scholarly journals Motoneuronal and muscle synergies involved in cat hindlimb control during fictive and real locomotion: a comparison study

2012 ◽  
Vol 107 (8) ◽  
pp. 2057-2071 ◽  
Author(s):  
Sergey N. Markin ◽  
Michel A. Lemay ◽  
Boris I. Prilutsky ◽  
Ilya A. Rybak
Keyword(s):  
Clustering Algorithm ◽  
Minimum Spanning Tree ◽  
Activity Patterns ◽  
Rectus Femoris ◽  
Afferent Feedback ◽  
Research Centre ◽  
Muscle Synergies ◽  
Fictive Locomotion ◽  
Decerebrate Cat ◽  
Level Walking

We compared the activity profiles and synergies of spinal motoneurons recorded during fictive locomotion evoked in immobilized decerebrate cat preparations by midbrain stimulation to the activity profiles and synergies of the corresponding hindlimb muscles obtained during forward level walking in cats. The fictive locomotion data were collected in the Spinal Cord Research Centre, University of Manitoba, and provided by Dr. David McCrea; the real locomotion data were obtained in the laboratories of M. A. Lemay and B. I. Prilutsky. Scatterplot representation and minimum spanning tree clustering algorithm were used to identify the possible motoneuronal and muscle synergies operating during both fictive and real locomotion. We found a close similarity between the activity profiles and synergies of motoneurons innervating one-joint muscles during fictive locomotion and the profiles and synergies of the corresponding muscles during real locomotion. However, the activity patterns of proximal nerves controlling two-joint muscles, such as posterior biceps and semitendinosus (PBSt) and rectus femoris (RF), were not uniform in fictive locomotion preparations and differed from the activity profiles of the corresponding two-joint muscles recorded during forward level walking. Moreover, the activity profiles of these nerves and the corresponding muscles were unique and could not be included in the synergies identified in fictive and real locomotion. We suggest that afferent feedback is involved in the regulation of locomotion via motoneuronal synergies controlled by the spinal central pattern generator (CPG) but may also directly affect the activity of motoneuronal pools serving two-joint muscles (e.g., PBSt and RF). These findings provide important insights into the organization of the spinal CPG in mammals, the motoneuronal and muscle synergies engaged during locomotion, and their afferent control.

Rhythmic activity of feline dorsal and ventral spinocerebellar tract neurons during fictive motor actions

2013 ◽  
Vol 109 (2) ◽  
pp. 375-388 ◽  
Author(s):  
Brent Fedirchuk ◽  
Katinka Stecina ◽  
Kasper Kyhl Kristensen ◽  
Mengliang Zhang ◽  
Claire F. Meehan ◽  
...  
Keyword(s):  
Central Pattern Generator ◽  
Sensory Input ◽  
Rhythmic Activity ◽  
Pattern Generator ◽  
Afferent Feedback ◽  
Fictive Locomotion ◽  
Decerebrate Cat ◽  
Motor Behaviors ◽  
Spinocerebellar Tract ◽  
Motor Actions

Neurons of the dorsal spinocerebellar tracts (DSCT) have been described to be rhythmically active during walking on a treadmill in decerebrate cats, but this activity ceased following deafferentation of the hindlimb. This observation supported the hypothesis that DSCT neurons primarily relay the activity of hindlimb afferents during locomotion, but lack input from the spinal central pattern generator. The ventral spinocerebellar tract (VSCT) neurons, on the other hand, were found to be active during actual locomotion (on a treadmill) even after deafferentation, as well as during fictive locomotion (without phasic afferent feedback). In this study, we compared the activity of DSCT and VSCT neurons during fictive rhythmic motor behaviors. We used decerebrate cat preparations in which fictive motor tasks can be evoked while the animal is paralyzed and there is no rhythmic sensory input from hindlimb nerves. Spinocerebellar tract cells with cell bodies located in the lumbar segments were identified by electrophysiological techniques and examined by extra- and intracellular microelectrode recordings. During fictive locomotion, 57/81 DSCT and 30/30 VSCT neurons showed phasic, cycle-related activity. During fictive scratch, 19/29 DSCT neurons showed activity related to the scratch cycle. We provide evidence for the first time that locomotor and scratch drive potentials are present not only in VSCT, but also in the majority of DSCT neurons. These results demonstrate that both spinocerebellar tracts receive input from the central pattern generator circuitry, often sufficient to elicit firing in the absence of sensory input.

COMMON AND DISTINCT MUSCLE SYNERGIES DURING LEVEL AND SLOPE LOCOMOTION IN THE CAT

2021 ◽  
Author(s):  
Alexander N Klishko ◽  
Adil Akyildiz ◽  
Ricky Mehta ◽  
Boris I. Prilutsky
Keyword(s):  
Stance Phase ◽  
Rectus Femoris ◽  
Emg Activity ◽  
Modular Organization ◽  
Muscle Synergies ◽  
Cycle Duration ◽  
Hindlimb Muscles ◽  
Level Walking ◽  
Adult Cats ◽  
Activity Cluster

Although it is well established that the motor control system is modular, the organization of muscle synergies during locomotion and their change with ground slope are not completely understood. For example, typical reciprocal flexor-extensor muscle synergies of level walking in cats break down in downslope: one-joint hip extensors are silent throughout the stride cycle, whereas hindlimb flexors demonstrate an additional stance phase-related EMG burst (Smith et al. 1998a). Here we investigated muscle synergies during Level, Upslope (27o) and Downslope (-27o) walking in adult cats to examine common and distinct features of modular organization of locomotor EMG activity. Cluster analysis of EMG burst onset-offset times of 12 hindlimb muscles revealed 5 flexor and extensor burst groups that were generally shared across slopes. Stance-related bursts of flexor muscles in downslope were placed in a burst group from Level and Upslope walking formed by the rectus femoris. Walking Upslope changed swing/stance phase durations of Level walking but not the cycle duration. Five muscle synergies computed using non-negative matrix factorization accounted for at least 95% of variance in EMG patterns in each slope. Five synergies were shared between Level and Upslope walking, whereas only 3 of those were shared with Downslope synergies; these synergies were active during the swing phase and phase transitions. Two stance-related synergies of downslope walking were distinct; they comprised a mixture of flexors and extensors. We suggest that the modular organization of muscle activity during Level and Slope walking results from interactions between motion-related sensory feedback, CPG, and supraspinal inputs.

Forms of Forward Quadrupedal Locomotion. III. A Comparison of Posture, Hindlimb Kinematics, and Motor Patterns for Downslope and Level Walking

1998 ◽  
Vol 79 (4) ◽  
pp. 1702-1716 ◽  
Author(s):  
Judith L. Smith ◽  
Patricia Carlson-Kuhta ◽  
Tamara V. Trank
Keyword(s):  
Ankle Joint ◽  
Neural Control ◽  
Activity Patterns ◽  
Motor Patterns ◽  
Quadrupedal Locomotion ◽  
Hindlimb Muscles ◽  
Level Walking ◽  
Angular Displacements ◽  
External Forces ◽  
Hindlimb Kinematics

Smith, Judith L., Patricia Carlson-Kuhta, and Tamara V. Trank. Forms of forward quadrupedal locomotion. III. A comparison of posture, hindlimb kinematics, and motor patterns for downslope and level walking. J. Neurophysiol. 79: 1702–1716, 1998. To gain further insight into the neural mechanisms for different forms of quadrupedal walking, data on postural orientation, hindlimb kinematics, and motor patterns were assessed for four grades of downslope walking, from 25% (14° slope) to 100% (45°), and compared with data from level and downslope walking at five grades (5–25%) on the treadmill (0.6 m/s). Kinematic data were obtained by digitizing ciné film, and electromyograms (EMGs) synchronized with kinematic records were taken from 13 different hindlimb muscles. At grades from 25 to 75%, cycle periods were similar, but at the steepest grade the cycle was shorter because of a reduced stance phase. Paw-contact sequences at all grades were consistent with lateral-sequence walking, but pace walking often occurred at the steepest grades. The cats crouched at the steeper grades, and crouching was associated with changes in fore- and hindlimb orientation that were consistent with increasing braking forces and decreasing propulsive forces during stance. The average ranges of motion at the hindlimb joints, except at the hip, were often different at the two steepest slopes. During swing, the range of knee- and ankle-joint flexion decreased, and the range and duration of extension increased at the ankle joint to lower the paw downward for contact. During stance the range of flexion during yield increased at the ankle joint, and the range of extension decreased at the knee and metatarsophalangeal joints. Downslope walking was also associated with EMG changes for several muscles. The hip extensors were not active during stance; instead, hip flexors were active, presumably to slow the rate of hip extension. Although ankle extensors were active during stance, their burst durations were truncated and centered around paw contact. Ankle flexors were active after midstance at the steeper slopes before the need to initiate swing, whereas flexor and extensor digit muscles were coactive throughout stance. Overall the changes in posture, hindlimb kinematics, and activity patterns of hindlimb muscles during stance reflected a need to counteract external forces that would accelerate angular displacements at some joints. Implications of these changes are discussed by using current models for the neural control of walking.

scholarly journals Muscular Force Patterns during Level Walking in ACL-Deficient Patients with a Concomitant Medial Meniscus Tear

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Hongshi Huang ◽  
Wei Yin ◽  
Shuang Ren ◽  
Yuanyuan Yu ◽  
Si Zhang ◽  
...  
Keyword(s):  
Stance Phase ◽  
Medial Meniscus ◽  
Rectus Femoris ◽  
Cartilage Degeneration ◽  
Meniscus Tear ◽  
Muscular Force ◽  
Acl Deficiency ◽  
Level Walking ◽  
Significant Difference ◽  
Acl Deficient

Background. The abnormal knee joint motion patterns caused by anterior cruciate ligament (ACL) deficiency are thought to be associated with articular cartilage degeneration. High rates of meniscus tear combined with ACL rupture are observed, and these knees suffer a higher risk of early cartilage degeneration. Research Question. This study investigated lower limb muscular force patterns of ACL-deficient knees with a concomitant medial meniscus tear. Methods. 12 volunteers and 22 patients were recruited, including 12 patients with isolated ACL deficiency (ACLD) and 10 ACL-deficient patients with a concomitant medial meniscus tear (ACLDM). Level walking data at a self-selected speed were collected before surgery. Then, a musculoskeletal dynamic analysis system, AnyBody, was applied to simulate tibiofemoral flexion moments and muscle forces. Results. Our results indicate that the tibiofemoral peak flexion and extension moments in ACLDM patients are significantly lower than in controls. The rectus femoris force in ACLDM patients was significantly lower than in isolated ACL-deficient patients and the controls during mid and terminal stance phase, while no significant difference was found in hamstring and vastus force. Additionally, the gastrocnemius force in ACL-deficient patients both with and without a medial meniscus tear was lower than in controls during mid-stance phase. Significance. The ACLDM patients had lower peak tibiofemoral flexion moment, lower gastrocnemius force in mid-stance phase, and lower rectus femoris force during the mid and terminal stance phase. These results may help clinicians to better understand the muscle function and gait pattern in ACL-deficient patients with a concomitant medial meniscus tear.

Muscle coordination in cycling: effect of surface incline and posture

1998 ◽  
Vol 85 (3) ◽  
pp. 927-934 ◽  
Author(s):  
Li Li ◽  
Graham E. Caldwell
Keyword(s):  
Lower Extremity ◽  
High Speed ◽  
Vastus Lateralis ◽  
Activity Patterns ◽  
Gluteus Maximus ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Knee Extensors ◽  
Emg Activity ◽  
Muscle Coordination

The purpose of the present study was to examine the neuromuscular modifications of cyclists to changes in grade and posture. Eight subjects were tested on a computerized ergometer under three conditions with the same work rate (250 W): pedaling on the level while seated, 8% uphill while seated, and 8% uphill while standing (ST). High-speed video was taken in conjunction with surface electromyography (EMG) of six lower extremity muscles. Results showed that rectus femoris, gluteus maximus (GM), and tibialis anterior had greater EMG magnitude in the ST condition. GM, rectus femoris, and the vastus lateralis demonstrated activity over a greater portion of the crank cycle in the ST condition. The muscle activities of gastrocnemius and biceps femoris did not exhibit profound differences among conditions. Overall, the change of cycling grade alone from 0 to 8% did not induce a significant change in neuromuscular coordination. However, the postural change from seated to ST pedaling at 8% uphill grade was accompanied by increased and/or prolonged muscle activity of hip and knee extensors. The observed EMG activity patterns were discussed with respect to lower extremity joint moments. Monoarticular extensor muscles (GM, vastus lateralis) demonstrated greater modifications in activity patterns with the change in posture compared with their biarticular counterparts. Furthermore, muscle coordination among antagonist pairs of mono- and biarticular muscles was altered in the ST condition; this finding provides support for the notion that muscles within these antagonist pairs have different functions.

scholarly journals Double-Valued Neutrosophic Sets, their Minimum Spanning Trees, and Clustering Algorithm

2018 ◽  
Vol 27 (2) ◽  
pp. 163-182 ◽  
Author(s):  
Ilanthenral Kandasamy
Keyword(s):  
Fuzzy Sets ◽  
Spanning Tree ◽  
Clustering Algorithm ◽  
Minimum Spanning Tree ◽  
Distance Measure ◽  
Clustering Algorithms ◽  
Neutrosophic Set ◽  
Neutrosophic Sets ◽  
Inconsistent Information ◽  
Intuitionistic Fuzzy

AbstractNeutrosophy (neutrosophic logic) is used to represent uncertain, indeterminate, and inconsistent information available in the real world. This article proposes a method to provide more sensitivity and precision to indeterminacy, by classifying the indeterminate concept/value into two based on membership: one as indeterminacy leaning towards truth membership and the other as indeterminacy leaning towards false membership. This paper introduces a modified form of a neutrosophic set, called Double-Valued Neutrosophic Set (DVNS), which has these two distinct indeterminate values. Its related properties and axioms are defined and illustrated in this paper. An important role is played by clustering in several fields of research in the form of data mining, pattern recognition, and machine learning. DVNS is better equipped at dealing with indeterminate and inconsistent information, with more accuracy, than the Single-Valued Neutrosophic Set, which fuzzy sets and intuitionistic fuzzy sets are incapable of. A generalised distance measure between DVNSs and the related distance matrix is defined, based on which a clustering algorithm is constructed. This article proposes a Double-Valued Neutrosophic Minimum Spanning Tree (DVN-MST) clustering algorithm, to cluster the data represented by double-valued neutrosophic information. Illustrative examples are given to demonstrate the applications and effectiveness of this clustering algorithm. A comparative study of the DVN-MST clustering algorithm with other clustering algorithms like Single-Valued Neutrosophic Minimum Spanning Tree, Intuitionistic Fuzzy Minimum Spanning Tree, and Fuzzy Minimum Spanning Tree is carried out.

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