Biomedical subjects

D Servan-Schreiber

Publications and source records attributed to D Servan-Schreiber.

7 recordsLinked to original sources

PubMed1992

Context, cortex, and dopamine: a connectionist approach to behavior and biology in schizophrenia.

Connectionist models are used to explore the relationship between cognitive deficits and biological abnormalities in schizophrenia. Schizophrenic deficits in tasks that tap attention and language processing are reviewed, as are biological disturbances involving prefrontal cortex and the mesocortical dopamine system. Three computer models are then presented that simulate normal and schizophrenic performance in the Stroop task, the continuous performance test, and a lexical disambiguation task. They demonstrate that a disturbance in the internal representation of contextual information can provide a common explanation for schizophrenic deficits in several attention- and language-related tasks. The models also show that these behavioral deficits may arise from a disturbance in a model parameter (gain) corresponding to the neuromodulatory effects of dopamine, in a model component corresponding to the function of prefrontal cortex.

Computer Simulation↗

PubMed1992

A parallel distributed processing approach to automaticity.

We consider how a particular set of information processing principles, developed within the parallel distributed processing (PDP) framework, can address issues concerning automaticity. These principles include graded, activation-based processing that is subject to attentional modulation; incremental, connection-based learning; and interactivity and competition in processing. We show how simulation models, based on these principles, can account for the major phenomena associated with automaticity, as well as many of those that have been troublesome for more traditional theories. In particular, we show how the PDP framework provides an alternative to the usual dichotomy between automatic and controlled processing and can explain the relative nature of automaticity as well as the fact that seemingly automatic processes can be influenced by attention. We also discuss how this framework can provide insight into the role that bidirectional influences play in processing: that is, how attention can influence processing at the same time that processing influences attention. Simulation models of the Stroop color-word task and the Eriksen response-competition task are described that help illustrate the application of the principles to performance in specific behavioral tasks.

Association Learning↗

PubMed1990

A network model of catecholamine effects: gain, signal-to-noise ratio, and behavior.

At the level of individual neurons, catecholamine release increases the responsivity of cells to excitatory and inhibitory inputs. A model of catecholamine effects in a network of neural-like elements is presented, which shows that (i) changes in the responsivity of individual elements do not affect their ability to detect a signal and ignore noise but (ii) the same changes in cell responsivity in a network of such elements do improve the signal detection performance of the network as a whole. The second result is used in a computer simulation based on principles of parallel distributed processing to account for the effect of central nervous system stimulants on the signal detection performance of human subjects.

Behavior↗

PubMed1989

Interaction with a 'sex-expert' system enhances attitudes towards computerized sex therapy.

The present experiment investigated whether a new rule-based expert system, Sexpert, designed to assess and treat sexual dysfunction would be positively evaluated by näive users. In a between groups design, four groups of eight students were randomly assigned to one of two experimental groups or one of two control groups. Ss in the experimental groups interacted with one of two versions of Sexpert. Ss in one control group filled out a questionnaire concerning their sexual functioning while Ss in the other interacted with a non-sex related computer program. Perceived dissimilarity to other established treatments for sexual dysfunction and semantic differential attitudes measures taken both before and after the experimental manipulations showed a significant positive shift in favor of computerized sex therapy for those Ss who interacted with either version of Sexpert but not for Ss in either of the control conditions.

Adult↗

PubMed1988

Intelligent computer-based assessment and psychotherapy. An expert system for sexual dysfunction.

New and converging developments in the areas of artificial intelligence, intelligent tutoring systems, and cognitive therapy have made possible a new approach to computer-assisted assessment and psychotherapy. This new approach combines the capacity for intelligent therapeutic dialogue with the presentation of individualized therapeutic interventions. Previous attempts at computerized psychotherapy are reviewed to highlight a newly developed rule-based expert system, Sexpert, which assesses and treats sexual dysfunction. Preliminary observations concerning couples' reaction to and acceptance of Sexpert are presented.

Artificial Intelligence↗

PubMed1986

Artificial intelligence and psychiatry.

This paper provides a brief historical introduction to the new field of artificial intelligence and describes some applications to psychiatry. It focuses on two successful programs: a model of paranoid processes and an expert system for the pharmacological management of depressive disorders. Finally, it reviews evidence in favor of computerized psychotherapy and offers speculations on the future development of research in this area.

Artificial Intelligence↗

PubMed1984

Knowledge engineering: a daily activity on a hospital ward.

Two common barriers against the development and diffusion of expert systems in medicine are the difficulty of design and the low level of acceptance. An original experience which entails potential solutions of these issues is reported on: the task of knowledge engineering is performed by residents and medical students on a psychiatry ward. They developed a computer program for the psychopharmacological treatment of depression, using a sophisticated knowledge acquisition system, EMYCIN. The knowledge engineering sessions are analysed in detail and a structured method is proposed. A transcript of a sample run of the resulting program is presented along with an evaluation of its performance, acceptance, educational potential, and amount of endeavour required. The impact of the knowledge engineering process itself is then assessed both from the residents and the medical students standpoint. Finally, the possibility of generalizing the experiment is examined.

Antidepressive Agents↗