An information-processing explanation of some perceptual phenomena.
Explore the source record for details and available documents.
SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Temporal discrimination by healthy young and senior adults and patients with senile dementia was studied using the measure of transmitted information and two psychophysical methods (single-stimulus-ranking and pair-comparison). The patients with senile dementia showed very severe impairment on both methods and performed much less efficiently than the healthy adults of the same age; thus the former revealed a deficit in both memory and discrimination. The healthy seniors showed less alteration of temporal judgment with significant loss only with the single-stimulus method, which reflects memory deficit alone. Temporal cognition is very sensitive to changes in brain function.
We investigated the effects of localized medial and lateral CPu lesions and fornix/fimbria lesions on responses to a local cue and to behavior based on cognitive-spatial information in the water maze. Rats were trained concurrently on the cue (visible platform) and spatial (submerged platform) components of the task, followed by a test in which responses to the two types of information were dissociated by a measure of competing response tendencies. Bilateral lesions of lateral CPu did not affect acquisition of either cue or spatial responding but produced a preference for the spatial response on the competition test. Bilateral lesions of the medial CPu retarded but did not prevent learning both components and produced a preference for the cue response on the competition test. The latter effect was accompanied by increased thigmotaxis (swimming in the periphery of the pool), primarily during the early acquisition trials, which was attributed to an impaired ability to respond to learned spatial information. Fornix/fimbria lesions prevented spatial but not cue learning and produced a preference for the cue response on the competition test. Asymmetric lesions (unilateral hippocampus and contralateral medial CPu) produced mild retardation of acquisition of both the cue and spatial tasks and a preference for the cue response on the competition test. These findings dissociate the functions of the lateral and medial CPu and suggest that the hippocampus and medial CPu may be parts of a system that promotes responding based on learned cognitive-spatial information, particularly in competitive cue-place response situations.
The properties of two classes of behavioral mutants of Escherichia coli (called tsr and tar) are described. The mutations in these strains define two complementary pathways of information flow in bacterial chemotaxis: behavioral responses to one set of stimuli are defective in tsr mutants, while responses to a complementary set of stimuli are defective in tar mutants. A double mutant containing both genetic lesions is defective in responses to all stimuli tested. The behavioral defects are shown to correlate with alterations in the properties of a methylation reaction involved in chemotaxis. Two independent sets of methyl-accepting proteins are demonstrated in the wild type, each set functioning in one of the two pathways mentioned above. Methylation of one set of proteins is defective in tsr mutants, while methylation of the complementary set is defective in tar mutants. The double mutant shows no methylation of either set. The relationship between the genetic loci (tsr and tar) and the methyl-accepting proteins is discussed.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Since the mid eighties the department of medical informatics at the University Hospital of Giessen (Germany) has been engaged in the development of a comprehensive hospital information system. The installation of a campus wide network has set the basis to provide not only clinical patient-oriented information, but also general information resources for research, medical education and administrative purposes, thus creating an environment which in the U.S. became known as an integrated academic information management system (IAIMS). The underlying concept of the whole approach is to provide one-stop information shopping capabilities at the clinicians and administrators desktop in order to meet the increasing information needs of health professionals with the emerging reality of the potential benefits of computer and communication technologies. This paper describes the various steps performed to realize this concept at Giessen University Hospital and the evaluation results derived from analysis of the acceptance of these new technologies among our hospital staff.
For human vision to be explained by a computational theory, the first question is plain: What are the problems that the brain solves when we see? It is argued that vision is the construction of efficient symbolic descriptions from images of the world. An important aspect of vision is therefore the choice of representations for the different kinds of information in a visual scene. An overall framework is suggested for extracting shape information from images, in which the analysis proceeds through three representations: (1) the primal sketch, which makes explicit the intensity changes and local two-dimensional geometry of an image; (2) 2 1/2-D sketch, which is a viewer-centred representation of the deplth, orientation and discontinuities of the visible surfaces; and (3) the 3-D model representation, which allows an object-centred description of the three-dimensional structure and organization of a viewed shape. The critical act in formulating computational theories for process capable of constructing these representations is the discovery of valid constraints on the way the world behaves, that provide sufficient additional information to allow recovery of the desired characteristic. Finally, once a computational theory for a process has been formulated, algorithms for implementing it may be designed, and their performance compared with that of the human visual processor.
One of the most important functions of any fire department is to provide selective contact with fire fighting units and to dispatch these units based on information gathered from street alarm boxes and telephones. This paper is concerned with the problem of dispatching tactical response information to remote fire fighting units and with the effect of workload on the dispatch function.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.