An interesting feature of the muscular organization of the human hand is that the main flexors and extensors of the fingers are compartmentalized and give rise to multiple parallel tendons that insert onto all the fingers. Previous studies of motor unit synchrony in extensor digitorum (Keen and Fuglevand 2004b) and flexor digitorum profundus (Reilly et al. 2004; Winges and Santello 2004) have i...

Spontaneous and evoked spinal activities interact to set the characteristics of emergent motor responses. Gamma motor neurons have feedforward and feedback functions in motor control, which are crucial for transforming motor commands into action. Meanwhile, the intrinsic excitability and functional connectivity of alpha motor neurons determine the accuracy of actions. In this study, we investig...

During spinal cord development, ventral neural progenitor cells that express the transcription factors Olig1 and Olig2, called pMN progenitors, produce motor neurons and then oligodendrocytes. Whether motor neurons and oligodendrocytes arise from common or distinct progenitors in vivo is not known. Using zebrafish, we found that motor neurons and oligodendrocytes are produced sequentially by di...

1. Using combined morphological and electrophysiological techniques, we have identified motor neurons in the right pleural ganglion of Aplysia californica that contribute to the release of opaline from the opaline gland. 2. Three pleural ganglion neurons were found to meet the requirements for identification as opaline gland motor neurons by a) sending processes in nerve P5, which innervates th...

The improvement of a perceptual or motor skill continues after training has ended. The central question is whether this improvement is just a function of time or whether sleep, a certain circadian phase, or their interaction (sleep occurring in a particular circadian phase) is favorable to the reprocessing of recent memory traces. In this issue of Neuron, provide behavioral evidence that most o...

Spinal muscular atrophy (SMA), characterized by specific degeneration of spinal motor neurons, is caused by mutations in the survival of motor neuron 1, telomeric (SMN1) gene and subsequent decreased levels of functional SMN. How the deficiency of SMN, a ubiquitously expressed protein, leads to spinal motor neuron-specific degeneration in individuals affected by SMA remains unknown. In this stu...

The analysis of the electrical activity (trains of spikes, volleys) of single neurons is proposed in form of a pattern function. From the pattern function and its variance it is possible to obtain full statistical description of volleys including the density distribution of spikes in the volley. An algorithm for finding the pattern function and the estimate of variance from a set of experimenta...

IT IS GENERALLY AGREED that most long-distance information transmission in the nervous system is accomplished by the propagation of all-or-none spikes along axons, and further that this information is carried in a single axon by the timing of spikes. When a neuron is discharging with a constant mean frequency, information is probably contained in the length of interspike intervals which, howeve...

The source of variability in the interval between action potentials has been identified in a class of cat spinal motoneurons. The observed random fluctuations in membrane potential (synaptic noise) together with an empirical description of spike generation accurately predict the statistical structure of variability observed to occur in the neuron's discharge.