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Wheaton,
Lewis A.
Wheaton,
Lewis A.
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ItemGrasp Posture Variability Leads to Greater Ipsilateral Sensorimotor Beta Activation during Prosthesis Use Data(Georgia Institute of Technology, 2022) Alterman, Bennett L. ; Ali, Saif ; Keeton, Emily ; Binkley, Katrina ; Hendrix, William ; Lee, Perry J. ; Johnson, John T. ; Wang, Shuo ; Kling, James ; Gale, Mary Kate ; Wheaton, Lewis A.
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ItemReconsidering parietofrontal activity during action encoding: translating basic science to motor rehabilitation( 2021-03-01) Wheaton, Lewis A.Over the last 20 years, numerous human brain imaging studies related to motor control have identified left hemispheric parietofrontal activity as central to motor planning and execution for complex movements. This has often been postulated to be ‘mirror neuron’ type network activity. Unfortunately, the precise nature of this activity has been difficult to understand given the consistency of the findings across numerous different paradigms. Our recent studies have suggested an alternative theory that could, in part, explain the preponderance of such activity and why it may be seen in motor-related paradigms. Further studies may demonstrate utility of this activity for motor rehabilitation efforts that utilize action-observation.
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ItemVisual encoding of tool-object interactions(Georgia Institute of Technology, 2021) Bayani, Kristel ; Natraj, Nikhilesh ; Gale, Mary Kate ; Temples, Danielle ; Atawala, Neel ; Wheaton, Lewis A.Tools and objects are associated with numerous action possibilities that are reduced depending on the task-related internal and external constraints presented to the observer. Action hierarchies propose that goals represent higher levels of the hierarchy while kinematic patterns represent lower levels of the hierarchy. Prior work suggests that tool-object perception is heavily influenced by grasp and action context. The current study sought to evaluate whether the presence of action hierarchy can be perceptually identified using eye tracking during tool-object observation. We hypothesize that gaze patterns will reveal a perceptual hierarchy based on the observed task context and grasp constraints. Participants viewed tool-objects scenes with two types of constraints: task-context and grasp constraints. Task-context constraints consisted of correct (e.g., frying pan-spatula) and incorrect tool-object pairings (e.g., stapler-spatula). Grasp constraints involved modified tool orientations, which requires participants to understand how initially awkward grasp postures can help achieve the task. The visual scene contained three areas of interests (AOIs): the object, the functional tool-end (e.g., spoon handle), and the manipulative tool-end (e.g., spoon bowl). Results revealed two distinct processes based on stimuli constraints. Goal-oriented encoding, the attentional bias towards the object and manipulative tool-end, was demonstrated when grasp did not lead to meaningful tool-use. In images where grasp postures were critical to action performance, attentional bias was primarily between the object and functional tool-end, which suggests means-related encoding of the graspable properties of the object. This study expands from previous work and demonstrates a flexible constraint hierarchy depending on the observed task constraints.
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ItemAlpha-Band Activity in Left Motor Cortex Predicts Future Availability of Vibrotactile Feedback in Prosthesis Use (Obsolete)(Georgia Institute of Technology, 2021) Johnson, John T. ; Gavetti De Mari, Daniele ; Doherty, Harper ; Hammond III, Frank L. ; Wheaton, Lewis A.See replacement item: http://hdl.handle.net/1853/66286
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ItemAlpha-Band Activity in Parietofrontal Cortex Predicts Future Availability of Vibrotactile Feedback in Prosthesis Use(Georgia Institute of Technology, 2021) Johnson, John T. ; Gavetti De Mari, Daniele ; Doherty, Harper ; Hammond III, Frank L. ; Wheaton, Lewis A.Prosthesis disuse and abandonment is an ongoing issue in upper-limb amputation. In addition to lost structural and motor function, amputation also results in decreased task-specific sensory information. One proposed remedy is augmenting somatosensory information using vibrotactile feedback to provide tactile feedback of grasping objects. While the role of frontal and parietal areas in motor tasks is well established, the neural and kinematic effects of this augmented vibrotactile feedback remain in question. In this study, we sought to understand the neurobehavioral effects of providing augmented feedback during a reach-grasp -transport task. Ten persons with sound limbs performed a motor task while wearing a prosthesis simulator with and without vibrotactile feedback. We hypothesized that providing vibrotactile feedback during prosthesis use would increase activity in frontal and parie tal areas and improve grasp-related behavior. Results show that anticipation of upcoming vibrotactile feedback may be encoded in motor and parietal areas during the reach-to-grasp phase of the task. While grasp aperture is unaffected by vibrotactile feedback, the availability of vibrotactile feedback does lead to a reduction in velocity during object transport. These results help shed light on how engineered feedback is utilized by prostheses users and provide methodologies for further assessment in advanced prosthetics research.
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ItemStonetool Study Dataset(Georgia Institute of Technology, 2021) Topping, Kristel ; Wheaton, Lewis A. ; Stout, Dietrich ; Pargeter, JustinStone tool making is a unique human motor skill dating back to the Paleolithic. It provides the earliest evidence of complex motor skills and social learning. Learning to intentionally shape a stone into a functional tool is thought to rely on the interaction of action observation and individual practice to support motor skill acquisition, but the emergence of adaptive and efficient perceptual processes during the observational learning of such a novel motor skill are not well understood. By examining eye movements and motor skills, the current study sought to evaluate the relationship between perceptual and motor processes related to approximately 90 hours of training on stone tool making. Participants’ (n = 11) gaze and motor performance were assessed at three different training time points: naïve (0 hours of training), post 1 (50 hours of training), post 2 (~90 hours of training). Gaze patterns reveal a transition from high gaze variability during initial observation to lower gaze variability after training. Furthermore, perceptual changes were strongly associated with motor performance improvement suggesting a coupling of perceptual and motor processes during motor learning, in order to attend to the technologically informative aspects of the tool making task. The complex emergence of perceptual-motor coupling in this study emphasizes the importance of naturalistic skill learning studies to understand real-world perceptual-motor interactions and technological skill development. This study also highlights “evolutionary neuroscience” methods for reliably reconstructing ancient motor-skill processes from archaeological evidence.
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ItemPartial-Hand Prosthesis Users Show Improved Reach-to-Grasp Behaviour Compared to Transradial Prosthesis Users with Increased Task Complexity(Georgia Institute of Technology, 2021) Wheaton, Lewis A. ; Alterman, Bennett L. ; Keeton, Emily ; Ali, Saif ; Binkley, Katrina ; Hendrix, William ; Lee, Perry J. ; Wang, Shuo ; Johnson, John T.Purpose: Approaches to improve outcomes after upper-extremity amputation remain poorly understood. Different levels of amputation may affect prosthetic device acceptance, function, and use. Examining differences in behavioural and functional performance for different levels of prosthesis use may provide vital information about unique motor control challenges across levels of amputation. Materials and methods: Participants without amputation completed simple and complex goal-directed reach-to-grasp motor actions using either a transradial or partial-hand prosthesis simulator. We hypothesised that participants using a partial-hand device would show greater functional adaptation compared to participants using a transradial device, measured by (1) lower movement duration, (2) lower reach duration, (3) higher reach peak velocity, and (4) lower placement error. Second, we hypothesised that increased task complexity would lead to greater functional adaptation, particularly in partial-hand users. Results: In the complex task, partial-hand users demonstrated variable grasp approaches, an effect not seen in the simple task or in transradial users. Partial-hand users showed significantly higher reach peak velocities compared to transradial users, regardless of grasp strategy in the complex but not the simple task. All groups showed decreases in movement duration over time in the complex task, but only partial-hand users improved in the simple task. Conclusion: There is a gap in our understanding of how people adapt to amputations of different levels. This work clarifies how device and environmental constraints contribute to unique action outcomes, and influence motor learning, which is crucial for optimising rehabilitation.
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ItemNeurobehavioral data for novel behavioral indicator of explicit awareness dataset(Georgia Institute of Technology, 2017-03-26) Wheaton, Lewis A. ; Lawson, Regan R. ; Gayle, Jordan O.Deficits in sequential motor learning have been observed in many patient populations. Having an understanding of the individual neural progression associated with sequential learning in healthy individuals may provide valuable insights for effective interventions with these patients. Due to individual variability in motor skill acquisition, the temporal course of such learning will be vary, suggesting a need for a more individualized approach. Knowing when a subject becomes aware of movement patterns may provide a marker with which to identify each individual's learning time course. To avoid interfering with the incidental nature of discovery during learning, such an indicator requires an indirect, behaviorally-based approach. In Part I, our study aimed to identify a reliable behavioral indicator predictive of the presence of incidental explicit awareness in a sequential motor learning task. Part II, utilized the predictive indicator and EEG to provide neural validation of perceptual processing changes temporally correlated with the indicator. Results of Part I provide a reliable predictive indicator for the timing of explicit awareness development. Results from Part II demonstrates strong classification reliability, as well as a significant neural correlation with behavior for subjects developing awareness (EXP), not observed with subjects without awareness (NOEXP). Additionally, a temporal correlation of peak activation between neural regions was noted over frontoparietal regions, suggesting that the incidental discovery of motor patterns may involve a facilitative network during awareness development. The proposed indicator provides a tool in which to further examine potential impacts of awareness associated with incidental, or exploratory, motor learning, while the individual nature of the indicator provides a tool for monitoring progress in rehabilitative, exploratory motor learning paradigms.