The hippocampo-cortical loop: spatio-temporal learning and goal-oriented planning in navigation.

We present a neural network model where the spatial and temporal components of a task are merged and learned in the hippocampus as chains of associations between sensory events. The prefrontal cortex integrates this information to build a cognitive map representing the environment. The cognitive map can be used after latent learning to select optimal actions to fulfill the goals of the animal. A simulation of the architecture is made and applied to learning and solving tasks that involve both spatial and temporal knowledge. We show how this model can be used to solve the continuous place navigation task, where a rat has to navigate to an unmarked goal and wait for 2 seconds without moving to receive a reward. The results emphasize the role of the hippocampus for both spatial and timing prediction, and the prefrontal cortex in the learning of goals related to the task.

[Automated analysis of electrocardiograms at rest: present status (author's transl)]. / L'analyse automatique de l'électrocardiogramme au repos. Bilan actuel.

Computer interpretation of electrocardiograms was developed twenty years ago and is now routinely performed in the United States, where 9 different programs are being used. Depending on diagnosis and program, computer interpretation shows an 80-100% correlation with human interpretation. The systems provide an aid to diagnosis in preventive medicine and in hospitals without cardiologists, but since interpretations are standardized they are also useful in cardiology units, where they can be used to build up data banks, compare repeat ECGs with clinical findings and thus ultamately perfect electrocardiographic criteria. The use of this technique in Europe remains limited. In France, only two centers possess routine equipment. This feable diffusion is partly due to the cost of computer analysis, which can only compete with that of human interpretation if each system performs a sufficient number of ECGs.

Hypertension management: the computer as a participant.

A computerized system called ARTEMIS has been taking part in the management of a referral hypertension clinic since September 1975. From January 1, 1976 to January 1, 1979, 3,624 patients' records were set up and updated, all of them accessible on line. The mean rate of response to 17 questions with obligatory answers concerning patients' past history was 97.6 per cent. The 10 routine laboratory tests included in the initial in-hospital work-up were registered in over 92 per 100 of the 2,651 hospital records examined. Negative responses were registered with the same accuracy as positive ones, when the computerized questionnaires were appropriately drafted. Standardized collection of information insured homogeneity of the medical staff and has already made possible epidemiologic studies. ARTEMIS has detected strategical errors such as the lack of yearly programmed tests for cardiovascular risk-factors associated with hypertension. The computer has helped to achieve a high rate of patient compliance at one year (81.3 per cent), by providing patients up-dated editions of their personal summary reports as well as sending periodical letters of recall to them and to their physicians. At a total annual cost of 11 dollars per patient, the computer provides continuous information on process and outcome, for each patient and physician, and for the entire population followed up at the clinic. It facilitates physician adherence to predefined protocols and reinforces follow-up continuity by creating a communications network between the referral clinic, the patient and the general practitioner.

[A computerized medical record for the follow-up of hypertensive patients (author's transl)]. / Utilisation d'un dossier informatique pour la surveillance des malades hypertendus.

The authors present a computer system for hypertension control in a specialized department in Paris. The hypertension clinic performs the initial evaluation of the disease in ambulatory care or during a short hospitalization period. The general practitioner (GP) is mainly in charge of the long term follow-up. The objective of the system is to improve the communication between the patient, the clinic and the GP. Data are collected during each visit at the clinic. The computer is used to produce evolutive summary reports for each patient and to control the appointment system. Thus, the data processing system improves the quality of the individual follow-up and, at the same time, a medical data bank is available for epidemiological and pharmacovigilance studies.

CHRONOS: a data base management package for physicians and researchers.

This paper describes a general data base management package defined for medical applications. CHRONOS is a user-oriented system which has been designed for physicians to get periodical reports and for researchers to prepare statistical treatments. The basic principles of the data base and program organization are described: many possibilities are offered for data acquisition and specific efforts have been made in order to analyze easily the evolution of patients. Several medical applications are now operational with CHRONOS in fields as different as psychiatry and nephrology.