1
|
Scarlat KA, Tchoumi CA, Feldman AG, Levin MF. Referent Control of Side-to-Side Body-Weight Transfer During Standing and Stepping in Adults. Neuroscience 2024; 551:94-102. [PMID: 38762084 DOI: 10.1016/j.neuroscience.2024.05.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 05/08/2024] [Accepted: 05/13/2024] [Indexed: 05/20/2024]
Abstract
Research suggests that locomotion may be primarily caused by shifting stable body balance from one location in the environment to another with subsequent rhythmical muscle activation by the central pattern generator (CPG), constituting a multi-level control system. All levels interact with environmental forces affected by proprioceptive and vestibular reflexes as well as vision. A similar multi-level control schema is likely used to shift body balance laterally when the body weight is rhythmically transferred from side-to-side. In order to do so, the system shifts a specific body posture in space. This body posture is referred to as the threshold or referent body posture, R, at which all muscles involved can be at rest but are activated depending on the deflection of the actual body posture, Q, from R. This concept has previously been investigated for forward and backward locomotion. The purpose of the present study was to verify if it was also applicable to locomotor tasks in other directions such as sidestepping. We predicted that during sidestepping, the actual and referent posture can transiently match each other bringing the activity of multiple muscles to a minimum. The existence of such minima was demonstrated in healthy adults performing three locomotor tasks involving shifts of the body weight from side-to-side thus further supporting the validity of the multi-level control scheme of locomotion.
Collapse
Affiliation(s)
- Katharine A Scarlat
- Integrated Program in Neuroscience, McGill University, Montreal, Qc., Canada; Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal, Montreal, Qc., Canada
| | - Carl A Tchoumi
- Integrated Program in Neuroscience, McGill University, Montreal, Qc., Canada; Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal, Montreal, Qc., Canada
| | - Anatol G Feldman
- Department of Neuroscience, University of Montreal, Montreal, Qc., Canada; Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal, Montreal, Qc., Canada.
| | - Mindy F Levin
- School of Physical and Occupational Therapy, McGill University, Montreal, Qc., Canada; Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal, Montreal, Qc., Canada
| |
Collapse
|
2
|
Guberman S, Latash ML. The Role of Imitation, Primitives, and Spatial Referent Coordinates in Motor Control: Implications for Writing and Reading. Motor Control 2024:1-15. [PMID: 38364817 DOI: 10.1123/mc.2023-0122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 12/13/2023] [Accepted: 01/05/2024] [Indexed: 02/18/2024]
Abstract
We review a body of literature related to the drawing and recognition of geometrical two-dimensional linear drawings including letters. Handwritten letters are viewed not as two-dimensional geometrical objects but as one-dimensional trajectories of the tip of the implement. Handwritten letters are viewed as composed of a small set of kinematic primitives. Recognition of objects is mediated by processes of their creation (actual or imagined)-the imitation principle, a particular example of action-perception coupling. The concept of spatial directional field guiding the trajectories is introduced and linked to neuronal population vectors. Further, we link the kinematic description to the theory of control with spatial referent coordinates. This framework allows interpreting a number of experimental observations and clinical cases of agnosia. It also allows formulating predictions for new experimental studies of writing.
Collapse
Affiliation(s)
- Shelia Guberman
- Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, San Jose, CA, USA
| | - Mark L Latash
- Department of Kinesiology, The Pennsylvania State University, University Park, PA, USA
| |
Collapse
|
3
|
Shoja O, Towhidkhah F, Hassanlouei H, Levin MF, Bahramian A, Nadeau S, Zhang L, Feldman AG. Reaction of human walking to transient block of vision: analysis in the context of indirect, referent control of motor actions. Exp Brain Res 2023; 241:1353-1365. [PMID: 37010540 DOI: 10.1007/s00221-023-06593-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 03/05/2023] [Indexed: 04/04/2023]
Abstract
Human locomotion may result from monotonic shifts in the referent position, R, of the body in the environment. R is also the spatial threshold at which muscles can be quiescent but are activated depending on the deflection of the current body configuration Q from R. Shifts in R are presumably accomplished with the participation of proprioceptive and visual feedback and responsible for transferring stable body balance (equilibrium) from one place in the environment to another, resulting in rhythmic activity of multiple muscles by a central pattern generator (CPG). We tested predictions of this two-level control scheme. In particular, in response to a transient block of vision during locomotion, the system can temporarily slow shifts in R. As a result, the phase of rhythmical movements of all four limbs will be changed for some time, even though the rhythm and other characteristics of locomotion will be fully restored after perturbation, a phenomenon called long-lasting phase resetting. Another prediction of the control scheme is that the activity of multiple muscles of each leg can be minimized reciprocally at specific phases of the gait cycle both in the presence and absence of vision. Speed of locomotion is related to the rate of shifts in the referent body position in the environment. Results confirmed that human locomotion is likely guided by feedforward shifts in the referent body location, with subsequent changes in the activity of multiple muscles by the CPG. Neural structures responsible for shifts in the referent body configuration causing locomotion are suggested.
Collapse
Affiliation(s)
- Otella Shoja
- Department of Neuroscience, University of Montreal, Montreal, QC, Canada
| | - Farzad Towhidkhah
- Department of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
| | - Hamidollah Hassanlouei
- Department of Motor Behaviour, Faculty of Sport Science and Health, Shahid Beheshti University, Tehran, Iran
| | - Mindy F Levin
- School of Physical and Occupational Therapy, McGill University, Montreal, QC, Canada
- Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, QC, Canada
| | - Alireza Bahramian
- Department of Neuroscience, University of Montreal, Montreal, QC, Canada
| | - Sylvie Nadeau
- Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, QC, Canada
- Faculté de Médecine-École de Réadaptation, Montreal, QC, Canada
| | - Lei Zhang
- Institute for Neural Computation, Ruhr University Bochum, Bochum, Germany
| | - Anatol G Feldman
- Department of Neuroscience, University of Montreal, Montreal, QC, Canada.
- Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, QC, Canada.
- Institut de réadaptation Gingras-Lindsay-de-Montréal (IRGLM), 6300 Darlington, Montreal, QC, H3S 2J4, Canada.
| |
Collapse
|
4
|
A Narrative Literature Review About the Role of Microsaccades in Sports. Motor Control 2023:1-15. [PMID: 36640777 DOI: 10.1123/mc.2022-0102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/18/2022] [Accepted: 11/15/2022] [Indexed: 01/15/2023]
Abstract
In many daily and sport situations, people have to simultaneously perceive and process multiple objects and scenes in a short amount of time. A wrong decision may lead to a disadvantage for a team or for a single athlete, and during daily life (i.e., driving, surgery), it could have more dangerous consequences. Considering the results of different studies, the ability to distribute visual attention depends on different levels of expertise and environment-related constraints. This article is a narrative review of the current scientific evidence in the field of eye movements in sports, focusing on the role of microsaccades in sporting task situations. Over the past 10 years, microsaccades have become one of the most increasing areas of research in visual and oculomotor studies and even in the area of sport science. Here, we review the latest findings and discuss the relationships between microsaccades and attention, perception, and action in sports.
Collapse
|
5
|
Latash ML. The control and perception of antagonist muscle action. Exp Brain Res 2023; 241:1-12. [PMID: 36309879 DOI: 10.1007/s00221-022-06498-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 10/20/2022] [Indexed: 01/26/2023]
Abstract
The review covers a range of topics related to the role of the antagonist muscles in agonist-antagonist pairs within the theory of the neural control of movements with spatial referent coordinates, the principle of abundance, and the uncontrolled manifold hypothesis. It starts with the mechanical role of the antagonist in stopping movements and providing necessary levels of effector mechanical characteristics for fast movements. Further, it discusses the role of antagonist muscle activation bursts during voluntary movements, force production, and postural tasks. Recent studies show that agonist and antagonist motor units are united into common groups related to two basic commands, reciprocal and coactivation. A number of phenomena are considered including intra-muscle synergies stabilizing net force production, unintentional force drifts during isometric force production, effects of voluntary muscle coactivation on force production and perception, and perceptual errors caused by various factors including lack of visual feedback and muscle vibration. Taken together, the findings suggest inherent instability of neural commands (time functions of the stretch reflex threshold) to antagonist muscles requiring visual information for accurate performance. They also suggest that neural commands to antagonist muscles are not readily incorporated into kinesthetic perception leading to illusions and errors in matching tasks.
Collapse
Affiliation(s)
- Mark L Latash
- Department of Kinesiology, The Pennsylvania State University, University Park, PA, 16802, USA.
| |
Collapse
|