Sideslip of the medial rectus muscle during vertical eye rotation

PURPOSE: The kinematics of eye rotation is not entirely elucidated despite two centuries of fascination with the deceptively simple yet geometrically complex nature of the movement. Recently, the traditional view that oculorotatory muscles except the superior oblique muscle exert straight pull on the globe has been challenged by the claim that the muscles also go through a connective tissue pulley-like structure that holds them steady during eye rotation. Although earlier studies failed to observe sideslippage at the posterior part of muscles, a finding supportive of the pulley hypothesis, the conclusions should not be taken as conclusive given short-comings in the techniques used in the studies. METHODS: The authors developed a novel method of image analysis to improve spatial resolution and applied the method for investigating the medial rectus muscle, the entire length of which can easily be identified in magnetic resonance images. RESULTS: Contrary to previous reports, vertical sideslippage was observed at the posterior part of the muscle during vertical eye rotation between two tertiary eye positions. Furthermore, the sideslip varied as a function of horizontal eye position, in accordance with the half-angle rule of Listing's law. CONCLUSIONS: These findings are more consistent with the traditional view of the restrained shortest-path model than with the pulley model and have further implications for basic and clinical understanding of ocular kinematics

Modeling Brain Resonance Phenomena Using a Neural Mass Model

Stimulation with rhythmic light flicker (photic driving) plays an important role in the diagnosis of schizophrenia, mood disorder, migraine, and epilepsy. In particular, the adjustment of spontaneous brain rhythms to the stimulus frequency (entrainment) is used to assess the functional flexibility of the brain. We aim to gain deeper understanding of the mechanisms underlying this technique and to predict the effects of stimulus frequency and intensity. For this purpose, a modified Jansen and Rit neural mass model (NMM) of a cortical circuit is used. This mean field model has been designed to strike a balance between mathematical simplicity and biological plausibility. We reproduced the entrainment phenomenon observed in EEG during a photic driving experiment. More generally, we demonstrate that such a single area model can already yield very complex dynamics, including chaos, for biologically plausible parameter ranges. We chart the entire parameter space by means of characteristic Lyapunov spectra and Kaplan-Yorke dimension as well as time series and power spectra. Rhythmic and chaotic brain states were found virtually next to each other, such that small parameter changes can give rise to switching from one to another. Strikingly, this characteristic pattern of unpredictability generated by the model was matched to the experimental data with reasonable accuracy. These findings confirm that the NMM is a useful model of brain dynamics during photic driving. In this context, it can be used to study the mechanisms of, for example, perception and epileptic seizure generation. In particular, it enabled us to make predictions regarding the stimulus amplitude in further experiments for improving the entrainment effect

La personnalité et les préférences esthétiques chez l'adulte

Jampolsky P. La personnalité et les préférences esthétiques chez l'adulte. In: L'année psychologique. 1954 vol. 54, n°2. pp. 377-395

Les tests en psychiatrie

Jampolsky P. Les tests en psychiatrie. In: L'année psychologique. 1954 vol. 54, n°1. pp. 165-171

La collaboration de la vue et du sens statique dans les perceptions spatiales

Jampolsky P. La collaboration de la vue et du sens statique dans les perceptions spatiales. In: L'année psychologique. 1940 vol. 41-42. pp. 46-64

Les tests de dessin en psychologie clinique

Jampolsky P. Les tests de dessin en psychologie clinique. In: L'année psychologique. 1955 vol. 55, n°1. pp. 119-127

L'échelle d'"anxiété manifeste" de Taylor et son utilisation expérimentale

Jampolsky P. L'échelle d'"anxiété manifeste" de Taylor et son utilisation expérimentale. In: L'année psychologique. 1956 vol. 56, n°1. pp. 91-99

À propos des tests moteurs : quelques remarques et essais méthodologiques

Jampolsky P. À propos des tests moteurs : quelques remarques et essais méthodologiques. In: L'année psychologique. 1954 vol. 54, n°1. pp. 111-114

VI. Psychopathologie, psychologie clinique.

Gratiot-Alphandéry H., Jampolsky P. VI. Psychopathologie, psychologie clinique.. In: L'année psychologique. 1955 vol. 55, n°1. pp. 324-325