Segmentation, grouping and accentuation during stimulus perception.

Grouping, segmentation, and accentuation - processes involved in stimulus perception - are discussed. These effects are explained in terms of the universal vector coding model in neural networks. Grouping is the combination of objects or events into units on the basis of their similarity.

[Segmentation, grouping and accentuation during stimuli perception].

The paper is concerned with grouping, segmentation and accentuation occurring in the processes of stimuli perception. An universal model of these events is based on vector coding in neuronal networks. Grouping is unification of objects or events into collections according to their similarity.

The conditioned reflex: detectors and command neurons.

The conditioned reflex is characterized by plasticity supporting bilateral selective connections between its input and output. In simple nervous systems, input stimuli are represented by selective detectors connected to command neurons by plastic synapses whose activity increases on learning and decreases on extinction. The process of associative learning occurs when excitation of the detector and the command neuron coincide.

The evoked potential as a measure of perceptual and semantic differences.

This review discusses the information content of perceptual and semantic evoked potentials arising in humans as a result of instantaneous changes in nonverbal and verbal stimuli. The amplitudes of perceptual and semantic evoked potentials were found to correlate positively with subjects' assessments of the differences between these stimuli. Multidimensional scaling matrixes of evoked potential amplitudes and subjective assessments of differences on pairwise substitution of stimuli showed that the actual colors and color names occupied a four-dimensional spherical color space and were encoded by excitation vectors of identical lengths.

[Conditioned reflex: detector and command neuron].

Conditioned reflex is characterized by plasticity resulting in a bilateral selective input-output linking. In simple nervous systems, input stimuli are represented by selective detectors connected with command neurons through plastic synapses strengthened during associative learning and weakened during extinction. The process of associative learning is due to temporal coincidence of excitation in both detector and command neurons.