Congenitally Blind Individuals Rapidly Adapt to Coriolis Force Perturbations of Their Reaching Movements

2000 ◽  
Vol 84 (4) ◽  
pp. 2175-2180 ◽  
Author(s):  
Paul DiZio ◽  
James R. Lackner
Keyword(s):  
Visual Feedback ◽  
Target Location ◽  
Mirror Image ◽  
Reaching Movements ◽  
Coriolis Forces ◽  
Rotation Pattern ◽  
Congenitally Blind ◽  
Motor Information ◽  
Blind Individuals ◽  
Straight Ahead

Reaching movements made to visual targets in a rotating room are initially deviated in path and endpoint in the direction of transient Coriolis forces generated by the motion of the arm relative to the rotating environment. With additional reaches, movements become progressively straighter and more accurate. Such adaptation can occur even in the absence of visual feedback about movement progression or terminus. Here we examined whether congenitally blind and sighted subjects without visual feedback would demonstrate adaptation to Coriolis forces when they pointed to a haptically specified target location. Subjects were tested pre-, per-, and postrotation at 10 rpm counterclockwise. Reaching to straight ahead targets prerotation, both groups exhibited slightly curved paths. Per-rotation, both groups showed large initial deviations of movement path and curvature but within 12 reaches on average had returned to prerotation curvature levels and endpoints. Postrotation, both groups showed mirror image patterns of curvature and endpoint to the per-rotation pattern. The groups did not differ significantly on any of the performance measures. These results provide compelling evidence that motor adaptation to Coriolis perturbations can be achieved on the basis of proprioceptive, somatosensory, and motor information in the complete absence of visual experience.

The Role of Reafference in Recalibration of Limb Movement Control and Locomotion

1997 ◽  
Vol 7 (4) ◽  
pp. 303-310
Author(s):  
James R. Lackner ◽  
Paul DiZio
Keyword(s):  
Movement Control ◽  
Mirror Image ◽  
The Body ◽  
Head Movements ◽  
Reaching Movements ◽  
Optomotor Response ◽  
Coriolis Forces ◽  
Effects Of Rotation ◽  
Centripetal Forces

The reafference model has frequently been used to explain spatial constancy during eye and head movements. We have found that its basic concepts also form part of the information processing necessary for the control and recalibration of reaching movements. Reaching was studied in a novel force environment–a rotating room that creates centripetal forces of the type that could someday substitute for gravity in space flight, and Coriolis forces which are side effects of rotation. We found that inertial, noncontacting Coriolis forces deviate the path and endpoint of reaching movements, a finding that shows the inadequacy of equilibrium position models of movement control. Repeated movements in the rotating room quickly lead to normal movement patterns and to a failure to perceive the perturbing forces. The first movements made after rotation stops, without Coriolis forces present, show mirror-image deviations and evoke perception of a perturbing force even though none is present. These patterns of sensorimotor control and adaptation can largely be explained on the basis of comparisons of efference copy, reafferent muscle spindle, and cutaneous mechanoreceptor signals. We also describe experiments on human iocomotion using an apparatus similar to that which Mittelstaedt used to study the optomotor response of the Eristalis fly. These results show that the reafference principle relates as well to the perception of the forces acting on and exerted by the body during voluntary locomotion.

Reaching During Virtual Rotation: Context Specific Compensations for Expected Coriolis Forces

2000 ◽  
Vol 83 (6) ◽  
pp. 3230-3240 ◽  
Author(s):  
Joseph V. Cohn ◽  
Paul DiZio ◽  
James R. Lackner
Keyword(s):  
Target Location ◽  
Arm Movements ◽  
Open Loop ◽  
Tactile Feedback ◽  
Body Motion ◽  
Reaching Movements ◽  
Coriolis Forces ◽  
Enclosed Chamber ◽  
Path Curvature ◽  
Context Specific

Subjects who are in an enclosed chamber rotating at constant velocity feel physically stationary but make errors when pointing to targets. Reaching paths and endpoints are deviated in the direction of the transient inertial Coriolis forces generated by their arm movements. By contrast, reaching movements made during natural, voluntary torso rotation seem to be accurate, and subjects are unaware of the Coriolis forces generated by their movements. This pattern suggests that the motor plan for reaching movements uses a representation of body motion to prepare compensations for impending self-generated accelerative loads on the arm. If so, stationary subjects who are experiencing illusory self-rotation should make reaching errors when pointing to a target. These errors should be in the direction opposite the Coriolis accelerations their arm movements would generate if they were actually rotating. To determine whether such compensations exist, we had subjects in four experiments make visually open-loop reaches to targets while they were experiencing compelling illusory self-rotation and displacement induced by rotation of a complex, natural visual scene. The paths and endpoints of their initial reaching movements were significantly displaced leftward during counterclockwise illusory rotary displacement and rightward during clockwise illusory self-displacement. Subjects reached in a curvilinear path to the wrong place. These reaching errors were opposite in direction to the Coriolis forces that would have been generated by their arm movements during actual torso rotation. The magnitude of path curvature and endpoint errors increased as the speed of illusory self-rotation increased. In successive reaches, movement paths became straighter and endpoints more accurate despite the absence of visual error feedback or tactile feedback about target location. When subjects were again presented a stationary scene, their initial reaches were indistinguishable from pre-exposure baseline, indicating a total absence of aftereffects. These experiments demonstrate that the nervous system automatically compensates in a context-specific fashion for the Coriolis forces associated with reaching movements.

Gravitoinertial Force Background Level Affects Adaptation to Coriolis Force Perturbations of Reaching Movements

1998 ◽  
Vol 80 (2) ◽  
pp. 546-553 ◽  
Author(s):  
James R. Lackner ◽  
Paul Dizio
Keyword(s):  
Centrifugal Force ◽  
Coriolis Force ◽  
Normal Gravity ◽  
Background Level ◽  
Mirror Image ◽  
Reaching Movements ◽  
Coriolis Forces ◽  
Straight Line ◽  
Gravitoinertial Force ◽  
Reaching Accuracy

Lackner, James R. and Paul DiZio. Gravitoinertial force background level affects adaptation to Coriolis force perturbations of reaching movements. J. Neurophysiol. 80: 546–553, 1998. We evaluated the combined effects on reaching movements of the transient, movement-dependent Coriolis forces and the static centrifugal forces generated in a rotating environment. Specifically, we assessed the effects of comparable Coriolis force perturbations in different static force backgrounds. Two groups of subjects made reaching movements toward a just-extinguished visual target before rotation began, during 10 rpm counterclockwise rotation, and after rotation ceased. One group was seated on the axis of rotation, the other 2.23 m away. The resultant of gravity and centrifugal force on the hand was 1.0 g for the on-center group during 10 rpm rotation, and 1.031 g for the off-center group because of the 0.25 g centrifugal force present. For both groups, rightward Coriolis forces, ≈0.2 g peak, were generated during voluntary arm movements. The endpoints and paths of the initial per-rotation movements were deviated rightward for both groups by comparable amounts. Within 10 subsequent reaches, the on-center group regained baseline accuracy and straight-line paths; however, even after 40 movements the off-center group had not resumed baseline endpoint accuracy. Mirror-image aftereffects occurred when rotation stopped. These findings demonstrate that manual control is disrupted by transient Coriolis force perturbations and that adaptation can occur even in the absence of visual feedback. An increase, even a small one, in background force level above normal gravity does not affect the size of the reaching errors induced by Coriolis forces nor does it affect the rate of reacquiring straight reaching paths; however, it does hinder restoration of reaching accuracy.

Motor adaptation to Coriolis force perturbations of reaching movements: endpoint but not trajectory adaptation transfers to the nonexposed arm

1995 ◽  
Vol 74 (4) ◽  
pp. 1787-1792 ◽  
Author(s):  
P. Dizio ◽  
J. R. Lackner
Keyword(s):  
Muscle Spindle ◽  
Mirror Image ◽  
Tactile Feedback ◽  
Reaching Movements ◽  
Mechanical Contact ◽  
Experimental Conditions ◽  
Coriolis Forces ◽  
Muscle Dynamics ◽  
The Right ◽  
Made In

1. Reaching movements made in a rotating room generate Coriolis forces that are directly proportional to the cross product of the room's angular velocity and the arm's linear velocity. Such Coriolis forces are inertial forces not involving mechanical contact with the arm. 2. We measured the trajectories of arm movements made in darkness to a visual target that was extinguished at the onset of each reach. Prerotation subjects pointed with both the right and left arms in alternating sets of eight movements. During rotation at 10 rpm, the subjects reached only with the right arm. Postrotation, the subjects pointed with the left and right arms, starting with the left, in alternating sets of eight movements. 3. The initial perrotary reaching movements of the right arm were highly deviated both in movement path and endpoint relative to the prerotation reaches of the right arm. With additional movements, subjects rapidly regained straight movement paths and accurate endpoints despite the absence of visual or tactile feedback about reaching accuracy. The initial postrotation reaches of the left arm followed straight paths to the wrong endpoint. The initial postrotation reaches of the right arm had paths with mirror image curvature to the initial perrotation reaches of the right arm but went to the correct endpoint. 4. These observations are inconsistent with current equilibrium point models of movement control. Such theories predict accurate reaches under our experimental conditions. Our observations further show independent implementation of movement and posture, as evidenced by transfer of endpoint adaptation to the nonexposed arm without transfer of path adaptation. Endpoint control may occur at a relatively central stage that represents general constraints such as gravitoinertial force background or egocentric direction relative to both arms, and control of path may occur at a more peripheral stage that represents moments of inertia and muscle dynamics unique to each limb. 5. Endpoint and path adaptation occur despite the absence both of mechanical contact cues about the perturbing force and visual or tactile cues about movement accuracy. These findings point to the importance of muscle spindle signals, monitoring of motor commands, and possibly joint and tendon receptors in a detailed trajectory monitoring process. Muscle spindle primary and secondary afferent signals may differentially influence adaptation of movement shape and endpoint, respectively.

scholarly journals Occipital Cortex of Blind Individuals Is Functionally Coupled with Executive Control Areas of Frontal Cortex

2015 ◽  
Vol 27 (8) ◽  
pp. 1633-1647 ◽  
Author(s):  
Ben Deen ◽  
Rebecca Saxe ◽  
Marina Bedny
Keyword(s):  
Working Memory ◽  
Functional Connectivity ◽  
Sentence Comprehension ◽  
Memory Load ◽  
Memory Task ◽  
Occipital Cortex ◽  
Memory Systems ◽  
Functional Responses ◽  
Congenitally Blind ◽  
Blind Individuals

In congenital blindness, the occipital cortex responds to a range of nonvisual inputs, including tactile, auditory, and linguistic stimuli. Are these changes in functional responses to stimuli accompanied by altered interactions with nonvisual functional networks? To answer this question, we introduce a data-driven method that searches across cortex for functional connectivity differences across groups. Replicating prior work, we find increased fronto-occipital functional connectivity in congenitally blind relative to blindfolded sighted participants. We demonstrate that this heightened connectivity extends over most of occipital cortex but is specific to a subset of regions in the inferior, dorsal, and medial frontal lobe. To assess the functional profile of these frontal areas, we used an n-back working memory task and a sentence comprehension task. We find that, among prefrontal areas with overconnectivity to occipital cortex, one left inferior frontal region responds to language over music. By contrast, the majority of these regions responded to working memory load but not language. These results suggest that in blindness occipital cortex interacts more with working memory systems and raise new questions about the function and mechanism of occipital plasticity.

scholarly journals Spatial navigation by congenitally blind individuals

2015 ◽  
Vol 7 (1) ◽  
pp. 37-58 ◽  
Author(s):  
Victor R. Schinazi ◽  
Tyler Thrash ◽  
Daniel-Robert Chebat
Keyword(s):  
Spatial Navigation ◽  
Congenitally Blind ◽  
Blind Individuals

scholarly journals Shared understanding of color among congenitally blind and sighted adults

2020 ◽  
Author(s):  
Judy Sein Kim ◽  
Brianna Aheimer ◽  
Veronica Montane Manrara ◽  
Marina Bedny
Keyword(s):  
Visual Experience ◽  
Natural Kinds ◽  
Shared Understanding ◽  
Linguistic Communication ◽  
Causal Explanations ◽  
Stop Sign ◽  
Congenitally Blind ◽  
Novel Objects ◽  
Blind Individuals

Empiricist philosophers such as Locke famously argued that people born blind could only acquire shallow, fragmented facts about color. Contrary to this intuition, we report that blind and sighted people share an in-depth understanding of color, despite disagreeing about arbitrary color facts. Relative to the sighted, blind individuals are less likely to generate ‘yellow’ for banana and ‘red’ for stop-sign. However, blind and sighted adults are equally likely to infer that two bananas (natural kinds) and two stop-signs (artifacts with functional colors) are more likely to have the same color than two cars (artifacts with non-functional colors), make similar inferences about novel objects’ colors, and provide similar causal explanations. We argue that people develop inferentially-rich and intuitive “theories” of color regardless of visual experience. Linguistic communication is more effective at aligning people’s theories than their knowledge of verbal facts.

scholarly journals Changes in thalamocortical connectivity as a potential mechanism of cross-modal plasticity in congenitally blind individuals

2018 ◽  
Author(s):  
Theo Marins ◽  
Maite Russo ◽  
Erika Rodrigues ◽  
jorge Moll ◽  
Daniel Felix ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Cortical Thickness ◽  
Visual Information ◽  
Brain Plasticity ◽  
Temporal Cortex ◽  
Occipital Cortex ◽  
Brain Structures ◽  
Congenitally Blind ◽  
Blind Individuals ◽  
Neuroimaging Techniques

ABSTRACTEvidence of cross-modal plasticity in blind individuals has been reported over the past decades showing that non-visual information is carried and processed by classical “visual” brain structures. This feature of the blind brain makes it a pivotal model to explore the limits and mechanisms of brain plasticity. However, despite recent efforts, the structural underpinnings that could explain cross-modal plasticity in congenitally blind individuals remain unclear. Using advanced neuroimaging techniques, we mapped the thalamocortical connectivity and assessed cortical thickness and integrity of white matter of congenitally blind individuals and sighted controls to test the hypothesis that aberrant thalamocortical pattern of connectivity can pave the way for cross-modal plasticity. We described a direct occipital takeover by the temporal projections from the thalamus, which would carry non-visual information (e.g. auditory) to the visual cortex in congenitally blinds. In addition, the amount of thalamo-occipital connectivity correlated with the cortical thickness of primary visual cortex (V1), supporting a probably common (or related) reorganization phenomena. Our results suggest that aberrant thalamocortical connectivity as one possible mechanism of cross-modal plasticity in blinds, with potential impact on cortical thickness of V1.SIGNIFICANT STATEMENTCongenitally blind individuals often develop greater abilities on spared sensory modalities, such as increased acuity in auditory discrimination and voice recognition, when compared to sighted controls. These functional gains have been shown to rely on ‘visual’ cortical areas of the blind brain, characterizing the phenomenon of cross-modal plasticity. However, its anatomical underpinnings in humans have been unsuccessfully pursued for decades. Recent advances of non-invasive neuroimaging techniques allowed us to test the hypothesis of abnormal thalamocortical connectivity in congenitally blinds. Our results showed an expansion of the thalamic connections to the temporal cortex over those that project to the occipital cortex, which may explain, the cross-talk between the visual and auditory systems in congenitally blind individuals.

scholarly journals Mental Imagery Follows Similar Cortical Reorganization as Perception: Intra-Modal and Cross-Modal Plasticity in Congenitally Blind

2018 ◽  
Vol 29 (7) ◽  
pp. 2859-2875 ◽  
Author(s):  
A W de Borst ◽  
B de Gelder
Keyword(s):  
Visual Cortex ◽  
Mental Imagery ◽  
Cortical Plasticity ◽  
Tactile Perception ◽  
Cortical Reorganization ◽  
Area V4 ◽  
Congenitally Blind ◽  
Early Visual Cortex ◽  
Blind Individuals ◽  
Discriminative Patterns

Abstract Cortical plasticity in congenitally blind individuals leads to cross-modal activation of the visual cortex and may lead to superior perceptual processing in the intact sensory domains. Although mental imagery is often defined as a quasi-perceptual experience, it is unknown whether it follows similar cortical reorganization as perception in blind individuals. In this study, we show that auditory versus tactile perception evokes similar intra-modal discriminative patterns in congenitally blind compared with sighted participants. These results indicate that cortical plasticity following visual deprivation does not influence broad intra-modal organization of auditory and tactile perception as measured by our task. Furthermore, not only the blind, but also the sighted participants showed cross-modal discriminative patterns for perception modality in the visual cortex. During mental imagery, both groups showed similar decoding accuracies for imagery modality in the intra-modal primary sensory cortices. However, no cross-modal discriminative information for imagery modality was found in early visual cortex of blind participants, in contrast to the sighted participants. We did find evidence of cross-modal activation of higher visual areas in blind participants, including the representation of specific-imagined auditory features in visual area V4.

Abstract TP92: Brain Activity Related To The Effects Of Augmented Feedback On Learning Movements In A Dynamic Environment In Healthy Subjects And Stroke Survivors

Stroke ◽  
2013 ◽  
Vol 44 (suppl_1) ◽  
Author(s):  
Mukul Mukherjee ◽  
Wen-Pin Chang ◽  
Ka-Chun Siu ◽  
Pierre Fayad ◽  
Nicholas Stergiou
Keyword(s):  
Older Adults ◽  
Force Field ◽  
Cognitive Processing ◽  
Visual Feedback ◽  
Brain Activity ◽  
Dynamic Environments ◽  
Reaching Movements ◽  
Stroke Survivors ◽  
Frequency Bands ◽  
Dynamic Task

Augmented visual feedback has been shown to be effective for learning reaching movements in dynamic environments after a stroke. However, the mechanisms behind such changes are not known. In addition, how brain activity changes with age as we learn novel dynamic tasks is also not clear. The purpose of this study was to examine brain activity changes that are observed when healthy younger and older adults and stroke survivors learn reaching movements in dynamic environments using augmented visual feedback. Healthy young and older adults and chronic stroke survivors were randomly assigned to either a control or an experimental group. They all performed reaching movements with the Inmotion2 robotic system (Interactive Motion Tech Inc., MA) using the dominant/affected arm in a velocity-dependent force field. Controls received actual feedback of their movement, while experimental subjects received augmented visual feedback. Electroencephalogram recordings were analyzed to determine Event Related Desynchronization percent (ERD%). The theta, alpha, and beta frequency bands were examined during movement and pre-movement phases. With learning, the absolute power of the frequency bands increased from the baseline to the adaptation condition, which was then washed out when the force field was removed. With age, there was a reduction in ERD% in alpha and beta bands as the motor task was learned. Stroke subjects had a further reduction in the ERD% in comparison to the healthy older adults. In addition, augmented visual feedback led to a significant increase in the ERD% in comparison to controls during the planning and execution stages of the movement. Past studies have shown when novel dynamics are learned, ERD% reduces indicating increased cognitive processing and memory load. We found that with aging, the cognitive processing and memory required for performing the same dynamic task, increased. After a stroke, there was a further increase. However, the utilization of augmented visual feedback may reduce such requirements and lessen the load on higher centers. These results provide mechanistic support for employing augmented visual feedback for stroke rehabilitation specific to reaching movements in dynamic environments.

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