Motoneurons supplying the dorsal and ventral parts of the myotome in the lamprey are shown to have different morphological characteristics; furthermore, their pattern of activation during fictive locomotion may differ considerably. Intracellular recordings from motoneurons were performed in an in vitro spinal cord-myotome preparation from segments rostra1 to the fins. The location of the contra...

In some motoneurons, L-type Ca channels that partly mediate persistent inward currents (PICs) have been estimated to be arranged in 50 to 200 μm long discrete regions in the dendrites, centered 100 to 400 μm from the soma. As a consequence of this non-uniform distribution, the interaction between synaptic inputs to motoneurons and these channels may vary according to the distribution of the syn...

Axotomy of the sciatic nerve have been documented to cause neuronal loss, especially in newborn rats. Few works have focused on time course of neuronal loss and the type of cell death, which occurs after axotomy. Forty rat pups were anesthetized by hypothermia and the right sciatic nerve transected at five days of their age and the left side was used as control. The operated animals were sacrif...

Stick insect middle leg (mesothoracic) motoneurons receive tonic excitatory input during front leg stepping on a treadmill. We studied the pharmacology of this excitatory input to the motoneurons during single-legged treadmill walking (in situ). During bath application of drugs restricted to the mesothoracic ganglion, activity in motoneurons contralateral to the stepping front leg was recorded ...

Spinal muscular atrophy (SMA) is a motoneuron disease caused by loss or mutation in Survival of Motor Neuron 1 (SMN1) gene. Recent studies have shown that selective restoration of SMN protein in astrocytes partially alleviates pathology in an SMA mouse model, suggesting important roles for astrocytes in SMA. Addressing these underlying mechanisms may provide new therapeutic avenues to fight SMA...

NECDIN belongs to the type II Melanoma Associated Antigen Gene Expression gene family and is located in the Prader-Willi Syndrome (PWS) critical region. Necdin-deficient mice develop symptoms of PWS, including a sensory and motor deficit. However, the mechanisms underlying the motor deficit remain elusive. Here, we show that the genetic ablation of Necdin, whose expression is restricted to post...

About 50% of spinal motoneurons undergo programmed cell death (PCD) after target contact, but little is known about how this process is initiated. Embryonic motoneurons coexpress the death receptor Fas and its ligand FasL at the stage at which PCD is about to begin. In the absence of trophic factors, many motoneurons die in culture within 2 d. Most (75%) of these were saved by Fas-Fc receptor b...

These experiments were performed to re-examine the presence of a recurrent inhibitory pathway to phrenic motoneurons in cats. Following intracellular staining of 49 phrenic motoneurons with horseradish peroxidase, initial axon collaterals were demonstrated in six axons (12%). Intracellular recording and averaging of the synaptic responses evoked by stimulation of the phrenic roots with an inten...

In the stick insect, Cuniculina impigra, intracellular recordings from mesothoracic motoneurons that control flexion and extension of the tibia and depression and levation of the trochantero-femur were made while the leg performed walking-like movements on a treadband or stereotyped rhythmic searching movements. We were interested in how synaptic input and intrinsic properties contribute to for...

During nervous system development, combinatorial codes of regulators act to specify different neuronal subclasses. However, within any given subclass, there exists a further refinement, apparent in Drosophila and C. elegans at single-cell resolution. The mechanisms that act to specify final and unique neuronal cell fates are still unclear. In the Drosophila embryo, one well-studied motoneuron s...