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At least 1,189 records · Page 66Linked to original sources
PubMed1991

Classifying simple and complex cells on the basis of response modulation.

Hubel and Wiesel (1962; Journal of Physiology, London, 160, 106-154) introduced the classification of cortical neurons as simple and complex on the basis of four tests of their receptive field structure. These tests are partly subjective and no one of them unequivocally places neurons into distinct classes. A simple, objective classification criterion based on the form of the response to drifting sinusoidal gratings has been used by several laboratories, although it has been criticized by others. We review published and unpublished evidence which indicates that this simple and objective criterion reliability divides neurons of the striate cortex in both cats and monkeys into two groups that correspond closely to the classically-described simple and complex classes.

Animals↗
PubMed1995

Using spoken attributions to classify abusive families.

Despite claims that beliefs held by abusive parents are important indicators of family functioning, few studies have explored the relationship between patterns of beliefs and severity of abuse. This study applies findings from marital research that demonstrate that maladaptive attributional patterns predict the level of distress experienced in adult relationships. It examines spoken attributions produced by 18 families during diagnostic therapy sessions following serious abuse of a child. Attributions were identified from transcripts and coded using a standard system. Patterns of attributions, defined on the basis of previous work, successfully predicted classification of families by therapists as Good, Uncertain, and Poor, in terms of prognosis for rehabilitation. Using this classification to test hypotheses based on attributional style, group differences were found. In families rated Good, parents were more likely to attribute more control to self than child for negative outcomes. They were also more likely to nominate themselves as causing negative events. Case accounts of families from each category are presented to illustrate how attributional analysis can contribute to an understanding of the individual nature of child abuse.

Adult↗
PubMed1990

Development of a computer program classifying rat sleep stages.

We developed a simple and precise program for the on-line judgement of the sleep stages of four rats simultaneously for an unlimited period, using a commercially available general purpose signal processor (NEC-Sanei 7T17; 32-bit, 5 MHz, 4 Mbyte, 1 Mbyte 1 floppy disc drive). EEG and EMG were recorded with an 8-channel polygraph (NEC-Sanei, System 380) through electrodes chronically implanted into the brain. The signals were A/D converted every ms and integrated for 2760 ms after full-wave rectification, and the subsequent 2240 ms was used for calculation and further analysis. All data were handled with this 5000 ms as the minimum unit. Then 3 sleep stages, i.e., waking, slow-wave sleep, and REM sleep, were determined by a template matching method from the relative amplitudes and durations of the integrated EEG, EMG and EMG surge data based on algorithms of standard visual amplitude analysis criteria for the sleep-stage classification. An agreement matrix was constructed between the data scored by the visual and by the automatic analysis, and the agreement value was satisfactory, although slight variability was seen in the REM sleep-stage determination. This result indicated that EEG and EMG data analysis is appropriate for researching the circadian rhythmic mechanism of the sleep-wake cycle.

Animals↗
PubMed1989

PC-based system for classifying dysmorphic syndromes in children.

A system is described running on any IBM-compatible personal computer operating under MS-DOS which permits an expert in pediatric dysmorphology to formulate dysmorphic features and syndromes in a knowledge base, and a user to enter, analyze, store and retrieve case data. For each case, the system calculates the Bayesian probability of the presence of each syndrome in the knowledge base and lists as the differential diagnosis those syndrome whose probability exceeds 90%. For explanatory purposes, the syndrome definitions can be displayed and compared to the case data. The system has been tested and used in the Department of Clinical Genetics at Uppsala University Hospital. The current scope of the system's knowledge was found to be of valuable assistance to the pediatric practitioner but it must be expanded and refined for use by a clinical geneticist. This study has shown the validity of the system's design and structure and further work is under way to extend its knowledge capability.

Abnormalities, Multiple↗
PubMedDate not supplied

DIABETEX decision module 2--calculation of insulin dose proposals and situation recognition by means of classifiers.

Current research in the field of medical decision making tries to represent and to analyse complex, uncertain and complicated situations. The first version of DIABETEX, which is a decision support system for the treatment of diabetic out-patients, accepts the challenge to overcome these difficulties. It includes a network of rules on the basis of known glucose-insulin relationships under different situations. The insulin dose for type I diabetic patients is suggested accordingly. In this, the application of special cybernetic methods offers the chance to overcome complexity, uncertainty, fuzzyness and incompleteness of data. Two methods of classification are presented to complete the DIABETEX decision unit: (1) the Bayes' classification is used in the calculation of insulin doses for type I diabetic patients on multiple subcutaneous insulin injections considering the basis-bolus concept; (2) fuzzy classification is employed in separating 'normal diabetic days' from days with information on special situations such as exercise, illness, menstruation on the one side, from stress, hypoglycaemia etc. on the other.

Bayes Theorem↗
PubMed1986

Polychlorinated biphenyls, classified as either phenobarbital- or 3-methylcholanthrene-type inducers of cytochrome P-450, are both hepatic tumor promoters in diethylnitrosamine-initiated rats.

The cytochrome P-450 isozymes, cytochrome P-450 MC1 and MC2, purified from rats treated with 3-methylcholanthrene (MC), were found by immunohistochemical staining to be strongly induced in the livers of rats treated with 3,3', 4,4'-tetrachlorobiphenyl (TCBP), while the cytochrome P-450 isozymes, PB1 and PB2, purified from the livers of rats treated with phenobarbital (PB), were shown to be induced in the livers of rats treated with 2,2', 4,4', 5,5'-hexachlorobiphenyl (HCBP). The latter compound also strongly induced NADPH-cytochrome P-450-reductase. Following induction, all 5 enzymes were located preferentially in the centrilobular and midzonal region of the liver acinus. The influence of these polychlorinated biphenyls (PCBs) on diethylnitrosamine (DEN)-initiated hepatocarcinogenesis was investigated by analyzing the evolution of adenosine triphosphatase-deficient focal lesions. Whereas DEN alone produced very few islets, the administration of either PCB congener (150 mumol/kg, i.p., once weekly over a period of 8 weeks) subsequent to DEN treatment (50 ppm in the drinking water, 10 days) strongly enhanced the number of islets as well as the relative volume of liver occupied by islet tissue. These effects were evident, both 1 and 9 weeks, after cessation of PCB treatment. Unexpectedly the less persistent PCB congener, TCBP, showed a much more potent enhancing effect after the 9 weeks recovery period than did (HCBP).

Animals↗
PubMed1994

Neonatal encephalopathies as classified by EEG-sleep criteria: severity and timing based on clinical/pathologic correlations.

Neonatal encephalopathies can be characterized in functional terms using electroencephalography. Severity of an encephalopathic state can also be estimated by electrographic interpretation independent of the time of disease process onset. Moderately or markedly abnormal electroencephalographic patterns on serial studies are highly correlated with neurologic sequelae in survivors. Electroencephalography is rarely pathognomonic or specific in determining when a condition initially occurred. However, electroencephalographic abnormalities are associated with different clinical situations, and brain lesions documented on neuroimaging or with postmortem neuropathologic examination are observed in infants with certain abnormal electrographic patterns. When interpreted in the context of history, clinical findings, and other laboratory information, the neurophysiologic studies augment the understanding of both the severity and timing of an encephalopathic state.

Brain↗