Animals propel themselves by rhythmic oscillatory movements of their body and limbs. In vertebrates these are driven by specialized neuronal circuits in the spinal cord. As for other primeval neural functions, locomotion is studied in a variety of animal models, having recognized that similar solutions may have served common problems through evolution. In a recent series of experiments we have shed light on the functional organization of the spinal networks generating locomotor rhythmicity in the lamprey, a primitive aquatic vertebrate. By sectioning the spinal cord midline, we found that the antagonistic muscles on the left and right sides of the body are controlled by unilateral networks endowed with intrinsic rhythmic capability. Inhibitory connections between antagonistic networks ensure alternation of activity-thereby driving oscillatory movements of the body-but also downregulate the locomotor frequency. The mechanisms underlying unilateral rhythm generation were explored by recording the fring pattern of spinal neurons. A parsimonious model for the emergence of rhythmicity was formulated and integrated with previous knowledge about the lamprey spinal cord. These results may bear relevance for the organization of stepping locomotion in higher vertebrates and humans.
From behavior to its underlying biological substrate: an experimental journey into the genesis of movement
CANGIANO, LORENZO
2010-01-01
Abstract
Animals propel themselves by rhythmic oscillatory movements of their body and limbs. In vertebrates these are driven by specialized neuronal circuits in the spinal cord. As for other primeval neural functions, locomotion is studied in a variety of animal models, having recognized that similar solutions may have served common problems through evolution. In a recent series of experiments we have shed light on the functional organization of the spinal networks generating locomotor rhythmicity in the lamprey, a primitive aquatic vertebrate. By sectioning the spinal cord midline, we found that the antagonistic muscles on the left and right sides of the body are controlled by unilateral networks endowed with intrinsic rhythmic capability. Inhibitory connections between antagonistic networks ensure alternation of activity-thereby driving oscillatory movements of the body-but also downregulate the locomotor frequency. The mechanisms underlying unilateral rhythm generation were explored by recording the fring pattern of spinal neurons. A parsimonious model for the emergence of rhythmicity was formulated and integrated with previous knowledge about the lamprey spinal cord. These results may bear relevance for the organization of stepping locomotion in higher vertebrates and humans.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
