scholarly journals tDCS Modulation of Visually Induced Analgesia

2012 ◽  
Vol 24 (12) ◽  
pp. 2419-2427 ◽  
Author(s):  
Flavia Mancini ◽  
Nadia Bolognini ◽  
Patrick Haggard ◽  
Giuseppe Vallar
Keyword(s):  
Visual Cortex ◽  
Pain Perception ◽  
Occipital Cortex ◽  
Body Representation ◽  
The Body ◽  
Left Hand ◽  
Analgesic Effects ◽  
Extrastriate Visual Cortex ◽  
Multisensory Interactions ◽  
The Right

Multisensory interactions can produce analgesic effects. In particular, viewing one's own body reduces pain levels, perhaps because of changes in connectivity between visual areas specialized for body representation, and sensory areas underlying pain perception. We tested the causal role of the extrastriate visual cortex in triggering visually induced analgesia by modulating the excitability of this region with transcranial direct current stimulation (tDCS). Anodal, cathodal, or sham tDCS (2 mA, 10 min) was administered to 24 healthy participants over the right occipital or over the centro-parietal areas thought to be involved in the sensory processing of pain. Participants were required to rate the intensity of painful electrical stimuli while viewing either their left hand or an object occluding the left hand, both before and immediately after tDCS. We found that the analgesic effect of viewing the body was enhanced selectively by anodal stimulation of the occipital cortex. The effect was specific for the polarity and the site of stimulation. The present results indicate that visually induced analgesia may depend on neural signals from the extrastriate visual cortex.

Phosphene perceptions and safety of chronic visual cortex stimulation in a blind subject

2020 ◽  
Vol 132 (6) ◽  
pp. 2000-2007 ◽  
Author(s):  
Soroush Niketeghad ◽  
Abirami Muralidharan ◽  
Uday Patel ◽  
Jessy D. Dorn ◽  
Laura Bonelli ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Adverse Events ◽  
Clinical Intervention ◽  
Occipital Cortex ◽  
Neuronal Population ◽  
Serious Adverse Events ◽  
Stimulation Parameters ◽  
The Right ◽  
Visual Cortical ◽  
Stimulation Of

Stimulation of primary visual cortices has the potential to restore some degree of vision to blind individuals. Developing safe and reliable visual cortical prostheses requires assessment of the long-term stability, feasibility, and safety of generating stimulation-evoked perceptions.A NeuroPace responsive neurostimulation system was implanted in a blind individual with an 8-year history of bare light perception, and stimulation-evoked phosphenes were evaluated over 19 months (41 test sessions). Electrical stimulation was delivered via two four-contact subdural electrode strips implanted over the right medial occipital cortex. Current and charge thresholds for eliciting visual perception (phosphenes) were measured, as were the shape, size, location, and intensity of the phosphenes. Adverse events were also assessed.Stimulation of all contacts resulted in phosphene perception. Phosphenes appeared completely or partially in the left hemifield. Stimulation of the electrodes below the calcarine sulcus elicited phosphenes in the superior hemifield and vice versa. Changing the stimulation parameters of frequency, pulse width, and burst duration affected current thresholds for eliciting phosphenes, and increasing the amplitude or frequency of stimulation resulted in brighter perceptions. While stimulation thresholds decreased between an average of 5% and 12% after 19 months, spatial mapping of phosphenes remained consistent over time. Although no serious adverse events were observed, the subject experienced mild headaches and dizziness in three instances, symptoms that did not persist for more than a few hours and for which no clinical intervention was required.Using an off-the-shelf neurostimulator, the authors were able to reliably generate phosphenes in different areas of the visual field over 19 months with no serious adverse events, providing preliminary proof of feasibility and safety to proceed with visual epicortical prosthetic clinical trials. Moreover, they systematically explored the relationship between stimulation parameters and phosphene thresholds and discovered the direct relation of perception thresholds based on primary visual cortex (V1) neuronal population excitation thresholds.

Interhemispheric EEG asymmetries during unilateral bright-light exposure and subsequent sleep in humans

2008 ◽  
Vol 294 (3) ◽  
pp. R1053-R1060 ◽  
Author(s):  
Christian Cajochen ◽  
Rosalba Di Biase ◽  
Makoto Imai
Keyword(s):  
Visual Cortex ◽  
Time Course ◽  
Visual Stimulation ◽  
Light Exposure ◽  
Bright Light ◽  
Occipital Cortex ◽  
Alpha Activity ◽  
Hemispheric Dominance ◽  
Eeg Activity ◽  
The Right

We tested whether evening exposure to unilateral photic stimulation has repercussions on interhemispheric EEG asymmetries during wakefulness and later sleep. Because light exerts an alerting response in humans, which correlates with a decrease in waking EEG theta/alpha-activity and a reduction in sleep EEG delta activity, we hypothesized that EEG activity in these frequency bands show interhemispheric asymmetries after unilateral bright light (1,500 lux) exposure. A 2-h hemi-field light exposure acutely suppressed occipital EEG alpha activity in the ipsilateral hemisphere activated by light. Subjects felt more alert during bright light than dim light, an effect that was significantly more pronounced during activation of the right than the left visual cortex. During subsequent sleep, occipital EEG activity in the delta and theta range was significantly reduced after activation of the right visual cortex but not after stimulation of the left visual cortex. Furthermore, hemivisual field light exposure was able to shift the left predominance in occipital spindle EEG activity toward the stimulated hemisphere. Time course analysis revealed that this spindle shift remained significant during the first two sleep cycles. Our results reflect rather a hemispheric asymmetry in the alerting action of light than a use-dependent recovery function of sleep in response to the visual stimulation during prior waking. However, the observed shift in the spindle hemispheric dominance in the occipital cortex may still represent subtle local use-dependent recovery functions during sleep in a frequency range different from the delta range.

scholarly journals XIV.—Ancient Gold Ornaments: described by John Yonge Akerman, Esq. Secretary

Archaeologia ◽  
1853 ◽  
Vol 35 (1) ◽  
pp. 190-193
Author(s):  
John Yonge Akerman
Keyword(s):  
Light Chain ◽  
The Body ◽  
The Other ◽  
Asia Minor ◽  
Plate Viii ◽  
Left Hand ◽  
Small Loop ◽  
The Individual ◽  
The Right ◽  
Of Greece

With the exception of Figs. 1, 2, 3, the Gold Ornaments engraved in Plate VIII. have no reference whatever to each other. The first three were obtained by Viscount Strangford, Director of the Society, from a Greek priest at Milo, in the year 1820. Figs. 1 and 3 appear to have formed the ends of a light chain, and the other (fig. 2) to have been pendent by a small loop on the top of the head. The figure has unfortunately lost the feet and the left hand, but the other parts are perfect. The right hand is raised in an admonitory attitude. The forehead appears as if encircled with a wreath, while the body is crossed by what would seem to be intended for the tendril of a vine. The necklace was formerly in the collection of the late Mr. H. P. Borrell, of Smyrna, but I am informed by his brother, Mr. Maximilian Borrell, who now possesses it, that no record exists of its discovery, and that he cannot learn the name of the individual from whom it was purchased. It was well known that Mr. H. P. Borrell was in the habit of purchasing ancient coins, which were sent to him from all parts of Greece and Asia-Minor, and that many rare and unique specimens fell into his hands, of which he contributed descriptions in various volumes of the Numismatic Chronicle. The necklace may, therefore, have been included in one of these numerous consignments, and we can scarcely indulge the hope that the place of its discovery will ever be made known. As an example of ancient art, it may vie with the most elaborate and beautiful specimens of goldsmiths' work of any age or period. The details are wonderfully minute and delicate, even the backs of the button-like objects at the ends of the pendent cords being elaborately finished.

scholarly journals Realization of Low Profile Leaky Wave Antennas Using the Bending Technique for Frequency Scanning and Sensor Applications

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2265 ◽  
Author(s):  
Abhishek Kandwal ◽  
Zedong Nie ◽  
Lei Wang ◽  
Louis W. Y. Liu ◽  
Ranjan Das
Keyword(s):  
Transmission Line ◽  
The Body ◽  
Leaky Wave ◽  
Left Hand ◽  
Sensor Applications ◽  
Frequency Scanning ◽  
Right Hand ◽  
Low Profile ◽  
The Right ◽  
Ku Band

This paper proposes an efficient transmission line modulation by using the bending technique to realize low profile leaky wave antennas in the Ku-band for frequency scanning and sensor applications. The paper focuses mainly on the bending effects of the transmission line in terms of the sharpness of edges. The right-hand/left-hand transmission line can be designed in the form of zig-zag pattern with sharp corners and only the right-hand transmission line in the form of sinusoidal patterns with smooth corners. In this presentation, we demonstrate that transmission lines of this kind can be used to realize highly efficient leaky wave antennas with broadband impedance matching and high gain characteristics in the Ku-band. Dispersion analysis and ladder network analysis have been performed for investigating the performance of the proposed designs. The sharpness of the bends periodically distributed along the body of the antenna has been used to our advantage for frequency scanning in the left-hand and right-hand quadrants at different frequencies. The proposed bending technique has been proven to be instrumental in achieving the desired characteristics of low profile leaky wave antennas.

scholarly journals Studi Ergonomi tentang Keluhan-keluhan Fisik yang Dialami Karyawan di Unit Perpustakaan Fakultas Kedokteran Universitas Gadjah Mada Yogyakarta

2015 ◽  
Vol 10 (1) ◽  
pp. 22
Author(s):  
Heru Wibowo
Keyword(s):  
Quantitative Research ◽  
Mechanical Vibration ◽  
Left Knee ◽  
The Body ◽  
Upper Body ◽  
Left Shoulder ◽  
Research Approach ◽  
Left Hand ◽  
Left Elbow ◽  
The Right

In carrying out the activities at the library needed a comfort, safety and job security in order to create a condition that is in line with expectations and make history in enjoying what will be done. To create an environment and atmosphare is influenced by temperature, humidity, air circulation, lighting, mechanical vibration, color, ordor, and a number of tools used to support the activities of the library includes tables, ahairs, shelves, cabinets, atc. Furniture or equipment use in the library must also be designed so that a safe and compfortable when used. This study aims to determine the grievances suffered by employees (librarian. This study is a quantitative research approach to ergonomics so that the methods used include: (1) observation by direct observation, (2) interview were conducted using a questionnaire sheet Nordi Body Map and (3) documentation. The results obtained from this study: (1) in the upper body 70% complained of pain in the shoulders and neck, 50 % left shoulder , right shoulder 55 % , and 45 % on the left arm. (2) the body of the middle 60 % complained of back pain , 50 % in the upper right arm , 60 % pain in the waist , 20 % on the buttocks , 15 % on the buttocks , the left elbow 25 % , 20 % right elbow , 30 % below the left arm , forearm 25 % right, 35 % left wrist , right wrist 45 % , 30 % and 40 % left hand right hand. (3) in the lower body as much as 20 % complained of pain in the left thigh , right thigh 20 % , 30 % left knee , right knee 25 % , 35 % left calf , calf 35 % right, 20 % left ankle , 30 % on the right ankle , 20 % of the left leg and 25 % pain in the right foot . It can be concluded that most of the employees (librarians) complained of pain in the right side of the body member .

Herakles Crowning Himself: New Greek Statuary Types and Their Place in Hellenistic and Roman Art

1957 ◽  
Vol 77 (2) ◽  
pp. 283-299 ◽  
Author(s):  
C. C. Vermeule
Keyword(s):  
General Problem ◽  
Apple Tree ◽  
The Body ◽  
Roman Art ◽  
Left Hand ◽  
Central Figure ◽  
Marcus Aurelius ◽  
The Moment ◽  
The Right ◽  
Made In

In the course of examining Roman imperial medallions and coins in connexion with a study of Roman cult images, representations of Herakles Crowning Himself, a figure which appears on the reverses of medallions of Marcus Aurelius, Lucius Verus (Plate I, 2), and Commodus (Plate I, 3), merit further comment. These reverses, whether with or without legend, exhibit identical compositions. In the centre a young, beardless Herakles stands facing, his right hand raised in the act of placing a crown on his head; his left hand, close to his left hip, holds the club upwards in the crook of the elbow. Between club and elbow, the lion's skin hangs down over the forearm to a point midway along the left leg. The head, both forepaws, and tail are clearly visible dangling below. On all the medallions the die designer has made very clear the, important point that Herakles rests his weight on the left foot, with left hip thrown out and the right foot slightly back and out, giving a pronounced bow curve to the right side of the body from foot to shoulder. To Herakles' right and slightly behind him appears an apple tree on one branch of which hang the hero's quiver and bow; to his left rear is seen a square altar, festooned with garlands and with an offering burning on the top, and in her comprehensive monograph on Roman medallions J. M. C. Toynbee suggests that ‘the picture as a whole had been inspired by some bas-relief or painting now lost to us’. The question of relating the central figure to the whole composition will be taken up in Part II, in reappraising the general problem of famous statue types in medallion compositions. For the moment we may see what further progress may be made in identifying the statue type of the young Herakles Crowning Himself.

Cerebral Mechanisms of Hypnotic Induction and Suggestion

1999 ◽  
Vol 11 (1) ◽  
pp. 110-125 ◽  
Author(s):  
Pierre Rainville ◽  
Robert K. Hofbauer ◽  
Tomáš Paus ◽  
Gary H. Duncan ◽  
M. Catherine Bushnell ◽  
...  
Keyword(s):  
Pain Perception ◽  
State Theory ◽  
Hot Water ◽  
Anterior Cingulate ◽  
Experimental Conditions ◽  
Left Hand ◽  
Positron Emission ◽  
Highly Correlated ◽  
The Right ◽  
Hypnotic Suggestions

The neural mechanisms underlying hypnotic states and responses to hypnotic suggestions remain largely unknown and, to date, have been studied only with indirect methods. Here, the effects of hypnosis and suggestions to alter pain perception were investigated in hypnotizable subjects by using positron emission tomography (PET) measures of regional cerebral blood flow (rCBF) and electroencephalographic (EEG) measures of brain electrical activity. The experimental conditions included a restful state (Baseline) followed by hypnotic relaxation alone (Hypnosis) and by hypnotic relaxation with suggestions for altered pain unpleasantness (Hypnosis-with-Suggestion). During each scan, the left hand was immersed in neutral (35°C) or painfully hot (47°C) water in the first two conditions and in painfully hot water in the last condition. Hypnosis was accompanied by significant increases in both occipital rCBF and delta EEG activity, which were highly correlated with each other (r = 0.70, p < 0.0001). Peak increases in rCBF were also observed in the caudal part of the right anterior cingulate sulcus and bilaterally in the inferior frontal gyri. Hypnosis-related decreases in rCBF were found in the right inferior parietal lobule, the left precuneus, and the posterior cingulate gyrus. Hypnosis-with-suggestions produced additional widespread increases in rCBF in the frontal cortices predominantly on the left side. Moreover, the medial and lateral posterior parietal cortices showed suggestion-related increases overlapping partly with regions of hypnosis-related decreases. Results support a state theory of hypnosis in which occipital increases in rCBF and delta activity reflect the alteration of consciousness associated with decreased arousal and possible facilitation of visual imagery. Frontal increases in rCBF associated with suggestions for altered perception might reflect the verbal mediation of the suggestions, working memory, and top-down processes involved in the reinterpretation of the perceptual experience. These results provide a new description of the neurobiological basis of hypnosis, demonstrating specific patterns of cerebral activation associated with the hypnotic state and with the processing of hypnotic suggestions.

Body Scheme Gates Visual Processing

2004 ◽  
Vol 91 (5) ◽  
pp. 2376-2379 ◽  
Author(s):  
Christian Dohle ◽  
Raimund Kleiser ◽  
Rüdiger J. Seitz ◽  
Hans-Joachim Freund
Keyword(s):  
Visual Cortex ◽  
Visual Processing ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Body Scheme ◽  
Left Hand ◽  
Opposite Hand ◽  
The Right ◽  
First Time ◽  
Motor Acts

We used functional magnetic resonance imaging (fMRI) to explore how guidance of motor acts is influenced by the visually perceived body scheme. We found that when subjects view their hand as their opposite hand, i.e., the right hand is seen as the left hand and vice versa, activation in the visual cortex was lateralized opposite to the seen hand. This demonstrates for the first time that our body scheme to which vision relates our environment is already represented at the level of visual cortex.

A Statuette in private Possession

1926 ◽  
Vol 27 ◽  
pp. 149-150
Author(s):  
H. W. Law
Keyword(s):  
Flat Surface ◽  
The Body ◽  
Front Side ◽  
Left Hand ◽  
The Right ◽  
Shoulder Blade ◽  
The Way

The statuette represented in the accompanying photograph is about 37·6 cm. in height. The left leg is broken off above the knee, and supported on a prop which forms part of the base. The right leg is only roughly chiselled at the back, which suggests that the front side alone was visible in the position in which the statuette was originally placed. The nature of the object on the right shoulder is uncertain. The upper portion is like a kind of boss, and the lower front portion resembles an animal's claw. It has been suggested that it represents a pedum; but the angle at which the missing portion (if there has been a fracture, which is not certain) would project puts some difficulty in the way of this hypothesis. If, however, the object on the shoulder was part of an animal's skin extended across the breast, all traces of that have disappeared; though in a spot over the right ribs the marble has been shaved away to a flat surface, against which some object may have rested. There are three similar shaved spots in other parts of the body: behind each shoulder-blade and on the nates, and these may well indicate the places at which the statuette touched a wall. The position of the shaved spots behind the shoulder-blades does not suggest that they were the starting-points of wings. A small portion of lead piping is inserted under the left arm in the back of the mask—apparently a Comic one—carried in the left hand. The marble is of a rough crystalline character, probably Parian or Naxian. In the absence of the head and of all certain attributes it is difficult to say whether the statuette represents an Eros or a Satyr.

The role of the right parietal lobe in anorexia nervosa

2009 ◽  
Vol 40 (9) ◽  
pp. 1531-1539 ◽  
Author(s):  
D. Nico ◽  
E. Daprati ◽  
N. Nighoghossian ◽  
E. Carrier ◽  
J.-R. Duhamel ◽  
...  
Keyword(s):  
Anorexia Nervosa ◽  
Healthy Volunteers ◽  
Parietal Lobe ◽  
Body Schema ◽  
Body Representation ◽  
The Body ◽  
Subjective Perception ◽  
Body Boundary ◽  
The Right

BackgroundPatients with anorexia nervosa (AN) overestimate their size despite being severely underweight. Whether this misperception echoes an underlying emotional disturbance or also reflects a genuine body-representation deficit is debatable. Current measures inquire directly about subjective perception of body image, thus distinguishing poorly between top-down effects of emotions/attitudes towards the body and disturbances due to proprioceptive disorders/distorted body schema. Disorders of body representation also emerge following damage to the right parietal lobe. The possibility that parietal dysfunction might contribute to AN is suspected, based on the demonstrated association of spatial impairments, comparable to those found after parietal lesion, with this syndrome.MethodWe used a behavioral task to compare body knowledge in severe anorexics (n=8), healthy volunteers (n=11) and stroke patients with focal damage to the left/right parietal lobe (n=4). We applied a psychophysical procedure based on the perception, in the dark, of an approaching visual stimulus that was turned off before reaching the observer. Participants had to predict whether the stimulus would have hit/missed their body, had it continued its linear motion.ResultsHealthy volunteers and left parietal patients estimated body boundaries very close to the real ones. Conversely, anorexics and right parietal patients underestimated eccentricity of their left body boundary.ConclusionsThese findings are in line with the role the parietal cortex plays in developing and maintaining body representation, and support the possibility for a neuropsychological component in the pathogenesis of anorexia, offering alternative approaches to treatment of the disorder.

Sign in / Sign up

Export Citation Format

Share Document