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Visual Control (visual + control)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

Differences in endoscopic views during biopsy through the right and left lower biopsy channels of the upper gastrointestinal endoscope

DIGESTIVE ENDOSCOPY, Issue 3 2004
Naoki Mantani
Background:, It has not been established as to which side the biopsy (instrument) channel should be placed in the tip of a front-viewing upper gastrointestinal (GI) endoscope to allow an en-face approach to lesions on various aspects of the stomach wall. Methods:, Using a front-viewing two-channel endoscope, we identi,ed a difference in endoscopic views during biopsy between lower-right and lower-left channels. Colored marks were distributed on the lesser curvature (LC), greater curvature (GC), anterior wall (AW), and posterior wall (PW) in the ,stomach' of a dummy for mock-performance of upper GI endoscopy. When biopsy forceps through the different channels touched the marks, an endoscopic photograph was taken. Furthermore, when biopsy specimens were obtained from PW lesions in several patients, endoscopic views were compared between the two biopsy channels. Results:, In the dummy study, no remarkable difference was detected in targeting the marks on AW, LC, or GC of the stomach. The dummy and the patient study showed that the lower-right approach could target PW lesions with a more adequate endoscopic view than from the lower left. The lower-left approach targeted PW lesions on the higher body with a nearly blinded endoscopic view. Specimens from PW of the upper body, which could be precisely obtained under direct visual control through the lower-right channel, were no smaller than those obtained using the channel on the lower left. Conclusion:, The present study suggests that the lower-right channel may be preferable to the lower-left channel in the tip of a front-viewing upper GI endoscope. [source]

The role of V5 (hMT+) in visually guided hand movements: an fMRI study

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2004
C. Oreja-Guevara
Abstract Electrophysiological studies in animals suggest that visuomotor control of forelimb and eye movements involves reciprocal connections between several areas (striate, extrastriate, parietal, motor and premotor) related to movement performance and visuospatial coding of movement direction. The extrastriate area MT [V5 (hMT+) in humans] located in the ,dorsal pathway' of the primate brain is specialized in the processing of visual motion information. The aim of our study was to investigate the functional role of V5 (hMT+) in the control of visually guided hand movements and to identify the corresponding cortex activation implicated in the visuomotor tasks using functional magnetic resonance imaging. Eight human subjects performed visually guided hand movements, either continuously tracking a horizontally moving target or performing ballistic tracking movements of a cursor to an eccentric stationary target while fixating a central fixation cross. The tracking movements were back-projected onto the screen using a cursor which was moved by an MRI-compatible joystick. Both conditions activated area V5 (hMT+), right more than left, particularly during continuous tracking. In addition, a large-scale sensorimotor circuit which included sensorimotor cortex, premotor cortex, striatum, thalamus and cerebellum as well as a number of cortical areas along the intraparietal sulcus in both hemispheres were activated. Because activity was increased in V5 (hMT+) during continuous tracking but not during ballistic tracking as compared to motion perception, it has a pivotal role during the visual control of forelimb movements as well. [source]

RTSVC: Real-time system for visual control of robots

INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 4 2008
Eusebio Bugarin
Abstract This article presents an image processing system that can work in hard real-time. Compared with systems that use the traditional multiprocessor architecture approach, this computer system takes advantage on recent technological advances and it is designed to work with a single processor PC under RTLinux. Its programming environment is similar to C programming language and it offers a friendly graphical user interface. The performance of the system is illustrated by means of experiments applied to visual guidance of mobile robots via velocity fields using a fixed high-speed camera. The experiments were carried out with a strict sampling frequency of 100 Hz. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 251,256, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). [source]

The GlideScope Ranger® video laryngoscope can be useful in airway management of entrapped patients

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 10 2009
A. R. NAKSTAD
Background: Airway management of entrapped patients is challenging and alternatives to endotracheal intubation with a Macintosh laryngoscope must be considered. In this study, the GlideScope Ranger® video laryngoscope has been evaluated as an alternative to standard laryngoscopy. Methods: Eight anaesthesiologists from a Helicopter Emergency Medical Service intubated the trachea of a Laerdal SimMan® manikin using the studied laryngoscopes in two scenarios: (A) unrestricted access to the manikin in an ambulance and (B) no access from the head end, simulating an entrapped patient. The time used to secure the airway and the scored level of difficulty were the main variables. Results: In scenario A, all anaesthesiologists managed to secure the airway using both techniques within the 60-s time limit. In scenario B, all secured the airway when using the video laryngoscope, while 50% succeeded with endotracheal intubation using the Macintosh laryngoscope. The difference in the success rate was statististically significant (P=0.025). There were no significant differences in the time spent on endotracheal intubation in the two scenarios or between the devices. All stated that the availability of a video laryngsoscope would make drug-facilitated intubation a realistic alternative when access to patients is limited. The lack of visual control when using the Macintosh laryngoscope excludes this technique in real-life settings. Conclusion: This study suggests that the Glidescope Ranger® may be merited in situations requiring endotracheal intubation by an experienced intubator in patient entrapment. Further studies are required to clarify whether performance in patients mimics that in a manikin. [source]

The graphemic/motor frontal area Exner's area revisited,

ANNALS OF NEUROLOGY, Issue 4 2009
Franck-Emmanuel Roux MD
Objective In 1881, Exner first described a "graphic motor image center" in the middle frontal gyrus. Current psycholinguistic models of handwriting involve the conversion of abstract, orthographic representations into motor representations before a sequence of appropriate hand movements is produced. Direct cortical stimulation and functional magnetic resonance imaging (fMRI) were used to study the human frontal areas involved in writing. Methods Cortical electrical stimulation mapping was used intraoperatively in 12 patients during the removal of brain tumors to identify the areas involved in oral language (sentence reading and naming) and writing, and to spare them during surgery. The fMRI activation experiment involved 12 right-handed and 12 left-handed healthy volunteers using word dictation (without visual control) and 2 control tasks. Results Direct cortical electrical stimulation of restricted areas rostral to the primary motor hand area (Brodmann area [BA] 6) impaired handwriting in 6 patients, without disturbing hand movements or oral language tasks. In 6 other patients, stimulation of lower frontal regions showed deficits combining handwriting with other language tasks. fMRI also revealed selective activation during word handwriting in left versus right BA6 depending on handedness. This area was anatomically matched to those areas that affected handwriting on electrical stimulation. Interpretation An area in middle frontal gyrus (BA6) that we have termed the graphemic/motor frontal area supports bridging between orthography and motor programs specific to handwriting. Ann Neurol 2009;66:537,545 [source]