When moving through space, both dynamic visual information (i.e. optic flow) and body-based cues (i.e. proprioceptive and vestibular) jointly specify the extent of a travelled distance. Little is currently known about the relative contributions of each of these cues when several are simultaneously available. In this series of experiments participants travelled a predefined distance and subsequently reproduced this distance by adjusting a visual target until the self-to-target distance matched the distance they had moved. Visual information was presented through a head-mounted display and consisted of a long, richly textured, virtual hallway. Body-based cues were provided either by A) natural walking in a fully-tracked free walking space (proprioception and vestibular) B) being passively moved by a robotic wheelchair (vestibular) or C) walking in place on a treadmill (proprioception). Distances were either presented through vision alone, body-based cues alone, or both visual and body-based cues combined. In the combined condition, the visually-specified distances were either congruent (1.0x) or incongruent (0.7x/1.4x) with distances specified by body-based cues. Incongruencies were created by either changing the visual gain or changing the proprioceptive gain (during treadmill walking). Further, in order to obtain a measure of “perceptual congruency” between visual and body-based cues, participants were asked to adjust the rate of optic flow during walking so that it matched the proprioceptive information. This value was then used as the basis for later congruent cue trials. Overall, results demonstrate a higher weighting of body-based cues during natural walking, a higher weighting of proprioceptive information during treadmill walking, and an equal weighting of visual and vestibular cues during passive movement. These results were not affected by whether visual or proprioceptive gain was manipulated. Adopting the obtained measure of perceptual congruency for each participant also did not change the conclusions such that proprioceptive cues continued to be weighted higher
Although self-motion perception is believed to rely heavily on visual cues, the inertial system also provides valuable information about movement through space. How the brain integrates inertial signals to update position can be better understood through a detailed characterization of self-motion perception during passive transport. In this study, we employed an intuitive method for measuring the perception of self-motion in real-world coordinates. Participants were passively translated by a robotic wheelchair in the absence of visual and auditory cues. The traveled trajectories consisted of twelve straight paths, five to six meters in length, each with a unique velocity profile. As participants moved, they pointed continuously toward a stationary target viewed at the beginning of each trial. By using an optical tracking system to measure the position of a hand-held pointing device, we were able to calculate participants' perceived locations with a high degree of spatial and temporal precision. Differentiating perceived location yielded absolute instantaneous perceived velocity (in units of meters per second), a variable that, to the best of our knowledge, has not previously been measured. Results indicate that pointing behavior is updated as a function of changes in wheelchair velocity, and that this behavior reflects differences in starting position relative to the target. During periods of constant, nonzero velocity, the perceived velocity of all participants decreases systematically over the course of the trajectory. This suggests that the inertial signal is integrated in a leaky fashion, even during the relatively short paths used in this experiment. This methodology allows us to characterize such nonveridical aspects of self-motion perception with more precision than has been achieved in the past. The continuous-pointing paradigm used here can also be effectively adapted for use in other research domains, including spatial updating, vection, and visual-vestibular integration
Background and Aims Although the interscalene block of the brachial plexus is the gold standard for clavicle osteosynthesis surgery 1 , it´s not free from complications 2 . The objective was to evaluate the anaesthetic and analgesic efficacy of the clavipectoral fascia plane block (CPB) 3 in mid-clavicular fracture surgery.Methods Descriptive observational study in 50 patients treated for osteosynthesis of mid-clavicular fracture (12 months period). The main objective was to assess pain (VAS) in the immediate postoperative period (POI), and at 6-12 and 24 hours. As secondary objectives: degree of intraoperative sedation (IOP) (Ramsay Score), perioperative fentanyl consumption, rescue analgesia, unplanned general anaesthesia, the presence of motor or sensory block, and diaphragmatic paralysis evaluated by ultrasound.After intravenous premedication with midazolam 3mg, fentanyl 0.5-1mcg/kg, ketorolac 30mg, dexamethasone 8mg, and cephalothin1g, CPB was performed according to the technique described related with the supraclavicular nerve block 4,5 . IOP sedation was with dexmedetomidine IV 0.2-0.5 mg/kg/h. As postoperative analgesia ketorolac 30 mg/12 h IV, and as rescue analgesia (VAS ! 4/10) tramadol 50 mg IV bolus. Results El dolor postoperatorio POI a las 6-12 ya las 24 h fue de 1,04(DE=1,26);1,24(DE=1,42);1,34(DE=1,92);0, 96 (DE= 1,29) respectivamente (figure 1). La dosis total perioperatoria media de fentanilo fue de 0,88 mcg/kg.Durante el postoperatorio, 9 pacientes (18%) solicitaron analgesia de rescate.No hubo conversiones a anestesia En general, no se eliminará bloqueo motor ni sensible de la extremidad superior ni parálisis diafragmática (table 1).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.