Search results for "movement"
showing 10 items of 2021 documents
Sensorimotor aspects of high-speed artificial gravity: I. Sensory conflict in vestibular adaptation
2003
Short-radius centrifugation offers a promising and affordable countermeasure to the adverse effects of prolonged weightlessness. However, head movements made in a fast rotating environment elicit Coriolis effects, which seriously compromise sensory and motor processes. We found that participants can adapt to these Coriolis effects when exposed intermittently to high rotation rates and, at the same time, can maintain their perceptual-motor coordination in stationary environments. In this paper, we explore the role of inter-sensory conflict in this adaptation process. Different measures (vertical nystagmus, illusory body tilt, motion sickness) react differently to visual-vestibular conflict a…
General remarks on the role of the vestibular system in weightlessness
1987
Different methods are described to experimentally achieve weightlessness. Since the function of the otolith system depends on the presence of contact forces opposing gravity, it is disabled in weightlessness and may send misleading positional information to the brain. Without the contributions of the otolith system it is difficult in space to distinguish self-motion from object motion. Furthermore, the disintegration of information from the neck position receptors from those of the otolith system can lead to additional illusory positional sensations. Since the function of the semicircular canal system in previous space flights was found to be essentially undisturbed, the vestibular experime…
Threshold-based vestibular adaptation to cross-coupled canal stimulation
2008
Prior experiments have demonstrated that people are able to adapt to cross-coupled accelerations associated with head movements while spinning at high rotation rates (e.g., 23 rpm or 138°/s). However, while adapting, subjects commonly experience serious side effects, such as motion sickness, non-compensatory eye movements, and strong and potentially disorienting illusory body tilt or tumbling sensations. In the present study, we investigated the feasibility of adaptation using a threshold-based method, which ensured that the illusory tilt sensations remained imperceptible or just barely noticeable. This was achieved by incrementally increasing the angular velocity of the horizontal centrifu…
Membrane Insertion and Biogenesis of the Turnip Crinkle Virus p9 Movement Protein
2010
ABSTRACT Plant viral infection and spread depends on the successful introduction of a virus into a cell of a compatible host, followed by replication and cell-to-cell transport. The movement proteins (MPs) p8 and p9 of Turnip crinkle virus are required for cell-to-cell movement of the virus. We have examined the membrane association of p9 and found that it is an integral membrane protein with a defined topology in the endoplasmic reticulum (ER) membrane. Furthermore, we have used a site-specific photo-cross-linking strategy to study the membrane integration of the protein at the initial stages of its biosynthetic process. This process is cotranslational and proceeds through the signal recog…
Sec61alpha and TRAM are Sequentially Adjacent to a Nascent Viral Membrane Protein during its ER Integration
2007
Co-translational integration of a nascent viral membrane protein into the endoplasmic reticulum membrane takes place via the translocon. We have been studying the early stages of the integration of a double-spanning plant viral movement protein to gain insights into how viral membrane proteins are transferred from the hydrophilic interior of the translocon into the hydrophobic environment of the bilayer, where the transmembrane (TM) segments of the viral proteins can diffuse freely. Photocrosslinking experiments reveal that this integration involves the sequential passage of the TM segments past Sec61alpha and translocating chain-associating membrane protein (TRAM). Each TM segment is first…
''Forward to the past''
2012
Carlini, Alessandro | Actis-Grosso, Rossana | Stucchi, Natale | Pozzo, Thierry; International audience; ''Our daily experience shows that the CNS is a highly efficient machine to predict the effect of actions into the future; are we so efficient also in reconstructing the past of an action? Previous studies demonstrated we are more effective in extrapolating the final position of a stimulus moving according to biological kinematic laws. Here we address the complementary question: are we more effective in extrapolating the starting position (SP) of a motion following a biological velocity profile? We presented a dot moving upward and corresponding to vertical arm movements that were masked i…
Looking in Depth: Visual Distance Perception of Stimuli on Volumetric Multi-Planar Display
2018
Ability to distinguish relative location of visual stimuli on a multi-planar display was evaluated within psychophysical experiment in order to figure out the impact of physical distance between stimuli across depth of volumetric data.
Does the brain know who is at the origin of what in an imitative interaction?
2012
International audience; Brain correlates of the sense of agency have recently received increased attention. However, the explorations remain largely restricted to the study of brains in isolation. The prototypical paradigm used so far consists of manipulating visual perception of own action while asking the subject to draw a distinction between self- versus externally caused action. However, the recent definition of agency as a multifactorial phenomenon combining bottom-up and top-down processes suggests the exploration of more complex situations. Notably there is a need of accounting for the dynamics of agency in a two-body context where we often experience the double faceted question of w…
Movement Perception in the Colliculus Superior
1977
Summary Neurophysiological measurements on cats' colliculus superior show results which are dependent on the movement of visual stimuli and movement of the background as well as on the movement of stimulus and background n!lative to each other. The movement dependent problems involved in pattern recognition by space time filters as regards resolution of details, distortion and eye movement are outlined in principle.
Image Content Enhancement Through Salient Regions Segmentation for People With Color Vision Deficiencies
2019
Color vision deficiencies affect visual perception of colors and, more generally, color images. Several sciences such as genetics, biology, medicine, and computer vision are involved in studying and analyzing vision deficiencies. As we know from visual saliency findings, human visual system tends to fix some specific points and regions of the image in the first seconds of observation summing up the most important and meaningful parts of the scene. In this article, we provide some studies about human visual system behavior differences between normal and color vision-deficient visual systems. We eye-tracked the human fixations in first 3 seconds of observation of color images to build real f…