Facilitation of postural limb reflexes in spinal rabbits by serotonergic agonist administration, epidural electrical stimulation, and postural training.

In quadrupeds, spinalization in the thoracic region severely impairs postural control in the hindquarters. The goal of this study was to improve postural functions in chronic spinal rabbits by regular application of different factors: intrathecal injection of the 5-HT(2) agonist (±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI), epidural electrical spinal cord stimulation (EES), and specific postural training (SPT). The factors were used either alone (SPT group) or in combination (DOI+SPT, EES+SPT, and DOI+EES+SPT groups) or not used (control group).

Activity of motor cortex neurons during backward locomotion.

Forward walking (FW) and backward walking (BW) are two important forms of locomotion in quadrupeds. Participation of the motor cortex in the control of FW has been intensively studied, whereas cortical activity during BW has never been investigated. The aim of this study was to analyze locomotion-related activity of the motor cortex during BW and compare it with that during FW.

Activity of pyramidal tract neurons in the cat during standing and walking on an inclined plane.

To keep balance when standing or walking on a surface inclined in the roll plane, the cat modifies its body configuration so that the functional length of its right and left limbs becomes different. The aim of the present study was to assess the motor cortex participation in the generation of this left/right asymmetry. We recorded the activity of fore- and hindlimb-related pyramidal tract neurons (PTNs) during standing and walking on a treadmill.

Maintenance of lateral stability during standing and walking in the cat.

During free behaviors animals often experience lateral forces, such as collisions with obstacles or interactions with other animals. We studied postural reactions to lateral pulses of force (pushes) in the cat during standing and walking. During standing, a push applied to the hip region caused a lateral deviation of the caudal trunk, followed by a return to the initial position.

Influences of sensory input from the limbs on feline corticospinal neurons during postural responses.

The dorsal-side-up body posture of standing quadrupeds is maintained by coordinated activity of all limbs. Somatosensory input from the limbs evokes postural responses when the supporting surface is perturbed. The aim of this study was to reveal the contribution of sensory inputs from individual limbs to the posture-related modulation of pyramidal tract neurons (PTNs) arising in the primary motor cortex.

Responses of reticulospinal neurons in the lamprey to lateral turns.

When swimming, the lamprey maintains a definite orientation of its body in the vertical planes, in relation to the gravity vector, as the result of postural vestibular reflexes. Do the vestibular-driven mechanisms also play a role in the control of the direction of swimming in the horizontal (yaw) plane, in which the gravity cannot be used as a reference direction? In the present study, we addressed this question by recording responses to lateral turns in reticulospinal (RS) neurons mediating vestibulospinal reflexes. In intact lampreys, the activity of axons of RS neurons was recorded in the spinal cord by implanted electrodes.

Impairment and recovery of postural control in rabbits with spinal cord lesions.

The aim of this study was to characterize impairment and subsequent recovery of postural control after spinal cord injuries. Experiments were carried out on rabbits with three types of lesion--a dorsal (D), lateral (L), or ventral (V) hemisection (HS) at T(12) level. The animals were maintaining equilibrium on a platform periodically tilted in the frontal plane.