Is it better to sit down, stand up or walk when performing memory and arithmetic activities?

It is now accepted that performing a cognitive task impacts postural control (Polskaia and Lajoie 2016; Vuillerme et al. Neurosci Lett 291: 77-80, 2000). However, the reverse impact of posture on cognitive performance is less documented. The present study investigated performance in two cognitive activities (memory and arithmetic) performed in three different postural conditions (sitting, standing, and walking). Overall, our data suggest that the posture adopted during a task can improve cognitive performance with a better answer for arithmetic in the sitting position than during walking but more correctly recalled words while walking. This study, thus, suggests that there could be preferential association between cognition and posture, i.e., memory cognitive performance can be improved when walking and mental arithmetic while sitting.

Physiological mechanisms for stabilizing the limb when acting against physical constraints.

Smooth physical interaction with our environment, such as when working with tools, requires adaptability to unpredictable perturbations that can be achieved through impedance control of multi-joint limbs. Modulation of arm stiffness can be achieved either increasing co-contraction of antagonistic muscles or by increasing the gain of spinal reflex loops. According to the "automatic gain scaling" principle, the spinal reflex gain, as measured via the H-reflex, scales with muscle activation. A previous experiment from our labs suggested, however, that reflex gains might instead be scaled to the force exerted by the limb, perhaps as a means to counteract destabilizing external forces. The goal of our experiment was to test whether force output, rather than the muscular activity per se, could be the critical factor determining reflex gain. Five subjects generated different levels of force at the wrist with or without assistance to dissociate applied force from agonist muscular activity. We recorded contact force, EMG and H-reflex response from a wrist flexor. We did not find a strict relationship between reflex gain and contact force but nor did we observe consistent modulation of reflex gain simply as a function of agonist muscle activity. These results are discussed in relation to the stability of the task constraints.

[Quantification of ocular dominance for better management of eye disease]. / Vers une quantification de la dominance oculaire pour une meilleure prise en charge des pathologies de l'œil.

INTRODUCTION: The dominant eye is defined as the one we unconsciously choose when we have to perform monocular tasks. In the field of clinical neuro-ophthalmology, it is well-established that ocular dominance plays a key role in several eye diseases. Furthermore, the accurate quantification of ocular dominance is crucial with regard to certain surgical techniques. However, classical preoperative tests cannot determine the amount of ocular dominance. MATERIALS AND METHODS: In order to obtain further insight into the phenomenon of ocular dominance, we study its influence at behavioral and neurophysiological levels (experiments 1 and 2). Based on these new data, we suggest a method to improve quantification of ocular dominance (experiment 3). RESULTS: We demonstrate that ocular dominance has an influence on hand movements and on interhemispheric transfer time. Moreover, we show that an analysis of the dynamics of saccades allows us to sort out participants with strong or weak ocular dominance. CONCLUSION: In conclusion, this better understanding of the phenomenon of ocular dominance, coupled with the analysis of saccadic dynamics, might, in the short or medium term, lead to the establishment of a quick and straightforward battery of tests allowing determination of the amount of ocular dominance for each patient.

Gastric retention and gastric ileus in diabetes mellitus.

Report of 2 cases of paralytic ileus of the stomach (gastric atony) and of 14 cases of gastric retention, diagnosed from the radiographs obtained from a group of 1500 diabetic patients within seven years. These disorders occur in diabetes mellitus present for many years and associated with peripheral neuropathy. The above findings often present diagnostic and therapeutic problems. Conservative drug therapy is usually sufficient management.

Oral cholecystography: is the fatty meal always necessary?

In our study we have collected 1000 consecutive cases of oral cholecystographic opacification of the gall-bladder and common bile duct; occasionally a complimentary intra-venous cholangiography had also been carried out. In 360 cases there was disease of the gall-bladder or a faint opacification of the common bile duct was abnormal in only three cases, which is a rate of 0,47%. Therefore the fatty meal after oral cholecystography should not be done in each case but only if there is a presumptive diagnosis of pancreatic disease, if there is pancreatic calcification, or if surgery has been previously performed on the biliary tract or duodenum.

[Oral cholecystography: is the fatty meal compulsory (author's transl)]. / Cholécystographies orales: le repas de Boyden est-il indispensable?

An investigation on 1000 cases of oral cholecystography allowed us to collect 640 non pathologic opacifications of the gallblader and among them only 3 cases of pathological common bile ducts (0,47 percent). Consequently when the gallbladder appears normal on the oral cholecystography, the fatty meal seems to be non compulsory but only when clinical findings are in favor of a pancreatic disease or if there are pancreatic calcifications or if surgery has been performed anteriorly on the bile ducts, the liver or the pancreas.