Neural Control of Movement - Copenhagen > Research > Spinal locomotion

Spinal locomotor networks in the cat and monkey

It is now well established that spinal networks have the capability of generating the fundamental rhythm for locomotion in a large number of vertebrates. This has been investigated in decerebrate animals in which the locomotor circuits were activated either by stimulation of locomotor centres of the brain stem, or by pharmacological means. Usually the locomotor activity is recorded in paralyzed preparations where the locomotor activity is recorded directly from the muscle nerves – fictive locomotion.

In mammals it has been difficult to define the intrinsic organization of these networks (central pattern generators; CPG) with the clarity and precision that has been possible for work performed on primitive vertebrates or on the rhythmic locomotor generators of invertebrates. Investigations on sensory control of the spinal locomotor rhythm have revealed that several sensory afferents interact with the rhythm
 generator. For example, external flexion/extension of the hip can entrain the spinal locomotor rhythm. We have investigated the effect from load-signalling group I afferents from extensor muscles – these signals cause a prolongation of the extensor phase of the locomotor cycle. Short stimulus trains can reset the rhythm. In the case of the load-signalling group I muscle afferents (from Golgi tendon organs) we have demonstrated that the rhythm is reset to extension (stance) within a few milliseconds.

We have been using the discovery of a number of sensory pathways that effectively reset the locomotor rhythm as a tool for investigating the intrinsic organization of the mammalian spinal network for locomotion and for identification of interneurones which are part in the “Central Pattern Generator”.

Research group members:
Hans Hultborn (Coordinator)
Svend Sparre Geertsen
Claire Meehan
Jens Bo Nielsen
Katinka Stecina