scholarly journals Sensory Reweighting in Targeted Reaching: Effects of Conscious Effort, Error History, and Target Salience

2010 ◽  
Vol 103 (1) ◽  
pp. 206-217 ◽  
Author(s):  
Hannah J. Block ◽  
Amy J. Bastian
Keyword(s):  
Minimum Variance ◽  
The Body ◽  
The Other ◽  
Proprioceptive Information ◽  
Sensory Reweighting ◽  
Sensorimotor Processing ◽  
Important Principle ◽  
Conscious Effort ◽  
Visual Error ◽  
The Brain

When both visual and proprioceptive information are available about the position of a part of the body, the brain weights and combines these sources to form a single estimate, often modeled by minimum variance integration. These weights are known to vary with different circumstances, but the type of information causing the brain to change weights (reweight) is unknown. Here we studied reweighting in the context of estimating the position of a hand for the purpose of reaching it with the other hand. Subjects reached to visual (V), proprioceptive (P), or combined (VP) targets in a virtual reality setup. We calculated weights for vision and proprioception by comparing endpoints on VP reaches with endpoints on P and V reaches. Endpoint visual feedback was manipulated to control completely for the error history seen by subjects. In different experiments, we manipulated target salience, conscious effort, or statistics of the visual error history to see if these cues could cause reweighting. Most subjects could reweight strongly by conscious effort. Changes in target salience reliably caused reweighting, but seen error history alone did not. We also found that experimental weights can be predicted by minimizing the variance of visual and proprioceptive estimates, supporting the idea that minimum variance integration is an important principle of sensorimotor processing.

William Croone’s theory of muscular contraction

1961 ◽  
Vol 16 (2) ◽  
pp. 158-178 ◽  
Keyword(s):  
Spinal Cord ◽  
Seventeenth Century ◽  
Muscle Contraction ◽  
Muscular Contraction ◽  
The Body ◽  
The Other ◽  
First Person ◽  
Muscular Movement ◽  
The One ◽  
The Brain

In the mid-seventeenth century William Croone had been the earliest among his contemporaries to concern himself with muscular motion. Thus, much of the discussion on muscular movement in the period after 1664 is either a commentary upon Croone’s views or is derived from them, and his influence was thus widespread, especially on the Continent. The background to Croone’s own views is largely that of Greek physiology as represented in the works of Galen. The first person who had a theory of muscle contraction seems to have been Erasistratus. Galen says that Erasistratus of Chios (fl. 290 b.c.) considered that when a muscle is filled with pneuma its breadth increases while its length diminishes and for this reason it is contracted. (1) Galen himself was impressed by the contractility of muscle and by the fact that this contractility depends on the nerve arising from the spinal cord and entering the muscle, where it branches repeatedly and sends its branches into all parts of the muscle. If the nerve, entering the muscle, be cut or injured or merely compressed the muscle loses all movement and sensitivity. (2) Galen considered that a muscle is made up of fibres and flesh. (3) The fibres of the muscle are continuous with those of its tendons at either end. In the body of the muscle itself the fibres are spread apart by the flesh contained in the interspaces between them. Each of these continuous fibres extending through both the tendon and the muscle Galen considers to be made up of finer fibres—on the one hand of inert and insensitive fibres of the same kind as occur in ligaments and, on the other hand, of sensitive fibres which are simply fine extensions of the branches of the nerves. (4) Galen does not, however, seem to offer, as does Erasistratus any mechanism to account for muscle contraction. To Galen the muscle is simply moved by the motor faculty which comes from the brain.

scholarly journals Anisotropic distortion in the perceived orientation of stimuli on the arm

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Scinob Kuroki
Keyword(s):  
Line Shape ◽  
Shape Perception ◽  
Frame Of Reference ◽  
The Body ◽  
The Other ◽  
Neural Signals ◽  
Perceptual Distortion ◽  
Braille Display ◽  
The Brain ◽  
Volar Surface

AbstractMechanoreceptors on the skin are heterogeneously distributed, and the sampling of neural signals in the brain can vary depending on the part of the body. Therefore, it can be challenging for the brain to consistently represent stimuli applied to different body sites. Here, we report an example of a regional perceptual distortion of the tactile space. We used a piezoelectric braille display to examine shape perception on the volar surface of the arm and to compare it to that on the palm. We found that the orientation of perceived stimuli on the arm was distorted in certain areas. In particular, an inwardly-inclined line shape was perceived as being more inwardly-inclined than it actually was. On the other hand, an outwardly-inclined line was perceived accurately. When the same stimuli were applied to the palm, this anisotropic bias was not observed. We also found that changing the posture of the arm changed the angle at which this anisotropic distortion occurred, suggesting the influence of the skin frame of reference on this illusion. This study showed a clear example of how the representation of even simple stimuli is complexly distinct when the stimuli are applied to different body sites.

scholarly journals The visual encoding of purely proprioceptive intermanual tasks is due to the need of transforming joint signals, not to their interhemispheric transfer

2017 ◽  
Vol 118 (3) ◽  
pp. 1598-1608 ◽  
Author(s):  
Léo Arnoux ◽  
Sebastien Fromentin ◽  
Dario Farotto ◽  
Mathieu Beraneck ◽  
Joseph McIntyre ◽  
...  
Keyword(s):  
Mirror Symmetry ◽  
Hand Movement ◽  
Visual Space ◽  
Interhemispheric Transfer ◽  
The Other ◽  
Proprioceptive Information ◽  
Brain Hemispheres ◽  
Visual Encoding ◽  
Per Se ◽  
The Brain

To perform goal-oriented hand movement, humans combine multiple sensory signals (e.g., vision and proprioception) that can be encoded in various reference frames (body centered and/or exo-centered). In a previous study (Tagliabue M, McIntyre J. PLoS One 8: e68438, 2013), we showed that, when aligning a hand to a remembered target orientation, the brain encodes both target and response in visual space when the target is sensed by one hand and the response is performed by the other, even though both are sensed only through proprioception. Here we ask whether such visual encoding is due 1) to the necessity of transferring sensory information across the brain hemispheres, or 2) to the necessity, due to the arms’ anatomical mirror symmetry, of transforming the joint signals of one limb into the reference frame of the other. To answer this question, we asked subjects to perform purely proprioceptive tasks in different conditions: Intra, the same arm sensing the target and performing the movement; Inter/Parallel, one arm sensing the target and the other reproducing its orientation; and Inter/Mirror, one arm sensing the target and the other mirroring its orientation. Performance was very similar between Intra and Inter/Mirror (conditions not requiring joint-signal transformations), while both differed from Inter/Parallel. Manipulation of the visual scene in a virtual reality paradigm showed visual encoding of proprioceptive information only in the latter condition. These results suggest that the visual encoding of purely proprioceptive tasks is not due to interhemispheric transfer of the proprioceptive information per se, but to the necessity of transforming joint signals between mirror-symmetric limbs. NEW & NOTEWORTHY Why does the brain encode goal-oriented, intermanual tasks in a visual space, even in the absence of visual feedback about the target and the hand? We show that the visual encoding is not due to the transfer of proprioceptive signals between brain hemispheres per se, but to the need, due to the mirror symmetry of the two limbs, of transforming joint angle signals of one arm in different joint signals of the other.

Recent Contributions to the Pathology of Nervous Diseases

1867 ◽  
Vol 13 (61) ◽  
pp. 44-58 ◽  
Author(s):  
H. M.
Keyword(s):  
Physical Method ◽  
The Body ◽  
The Other ◽  
Physiological Basis ◽  
Natural Laws ◽  
Positive Science ◽  
Positive Method ◽  
Holy Ground ◽  
The Brain ◽  
Structure And Functions

When we reflect that the sciences of astronomy, physics, and chemistry have only recently got rid of the metaphysical spirit, we cannot wonder much that physiology is not yet entirely emancipated from the pernicious thraldom. It was plainly impossible that physiology should be cultivated in the spirit of the positive method of investigation while the sciences upon the advance of which itsadvance is dependent were not sciences at all, but clouds of idle andshifting fancies. But there has been another and weighty reason why the science dealing with the structure and functions of the organism has remained so long in a metaphysical bondage: because psychology, the last stronghold and the forlorn hope of the meta physical method, is an important branch of it. Metaphysicians have for at least two thousand years been supremely self-satisfied to evolve, from the unfathomable depths of the inner consciousness, ingenious mazes of vague and ill-defined words which they have dignified with the name of mental philosophy; and the consequence has been that the physiologist, when he came in the course of his inquiries to the brain, contented himself with the anatomical de scription of it, and never dreamed of studying its functions as the mental organ. By a prescriptive right, sanctioned by the authority of generations, mind belonged to the metaphysician; and it naturally seemed sacrilegious to venture a scientific step in such holy ground. Not only so, but the mischievous influence of the metaphysical spirit spread beyond the department of psychology, and infected more or less strongly all physiological inquiries. However, this state of things could not last in face of the active progress of positive science; the or ans and functions of the body became objects of positive investigation, and even the brain no longer escaped scientific study. So it has come to pass that the germs of a mental science having a physiological basis have appeared, and now threaten to disturb the ancient ascendancy of metaphysical mental philosophy. The present position of matters is this: there are two systems of philosophy dealing with the same subject, but not having the slightest connection one with the other, and cultivated according to different methods by different men-metaphysical mental philosophy and positive mental science. A man might be deeply learned in all the wisdom of the former, and yet entirely ignorant of the very meaning of the simplest facts of the latter. It is hardly worth while considering seriously at the present day which of these rival systems is likely to prevail over the other; one of them is the latest issue of the advance of positive science, has its foundations deep rooted in the relations of natural laws, and exhibits a promising growth; while the other has moved in an everlasting circle, has no better foundations than the clouds and conceits of men's thoughts, and exhibits symptoms of active decay. Now and then it is skilfully galvanized into a spasmodic semblance of life, but each artificially excited convulsion is plainly the fore runner of an increase of the inevitable paralysis. Much remains to be done, however, before we can claim acceptance for a positive mental science. Not only is our knowledge of the structure and functions of the brain very defective, but there is nothing like exact information to be had regarding its pathology. It has been the fashion to give the name of some disease to a group of symptoms, without attempting to connect these with particular diseased states of the nervous centres. The pathology of all the diseases of the nervous system is, it must be confessed, in a most unsatisfactory condition.

scholarly journals Integration of Proprioceptive and Visual Position-Information: An Experimentally Supported Model

1999 ◽  
Vol 81 (3) ◽  
pp. 1355-1364 ◽  
Author(s):  
Robert J. van Beers ◽  
Anne C. Sittig ◽  
Jan J. Denier van der Gon
Keyword(s):  
Visual Information ◽  
The Body ◽  
The Other ◽  
Proprioceptive Information ◽  
Position Information ◽  
Left Hand ◽  
The Mean ◽  
The Right ◽  
Variable Errors ◽  
Available Information

Integration of proprioceptive and visual position-information: an experimentally supported model. To localize one’s hand, i.e., to find out its position with respect to the body, humans may use proprioceptive information or visual information or both. It is still not known how the CNS combines simultaneous proprioceptive and visual information. In this study, we investigate in what position in a horizontal plane a hand is localized on the basis of simultaneous proprioceptive and visual information and compare this to the positions in which it is localized on the basis of proprioception only and vision only. Seated at a table, subjects matched target positions on the table top with their unseen left hand under the table. The experiment consisted of three series. In each of these series, the target positions were presented in three conditions: by vision only, by proprioception only, or by both vision and proprioception. In one of the three series, the visual information was veridical. In the other two, it was modified by prisms that displaced the visual field to the left and to the right, respectively. The results show that the mean of the positions indicated in the condition with both vision and proprioception generally lies off the straight line through the means of the other two conditions. In most cases the mean lies on the side predicted by a model describing the integration of multisensory information. According to this model, the visual information and the proprioceptive information are weighted with direction-dependent weights, the weights being related to the direction-dependent precision of the information in such a way that the available information is used very efficiently. Because the proposed model also can explain the unexpectedly small sizes of the variable errors in the localization of a seen hand that were reported earlier, there is strong evidence to support this model. The results imply that the CNS has knowledge about the direction-dependent precision of the proprioceptive and visual information.

Benjamin Libet’s Big Experiment

2019 ◽  
pp. 186-199
Author(s):  
Alan J. McComas
Keyword(s):  
Electrical Activity ◽  
Neural Activity ◽  
The Body ◽  
The Other ◽  
Sensory Stimulus ◽  
Conscious Awareness ◽  
Evoked Responses ◽  
Temporal Reference ◽  
The Mind ◽  
The Brain

This chapter describes Benjamin Libet’s finding that electrical activity in the brain precedes conscious awareness. Libet’s work had shown that, no matter how brief it was, a sensory stimulus evoked responses in the cortex that lasted hundreds of milliseconds. He also suggested that, just as the somatosensory cortex was able to refer sensations to a particular point on the opposite side of the body (“spatial reference”) so it could refer sensations to an earlier moment—the time when impulse activity had first been initiated in the cortex following the stimulus (“temporal reference”). These were important conclusions and inevitably became the subjects of debate following their publication. But Libet was soon to deliver a greater surprise when he discovered that a decision only entered consciousness when the underlying neural activity was already far advanced. Rather than the mind controlling the brain—thought by thought—it was the other way round and “free will,” seemingly so self-evident, was an illusion.

VI. Experiments made with a view to ascertain the principle on which the action of the heart depends, and the relation which subsists between that organ and the nervous system

1815 ◽  
Vol 105 ◽  
pp. 65-90 ◽  
Keyword(s):  
Nervous System ◽  
The Body ◽  
The Other ◽  
Modus Operandi ◽  
Spinal Marrow ◽  
Difference Of Opinion ◽  
The Subject ◽  
The Brain ◽  
General Opinion ◽  
Nervous Influence

The following experiments were begun with a view to as­ certain the manner in which certain poisons act in destroying life. I soon found that, in order to make any considerable progress in such an inquiry, it is necessary to ascertain how far the powers of the nervous and sanguiferous systems di­rectly depend on each other. There seems never to have been any difference of opinion respecting the direct depend­ence of the nervous on the sanguiferous system. When the powers of circulation are increased or diminished, the nervous system always suffers a corresponding change, nor can the latter, under any circumstances, continue to perform its functions after the former are destroyed. I speak of the warm blooded animals. In cold blooded animals the process of dying is so slow, that the functions of the nervous system abate very gradually, after the circulation has wholly ceased. The converse of the above proposition is by no means so generally admitted. It is evident that certain changes of the nervous, produce corresponding changes in the sanguiferous, system ; yet, while some assert, that the action of the heart depends as immediately on the brain, as that of the latter does on the heart, others maintain, that the nervous power may be wholly destroyed without impairing the vigour of this organ. This point it is necessary to determine, before we can trace with precision the modus operandi of poisons. The following inquiry therefore may be divided into two parts. In the first, I shall endeavour to ascertain how far the power of the heart is influenced by the state of the nervous system; in the other, by what steps certain poisons destroy the powers of both. This I shall reserve for another paper, and here confine my­self to the first part of the subject. Till the time of Haller, it seems to have been the general opinion, that the muscles derive their power from the nervous system. He taught, that the power of the muscles depends on their mechanism, that the nervous influence is merely a stimulus which calls it into action, and consequently that those muscles, the heart for example, which act only by the appli­cation of one peculiar stimulus, unconnected with the nervous system, are wholly independent of it. This opinion seemed confirmed by its being generally admitted, that the action of the heart continues after it is removed from the body, and that it cannot be influenced by stimulating the brain, or spinal marrow, or the nerves which terminate in it. Haller and his followers maintain, that there are two distinct vital powers, one of the nervous and another of the sanguiferous system.

Sensory reweighting of proprioceptive information of the left and right leg during human balance control

2012 ◽  
Vol 108 (4) ◽  
pp. 1138-1148 ◽  
Author(s):  
J. H. Pasma ◽  
T. A. Boonstra ◽  
S. F. Campfens ◽  
A. C. Schouten ◽  
H. Van der Kooij
Keyword(s):  
Visual Information ◽  
Balance Control ◽  
The Other ◽  
Reliable Information ◽  
Proprioceptive Information ◽  
Sensory Reweighting ◽  
Perturbation Amplitude ◽  
Eyes Closed ◽  
Platform Translation ◽  
Support Surfaces

To keep balance, information from different sensory systems is integrated to generate corrective torques. Current literature suggests that this information is combined according to the sensory reweighting hypothesis, i.e., more reliable information is weighted more strongly than less reliable information. In this approach, no distinction has been made between the contributions of both legs. In this study, we investigated how proprioceptive information from both legs is combined to maintain upright stance. Healthy subjects maintained balance with eyes closed while proprioceptive information of each leg was perturbed independently by continuous rotations of the support surfaces (SS) and the human body by platform translation. Two conditions were tested: perturbation amplitude of one SS was increased over trials while the other SS 1) did not move or 2) was perturbed with constant amplitude. With the use of system identification techniques, the response of the ankle torques to the perturbation amplitudes (i.e., the torque sensitivity functions) was determined and how much each leg contributed to stabilize stance (i.e., stabilizing mechanisms) was estimated. Increased amplitude of one SS resulted in a decreased torque sensitivity. The torque sensitivity to the constant perturbed SS showed no significant differences. The properties of the stabilizing mechanisms remained constant during perturbations of each SS. This study demonstrates that proprioceptive information from each leg is weighted independently and that the weight decreases with perturbation amplitude. Weighting of proprioceptive information of one leg has no influence on the weight of the proprioceptive information of the other leg. According to the sensory reweighting hypothesis, vestibular information must be up-weighted, because closing the eyes eliminates visual information.

scholarly journals The body-ownership is unconsciously distorted in the brain: An event-related potential study of rubber hand illusion

Psihologija ◽  
2022 ◽  
pp. 2-2
Author(s):  
Aitao Lu ◽  
Xuebin Wang ◽  
Xiuxiu Hong ◽  
Tianhua Song ◽  
Meifang Zhang ◽  
...  
Keyword(s):  
Early Stage ◽  
Event Related Potential ◽  
The Body ◽  
Rubber Hand Illusion ◽  
Proprioceptive Information ◽  
Body Ownership ◽  
Conflict Monitoring ◽  
Rubber Hand ◽  
Bottom Up ◽  
The Brain

Many studies have reported that bottom-up multisensory integration of visual, tactile, and proprioceptive information can distort our sense of body-ownership, producing rubber hand illusion (RHI). There is less evidence about when and how the body-ownership is distorted in the brain during RHI. To examine whether this illusion effect occurs preattentively at an early stage of processing, we monitored the visual mismatch negativity (vMMN) component (the index of automatic deviant detection) and N2 (the index for conflict monitoring). Participants first performed an RHI elicitation task in a synchronous or asynchronous setting and then finished a passive visual oddball task in which the deviant stimuli were unrelated to the explicit task. A significant interaction between Deviancy (deviant hand vs. standard hand) and Group (synchronous vs. asynchronous) was found. The asynchronous group showed clear mismatch effects in both vMMN and N2, while the synchronous group had such effect only in N2. The results indicate that after the elicitation of RHI bottom-up integration could be retrieved at the early stage of sensory processing before top-down processing, providing evidence for the priority of the bottom-up processes after the generation of RHI and revealing the mechanism of how the body-ownership is unconsciously distorted in the brain.

scholarly journals Heavy Metals in Liver, Kidney, Brain and Muscle Slender-Billed Gull (Chroicocephalus Genei) From the Chahnimeh Water Reservoirs Sistan and Coast Oman Sea (Iran)

2021 ◽  
Author(s):  
Reza Dahmardeh Behrooz ◽  
Joanna Burger
Keyword(s):  
Heavy Metals ◽  
Gender Differences ◽  
Adverse Effects ◽  
Brain Tissue ◽  
The Body ◽  
The Other ◽  
Water Reservoirs ◽  
Oman Sea ◽  
The Brain ◽  
Sea Coast

Abstract The concentrations of four heavy metals nickel (Ni), cadmium (Cd), lead (Pb) and zinc (Zn) were determined in liver, kidney, muscle and brain tissues of 20 slender-billed gulls (Chroicocephalus genei) from the Chahnimeh water reservoirs of Sistan and the Oman Sea coast of Iran. There were significant differences between nickel Ni, Cd, Pb and Zn concentrations observed in the liver and brains of birds from the Oman Sea coast than in liver and brains of gulls from the Chahnimeh water reservoirs (P < 0.05). Higher levels of Pb, Cd and Zn were found in the brain and liver of gulls than in the kidney and muscles tissues. There were significant gender differences in heavy metals in liver and brain tissue. In gulls from the coast of Oman Sea, all four elements (Cd, Pb, Ni and Zn) were positively correlated with levels in all organs, and except for muscle, the elements were positively correlated with the other elements in the other tissue (except Ni in brain). Thus, the pathways and sources of entry for the elements are similar, and the pathways for accumulation of these elements, and the reactions of different organs of the body to these elements, are very similar. Also, 40% of gulls in Oman Sea coast had levels of lead in the brain that were above the adverse effects levels, Ni concentrations in liver of slender-billed gull in Oman Sea coast (100 %) and Chahnimeh water reservoirs (90 %) were above toxic levels, and 80% of Ni concentration in kidneys in gulls from the Oman Sea coast and Chahnimeh water reservoirs were higher than the toxicity levels.

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