamische Eigenschaften von Nervennetzen im visuellen System (1972)
    Springer
    Biological cybernetics 10 (1972), S. 64-77 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract The preprocessing of optical information in the visual system takes place in the two-dimensional homogeneous nervous nets of the retina and the geniculate body. These networks can be considered as band-pass filters for space-dependent oscillations if the input stimuli are independent of time. If the synapses of the neurons have timefrequency dependent properties the performance of the system in the space domain, which is important for pattern recognition, is determined by the time dependence of input signal. For a description of these networks in this investigation the space spectrum for various values of the time frequency ω is used. The answers of real nervous nets can be interpreted by the model when the two-dimensional input signals are switched, flickered or moved. For this reason these dynamic stimuli are necessary for an analysis of the cortex. The theoretical combination of space- and time-dependent filtering is essential for an understanding of cortical transformations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00292232
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  • 8
    Electronic Resource
    Electronic Resource
    Neurobiologie und System-Theorie eines visuellen Muster-Erkennungsmechanismus bei Kröten (1973)
    Springer
    Biological cybernetics 14 (1973), S. 167-183 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract Quantitative behavioral experiments have shown that the toad uses mainly two types of gestalt information in prey/enemy discrimination: pattern extension in the direction of movement promotes, in general, the signal value prey, while extension perpendicular to the direction of movement promotes that of enemy. Registrations from single fibers and single cells at different stages on the visual path showed that the object extension perpendicular to the direction of movement is chiefly analysed by means of the retinal and thalamus pretectal nerve nets, whereas the extension in the direction of movement is analysed mostly by certain tectal nerve nets. Further neurobiological findings indicated that the prey/enemy discrimination is the result of subtractive interaction between the tectal and thalamus pretectal nerve nets. The system answers given by the retina, the retina-pretectum and the retinatectum to the input patterns used in the neurobiological experiments were determined for relevant space and time parameters on the basis of two dimensional neuron network models. The experimental results agree well with the theoretical ones. If the subtractive interaction between the model networks hypothesized from the neurophysiological results is applied, the resulting system answer describes the behavioral findings very well. So it is shown that the networks investigated would suffice in principle for the behavioral interpretations of the key stimulus prey/enemy — so far as these are known.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00288919
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  • 9
    Electronic Resource
    Electronic Resource
    On the classification of visual patterns: Systems analysis using detection experiments (1977)
    Springer
    Biological cybernetics 25 (1977), S. 121-130 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract Behavioral experiments are indispensable for the analysis of biological systems for cognition and recognition. When these are carried out as detection experiments three types of description can be used for the problem of visual pattern recognition which allow conclusions to be drawn on the operating function of the system. Provided that the signals to be recognized have additive noise superimposed on them, system description is possible: 1. on the basis on the probabilities of recognition and of mix-up,—2. through the analysis of the transformation of distribution densities of the noise,—3. by means of the measurable distances of the patterns from each other in feature space.-The analysis of the distribution densities shows that the human visual system acts like a linear classifier in the classification of six geometrical patterns. The independence of the classification from intensity as well as the human reaction to alteration in the power spectrum of the noise support this result. Simulation experiments on a computer show the efficacy of various biological relevant parameters for the linear classification and suggest that a narrow band and probably feature specific filtering precedes the classification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00365209
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  • 10
    Electronic Resource
    Electronic Resource
    Analysis of neuronal networks in the visual system of the cat using statistical signals — Simple and complex cells (1978)
    Springer
    Biological cybernetics 31 (1978), S. 175-185 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract Superimposing additively a two-dimensional noise process to deterministic input signals (bars) the neurons of area 17 show a class-specific reaction for the task of signal extraction. Moving both parts of the signals simultaneously and varying the signal to noise ratio (S/N) the simple cells achieve the same performance as resulted from the psychophysical experiment. Type I complex cells extract moving deterministic signals (i.e. bars) from the stationary noise, whereas in the answers of Type II complex cells the statistical parts of the signals predominate. Considering the different cell types each as a series of a linear and a nonlinear system one obtains the cell specific space-time frequency and the amplitude characteristics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00337004
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