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Alterman BL, Ali S, Keeton E, Binkley K, Hendrix W, Lee PJ, Johnson JT, Wang S, Kling J, Gale MK, Wheaton LA. Grasp Posture Variability Leads to Greater Ipsilateral Sensorimotor Beta Activation During Simulated Prosthesis Use. J Mot Behav 2024; 56:579-591. [PMID: 39041372 PMCID: PMC11343659 DOI: 10.1080/00222895.2024.2364657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 03/28/2024] [Accepted: 05/30/2024] [Indexed: 07/24/2024]
Abstract
Motor behaviour using upper-extremity prostheses of different levels is greatly variable, leading to challenges interpreting ideal rehabilitation strategies. Elucidating the underlying neural control mechanisms driving variability benefits our understanding of adaptation after limb loss. In this follow-up study, non-amputated participants completed simple and complex reach-to-grasp motor tasks using a body-powered transradial or partial-hand prosthesis simulator. We hypothesised that under complex task constraints, individuals employing variable grasp postures will show greater sensorimotor beta activation compared to individuals relying on uniform grasping, and activation will occur later in variable compared to uniform graspers. In the simple task, partial-hand variable and transradial users showed increased neural activation from the early to late phase of the reach, predominantly in the hemisphere ipsilateral to device use. In the complex task, only partial-hand variable graspers showed a significant increase in neural activation of the sensorimotor cortex from the early to the late phase of the reach. These results suggest that grasp variability may be a crucial component in the mechanism of neural adaptation to prosthesis use, and may be mediated by device level and task complexity, with implications for rehabilitation after amputation.
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Affiliation(s)
- Bennett L Alterman
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Saif Ali
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Emily Keeton
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Katrina Binkley
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - William Hendrix
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Perry J Lee
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - John T Johnson
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Shuo Wang
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - James Kling
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Mary Kate Gale
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Lewis A Wheaton
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
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Esser S, Lustig C, Haider H. What triggers explicit awareness in implicit sequence learning? Implications from theories of consciousness. PSYCHOLOGICAL RESEARCH 2022; 86:1442-1457. [PMID: 34586489 PMCID: PMC9177494 DOI: 10.1007/s00426-021-01594-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 09/04/2021] [Indexed: 12/13/2022]
Abstract
This article aims to continue the debate on how explicit, conscious knowledge can arise in an implicit learning situation. We review hitherto existing theoretical views and evaluate their compatibility with two current, successful scientific concepts of consciousness: The Global Workspace Theory and Higher-Order Thought Theories. In this context, we introduce the Unexpected Event Hypothesis (Frensch et al., Attention and implicit learning, John Benjamins Publishing Company, 2003) in an elaborated form and discuss its advantage in explaining the emergence of conscious knowledge in an implicit learning situation.
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Affiliation(s)
- Sarah Esser
- Department of General Psychology 1, University of Cologne, NRW, Cologne, Germany.
| | - Clarissa Lustig
- Department of General Psychology 1, University of Cologne, NRW, Cologne, Germany
| | - Hilde Haider
- Department of General Psychology 1, University of Cologne, NRW, Cologne, Germany
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Lustig C, Esser S, Haider H. The interplay between unexpected events and behavior in the development of explicit knowledge in implicit sequence learning. PSYCHOLOGICAL RESEARCH 2021; 86:2225-2238. [PMID: 34951662 PMCID: PMC9470660 DOI: 10.1007/s00426-021-01630-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 12/10/2021] [Indexed: 01/25/2023]
Abstract
Some studies in implicit learning investigate the mechanisms by which implicitly acquired knowledge (e.g., learning a sequence of responses) becomes consciously aware. It has been suggested that unexpected changes in the own behavior can trigger search processes, of which the outcome then becomes aware. A consistent empirical finding is that participants who develop explicit knowledge show a sudden decrease in reaction times, when responding to sequential events. This so called RT-drop might indicate the point of time when explicit knowledge occurs. We investigated whether an RT-drop is a precursor for the development of explicit knowledge or the consequence of explicit knowledge. To answer this question, we manipulated in a serial reaction time task the timing of long and short stimulus-onset asynchronies (SOA). For some participants, the different SOAs were presented in blocks of either long or short SOAs, while for others, the SOAs changed randomly. We expected the participants who were given a blocked presentation to express an RT-drop because of the predictable timing. In contrast, randomly changing SOAs should hamper the expression of an RT-drop. We found that more participants in the blocked-SOA condition than in the random-SOA condition showed an RT-drop. Furthermore, the amount of explicit knowledge did not differ between the two conditions. The findings suggest that the RT-drop does not seem to be a presupposition to develop explicit knowledge. Rather, it seems that the RT-drop indicates a behavioral strategy shift as a consequence of explicit knowledge.
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Affiliation(s)
- Clarissa Lustig
- Department of Psychology, University of Cologne, Richard-Strauss-Str. 2, 50931, Cologne, Germany.
| | - Sarah Esser
- Department of Psychology, University of Cologne, Richard-Strauss-Str. 2, 50931, Cologne, Germany
| | - Hilde Haider
- Department of Psychology, University of Cologne, Richard-Strauss-Str. 2, 50931, Cologne, Germany
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