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L’isolement est une mesure indispensable à la prise en charge de certaines situations psychiatriques aiguës, mais soulève de nombreuses questions cliniques et éthiques invitant à en limiter la fréquence d’utilisation et la durée. Connaître les facteurs associés à la durée des isolements pourrait permettre l’élaboration de mesures de réduction. Cette étude explore les facteurs prédictifs d’une longue durée d’isolement.

Spinalized frogs were microstimulated in the intermediate grey layers of the lumbar spinal cord; the forces evoked in the hindlimb were measured at several limb positions. The data were expressed as force fields. After the collection of many force fields, the dorsal roots were cut with the stimulating electrode in place, and the position-dependent stimulation-evoked forces were again measured repeatedly. We found that the position-dependent pattern of evoked forces - the force fields - did not change after the dorsal roots were cut. In other words, the postcut evoked forces pointed in the same direction as the precut evoked forces. This result was predicted and confirmed by the muscle activations (EMGs): Before and after the dorsal roots were cut, the same muscles were activated in the same proportions. In all limb positions, the rank ordering of the muscle activations remained fixed. The stimulation needed to evoke forces was increased by deafferentation, and there were subtle changes in the force magnitudes that were consistent with a linearization of the muscle stiffness by the afferents. We conclude that the microstimulation activated specific muscle synergies that resulted in limb forces pointing toward a particular posture. The patterns of evoked forces were predominantly attributable to feedforward activation of these muscle synergies.

1. Desiccated liver powder as a dietary supplement to a low sodium diet is effective in counteracting the growth inhibition induced by cortisone acetate in rats only if the steroid is presented orally. It is without demonstrable effect in animals receiving the hormone by injection. It is also without effect in adrenalectomized animals, irrespective of the route of hormone administration. 2. The prevention of growth inhibition by liver powder is not accompanied by other evidences of diminished cortisone activity, i.e., despite normal growth such animals exhibit physiological, anatomical and biochemical changes of the same degree as do cortisone treated rats without liver supplement.

In response to cytotoxic serum nephritis, bilaterally adrenalectomized rats develop hypertension as frequently as do animals with intact adrenals. In order for hypertension to appear among such adrenalectomized rats, it is necessary that a satisfactory state of nutrition be maintained over a period of weeks. In our laboratory, the difficulties encountered in fulfilling this provision have been considerable in spite of the employment of a high NaCl regimen. This experience has led us to wonder whether the conflicting results in the literature relating to the question of hypertension in adrenalectomized animals may not be due, in part, to similar difficulties.