scholarly journals Online sensory feedback during active search improves tactile localization

2019 ◽  
Author(s):  
Xaver Fuchs ◽  
Dirk U. Wulff ◽  
Tobias Heed
Keyword(s):  
Visual Memory ◽  
Sensory Feedback ◽  
Target Location ◽  
Motor Behavior ◽  
Tactile Feedback ◽  
The Body ◽  
Natural Setting ◽  
Action Perception ◽  
Body Representations ◽  
Tactile Localization

AbstractMany natural behaviors involve closed feedback loops in which ongoing sensory input refines motor behavior. Previous research on tactile localization, however, has implemented localization as open-loop behavior. For instance, participants indicate a touched position on a silhouette shape of the body or on an occluding board mounted above the hand. Such studies have suggested that humans often make large errors when localizing touch on the skin, or that “perceptual body representations” are distorted. However, by artificially preventing tactile feedback from the target body area, the natural action-perception loop is interrupted. Therefore, these localization approaches may underestimate individuals’ localization ability and draw erroneous conclusions about the role and precision of body representations. Here, we tested tactile localization in a natural setting, in which participants first received brief touches on their left forearm and then searched for the target location by moving the right index finger across the skin. Tactile search reduced localization error when the searching finger was far from, but not when it was near the target, resulting in a remaining error of 1-2 cm. Error reduction was absent when participants searched on an acrylic barrier mounted above the arm, suggesting that availability of tactile feedback on the target arm but not proprioceptive and motor signals of the searching arm determined precision, thus confirming the pivotal role of closed-loop sensory feedback for tactile localization. We suggest that actively produced online tactile feedback routinely refines coarse spatial body representations, similar to the refinement of sparse spatial representations in visual memory through consecutive saccades.

scholarly journals Implicit and Explicit Body Representations

2015 ◽  
Vol 20 (1) ◽  
pp. 6-15 ◽  
Author(s):  
Matthew R. Longo
Keyword(s):  
Sensory Information ◽  
Body Representation ◽  
Position Sense ◽  
The Body ◽  
Size Perception ◽  
Somatosensory Processing ◽  
Body Representations ◽  
Size And Shape ◽  
Tactile Localization ◽  
Somatosensory Information

Several forms of perception require that sensory information be referenced to representations of the size and shape of the body. This requirement is especially acute in somatosensation in which the main receptor surface (i.e., the skin) is itself coextensive with the body. This paper reviews recent research investigating the body representations underlying somatosensory information processing, including abilities such as tactile localization, tactile size perception, and position sense. These representations show remarkably large and stereotyped distortions of represented body size and shape. Intriguingly, these distortions appear to mirror distortions characteristic of somatosensory maps, though in attenuated form. In contrast, when asked to make overt judgments about perceived body form, participants are generally quite accurate. This pattern of results suggests that higher-level somatosensory processing relies on a class of implicit body representation, distinct from the conscious body image. I discuss the implications of these results for understanding the nature of body representation and the factors that influence it.

Tactile Surface Detector for a Prosthetic Hand

2011 ◽  
Author(s):  
Kai Yuen Lim ◽  
Emily Cook ◽  
S. Philip Kirkpatrick ◽  
Neophytos Palettas
Keyword(s):  
Upper Limb ◽  
User Satisfaction ◽  
Visual Information ◽  
Sensory Feedback ◽  
Motor Coordination ◽  
The United States ◽  
Tactile Feedback ◽  
The Body ◽  
Surface Detector ◽  
Artificial Hand

Currently, the number of amputees in the United States is estimated at 1.7 million people [1], and of those 1.7 million people, only approximately 300,000 are upper limb amputees [2]. However, the number of amputees is growing at a rate of more than 18,000 people per year [3]. Although the body powered and myoelectric prosthetics have been invented to provide a cosmetic solution and functionally allow the user to employ leverage or grasp an object, there are no marketed products which provide tactile feedback. Often amputees will not use their current prosthetics due to their unnatural feel. In terms of functional use of the prosthetics, reports show as low as 29% of amputees with prosthetics make use of the grasp feature [4]. Due to the general lack of user satisfaction, it is necessary to improve the prosthetic market by incorporating sensory feedback into upper limb prosthetics so that the user feels like they are using their own arm. With the incorporation of sensory-motor coordination, amputees’ reliance on visual information to be aware of the artificial hand and arm will be decreased, thereby, decreasing their cognitive load [5]. Additionally, due to the increased feedback from the arm regarding the environment, the amputee will be able to use their artificial limb more effectively and with more of native feel.

Human Cerebral Potentials During Motor Training Under Different Forms of Sensory Feedback

1999 ◽  
Vol 13 (4) ◽  
pp. 234-244
Author(s):  
Uwe Niederberger ◽  
Wolf-Dieter Gerber
Keyword(s):  
Healthy Subjects ◽  
Sensory Feedback ◽  
Motor Task ◽  
Tactile Feedback ◽  
Proprioceptive Feedback ◽  
Motor Training ◽  
Feedback Group ◽  
Emg Feedback ◽  
The Right ◽  
Training Success

Abstract In two experiments with four and two groups of healthy subjects, a novel motor task, the voluntary abduction of the right big toe, was trained. This task cannot usually be performed without training and is therefore ideal for the study of elementary motor learning. A systematic variation of proprioceptive, tactile, visual, and EMG feedback was used. In addition to peripheral measurements such as the voluntary range of motion and EMG output during training, a three-channel EEG was recorded over Cz, C3, and C4. The movement-related brain potential during distinct periods of the training was analyzed as a central nervous parameter of the ongoing learning process. In experiment I, we randomized four groups of 12 subjects each (group P: proprioceptive feedback; group PT: proprioceptive and tactile feedback; group PTV: proprioceptive, tactile, and visual feedback; group PTEMG: proprioceptive, tactile, and EMG feedback). Best training results were reported from the PTEMG and PTV groups. The movement-preceding cortical activity, in the form of the amplitude of the readiness potential at the time of EMG onset, was greatest in these two groups. Results of experiment II revealed a similar effect, with a greater training success and a higher electrocortical activation under additional EMG feedback compared to proprioceptive feedback alone. Sensory EMG feedback as evaluated by peripheral and central nervous measurements appears to be useful in motor training and neuromuscular re-education.

scholarly journals The emulation theory of representation: Motor control, imagery, and perception

2004 ◽  
Vol 27 (3) ◽  
pp. 377-396 ◽  
Author(s):  
Rick Grush
Keyword(s):  
Motor Control ◽  
Sensory Feedback ◽  
Sensory Input ◽  
Neural Circuits ◽  
Sensory Information ◽  
The Body ◽  
Feedback Delay ◽  
Run Off ◽  
Effects Of Feedback ◽  
The Brain

The emulation theory of representation is developed and explored as a framework that can revealingly synthesize a wide variety of representational functions of the brain. The framework is based on constructs from control theory (forward models) and signal processing (Kalman filters). The idea is that in addition to simply engaging with the body and environment, the brain constructs neural circuits that act as models of the body and environment. During overt sensorimotor engagement, these models are driven by efference copies in parallel with the body and environment, in order to provide expectations of the sensory feedback, and to enhance and process sensory information. These models can also be run off-line in order to produce imagery, estimate outcomes of different actions, and evaluate and develop motor plans. The framework is initially developed within the context of motor control, where it has been shown that inner models running in parallel with the body can reduce the effects of feedback delay problems. The same mechanisms can account for motor imagery as the off-line driving of the emulator via efference copies. The framework is extended to account for visual imagery as the off-line driving of an emulator of the motor-visual loop. I also show how such systems can provide for amodal spatial imagery. Perception, including visual perception, results from such models being used to form expectations of, and to interpret, sensory input. I close by briefly outlining other cognitive functions that might also be synthesized within this framework, including reasoning, theory of mind phenomena, and language.

The problem of studying motor skills in connection with the peculiarities of the body and psyche

1927 ◽  
Vol 23 (6-7) ◽  
pp. 735-740
Author(s):  
I. N. Zhilin
Keyword(s):  
Motor Skills ◽  
Motor Behavior ◽  
The Body ◽  
Motor Functions ◽  
Mental Structure ◽  
General Pathology ◽  
Mental Diseases

Kretschmer's doctrine of the correlation between physique and character overlooks a question that lies in the plane of similar correlations, namely, that of the correlation between motor functions and the mental structure of personality. This question attracts much attention these days and must occupy the most legitimate place among other problems included in the study of personality, both healthy and sick. In the latter case, it is worth remembering at least the instructions of Wernicke (2), who opined that "the general pathology of mental diseases consists in nothing else than in peculiarities of motor behavior".

scholarly journals Experimentally induced pain does not influence updating of peripersonal space and body representations following tool-use

2018 ◽  
Author(s):  
Axel Davies Vittersø ◽  
Monika Halicka ◽  
Gavin Buckingham ◽  
Michael J Proulx ◽  
Mark Wilson ◽  
...  
Keyword(s):  
Chronic Pain ◽  
Tool Use ◽  
Experimental Pain ◽  
Peripersonal Space ◽  
The Body ◽  
Body Representations ◽  
Tactile Target ◽  
The Difference ◽  
Chronic Pain Conditions ◽  
Crossmodal Congruency

Representations of the body and peripersonal space can be distorted for people with some chronic pain conditions. Experimental pain induction can give rise to similar, but transient distortions in healthy individuals. However, spatial and bodily representations are dynamic, and constantly update as we interact with objects in our environment. It is unclear whether induced pain disrupts the mechanisms involved in updating these representations. In the present study, we sought to investigate the effect of induced pain on the updating of peripersonal space and body representations during and following tool-use. We compared performance under three conditions (pain, active placebo, neutral) on a visuotactile crossmodal congruency task and a tactile distance judgement task to measure updating of peripersonal space and body representations, respectively. We induced pain by applying 1% capsaicin cream to the arm, and for placebo we used a gel that induced non-painful warming. Consistent with previous findings, the difference in crossmodal interference from visual distractors in the same compared to opposite visual field to the tactile target was less when tools were crossed than uncrossed. This suggests an extension of peripersonal space to incorporate the tips of the tools. Also consistent with previous findings, estimates of the felt distance between two points (tactile distance judgements) decreased after active tool-use. In contrast to our predictions, however, we found no evidence that pain interfered with performance on either task when compared to the control conditions. This suggests that the updating of peripersonal space and body representations is not disrupted by induced pain. Therefore, acute pain does not account for the distorted representations of the body and peripersonal space that can endure in people with chronic pain conditions.

scholarly journals Possible mechanisms of anosognosia: a defect in self–awareness

1998 ◽  
Vol 353 (1377) ◽  
pp. 1903-1909 ◽  
Author(s):  
◽  
K. M. Heilman ◽  
A. M. Barrett ◽  
J. C. Adair
Keyword(s):  
Population Study ◽  
Sensory Feedback ◽  
Large Population ◽  
The Body ◽  
Spatial Neglect ◽  
Self Awareness ◽  
Knowledge Of Results ◽  
Present Evidence ◽  
Sensory Deficits ◽  
Parallel Processes

Anosognosia of hemiplegia is of interest for both pragmatic and theoretical reasons. We discuss several neuropsychological theories that have been proposed to explain this deficit. Although for psychological reasons people might deny deficits, the denial hypothesis cannot account for the hemispheric asymmetries associated with this disorder and cannot explain why some patients might deny one deficit and recognize another equally disabling deficit. There is some evidence that faulty feedback from sensory deficits, spatial neglect and asomatognosia might be responsible for anosognosia in some patients. However, these feedback hypotheses cannot account for anosognosia in all patients. Although the hemispheric disconnection hypothesis is appealing, disconnection is probably only a rare cause of this disorder. The feedforward intentional theory of anosognosia suggests that the discovery of weakness is dependent on attempted action and some patients might have anosognosia because they do not attempt to move. We present evidence that supports this theory. The presence of one mechanism of anosognosia, however, does not preclude the possibility that other mechanisms might also be working to produce this disorder. Although a large population study needs to be performed, we suspect that anosognosia might be caused by several of the mechanisms that we have discussed. On the basis of the studies of impaired corporeal self–awareness that we have reviewed, we can infer that normal self–awareness is dependent on several parallel processes. One must have sensory feedback and the ability to attend to both one's body and the space where parts of the body may be positioned or acting. One must develop a representation of the body, and this representation must be continuously modified by expectations (feedforward) and knowledge of results (feedback).

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