scholarly journals Reaching around obstacles accounts for uncertainty in coordinate transformations

2019 ◽  
Author(s):  
Parisa Abedi Khoozani ◽  
Dimitris Voudouris ◽  
Gunnar Blohm ◽  
Katja Fiehler
Keyword(s):  
Obstacle Avoidance ◽  
Visual Target ◽  
Avoidance Task ◽  
Coordinate Transformations ◽  
Movement Variability ◽  
Preferred Direction ◽  
Safety Margins ◽  
Head Roll ◽  
Movement Curvature ◽  
The Brain

AbstractWhen reaching to a visual target, humans need to transform the spatial target representation into the coordinate system of their moving arm. It has been shown that increased uncertainty in such coordinate transformations, for instance when the head is rolled toward one shoulder, leads to higher movement variability and influence movement decisions. However, it is unknown whether the brain incorporates such added variability in planning and executing movements. We designed an obstacle avoidance task in which participants had to reach with or without visual feedback of the hand to a visual target while avoiding collisions with an obstacle. We varied coordinate transformation uncertainty by varying head roll (straight, 30° clockwise and 30° counterclockwise). In agreement with previous studies, we observed that the reaching variability increased when the head was tilted. Indeed, head roll did not influence the number of collisions during reaching compared to the head straight condition, but it did systematically change the obstacle avoidance behavior. Participants changed the preferred direction of passing the obstacle and increased the safety margins indicated by stronger movement curvature. These results suggest that the brain takes the added movement variability during head roll into account and compensates for it by adjusting the reaching trajectories.

scholarly journals Reaching around obstacles accounts for uncertainty in coordinate transformations

2020 ◽  
Vol 123 (5) ◽  
pp. 1920-1932 ◽  
Author(s):  
Parisa Abedi Khoozani ◽  
Dimitris Voudouris ◽  
Gunnar Blohm ◽  
Katja Fiehler
Keyword(s):  
Movement Direction ◽  
Coordinate Transformations ◽  
Movement Variability ◽  
Head Roll ◽  
Reach Movements ◽  
The Brain

We show that changing body geometry such as head roll results in compensatory reaching behaviors around obstacles. Specifically, we observed head roll causes changed preferred movement direction and increased trajectory curvature. As has been shown before, head roll increases movement variability due to stochastic coordinate transformations. Thus these results provide evidence that the brain must consider the added movement variability caused by coordinate transformations for accurate reach movements.

scholarly journals Sotalol does not interfere with the antielectroshock action of selected second-generation antiepileptic drugs in mice

2021 ◽  
Author(s):  
Kinga K. Borowicz-Reutt ◽  
Monika Banach ◽  
Monika Rudkowska ◽  
Anna Stachniuk
Keyword(s):  
Antiepileptic Drugs ◽  
Second Generation ◽  
Antidepressant Drug ◽  
Experimental Models ◽  
Long Term Memory ◽  
Avoidance Task ◽  
Maximal Electroshock ◽  
Term Memory ◽  
The Brain

Abstract Background Due to blocking β-receptors, and potassium KCNH2 channels, sotalol may influence seizure phenomena. In the previous study, we have shown that sotalol potentiated the antielectroshock action of phenytoin and valproate in mice. Materials and methods As a continuation of previous experiments, we examined the effect of sotalol on the action of four chosen second-generation antiepileptic drugs (oxcarbazepine, lamotrigine, pregabalin, and topiramate) against the maximal electroshock in mice. Undesired effects were evaluated in the chimney test (motor impairment) and step-through passive-avoidance task (long-term memory deficits). Finally, brain concentrations of antiepileptics were determined by fluorescence polarization immunoassay, while those of sotalol by liquid chromatography–mass spectrometry. Results Sotalol at doses of up to 100 mg/kg did not affect the electroconvulsive threshold. Applied at doses of 80–100 mg/kg, sotalol did not affect the antielectroshock action of oxcarbazepine, lamotrigine, pregabalin, or topiramate. Sotalol alone and in combinations with antiepileptics impaired neither motor performance nor long-term memory. Finally, sotalol significantly decreased the brain concentrations of lamotrigine and increased those of oxcarbazepine and topiramate. Pharmacokinetic interactions, however, did not influence the final antielectroshock effects of above-mentioned drug combinations. On the other hand, the brain concentrations of sotalol were not changed by second-generation antiepileptics used in this study. Conclusion Sotalol did not reduce the antielectroshock action of four second-generation antiepileptic drugs examined in this study. Therefore, this antidepressant drug should not interfere with antiseizure effects of lamotrigine, oxcarbazepine, pregabalin, and topiramate in patients with epilepsy. To draw final conclusions, our preclinical data should still be confirmed in other experimental models and clinical conditions.

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.

scholarly journals Silver Nanoparticles Impair Cognitive Functions and Modify the Hippocampal Level of Neurotransmitters in a Coating-Dependent Manner

2021 ◽  
Vol 22 (23) ◽  
pp. 12706
Author(s):  
Katarzyna Dziendzikowska ◽  
Małgorzata Węsierska ◽  
Joanna Gromadzka-Ostrowska ◽  
Jacek Wilczak ◽  
Michał Oczkowski ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Spatial Memory ◽  
Antibacterial Properties ◽  
Coating Material ◽  
Long Term Memory ◽  
Avoidance Task ◽  
Dependent Manner ◽  
Memory Functioning ◽  
Place Avoidance ◽  
The Brain

Due to their potent antibacterial properties, silver nanoparticles (AgNPs) are widely used in industry and medicine. However, they can cross the brain–blood barrier, posing a risk to the brain and its functions. In our previous study, we demonstrated that oral administration of bovine serum albumin (BSA)-coated AgNPs caused an impairment in spatial memory in a dose-independent manner. In this study, we evaluated the effects of AgNPs coating material on cognition, spatial memory functioning, and neurotransmitter levels in rat hippocampus. AgNPs coated with BSA (AgNPs(BSA)), polyethylene glycol (AgNPs(PEG)), or citrate (AgNPs(Cit)) or silver ions (Ag+) were orally administered at a dose of 0.5 mg/kg b.w. to male Wistar rats for a period of 28 days, while the control (Ctrl) rats received 0.2 mL of water. The acquisition and maintenance of spatial memory related to place avoidance were assessed using the active allothetic place avoidance task, in which rats from AgNPs(BSA), AgNPs(PEG), and Ag+ groups performed worse than the Ctrl rats. In the retrieval test assessing long-term memory, only rats from AgNPs(Cit) and Ctrl groups showed memory maintenance. The analysis of neurotransmitter levels indicated that the ratio between serotonin and dopamine concentration was disturbed in the AgNPs(BSA) rats. Furthermore, treatment with AgNPs or Ag+ resulted in the induction of peripheral inflammation, which was reflected by the alterations in the levels of serum inflammatory mediators. In conclusion, depending on the coating material used for their stabilization, AgNPs induced changes in memory functioning and concentration of neurotransmitters.

Statocyst-Induced Eye Movements in the Crab Scylla Serrata

1973 ◽  
Vol 59 (1) ◽  
pp. 17-38
Author(s):  
D. C. SANDEMAN ◽  
A. OKAJIMA
Keyword(s):  
Eye Movement ◽  
Contralateral Side ◽  
Scylla Serrata ◽  
Slow Phase ◽  
Fast Phase ◽  
Preferred Direction ◽  
Sensory Axons ◽  
Proprioceptive Input ◽  
Motor Neurones ◽  
The Brain

1. The sensory axons of the thread hair receptors, free hook hair receptors and most receptors of the statolith area of the crab statocyst all project to the same dorsolateral part of the brain. Large sensory receptors which innervate some hairs surrounding the statolith project to a more ventral site, and send some branches across to the contralateral side of the brain. 2. The central projections of oculomotor neurones have a characteristically open branch pattern and their dendritic field corresponds closely with that of the thread hairs. There are no branches extending to the contralateral side of the brain. 3. Intracellular responses from the motor neurones of horizontal eye-movement muscles during nystagmus show that they are probably directly inhibited during a fast-phase movement of the eye opposite to the direction in which they act. During a slow-phase eye movement opposite to their preferred direction the input to the motor neurones is diminished pre-synaptically. 4. Sets of antagonist motor neurones maintain a fairly rigid relationship to one another so that an increase in activity of one set leads to a decrease in the antagonists. Neither this, nor the onset of the fast phase of nystagmus, is governed by proprioceptive input or by the frequency of discharge of the motor neurones themselves.

scholarly journals Apolipoprotein E Antibodies Affect the Retention of Passive Avoidance Memory in the Chick

1998 ◽  
Vol 6 (3) ◽  
pp. 29-40 ◽  
Author(s):  
Chris Lancashire ◽  
Radmila Mileusnic ◽  
Steven P.R. Rose
Keyword(s):  
Risk Factors ◽  
Apolipoprotein E ◽  
Passive Avoidance ◽  
Residence Time ◽  
Memory Formation ◽  
Avoidance Task ◽  
Brain Distribution ◽  
The Brain ◽  
Avoidance Memory

Isoforms of apolipoprotein E (ApoE) have been implicated as risk factors in Alzheimer’s disease. We have, therefore, examined the possible role of ApoE in memory formation, using a one-trial passive avoidance task in day-old chicks. Birds were trained on the task and then at various times pre or post-training were injected intracerebrally with anti-ApoE. Immunofluorescence staining demonstrated the presence of the antibody bound to the neuropil, close to the injection site and adjacent to the ventricle, with a residence time in the brain of up to 30 min. Chicks that were injected 30 min pre-training or just post-training with 5μg/ hemisphere of the antibody learned the task, but were amnesic when tested at 30 min or at subsequent times up to 24 hr Post-training. When tested at 24 hr, birds injected 5.5 hr post-training showed unimpaired retention. Birds injected with 5μg/hemisphere of anti-ApoA-I (which has a brain distribution similar to that of anti-ApoE) at 30 min pretraining showed no amnesia, indicating the specificity of the effect to the ApoE. Possible mechanisms for this effect are discussed.

scholarly journals Low Protein Diet Induces Memory Loss and Anxiety Like Behavior via Decreases of Neurotransmitters in Aged Male Mice (P14-028-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Hideaki Sato ◽  
Masako Tsukamoto-Yasui ◽  
Satoko Ueno ◽  
Keiko Matsunaga ◽  
Akihiko Kitamura
Keyword(s):  
Cerebral Cortex ◽  
Memory Loss ◽  
The Elderly ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Avoidance Task ◽  
Maze Task ◽  
Low Protein ◽  
Plus Maze ◽  
The Brain

Abstract Objectives Increase of elderly people, dementia and cognitive decline has been already one of the social problems all over the world. There are a lot of risk factors including dietary composition. Several studies have reported the importance of protein for maintaining brain functions in the elderly, but the details are not well understood. To clarify the relationship between protein intake and brain function in the elderly, we evaluated the effect of low protein diet on cognitive function and psychiatric symptoms in aged mice. Methods Male mice at 60 weeks of age were fed a control diet (NPD; casein 20%) or a low protein diet (LPD; casein 5%). To evaluate neurobehavioral abnormality, we performed the elevated plus maze task (Day 64) and Passive avoidance task (conditioning: Day 66, evaluation: Day 67). Cerebral cortex tissues and plasma were measured for free amino acid concentration by LC-MSMS method, and monoamine concentration in cerebral cortex was measured by HPLC method. Results In the Passive avoidance task, LPD group decreased the time to keep staying in the light box and the rate of individuals entering the dark box during the test period. In the elevated plus maze task, LPD group significantly increased in the number of entry and staying times in open arm. In addition, total travel distance was significantly increased. Moreover, LPD decreased the concentration of not only amino acid in plasma and cerebral cortex but also neurotransmitter such as Glutamate, GABA, Aspartate, Glycine, Dopamine, Norepinephrine, Serotonin. Conclusions We found that long-term intake of low-protein diet occurred memory loss and anxiety like behavior in elderly mice. Intracerebral neurotransmitters are mainly synthesized from amino acids, which is transferred from blood, within the brain. Therefore, behavioral change observed in LPD group might be induced by the decrease of neurotransmitters in the brain. Funding Sources Ajinomoto Co., Inc.

scholarly journals Robot Obstacle Avoidance Learning Based on Mixture Models

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Huiwen Zhang ◽  
Xiaoning Han ◽  
Mingliang Fu ◽  
Weijia Zhou
Keyword(s):  
Obstacle Avoidance ◽  
Avoidance Learning ◽  
Dynamic Environment ◽  
Main Idea ◽  
Control Policy ◽  
Gaussian Mixture ◽  
Avoidance Task ◽  
Human Beings ◽  
Training Set ◽  
Mixture Regression

We briefly surveyed the existing obstacle avoidance algorithms; then a new obstacle avoidance learning framework based on learning from demonstration (LfD) is proposed. The main idea is to imitate the obstacle avoidance mechanism of human beings, in which humans learn to make a decision based on the sensor information obtained by interacting with environment. Firstly, we endow robots with obstacle avoidance experience by teaching them to avoid obstacles in different situations. In this process, a lot of data are collected as a training set; then, to encode the training set data, which is equivalent to extracting the constraints of the task, Gaussian mixture model (GMM) is used. Secondly, a smooth obstacle-free path is generated by Gaussian mixture regression (GMR). Thirdly, a metric of imitation performance is constructed to derive a proper control policy. The proposed framework shows excellent generalization performance, which means that the robots can fulfill obstacle avoidance task efficiently in a dynamic environment. More importantly, the framework allows learning a wide variety of skills, such as grasp and manipulation work, which makes it possible to build a robot with versatile functions. Finally, simulation experiments are conducted on a Turtlebot robot to verify the validity of our algorithms.

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