Development of pharmacological strategies for the control of locomotion in patients with spinal cord injury or disease requires an understanding of the neuroactive substances involved in the activation of the spinal cord neural systems for the control of locomotion. Studies using the in vitro preparations of the lamprey, frog embryo, and newborn rat indicate that excitatory amino acids (EAAs) a...

23 We compared the activity profiles and synergies of spinal motoneurons recorded during 24 fictive locomotion evoked in immobilized decerebrate cat preparations by midbrain stimulation 25 to the activity profiles and synergies of the corresponding hindlimb muscles obtained during 26 forward level walking in cats. The fictive locomotion data were collected in the Spinal Cord 27 Research Centre,...

The activity of the motor cortex during locomotion is profoundly modulated in the rhythm of strides. The source of modulation is not known. In this study we examined the activity of one of the major sources of afferent input to the motor cortex, the ventrolateral thalamus (VL). Experiments were conducted in chronically implanted cats with an extracellular single-neuron recording technique. VL n...

This study examines the activity of different classes of neurons of the motor cortex in the rabbit during two locomotion tasks: a simple (on a flat surface) and a complex (overstepping a series of barriers) locomotion. Four classes of efferent neurons were studied: corticocortical (CC) neurons with ipsilateral projection (CCIs), those with contralateral projection (CCCs), descending corticofuga...

This paper explores controllability and efficient locomotion of a two-link planar robot balancing on a single, unactuated wheel. By actuating an internal degree of freedom, the model can indirectly produce ground reaction forces yielding net accelerations and decelerations, to achieve locomotion. As with classic humanoid locomotion, this toy system is particularly challenging to control due to ...

Locomotion and scratch are characterized by alternation of flexion and extension phases within one hindlimb, which are mediated by rhythm-generating circuitry within the spinal cord. By definition, the rhythm generator controls cycle period, phase durations, and phase transitions. The aim was to determine whether rhythm-generating mechanisms for locomotion and scratch are similar in adult decer...

The re-expression of hindlimb locomotion after complete spinal cord injuries (SCIs) is caused by the presence of a spinal central pattern generator (CPG) for locomotion. After partial SCI, however, the role of this spinal CPG in the recovery of hindlimb locomotion in the cat remains mostly unknown. In the present work, we devised a dual-lesion paradigm to determine its possible contribution aft...

Previous studies demonstrated that neuronal networks located in midlumbar segments (L3-L4) are critical for the expression of locomotion in cats following complete spinalization. In the present study the importance of several thoracolumbar segments (T8-L7) for the generation of spontaneous hindlimb locomotion in decerebrate cats was evaluated. Experiments were performed in high decerebrate cats...

We tested the hypothesis that the same spinal interneuronal pathways are activated by the reticulospinal system during locomotion and reaching. If such were the case, we expected that microstimulation within the pontomedullary reticular formation (PMRF) would evoke qualitatively similar responses in muscles active during both behaviors. To test this, we stimulated in 47 sites within the PMRF du...

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 ...