Publications by authors named "I R Rybak"
Article Synopsis
- Previous research has highlighted the importance of hindlimb muscle morphology in locomotion, but the role of forelimb muscle structure in motor outputs and sensory signal generation is less understood.
- This study measured the morphological features of 46 forelimb muscles in cats and analyzed their function during different types of locomotion, revealing significant relationships between muscle characteristics and force production.
- Results indicate that forelimb muscle morphology plays a vital role in controlling lateral stability and turning movements, emphasizing its importance beyond just propulsion in locomotion.
Article Synopsis
- Mammal locomotion is regulated by a spinal neuronal network that interacts with signals from the brain and sensory feedback from the limbs.
- * The study created a computational model to understand how this spinal network functions during different types of walking, particularly in cats, highlighting how it mimics real-life locomotion under various conditions.
- * Findings indicate that at slower speeds, the spinal network needs sensory feedback to function properly, while at faster speeds, it shifts to different operational modes, suggesting distinct control mechanisms for varying locomotor behaviors like exploring versus escaping.
Locomotor behaviors are performed by organisms throughout life, despite developmental changes in cellular properties, neural connectivity, and biomechanics. The basic rhythmic activity in the central nervous system that underlies locomotion is thought to be generated via a complex balance between network and intrinsic cellular properties. Within mature mammalian spinal locomotor circuitry, we have yet to determine which properties of spinal interneurons (INs) are critical to rhythmogenesis and how they change during development.
View Article and Find Full Text PDFIt was suggested that during locomotion, the nervous system controls movement by activating groups of muscles, or muscle synergies. Analysis of muscle synergies can reveal the organization of spinal locomotor networks and how it depends on the state of the nervous system, such as before and after spinal cord injury, and on different locomotor conditions, including a change in speed. The goal of this study was to investigate the effects of spinal transection and locomotor speed on hindlimb muscle synergies and their time-dependent activity patterns in adult cats.
View Article and Find Full Text PDFArticle Synopsis
- Cutaneous afferents in cats help coordinate muscle activity across all four limbs during movement, especially when external obstacles are encountered.
- The study investigated how reflex pathways in the limbs are affected after incomplete spinal cord injuries, using a staggered thoracic hemisection model to simulate the injury in seven adult cats.
- Results indicated a significant loss in reflex responses and limb coordination after spinal injury, with some reflexes preserving modulation, suggesting compromised but not entirely lost functionality in response to external disturbances.