This suggests that the sensory spinal cord network in P5-7 rats operates in an immature bursting mode, as do so many other neuronal networks in that period19,48,49.
When analysing spinal cord network dynamics during complex movements, we observed a phenomenon similar to that described for twitching epochs, with activity in intermediate-motor zones preceding complex movement onset, in turn followed by elevated firing of dorsal units, which was maximal after movement onset and declined through the time course of the complex movements (Fig. 2i l).
To explore the dynamics of spinal cord network activity in relation to early motor behaviour, we developed a method enabling recording simultaneously translaminar, spinal cord network events and movements, in vivo.
(d) Effect of deafferentation on spinal cord network dynamics during twitching (single animal).
To further understand temporal correlations between behaviour and spinal cord network activity, we detected activity bursts within sensory and motor zones, based on a previously described method70.
However, it remains unknown whether sensorimotor network activity and the local interactions described in the in vitro spinal cord preparation correspond to the spinal cord network dynamics in behaving animals.
In this study, we addressed the spatiotemporal dynamics of spinal cord circuitry in relation to neonatal spontaneous movements, in vivo, through simultaneous recordings of translaminar spinal cord network activity and spontaneous movements in spine-restrained behaving neonatal rats.
We describe how the phasic modulation of reticulospinal activity from the spinal CPG ensures reliable steering/turning commands without the need for a very precise timing of on- or offset, by using a biophysically detailed large-scale (19,600 model neurons and 646,800 synapses) computational model of the lamprey brainstem spinal cord network.
In non-silenced cells, F-actin was preferentially polarized at the leading edge of the plasma membrane and the cells were able to organize a cord-like network in vitro.
"... We use the lamprey as a model for investigating the role of this phasic modulation of the reticulospinal activity, because the brainstem spinal cord networks are known down to the cellular level in this phylogenetically oldest extant vertebrate.
Taken together, the existing evidence, based on behavioural observations and model studies at the level of spinal cord and recordings of neuronal activity at higher brain centres, suggests that sensory feedback is central to the roles fulfilled by spontaneous twitches in coordinating sensorimotor spinal cord networks.
