Prism adaptation and generalization during visually guided locomotor tasks

2011 ◽  
Vol 106 (2) ◽  
pp. 860-871 ◽  
Author(s):  
M. Scott Alexander ◽  
Brent W. G. Flodin ◽  
Daniel S. Marigold
Keyword(s):  
Nervous System ◽  
Obstacle Avoidance ◽  
Avoidance Task ◽  
Visually Guided ◽  
Initial Exposure ◽  
Foot Placement ◽  
Before And After ◽  
The Right ◽  
Placement Distance ◽  
Precision Stepping

The ability of individuals to adapt locomotion to constraints associated with the complex environments normally encountered in everyday life is paramount for survival. Here, we tested the ability of 24 healthy young adults to adapt to a rightward prism shift (∼11.3°) while either walking and stepping to targets (i.e., precision stepping task) or stepping over an obstacle (i.e., obstacle avoidance task). We subsequently tested for generalization to the other locomotor task. In the precision stepping task, we determined the lateral end-point error of foot placement from the targets. In the obstacle avoidance task, we determined toe clearance and lateral foot placement distance from the obstacle before and after stepping over the obstacle. We found large, rightward deviations in foot placement on initial exposure to prisms in both tasks. The majority of measures demonstrated adaptation over repeated trials, and adaptation rates were dependent mainly on the task. On removal of the prisms, we observed negative aftereffects for measures of both tasks. Additionally, we found a unilateral symmetric generalization pattern in that the left, but not the right, lower limb indicated generalization across the 2 locomotor tasks. These results indicate that the nervous system is capable of rapidly adapting to a visuomotor mismatch during visually demanding locomotor tasks and that the prism-induced adaptation can, at least partially, generalize across these tasks. The results also support the notion that the nervous system utilizes an internal model for the control of visually guided locomotion.

scholarly journals Foot placement relies on state estimation during visually guided walking

2017 ◽  
Vol 117 (2) ◽  
pp. 480-491 ◽  
Author(s):  
Rodrigo S. Maeda ◽  
Shawn M. O'Connor ◽  
J. Maxwell Donelan ◽  
Daniel S. Marigold
Keyword(s):  
Nervous System ◽  
State Estimation ◽  
Sensory Feedback ◽  
Computational Models ◽  
Target Location ◽  
Forward Model ◽  
General Mechanism ◽  
Visually Guided ◽  
Foot Placement ◽  
Model Predictions

As we walk, we must accurately place our feet to stabilize our motion and to navigate our environment. We must also achieve this accuracy despite imperfect sensory feedback and unexpected disturbances. In this study we tested whether the nervous system uses state estimation to beneficially combine sensory feedback with forward model predictions to compensate for these challenges. Specifically, subjects wore prism lenses during a visually guided walking task, and we used trial-by-trial variation in prism lenses to add uncertainty to visual feedback and induce a reweighting of this input. To expose altered weighting, we added a consistent prism shift that required subjects to adapt their estimate of the visuomotor mapping relationship between a perceived target location and the motor command necessary to step to that position. With added prism noise, subjects responded to the consistent prism shift with smaller initial foot placement error but took longer to adapt, compatible with our mathematical model of the walking task that leverages state estimation to compensate for noise. Much like when we perform voluntary and discrete movements with our arms, it appears our nervous systems uses state estimation during walking to accurately reach our foot to the ground. NEW & NOTEWORTHY Accurate foot placement is essential for safe walking. We used computational models and human walking experiments to test how our nervous system achieves this accuracy. We find that our control of foot placement beneficially combines sensory feedback with internal forward model predictions to accurately estimate the body's state. Our results match recent computational neuroscience findings for reaching movements, suggesting that state estimation is a general mechanism of human motor control.

Propofol-induced Increase in Vascular Capacitance Is Due to Inhibition of Sympathetic Vasoconstrictive Activity 

1998 ◽  
Vol 89 (6) ◽  
pp. 1495-1500 ◽  
Author(s):  
Sumio Hoka ◽  
Ken Yamaura ◽  
Tomoaki Takenaka ◽  
Shosuke Takahashi
Keyword(s):  
Nervous System ◽  
Sympathetic Nervous System ◽  
Circulatory Arrest ◽  
Bolus Administration ◽  
Block Group ◽  
Intact Group ◽  
Vascular Capacitance ◽  
Before And After ◽  
Sympathetic Nervous ◽  
The Right

Background Venodilation is thought to be one of the mechanisms underlying propofol-induced hypotension. The purpose of this study is to test two hypotheses: (1) propofol increases systemic vascular capacitance, and (2) the capacitance change produced by propofol is a result of an inhibition of sympathetic vasoconstrictor activity. Methods In 33 Wistar rats previously anesthetized with urethane and ketamine, vascular capacitance was examined before and after propofol infusion by measuring mean circulatory filling pressure (Pmcf). The Pmcf was measured during a brief period of circulatory arrest produced by inflating an indwelling balloon in the right atrium. Rats were assigned into four groups: an intact group, a sympathetic nervous system (SNS)-block group produced by hexamethonium infusion, a SNS-block + noradrenaline (NA) group, and a hypovolemic group. The Pmcf was measured at a control state and 2 min after a bolus administration of 2, 10, and 20 mg/kg of propofol. Results The mean arterial pressure (MAP) was decreased by propofol dose-dependently in intact, hypovolemic, and SNS-block groups, but the decrease in MAP was less in the SNS-block group (-25%) than in the intact (-50%) and hypovolemic (-61%) groups. In the SNS-block + NA group, MAP decreased only at 20 mg/kg of propofol (-18%). The Pmcf decreased in intact and hypovolemic groups in a dose-dependent fashion but was unchanged in the SNS-block and SNS-block + NA groups. Conclusions The results have provided two principal findings: (1) propofol decreases Pmcf dose-dependently, and (2) the decrease in Pmcf by propofol is elicited only when the sympathetic nervous system is intact, suggesting that propofol increases systemic vascular capacitance as a result of an inhibition of sympathetic nervous system.

Comparative Arterial Antithrombotic Activity of Clopidogrel and Acetyl Salicylic Acid in the Pig

1992 ◽  
Vol 68 (05) ◽  
pp. 500-505 ◽  
Author(s):  
Ch M Samama ◽  
Ph Bonnin ◽  
M Bonneau ◽  
G Pignaud ◽  
E Mazoyer ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Femoral Artery ◽  
Bleeding Time ◽  
Ex Vivo ◽  
Flow Reduction ◽  
Cyclic Flow ◽  
Left Femoral Artery ◽  
Before And After ◽  
The Right ◽  
Induced Aggregation

SummaryWe investigated the comparative antithrombotic properties of clopidogrel, an analogue of ticlopidine, and aspirin, using the Folts' model on femoral arteries in 22 pigs. On each animal, clopidogrel or aspirin were used to treat the thrombotic process on the left femoral artery and to prevent this process on the right femoral artery. Sequentially: an injury and stenosis were carried out on the left femoral artery; the thrombotic process was monitored with a Doppler during a 30-min observation period for cyclic flow reductions or permanent cessation of flow; after the first cyclic flow reduction occurred, clopidogrel (5 mg kg-1) or aspirin (2.5, 5, 100 mg kg-1) were injected intravenously; if cyclic flow reductions were abolished, epinephrine (0.4 µg kg-1 min-1) was injected to try to restore cyclic flow reductions and/or permanent cessation of flow; then injury and stenosis were applied on the right femoral artery. Before and after injection of clopidogrel or aspirin, ear immersion bleeding times and ex-vivo platelet aggregation were performed. Clopidogrel (n = 7) abolished cyclic flow reductions in all animals and epinephrine did not restore any cyclic flow reduction. On the right femoral artery, cyclic flow reductions were efficiently prevented, even for two injuries. Basal bleeding time (5 min 28) was lengthened (>15 min, 30 min after clopidogrel and remained prolonged even after 24 h). ADP-induced platelet aggregation was inhibited (more than 78%). Comparatively, aspirin had a moderate and no dose-dependent effect. Aspirin 2.5 mg kg-1 (n = 6) abolished cyclic flow reductions in 2 animals, CFR reoccurred spontaneously in one animal and epinephrine restored it in a second animal. Aspirin 5 mg kg-1 (n = 6) abolished cyclic flow reductions in only 3 animals and epinephrine always restored it. Aspirin 100 mg kg-1 (n = 3) was unable to abolish cyclic flow reductions. On the right femoral artery, aspirin did not significantly prevent cyclic flow reductions which occurred in all animals after one (n = 14) or two injuries (n = 1), except for one animal. Basal bleeding time was lengthened but it shortened rapidly, reaching its basal value after 24 h. ADP-induced aggregation was not significantly inhibited, whereas arachidonic acid induced aggregation was always inhibited. Clopidogrel appears as a more potent antithrombotic drug than aspirin in this model, in treating and preventing spontaneous or epinephrine-induced cyclic flow reductions and lengthening bleeding time.

EFEKTIVITAS METODE DEMONSTRASI DALAM MENINGKATKAN HASIL BELAJAR SISWA SEKOLAH MENENGAH KEJURUAN PADA PENGAJARAN SISTEM KOLOID

2013 ◽  
Vol 19 (1) ◽  
pp. 28
Author(s):  
Hamda Situmorang ◽  
Manihar Situmorang
Keyword(s):  
High School ◽  
High School Students ◽  
Abstract Concept ◽  
Vocational High School ◽  
School Students ◽  
Lecture Method ◽  
Colloid System ◽  
Before And After ◽  
The Right ◽  
And Control

Abstract Implementation of demonstration method in the teaching of chemistry is assigned as the right strategy to improve students’ achievement as it is proved that the method can bring an abstract concept to reality in the class. The study is conducted to vocational high school students in SMKN1 Pargetteng getteng Sengkut Pakfak Barat at accademic year 2013. The teaching has been carried out three cycles on the teaching of chemistry topic of colloid system. In the study, the class is divided into two class, experiment class and control class. The demontration method is used to teach students in experimental class while the teaching in control class is conducted with lecture method. Both are evaluated by using multiple choise tests before and after the teaching procedures, and the ability of students to answer the problems are assigned as students’ achievements. The results showed that demonstration method improved students’ achievement in chemistry. The students in experimental class who are taughed with demonstration method (M=19.08±0.74) have higher achievements compare with control class (M=12.91±2.52), and both are significantly different (tcalculation 22.85 > ttable 1.66). The effectivity of demostration method in experimental class (97%) is found higer compare to conventional method in control class (91%).

EDUKASI TERHADAP REMAJA DALAM PENINGKATAN PENGETAHUAN TENTANG PENGGUNAAN GAME DENGAN BIJAK

2020 ◽  
Vol 2 (1) ◽  
pp. 11
Author(s):  
Ikhsan Fuady ◽  
Rangga Saptya MP
Keyword(s):  
Side Effects ◽  
Violent Behavior ◽  
Daily Lives ◽  
Before And After ◽  
Improper Use ◽  
Effective Role ◽  
Education And Outreach ◽  
The Right ◽  
Dedicated Team ◽  
User Ratings

<p align="center"><strong>Abstrak</strong></p><p><em>Pemanfaatan game dikalangan remaja memiliki peran yang efektif sebagai wadah untuk hiburan. Tetapi pemanfaatan game tidak tepat memiliki efek samping game terhadap kehidupan sehari hari remaja, mulai dari kurang bersosialIsasi hingga perilaku kekerasan dikalangan remaja. Penyuluhan terhadap remaja bertujuan untuk memberikan pemahaman kepada remaja tentang variasi game berdasarkan rating pengguna, maupun cerdas dalam manajemen penggunaan game dalam kehidupan remaja sehari hari. Pengetahuan remaja tentang varian/ragam game berdasarkan rating relatif rendah sebagaian besar pemengetahuannya tersebar pada kategori sangat rendah dan rendah yaitu sebesar 65 persen. Metode edukasi dan sosialisasi ini adalah dengan beberapa tahapan. Tahap pertaman tim pengabdian memberikan edukasi dan diskusi tentang beragam bentuk game, karakteristik, serta karakteristik pengguna game yang tepat. Selanjutnya beberapa permainan dan kuis untuk meingkatkan literasi remaja tentang pemanfaatan game secara bijak. Kegiatan penyuluhan ini mampu meningkatkan pemahaman para remaja dalam mengenali game yang baik digunakan, hal ini dapat dilihat dari peningkatan pengetahuan remaja relatif signifikan sebelum dan sesudah penyuluhan.</em></p><p><strong>Kata kunci<em>:</em></strong><strong><em> </em></strong><strong><em>Edukasi, Game, Penyuluhan </em></strong></p><p align="center"><em> </em></p><p align="center"><strong>Abstract</strong> </p><p><em>The use of games among teenagers has an effective role as a forum for entertainment. But the improper use of games has the side effects of games on the daily lives of adolescents, ranging from lack of socialization to violent behavior in adolescents. Counseling against adolescents aims to provide understanding to adolescents about the variety/variance of games based on user ratings, as well as being smart in managing game use in daily teenage life. Teenagers' knowledge about game variants/based on the rating is relatively low, most of the knowledge is spread in the very low and low categories, which is 65 percent. The method of education and outreach is by several stages. The first stage of the dedicated team provided education and discussion about various forms of games, characteristics, and characteristics of the right game user. Furthermore, some games and quizzes to improve teen literacy about game use wisely. This counseling activity can increase the understanding of teenagers in recognizing games that are well used, this can be seen from the relatively significant increase in adolescent knowledge before and after counseling.</em></p><p><strong>Keywords<em>:</em></strong><em> <strong>Education, Games, Counseling</strong></em></p>

ASSESSMENT OF PHYSIOLOGICAL PARAMETERS OF THE TRIGEMINAL AND COCHLEOVESTIBULAR SYSTEMS IN TEMPOROMANDIBULAR JOINT PAIN DYSFUNCTION

2020 ◽  
Vol 17 (2) ◽  
pp. 110-120
Author(s):  
N.D. Sorokina ◽  
◽  
L.R. Shahalieva ◽  
S.S. Pertsov ◽  
L.V. Polma ◽  
...  
Keyword(s):  
Nervous System ◽  
Evoked Potentials ◽  
Temporomandibular Joint ◽  
Differential Diagnostics ◽  
Autonomous Nervous System ◽  
Dental Diseases ◽  
Grade Ii ◽  
The Right ◽  
Distal Occlusion ◽  
The Brain

One of the most common causes of chronic pain in the facial region, including in the trigeminal nerve link, which is not associated with dental diseases, is pain dysfunction of the temporomandibular joint. At the same time, there is evidence in the literature that there are relationships between pain dysfunction of the temporomandibular joint, abnormal occlusion, cervical-muscular tonic phenomena, postural disorders, dysfunction of the Autonomous nervous system and cochleovestibular manifestations. At the same time, neurophysiological indicators of functional disorders in the maxillofacial region and intersystem interactions in pain dysfunction of the temporomandibular joint are insufficiently studied.Goal. The aim of the work is to evaluate the neurophysiological features of trigeminal afferentation in terms of trigeminal somatosensory evoked potentials (TSWP) and the auditory conducting system of the brain in terms of acoustic stem evoked potentials (ASVP) in distal occlusion of the dentition with pain dysfunction of the temporomandibular joint (TMJ) in comparison with physiological occlusion in students 18-21 years old. Material and methods. The main study included 41 students with distal occlusion (21 girls and 20 boys), (grade II Engl, symmetrically right and left in 14 people, and grade II Engl on the left and grade I on the right in 12 people, grade I on the left and grade II on the right in 15 people). All respondents with distal occlusion and who were practically healthy signed an informed consent to participate in the study. We used complex orthodontic methods of examination, subjective degree of severity and intensity of pain in the TMJ, assessment of the Autonomous nervous system (samples and tests), and neurophysiological methods for assessing TSVP and ASVP. Results. Significant differences in ASEP parameters were found in the group of respondents with distal occlusion in the form of a decrease in the latency period of peak I, III, and V compared to physiological occlusion, that correlated with the subjective assessment (in points) of cochleovestibular disorders. According to the TSVP study, a decrease in the duration of latent periods was found, which indicates an increased excitability of non-specific brain stem structures at the medullo-ponto-mesencephalic level compared to the control group. Conclusions. The results obtained are supposed to be used for differential diagnostics, including such dental diseases as TMJ pain dysfunction, occlusion abnormalities accompanied by pain syndrome. Additional functional diagnostics of multi-modal VP of the brain (acoustic evoked potentials, trigeminal evoked potentials) can be performed in conjunction with indicators of autonomic nervous system dysfunction, with parameters of severity of clinical symptoms of cochleovestibular disorders, musculoskeletal dysfunction the maxillofacial area, with indicators of pain, which will determine the tactics and effectiveness of subsequent treatment.

scholarly journals Acute exudative polymorphous paraneoplastic vitelliform maculopathy (AEPPVM) associated with choroidal melanoma

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Aluisio Rosa Gameiro Filho ◽  
Guilherme Sturzeneker ◽  
Ever Ernesto Caso Rodriguez ◽  
André Maia ◽  
Melina Correia Morales ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Serous Retinal Detachment ◽  
Central Nervous System Involvement ◽  
Choroidal Melanoma ◽  
Posterior Pole ◽  
Pancreatic Metastasis ◽  
Small Areas ◽  
History Of ◽  
The Right

Abstract Background To report a case of acute exudative polymorphous paraneoplastic vitelliform maculopathy in a patient with a history of choroidal melanoma, with metastases to the pancreas, liver, and central nervous system. Case presentation A 63-year-old patient, with a history of enucleation of the right eye due to choroidal melanoma, complained of progressive visual loss during a follow-up visit. Fundoscopic examination revealed multiple small areas of serous retinal detachment scattered throughout the posterior pole and ancillary tests confirmed the diagnosis of acute exudative polymorphous paraneoplastic vitelliform maculopathy (AEPPVM). Screening for systemic metastases showed pancreatic, hepatic, and central nervous system involvement. Conclusions We describe a rare case of acute exudative polymorphous paraneoplastic vitelliform maculopathy, which should be considered in patients with or without a history of melanoma, who have vitelliform retinal detachments. Nevertheless, no previous reviews of literature have shown a correlation between AEPPVM and pancreatic metastasis.

scholarly journals Formation Tracking Control and Obstacle Avoidance of Unicycle-Type Robots Guaranteeing Continuous Velocities

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4374
Author(s):  
Jose Bernardo Martinez ◽  
Hector M. Becerra ◽  
David Gomez-Gutierrez
Keyword(s):  
Obstacle Avoidance ◽  
Tracking Control ◽  
Global Coordinate System ◽  
Avoidance Task ◽  
Time Varying ◽  
Control Laws ◽  
Formation Tracking ◽  
Control Scheme ◽  
First Time ◽  
Hierarchical Scheme

In this paper, we addressed the problem of controlling the position of a group of unicycle-type robots to follow in formation a time-varying reference avoiding obstacles when needed. We propose a kinematic control scheme that, unlike existing methods, is able to simultaneously solve the both tasks involved in the problem, effectively combining control laws devoted to achieve formation tracking and obstacle avoidance. The main contributions of the paper are twofold: first, the advantages of the proposed approach are not all integrated in existing schemes, ours is fully distributed since the formulation is based on consensus including the leader as part of the formation, scalable for a large number of robots, generic to define a desired formation, and it does not require a global coordinate system or a map of the environment. Second, to the authors’ knowledge, it is the first time that a distributed formation tracking control is combined with obstacle avoidance to solve both tasks simultaneously using a hierarchical scheme, thus guaranteeing continuous robots velocities in spite of activation/deactivation of the obstacle avoidance task, and stability is proven even in the transition of tasks. The effectiveness of the approach is shown through simulations and experiments with real robots.

Smartphone addiction and the relationship with head and neck pain and electromiographic activity of masticatory muscles

Work ◽  
2021 ◽  
pp. 1-8
Author(s):  
Fabiana Foltran Mescollotto ◽  
Érica Brito Gonçalves ◽  
Ester Moreira de Castro Carletti ◽  
Ana Beatriz Oliveira ◽  
Elisa Bizetti Pelai ◽  
...  
Keyword(s):  
College Students ◽  
Neck Pain ◽  
Head And Neck ◽  
Muscle Activity ◽  
Neck Region ◽  
Masticatory Muscles ◽  
Smartphone Addiction ◽  
Before And After ◽  
Smartphone Use ◽  
The Right

Background: Excessive use of smartphones may be associated with behavioral and physical health changes and might cause musculoskeletal alterations in the head and neck region. Objective: To evaluate the prevalence of smartphone addiction in college students and its correlation with symptoms of head and neck pain and masticatory and trapezius muscle activity while resting, before and after smartphone use. Methods: Twenty university students participated in the study. They answered the Smartphone Addiction Scale and the Fonseca Anamnestic Index. Next, the participants were seated and prepared for electromyography through the placement of surface electrodes on the masseter, temporal, and trapezius muscles. Rest condition data were collected for 10 seconds before and after 30 minutes of smartphone use. Results: The results showed that 35% of the evaluated individuals were classified as smartphone addicted and 35% reported no head or neck pain in the previous 30 days. There was no association between smartphone use and head and neck pain. In the electromyography, there was an increase in RMS values after smartphone use in the right and left masseter muscles and the left trapezius. Conclusion: College students presented a high prevalence of smartphone addiction and head and neck pain, but these were not statistically associated. There was a change in muscle activity only in the right trapezius muscles before and after 30 minutes of smartphone use. These findings are contrary to the current belief that the use of smartphones correlates with pain in the neck region and changes in the electrical muscle activity, leading to fatigue in the cervical muscles.

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