Biomedical subjects

A E Delgado

Publications and source records attributed to A E Delgado.

3 recordsLinked to original sources

PubMed2003

Neural modeling in cerebral dynamics.

For many years our current conception of neural modeling at cortical level has been marked by three convictions: (i) the representational, explanatory, and predictive capabilities of a model are always limited by the mathematical nature of the formal tools used in its formulation. The external observer in fact injects the additional knowledge, apparently resident in the model. (ii) The analogical and logical languages (and consequently, the neurophysiological data which serves as their basis) are not sufficient to describe, model and predict the most genuine aspects of the cortical determined behavior. (iii) We need new conceptual and formal tools capable of representing cooperative processes (not only physical interactions) in cerebral dynamics. In this paper, we use the neuropsychological findings on the residual function after traumatic and surgical lesions in animals and men, to think about the sort of requirements that are necessary to build these formal tools adequate to model neural information processing at cortical level. If we search for inspiration in the field of computation, we arrive to the conjecture that the cerebral dynamics is a dynamics of neurophysiological symbols and, consequently, we need a set of descriptions at an intermediate level (neural assemblies "programming"), in a similar way as we use programming languages at an intermediate level (the symbol level) between the physical machine and the knowledge level descriptions, in the sense of Newell and Marr.

Animals↗

PubMed1998

Towards the unification of inference structures in medical diagnostic tasks.

The central purpose of artificial intelligence applied to medicine is to develop models for diagnosis and therapy planning at the knowledge level, in the Newell sense, and software environments to facilitate the reduction of these models to the symbol level. The usual methodology (KADS, Common-KADS, GAMES, HELIOS, Protégé, etc) has been to develop libraries of generic tasks and reusable problem-solving methods with explicit ontologies. The principal problem which clinicians have with these methodological developments concerns the diversity and complexity of new terms whose meaning is not sufficiently clear, precise, unambiguous and consensual for them to be accessible in the daily clinical environment. As a contribution to the solution of this problem, we develop in this article the conjecture that one inference structure is enough to describe the set of analysis tasks associated with medical diagnoses. To this end, we first propose a modification of the systematic diagnostic inference scheme to obtain an analysis generic task and then compare it with the monitoring and the heuristic classification task inference schemes using as comparison criteria the compatibility of domain roles (data structures), the similarity in the inferences, and the commonality in the set of assumptions which underlie the functionally equivalent models. The equivalences proposed are illustrated with several examples. Note that though our ongoing work aims to simplify the methodology and to increase the precision of the terms used, the proposal presented here should be viewed more in the nature of a conjecture.

Algorithms↗

PubMed1986

A computational frame to study social behaviour in animals.

This paper presents new methods and procedures for studying collective behaviour in rats. The animals are assumed to be indistinguishable one from another and the behaviour of the group is represented analysed and interpreted in terms of the temporal evolution of a finite state probabilistic automaton. The automaton states are defined by measures on the clustering degree considered as a social response variable. The electronic system developed to carry out the cluster analysis and the automatic control of the social behaviour in the experimental environment includes a multimicroprocessor interacting with a 'social box' in which, together with classical sensors and effectors, a phototransistor based position sensor is included. Preliminary experiments show the discriminative power of the cluster automaton concerning sexual differences and emotivity, as well as the extensive of a basic mechanism of clustering as a collective response to stress. Pharmacologically, the new experimental medium proposed in this paper may be used to detect a new range of products affecting social but not individual behaviour. Also, well-known products, which in normal doses produce no detectable modification of individual behaviour, might have detectable effects on the collective level. Be this as it may, the experimental environment described constitutes a further experimental facility for the analysis and control of animal behaviour.

Animals↗