scholarly journals Robot-Aided Neuro-Recovery

2014 ◽  
Vol 136 (09) ◽  
pp. S3-S5 ◽  
Author(s):  
Neville Hogan
Keyword(s):  
Target Location ◽  
Movement Control ◽  
Visual Display ◽  
Neurological Injury ◽  
Joint Mobility ◽  
Back Wall ◽  
Current Location ◽  
Starting Location ◽  
Principles Of Learning ◽  
The Brain

This article explains how robots can help people recover after neurological injury. The most successful robot-administered therapy to aid neuro-recovery is based on several principles of learning. A visual display indicates a target location to which the patient should attempt to move. The robot sets up a virtual channel between the current location of the patient’s limb and the target location. If the patient moves along that channel, no forces are experienced. However, if the patient’s motion deviates to either side of that channel, those aiming errors are permitted but resisted by a programmable damped spring. If the patient moves too slowly (or does not initiate movement at all), the back wall of the channel (the end at the patient’s starting location) moves smoothly towards the target location, nudging the patient to the target. Repeating this process with high intensity provides the stimulus and statistics for the brain to reacquire movement control and coordination. Passively moving a patient’s limbs may help improve joint mobility.

Differences in the brain stem terminations of large- and small-diameter vestibular primary afferents

1995 ◽  
Vol 74 (3) ◽  
pp. 1362-1366 ◽  
Author(s):  
J. A. Huwe ◽  
E. H. Peterson
Keyword(s):  
Brain Stem ◽  
Large Diameter ◽  
Small Diameter ◽  
Movement Control ◽  
Three Dimensions ◽  
Significant Shift ◽  
Axon Diameter ◽  
Vestibular Complex ◽  
The Brain ◽  
Adjacent Brain

1. We visualized the central axons of 32 vestibular afferents from the posterior canal by extracellular application of horseradish peroxidase, reconstructed them in three dimensions, and quantified their morphology. Here we compare the descending limbs of central axons that differ in parent axon diameter. 2. The brain stem distribution of descending limb terminals (collaterals and associated varicosities) varies systematically with parent axon diameter. Large-diameter afferents concentrate their terminals in rostral regions of the medial/descending nuclei. As axon diameter decreases, there is a significant shift of terminal concentration toward the caudal vestibular complex and adjacent brain stem. 3. Rostral and caudal regions of the medial/descending nuclei have different labyrinthine, cerebellar, intrinsic, commissural, and spinal connections; they are believed to play different roles in head movement control. Our data help clarify the functions of large- and small-diameter afferents by showing that they contribute differentially to rostral and caudal vestibular complex.

A Novel Method for Automated Tool Path Optimisation for CNC Machining Operations

2010 ◽  
Vol 166-167 ◽  
pp. 357-362
Author(s):  
Shahed Shojaeipour
Keyword(s):  
Tool Path ◽  
Target Location ◽  
Imaging System ◽  
Optimal Path ◽  
Digital Camera ◽  
Basic Program ◽  
Cnc Machining ◽  
Cnc Machine ◽  
Current Location ◽  
Tool Diameter

In this article, a new method for rapid tool movement in CNC machines is presented. Firstly, a single digital camera, installed on the Z-axis, captures the image of the workpiece on the work table. Image processing techniques, implemented using MATLAB, are then used to convert the image into a binary black and white image. This allows the locations of protruding edge sections on the workpiece, which could impede tool movement, to be identified. Quadtree decomposition is then performed on the binary image, and possible paths from the tool current location to its target location are found. These paths are then analysed based on the tool diameter clearance and the distance to the goal, and the shortest path with sufficient tool clearance is selected. A Visual Basic program then converts the selected path into G-code commands that provides instructions to the CNC machine tool such that this path is followed. With this method, the workpiece fixture location would not have to be precise as the imaging system would be able to automatically identify the target location with respect to the tool current location, along with the optimal path to reach it.

Vestibular Signals in Self-Orientation and Eye Movement Control

Physiology ◽  
2001 ◽  
Vol 16 (5) ◽  
pp. 234-238 ◽  
Author(s):  
Bernhard J. M. Hess
Keyword(s):  
Signal Processing ◽  
Eye Movement ◽  
Vestibular System ◽  
Retinal Image ◽  
Internal Model ◽  
Movement Control ◽  
Head Position ◽  
Head Motion ◽  
Afferent Information ◽  
The Brain

The central vestibular system receives afferent information about head position as well as rotation and translation. This information is used to prevent blurring of the retinal image but also to control self-orientation and motion in space. Vestibular signal processing in the brain stem appears to be linked to an internal model of head motion in space.

scholarly journals Intrinsic spatial knowledge about terrestrial ecology favors the tall for judging distance

2016 ◽  
Vol 2 (8) ◽  
pp. e1501070 ◽  
Author(s):  
Liu Zhou ◽  
Teng Leng Ooi ◽  
Zijiang J. He
Keyword(s):  
Target Location ◽  
Spatial Relationship ◽  
Ground Surface ◽  
Spatial Knowledge ◽  
Superior Performance ◽  
Natural Scenes ◽  
Terrestrial Environment ◽  
Optical Images ◽  
Intermediate Distance ◽  
The Brain

Our sense of vision reliably directs and guides our everyday actions, such as reaching and walking. This ability is especially fascinating because the optical images of natural scenes that project into our eyes are insufficient to adequately form a perceptual space. It has been proposed that the brain makes up for this inadequacy by using its intrinsic spatial knowledge. However, it is unclear what constitutes intrinsic spatial knowledge and how it is acquired. We investigated this question and showed evidence of an ecological basis, which uses the statistical spatial relationship between the observer and the terrestrial environment, namely, the ground surface. We found that in dark and reduced-cue environments where intrinsic knowledge has a greater contribution, perceived target location is more accurate when referenced to the ground than to the ceiling. Furthermore, taller observers more accurately localized the target. Superior performance was also observed in the full-cue environment, even when we compensated for the observers’ heights by having the taller observer sit on a chair and the shorter observers stand on a box. Although fascinating, this finding dovetails with the prediction of the ecological hypothesis for intrinsic spatial knowledge. It suggests that an individual’s accumulated lifetime experiences of being tall and his or her constant interactions with ground-based objects not only determine intrinsic spatial knowledge but also endow him or her with an advantage in spatial ability in the intermediate distance range.

scholarly journals Learning what is irrelevant or relevant: Expectations facilitate distractor inhibition and target facilitation through distinct neural mechanisms

2019 ◽  
Author(s):  
Dirk van Moorselaar ◽  
Heleen A. Slagter
Keyword(s):  
Target Location ◽  
Response Times ◽  
Relevant Information ◽  
Distractor Location ◽  
Distractor Inhibition ◽  
Distractor Processing ◽  
Behavioral Studies ◽  
Outstanding Question ◽  
Target Locations ◽  
The Brain

AbstractIt is well known that attention can facilitate performance by top-down biasing processing of task-relevant information in advance. Recent findings from behavioral studies suggest that distractor inhibition is not under similar direct control, but strongly dependent on expectations derived from previous experience. Yet, how expectations about distracting information influence distractor inhibition at the neural level remains unclear. The current study addressed this outstanding question in three experiments in which search displays with repeating distractor or target locations across trials allowed observers to learn which location to selectively suppress or boost. Behavioral findings demonstrated that both distractor and target location learning resulted in more efficient search, as indexed by faster response times. Crucially, benefits of distractor learning were observed without target location foreknowledge, unaffected by the number of possible target locations, and could not be explained by priming alone. To determine how distractor location expectations facilitated performance, we applied a spatial encoding model to EEG data to reconstruct activity in neural populations tuned to the distractor or target location. Target location learning increased neural tuning to the target location in advance, indicative of preparatory biasing. This sensitivity increased after target presentation. By contrast, distractor expectations did not change preparatory spatial tuning. Instead, distractor expectations reduced distractor-specific processing, as reflected in the disappearance of the Pd ERP component, a neural marker of distractor inhibition, and decreased decoding accuracy. These findings suggest that the brain may no longer process expected distractors as distractors, once it has learned they can safely be ignored.Significance statementWe constantly try hard to ignore conspicuous events that distract us from our current goals. Surprisingly, and in contrast to dominant attention theories, ignoring distracting, but irrelevant events does not seem to be as flexible as is focusing our attention on those same aspects. Instead, distractor suppression appears to strongly rely on learned, context-dependent expectations. Here, we investigated how learning about upcoming distractors changes distractor processing and directly contrasted the underlying neural dynamics to target learning. We show that while target learning enhanced anticipatory sensory tuning, distractor learning only modulated reactive suppressive processing. These results suggest that expected distractors may no longer be considered distractors by the brain once it has learned that they can safely be ignored.

scholarly journals Parallel updating and weighting of multiple spatial maps for visual stability during whole body motion

2015 ◽  
Vol 114 (6) ◽  
pp. 3211-3219 ◽  
Author(s):  
J. J. Tramper ◽  
W. P. Medendorp
Keyword(s):  
Reference Frame ◽  
Reference Frames ◽  
Spatial Information ◽  
Target Location ◽  
Visual Space ◽  
Body Motion ◽  
Whole Body ◽  
Spatial Representations ◽  
Integration Model ◽  
The Brain

It is known that the brain uses multiple reference frames to code spatial information, including eye-centered and body-centered frames. When we move our body in space, these internal representations are no longer in register with external space, unless they are actively updated. Whether the brain updates multiple spatial representations in parallel, or whether it restricts its updating mechanisms to a single reference frame from which other representations are constructed, remains an open question. We developed an optimal integration model to simulate the updating of visual space across body motion in multiple or single reference frames. To test this model, we designed an experiment in which participants had to remember the location of a briefly presented target while being translated sideways. The behavioral responses were in agreement with a model that uses a combination of eye- and body-centered representations, weighted according to the reliability in which the target location is stored and updated in each reference frame. Our findings suggest that the brain simultaneously updates multiple spatial representations across body motion. Because both representations are kept in sync, they can be optimally combined to provide a more precise estimate of visual locations in space than based on single-frame updating mechanisms.

Precis of Vigor: Neuroeconomics of movement control

2020 ◽  
pp. 1-10
Author(s):  
Reza Shadmehr ◽  
Alaa A. Ahmed
Keyword(s):  
Decision Making ◽  
New York ◽  
Neural Circuits ◽  
Movement Control ◽  
Brain Structures ◽  
The Other ◽  
Neural Basis ◽  
Hand Control ◽  
Measured Activity ◽  
The Brain

Abstract Why do we run toward people we love, but only walk toward others? Why do people in New York seem to walk faster than other cities? Why do our eyes linger longer on things we value more? There is a link between how the brain assigns value to things, and how it controls our movements. This link is an ancient one, developed through shared neural circuits that on one hand teach us how to value things, and on the other hand control the vigor with which we move. As a result, when there is damage to systems that signal reward, like dopamine and serotonin, that damage not only affects our mood and patterns of decision making, but how we move. In this book, we first ask why in principle evolution should have developed a shared system of control between valuation and vigor. We then focus on the neural basis of vigor, synthesizing results from experiments that have measured activity in various brain structures and neuromodulators, during tasks in which animals decide how patiently they should wait for reward, and how vigorously they should move to acquire it. Thus, the way we move unmasks one of our well-guarded secrets: how much we value the thing we are moving toward.

Surface-based facial scan registration in neuronavigation procedures: a clinical study

2009 ◽  
Vol 111 (6) ◽  
pp. 1201-1206 ◽  
Author(s):  
Reuben R. Shamir ◽  
Moti Freiman ◽  
Leo Joskowicz ◽  
Sergey Spektor ◽  
Yigal Shoshan
Keyword(s):  
Target Location ◽  
Lateral Position ◽  
Surface Registration ◽  
Registration Accuracy ◽  
Registration Error ◽  
Head Surface ◽  
The Face ◽  
The Mean ◽  
Target Locations ◽  
The Brain

Object Surface-based registration (SBR) with facial surface scans has been proposed as an alternative for the commonly used fiducial-based registration in image-guided neurosurgery. Recent studies comparing the accuracy of SBR and fiducial-based registration have been based on a few targets located on the head surface rather than inside the brain and have yielded contradictory conclusions. Moreover, no visual feedback is provided with either method to inform the surgeon about the estimated target registration error (TRE) at various target locations. The goals in the present study were: 1) to quantify the SBR error in a clinical setup, 2) to estimate the targeting error for many target locations inside the brain, and 3) to create a map of the estimated TRE values superimposed on a patient's head image. Methods The authors randomly selected 12 patients (8 supine and 4 in a lateral position) who underwent neurosurgery with a commercial navigation system. Intraoperatively, scans of the patients' faces were acquired using a fast 3D surface scanner and aligned with their preoperative MR or CT head image. In the laboratory, the SBR accuracy was measured on the facial zone and estimated at various intracranial target locations. Contours related to different TREs were superimposed on the patient's head image and informed the surgeon about the expected anisotropic error distribution. Results The mean surface registration error in the face zone was 0.9 ± 0.35 mm. The mean estimated TREs for targets located 60, 105, and 150 mm from the facial surface were 2.0, 3.2, and 4.5 mm, respectively. There was no difference in the estimated TRE between the lateral and supine positions. The entire registration procedure, including positioning of the scanner, surface data acquisition, and the registration computation usually required < 5 minutes. Conclusions Surface-based registration accuracy is better in the face and frontal zones, and error increases as the target location lies further from the face. Visualization of the anisotropic TRE distribution may help the surgeon to make clinical decisions. The observed and estimated accuracies and the intraoperative registration time show that SBR using the fast surface scanner is practical and feasible in a clinical setup.

Visual Remapping by Vector Subtraction: Analysis of Multiplicative Gain Field Models

2007 ◽  
Vol 19 (9) ◽  
pp. 2353-2386 ◽  
Author(s):  
Carlos R. Cassanello ◽  
Vincent P. Ferrera
Keyword(s):  
Target Location ◽  
Target Position ◽  
Saccadic Eye Movements ◽  
Neural Mechanism ◽  
Spatial Modulation ◽  
Eye Position ◽  
Retinal Position ◽  
Population Activity ◽  
Firing Rates ◽  
The Brain

Saccadic eye movements remain spatially accurate even when the target becomes invisible and the initial eye position is perturbed. The brain accomplishes this in part by remapping the remembered target location in retinal coordinates. The computation that underlies this visual remapping is approximated by vector subtraction: the original saccade vector is updated by subtracting the vector corresponding to the intervening eye movement. The neural mechanism by which vector subtraction is implemented is not fully understood. Here, we investigate vector subtraction within a framework in which eye position and retinal target position signals interact multiplicatively (gain field). When the eyes move, they induce a spatial modulation of the firing rates across a retinotopic map of neurons. The updated saccade metric can be read from the shift of the peak of the population activity across the map. This model uses a quasi-linear (half-rectified) dependence on the eye position and requires the slope of the eye position input to be negatively proportional to the preferred retinal position of each neuron. We derive analytically this constraint and study its range of validity. We discuss how this mechanism relates to experimental results reported in the frontal eye fields of macaque monkeys.

scholarly journals IMPLEMENTASI MODEL PENDEKATAN BRAIN GYM UNTUK MENINGKATKAN HASIL BELAJAR MATEMATIKA

2021 ◽  
Vol 1 (4) ◽  
pp. 288-297
Author(s):  
PARTO PARTO
Keyword(s):  
Learning Outcomes ◽  
Teaching And Learning ◽  
Mathematics Learning ◽  
Model Learning ◽  
Brain Gym ◽  
The Third ◽  
Learning Mathematics ◽  
Learning Conditions ◽  
Principles Of Learning ◽  
The Brain

This study aims to determine whether students' mathematics learning outcomes increase after teaching and learning activities are carried out using the Brain Gym approach model (brain exercise). This study used a qualitative approach model and was conducted at SD Negeri Kebalen 05, Babelan District, Bekasi Regency with three cycles. In the first cycle, some students were not familiar with learning conditions using the Brain Gym approach model (brain gymnastics) so that action was taken by explaining the principles of learning with the Brain Gym approach model. On the other hand, the teacher as a collaborator in this research has not been maximal in implementing the Brain Gym approach model. In the second cycle, students and teachers (collaborators) have begun to understand the implementation of the Brain Gym approach model learning and show quite satisfactory results as well as in the third cycle. This can be seen from the results of observations of students and teachers that lead to the Brain Gym approach model. From the results of observations, student activity increased from 52% in the first cycle, 72% in the second cycle, and to 82% in the third cycle. Meanwhile the results of daily tests showed an increase, namely: in the first cycle with KKM 55.00 completed with an average of 63, cycle II KKM 65.00 an average of 71.4 and in the third cycle KKM 65.00 an average of 80.6 . From the results of the research in cycles I, II, and III, it was concluded that the implementation of the Brain Gym approach model could improve student learning outcomes and activities in learning mathematics in class IV.1 SD Negeri Kebalen 05, Babelan District, Bekasi Regency. ABSTRAKPenelitian ini bertujuan untuk mengetahui apakah hasil belajar matematika siswa meningkat setelah dilaksanakan kegiatan belajar mengajar dengan menggunakan model pendekatan Brain Gym (senam otak). Penelitian ini menggunakan model pendekatan kualitatif dan dilakukan di SD Negeri Kebalen 05 Kecamatan Babelan Kabupaten Bekasi dengan tiga siklus. Pada siklus pertama sebagian siswa belum terbiasa dengan kondisi belajar menggunakan model pendekatan Brain Gym (senam otak) sehingga dilakukan tindakan dengan memberi penjelasan tentang prinsip-prinsip pembelajaran dengan model pendekatan Brain Gym. Di sisi lain guru sebagai kolaborator dalam penelitian ini juga belum maksimal dalam mengimplementasikan model pendekatan Brain Gym. Dalam siklus kedua siswa dan guru (kolaborator) sudah mulai memahami implementasi pembelajaran model pendekatan Brain Gym dan menunjukkan hasil yang cukup memuaskan begitu juga pada siklus ketiga. Hal ini dilihat dari hasil observasi terhadap siswa dan guru yang mengarah kepada model pendekatan Brain Gym. Dari hasil observasi, aktivitas siswa meningkat dari 52% pada siklus I, 72% pada siklus II, dan menjadi 82% pada siklus III. Sementara itu hasil ulangan harian menunjukkan peningkatan yaitu: pada siklus I dengan KKM 55,00 tuntas dengan rata-rata 63, siklus II KKM 65,00 rata-rata 71,4 dan pada siklus III KKM 65,00 rata-rata 80,6. Dari hasil pelaksanaan penelitian siklus I, II, dan III disimpulkan bahwa implementasi model pendekatan Brain Gym (senam otak) dapat meningkatkan hasil belajar dan aktivitas siswa dalam pembelajaran matematika pada kelas IV.1 SD Negeri Kebalen 05 Kecamatan Babelan Kabupaten Bekasi.

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