37 Motoneurons often fire repetitively and for long periods. In sustained voluntary contractions the 38 excitability of motoneurons declines. We provide the first detailed description of the time-course of 39 human motoneuron recovery after sustained activity at a constant discharge rate. We recorded the 40 discharge of single motor units (MUs, n=30) with intramuscular wire electrodes inserted ...

1. A weak or moderate-intensity tactile stimulus delivered to the siphon skin of Aplysia californica elicits a defensive reflex withdrawal of the gill and siphon into the mantle cavity. The reflex undergoes both short- and long-term habituation and sensitization and has, therefore, been used as a model system to examine various forms of learning. In this paper we describe studies of the respons...

BACKGROUND The physiological characteristics of muscle activity and the assessment of muscle strength represent important diagnostic information. There are many devices that measure muscle force in humans, but some require voluntary contractions, which are difficult to assess in weak or unconscious patients who are unable to complete a full range of voluntary force assessment tasks. Other devic...

The corticospinal system plays an important role in control of voluntary movements in primates. Recently, we demonstrated that the effectiveness of this system is depressed after maximal exercise. Because the depression was absent after antidromic activation of the motoneurons, we argued that transmission across corticospinal synapses was involved. Here, we explore the possible functional conse...

Wild-type zebrafish embryos swim away in response to tactile stimulation. By contrast, relatively relaxed mutants swim slowly due to weak contractions of trunk muscles. Electrophysiological recordings from muscle showed that output from the CNS was normal in mutants, suggesting a defect in the muscle. Calcium imaging revealed that Ca(2+) transients were reduced in mutant fast muscle. Immunostai...

One proves the existence and uniqueness of a generalized (mild) solution for nonlinear Fokker–Planck equation (FPE) u t ? ? ( ? ) + div D x b = 0 , ? ? R d ? 2 ? in where L 1 C is nondecreasing function, bounded, ? ; with strictly increasing, if not constant. Moreover, ? semigroup contractions which leaves invariant set probability density functions . If ? r | ? ? 3 then m > extends to initial ...