An Interactive Account of visuo-spatial asymmetries: Developmental and crosscultural evidence

Abstract Introduction Temporal-spatial symmetry allows for optimal metabolic economy in unimpaired human gait. The gait of individuals with unilateral transfemoral amputation is characterized by temporal-spatial asymmetries and greater metabolic energy expenditure. The objective of this study was to determine whether temporal-spatial asymmetries account for greater metabolic energy expenditure in individuals with unilateral transfemoral amputation. Materials and Methods The relationship between temporal-spatial gait asymmetry and metabolic economy (metabolic power normalized by walking speed) was retrospectively examined in eighteen individuals with transfemoral amputation walking at a self-selected velocity overground. Pearson’s product-moment correlations were used to assess the relationship between: (1) step time symmetry and metabolic economy and (2) step length symmetry and metabolic economy. The retrospective analysis of this data was approved by the Walter Reed National Military Medical Center Institutional Review Board and all individuals provided written consent. Additional insights on this relationship are presented through a case series describing the temporal-spatial and metabolic responses of two individuals with transfemoral amputation who completed a split-belt treadmill walking test. Results For the cohort of individuals, there was no significant relationship between metabolic economy and either step time asymmetry or step length asymmetry. However, the case series showed a positive relationship between step length asymmetry and metabolic power as participants adapted to split-belt treadmill walking. Conclusion There is mixed evidence for the relationship between temporal-spatial asymmetries and metabolic energy expenditure. This preliminary study may suggest optimal metabolic energy expenditure in individuals with transfemoral amputation occurs at an individualized level of symmetry and resultant deviations incur a metabolic penalty. The results of this study support the idea that addressing only temporal-spatial gait asymmetries in individuals with transfemoral amputation through rehabilitation may not improve metabolic economy. Nevertheless, future prospective research is necessary to confirm these results and implications for clinical practice.

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Indigenous Labor and Land Resources: Guarani–Kaiowa’s Politico–Economic and Ethnic Challenges

Resources ◽

10.3390/resources9070084 ◽

2020 ◽

Vol 9 (7) ◽

pp. 84

Author(s):

Antonio A. R. Ioris

Keyword(s):

Indigenous Peoples ◽

Analytical Framework ◽

Land Resources ◽

Complex Situation ◽

Mato Grosso ◽

Indigenous Groups ◽

Management Processes ◽

Spatial Asymmetries ◽

Lived Spaces ◽

Mato Grosso Do Sul

The article deals with the meaning and the management of land-based resources by indigenous peoples, which are analyzed through an assessment of the lived spaces of the Guarani–Kaiowa indigenous people in the Brazilian state of Mato Grosso do Sul. The discussion follows an analytical framework that is focused on land, labor and ethnicity. These interconnected politico-economic categories provide the basis for understanding the violence and exploitation perpetrated against indigenous groups, as well as their capacity to reclaim ancestral territories lost to extractivism and agribusiness development. Empirical results indicate that ethnicity is integral to labor and land management processes. In the case of the Guarani–Kaiowa, not only have they become refugees in their own lands due to racist discrimination, but also their labor has been incorporated in the regional economy through interrelated peasantification and proleterianization tendencies. The result is a complex situation that combines major socio-spatial asymmetries with the strategic, exploitative use of land and labor and the growing political contestation by the indigenous groups.

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Spatial asymmetries in the perception of stimulus orientation using the OPTACON

International Journal of Rehabilitation Research ◽

10.1097/00004356-198509000-00013 ◽

1985 ◽

Vol 8 (3) ◽

pp. 347-349 ◽

Cited By ~ 2

Author(s):

Eugene C. Lechelt

Keyword(s):

Stimulus Orientation ◽

Spatial Asymmetries

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Spatial and Temporal Asymmetries in Gait Predict Split-Belt Adaptation Behavior in Stroke

Neurorehabilitation and Neural Repair ◽

10.1177/1545968313505912 ◽

2013 ◽

Vol 28 (3) ◽

pp. 230-240 ◽

Cited By ~ 52

Author(s):

Laura A. Malone ◽

Amy J. Bastian

Keyword(s):

Training Session ◽

Speed Ratio ◽

Stroke Patients ◽

Healthy Older Adults ◽

After Effects ◽

Spatial Domains ◽

After Effect ◽

Spatial Asymmetries ◽

Temporal Measures ◽

Measures Of Asymmetry

Background. Step asymmetries during gait in persons after stroke can occur in temporal or spatial domains. Prior studies have shown that split-belt locomotor adaptation can temporarily mitigate these asymmetries. Objective. We investigated whether baseline gait asymmetries affected how patients adapt and store new walking patterns. Methods. Subjects with stroke and age-matched controls were studied walking at a 2:1 speed ratio on the split-belt during adaptation and assessed for retention of the learned pattern (the after-effect) with both belts at the same speed. Results. Those with stroke adapted more slowly ( P < .0001), though just as much as healthy older adults. During split-belt walking, the participants with stroke adapted toward their baseline asymmetry (eg, F = 14.02, P < .01 for step symmetry), regardless of whether the subsequent after-effects improved or worsened their baseline step asymmetries. No correlation was found between baseline spatial and temporal measures of asymmetry ( P = .38). Last, the initial spatial and temporal asymmetries predicted after-effects independently of one another. The after-effects in the spatial domain (ie, center of oscillation difference) are only predicted by center of oscillation difference baseline ( F = 15.3, P = .001), while all other parameters were nonsignificant (all Ps > .17). Temporal coordination (ie, phasing) after-effects showed a significant effect only from phasing baseline ( F = 26.92, P < .001, all others P > .33). Conclusion. This work demonstrates that stroke patients adapt toward their baseline temporal and spatial asymmetries of walking independently of one another. We define how a given split-belt training session would affect asymmetries in these domains, which must be considered when developing rehabilitation interventions for stroke patients.

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Spatial Asymmetries in Tactile Discrimination of Line Orientation: A Comparison of the Sighted, Visually Impaired, and Blind

Perception ◽

10.1068/p170579 ◽

1988 ◽

Vol 17 (5) ◽

pp. 579-585 ◽

Cited By ~ 13

Author(s):

Eugene C Lechelt

Keyword(s):

Visually Impaired ◽

Index Finger ◽

Oblique Effect ◽

Distal Portion ◽

Blind Subject ◽

Left Index Finger ◽

Discrimination Accuracy ◽

Tactile Discrimination ◽

The Subject ◽

Spatial Asymmetries

Thresholds for tactile discrimination of stimulus orientation discrepancy from standard or referent vertical, horizontal, and diagonal orientations were determined for sighted, visually impaired, and blind subject groups. The stimuli were presented to the ventral distal portion of the tip of the subject's left index finger via an Optacon. Although the subject groups did not differ in overall discrimination accuracy, for each group the deviations from vertical and horizontal standard orientations were discriminated reliably more accurately than the deviations from standard diagonals, ie the oblique effect was obtained. The bases for this tactual spatial anisotropic effect appear to reflect both sensory—neurological and experiential factors.

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Reversed Spatial Asymmetries between El Niño and La Niña and Their Linkage to Decadal ENSO Modulation in CMIP3 Models

Journal of Climate ◽

10.1175/jcli-d-11-00024.1 ◽

2011 ◽

Vol 24 (20) ◽

pp. 5423-5434 ◽

Cited By ~ 28

Author(s):

Jin-Yi Yu ◽

Seon Tae Kim

Keyword(s):

El Niño ◽

El Nino ◽

Southern Oscillation ◽

Interaction Mechanism ◽

Tropical Pacific ◽

La Niña ◽

Enso Events ◽

La Nina ◽

Spatial Asymmetries ◽

Mean State

Abstract This study examines preindustrial simulations from Coupled Model Intercomparison Project, phase 3 (CMIP3), models to show that a tendency exists for El Niño sea surface temperature anomalies to be located farther eastward than La Niña anomalies during strong El Niño–Southern Oscillation (ENSO) events but farther westward than La Niña anomalies during weak ENSO events. Such reversed spatial asymmetries are shown to force a slow change in the tropical Pacific Ocean mean state that in return modulates ENSO amplitude. CMIP3 models that produce strong reversed asymmetries experience cyclic modulations of ENSO intensity, in which strong and weak events occur during opposite phases of a decadal variability mode associated with the residual effects of the reversed asymmetries. It is concluded that the reversed spatial asymmetries enable an ENSO–tropical Pacific mean state interaction mechanism that gives rise to a decadal modulation of ENSO intensity and that at least three CMIP3 models realistically simulate this interaction mechanism.

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Spatial asymmetries in cat retinal ganglion cell responses

Biological Cybernetics ◽

10.1007/s004220050467 ◽

1998 ◽

Vol 79 (2) ◽

pp. 151-159 ◽

Cited By ~ 1

Author(s):

Paolo Gaudiano ◽

Andrzej W. Przybyszewski ◽

Richard J. A. van Wezel ◽

Wim A. van de Grind

Keyword(s):

Ganglion Cell ◽

Retinal Ganglion Cell ◽

Retinal Ganglion ◽

Cell Responses ◽

Spatial Asymmetries

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Temporal and spatial asymmetries during stationary cycling cause different feedforward and feedback modifications in the muscular control of the lower limbs

10.1101/370262 ◽

2018 ◽

Author(s):

Magdalena Zych ◽

Ian Rankin ◽

Donal Holland ◽

Giacomo Severini

Keyword(s):

Lower Limb ◽

Motor Adaptation ◽

Neuromuscular Control ◽

Task Demands ◽

Lower Limbs ◽

Muscle Synergy ◽

Accelerometer Data ◽

Temporal Asymmetry ◽

Spatial Asymmetries ◽

The Right

AbstractMotor adaptations are useful for studying the way in which the lower limbs are controlled by the brain. However, motor adaptation paradigms for the lower limbs are typically based on locomotion tasks, where the necessity of maintaining postural stability is the main driver of adaptation and could possibly mask other underlying processes. In this study we investigated whether small temporal or spatial asymmetries can trigger motor adaptations during stationary cycling, where stability is not directly compromised. Fourteen healthy individuals participated in two experiments: in one of the experiments the angle between the crank arms of the pedals was altered by 10° to induce a temporal asymmetry; in the other the length of the right pedal was shortened by 2.4 cm to induce a spatial asymmetry. We recorded the acceleration of the crank arms and the EMG signals of 16 muscles (8 per leg). The analysis of the accelerometer data was used to investigate the presence of motor adaptations. Muscle synergy analysis was performed on each side to quantify changes in neuromuscular control. We found that feedforward motor adaptations are present in response to temporal asymmetries and are obtained by progressively shifting the activation patterns of two synergies on the right leg. Spatial asymmetries appear to trigger a feedback-driven response that does not present an aftereffect and is not consistent with a motor adaptation. This response is characterized by a step-like decrease in activity in the right gastrocnemius when the asymmetry is present and likely reflects the altered task demands.New and NoteworthyThe processes driving lower limb motor adaptations are not fully clear, and previous research appears to indicate that adaptations are mainly driven by stability. Here we show that lower limb adaptations can be obtained also in the absence of an explicit balance threat. We also show that adaptations are present also when kinematic error cannot be compensated for, suggesting the presence of intrinsic error measures regulating the timing of activation of the two legs.

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