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Weightman M, Brittain JS, Miall RC, Jenkinson N. Residual errors in visuomotor adaptation persist despite extended motor preparation periods. J Neurophysiol 2022; 127:519-528. [PMID: 35044854 PMCID: PMC8836731 DOI: 10.1152/jn.00301.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
A consistent finding in sensorimotor adaptation is a persistent undershoot of full compensation, such that performance asymptotes with residual errors greater than seen at baseline. This behavior has been attributed to limiting factors within the implicit adaptation system, which reaches a suboptimal equilibrium between trial-by-trial learning and forgetting. However, recent research has suggested that allowing longer motor planning periods prior to movement eliminates these residual errors. The additional planning time allows required cognitive processes to be completed before movement onset, thus increasing accuracy. Here, we looked to extend these findings by investigating the relationship between increased motor preparation time and the size of imposed visuomotor rotation (30°, 45°, or 60°), with regard to the final asymptotic level of adaptation. We found that restricting preparation time to 0.35 s impaired adaptation for moderate and larger rotations, resulting in larger residual errors compared to groups with additional preparation time. However, we found that even extended preparation time failed to eliminate persistent errors, regardless of magnitude of cursor rotation. Thus, the asymptote of adaptation was significantly less than the degree of imposed rotation, for all experimental groups. In addition, there was a positive relationship between asymptotic error and implicit retention. These data suggest that a prolonged motor preparation period is insufficient to reliably achieve complete adaptation, and therefore, our results suggest that factors beyond that of planning time contribute to asymptotic adaptation levels.NEW & NOTEWORTHY Residual errors in sensorimotor adaptation are commonly attributed to an equilibrium between trial-by-trial learning and forgetting. Recent research suggested that allowing sufficient time for mental rotation eliminates these errors. In a number of experimental conditions, we show that although restricted motor preparation time does limit adaptation-consistent with mental rotation-extending preparation time fails to eliminate the residual errors in motor adaptation.
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Affiliation(s)
- Matthew Weightman
- 1School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom,3MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Birmingham, Birmingham, United Kingdom,4Centre for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
| | - John-Stuart Brittain
- 2School of Psychology, University of Birmingham, Birmingham, United Kingdom,4Centre for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
| | - R. Chris Miall
- 2School of Psychology, University of Birmingham, Birmingham, United Kingdom,3MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Birmingham, Birmingham, United Kingdom,4Centre for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
| | - Ned Jenkinson
- 1School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom,3MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Birmingham, Birmingham, United Kingdom,4Centre for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
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Evidence for Pretreatment LICI Deficits Among Depressed Children and Adolescents With Nonresponse to Fluoxetine. Brain Stimul 2014; 7:243-51. [DOI: 10.1016/j.brs.2013.11.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 11/12/2013] [Accepted: 11/21/2013] [Indexed: 01/15/2023] Open
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Wilhelm EA, Jesse CR, Bortolatto CF, Barbosa NBV, Nogueira CW. Evidence of the involvement of K+ channels and PPARgamma receptors in the antidepressant-like activity of diphenyl diselenide in mice. J Pharm Pharmacol 2011; 62:1121-7. [PMID: 20796190 DOI: 10.1111/j.2042-7158.2010.01132.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
OBJECTIVES This study investigated the involvement of different types of K(+) channels and PPARgamma receptors in the antidepressant-like effect of diphenyl diselenide in mice. METHODS Mice were pretreated with subeffective doses of K(+) channel inhibitors (tetraethylammonium, glibenclamide, charybdotoxin and apamin), openers (cromakalim, minoxidil), GW 9662 (a PPARgamma antagonist) or vehicle. Thirty minutes later the mice received diphenyl diselenide in either an effective or a subeffective dose, 30 min before a tail-suspension test. KEY FINDINGS Pre-treatment with tetraethylammonium, charybdotoxin or apamin combined with a subeffective dose of diphenyl diselenide was effective in decreasing the immobility time in the mouse tail-suspension test. The reduction in the immobility time elicited by an effective dose of diphenyl diselenide in this test was prevented by the pretreatment of mice with minoxidil and GW 9662. CONCLUSIONS Diphenyl diselenide elicited an antidepressant-like effect and this action was mediated, at least in part, by modulation of K(+) channels and PPARgamma receptors.
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Affiliation(s)
- Ethel A Wilhelm
- Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Brazil
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Cerquera A, Freund J. Fast estimation of motion from selected populations of retinal ganglion cells. BIOLOGICAL CYBERNETICS 2011; 104:53-64. [PMID: 21287355 DOI: 10.1007/s00422-011-0418-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 01/12/2011] [Indexed: 05/30/2023]
Abstract
We explore how the reconstruction efficiency of fast spike population codes varies with population size, population composition and code complexity. Our study is based on experiments with moving light patterns which are projected onto the isolated retina of a turtle Pseudemys scripta elegans. The stimulus features to reconstruct are sequences of velocities kept constant throughout segments of 500 ms. The reconstruction is based on the spikes of a retinal ganglion cell (RGC) population recorded extracellularly via a multielectrode array. Subsequent spike sorting yields the parallel spike trains of 107 RGCs as input to the reconstruction method, here a discriminant analysis trained and tested in jack-knife fashion. Motivated by behavioral response times, we concentrate on fast reconstruction, i.e., within 150 ms following a trigger event defined via significant changes of the population spike rate. Therefore, valid codes involve only few (≤3) spikes per cell. Using only the latency t(1) of each cell (with reference to the trigger event) corresponds to the most parsimonious population code considered. We evaluate the gain in reconstruction efficiency when supplementing t(1) by spike times t(2) and t(3). Furthermore, we investigate whether sub-populations of smaller size benefit significantly from a selection process or whether random compilations are equally efficient. As selection criteria we try different concepts (directionality, reliability, and discriminability). Finally, we discuss the implications of a selection process and its inter-relation with code complexity for optimized reconstruction.
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Affiliation(s)
- Alexander Cerquera
- Faculty for Electronic and Biomedical Engineering, Antonio Nariño University, Bogotá, Colombia.
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Cortez MA, Shen L, Wu Y, Aleem IS, Trepanier CH, Sadeghnia HR, Ashraf A, Kanawaty A, Liu CC, Stewart L, Snead OC. Infantile spasms and Down syndrome: a new animal model. Pediatr Res 2009; 65:499-503. [PMID: 19190545 DOI: 10.1203/pdr.0b013e31819d9076] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Infantile spasms is a catastrophic childhood seizure disorder for which few animal models exist. Children with Down syndrome are highly susceptible to infantile spasms. The Ts65Dn mouse is a valid model for Down syndrome; therefore, we tested the hypothesis that the Ts65Dn mouse represents a substrate for an animal model of infantile spasms. The baseline of naïve Ts65Dn mice showed spontaneous spike-and-wave discharges, a pattern that worsened with baclofen and gamma-butyrolactone, which induced acute epileptic extensor spasms (AEES) associated with epileptiform polyspike bursts and an electrodecremental response on the EEG. GABABR-agonist-induced AEES were significantly reduced with vigabatrin, rodent ACTH fragment, valproic acid, ethosuximide, and CGP 35348. Porcine ACTH had no effect. GABABR protein expression was significantly increased in the thalamus and medulla oblongata of Ts65D mice in comparison with wild-type controls. The GABABR agonist-treated Ts65Dn mouse shows the unique clinical, electrographic, and pharmacologic signature of infantile spasms and represents a valid, acute model of this disorder. GABABR-mediated mechanisms may contribute to the increased susceptibility of children with Down syndrome to infantile spasms.
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Affiliation(s)
- Miguel A Cortez
- Division of Neurology, Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
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