We have examined the localization and activity of the neural circuitry that generates swimming behavior in developing zebrafish that were spinalized to isolate the spinal cord from descending brain inputs. We found that addition of the excitatory amino acid agonist N-methyl-d-aspartate (NMDA) to spinalized zebrafish at 3 days in development induced repeating episodes of rhythmic tail beating ac...

Electrical stimulation of neuromuscular system has been used in a variety of research and therapeutic applications. Although tri-polar transcutaneous electrical stimulation (TENS) is commonly used to change motoneuron excitabi1ity, but the effect of TENS on synaptic activities through dorsal column stimulation or cutaneous pathways is unknown. So, the aim of this research study was to determine...

Serotonin and octopamine, injected into the circulation of freely moving lobsters and crayfish, produce opposite behavioral effects. Octopamine injection produces sustained extension of the limbs and abdomen; serotonin injection produces sustained flexion. Neurophysiological analyses show that these postures can be accounted for by opposing, coordinated effects of these amines on patterns of mo...

The BMP pathway is essential for scaling of the presynaptic motoneuron arbor to the postsynaptic muscle cell at the Drosophila neuromuscular junction (NMJ). Genetic analyses indicate that the muscle is the BMP-sending cell and the motoneuron is the BMP-receiving cell. Nevertheless, it is unclear how this directionality is established as Glass bottom boat (Gbb), the known BMP ligand, is active i...

Whole cell current- and voltage-clamp recordings were obtained from lumbar motoneurons in the isolated neonatal rat spinal cord to characterize the behavior of motoneurons during neurochemically induced locomotor-like activity. Bath application of serotonin (10-100 muM) in combination with N-methyl-D-aspartate (1-12 muM) initially produced tonic membrane depolarization (mean = 26 mV), increased...

Although a cardinal symptom of Parkinsonian disease, up to now, rigidity has been investigated much less than spasticity in hemiplegic patients. Many pathophysiological mechanisms may at least theoretically contribute to Parkinsonian rigidity, from altered viscoelastic muscle properties to inability of parkinsonian patients to relax. However, as demonstrated many years ago, motoneuron responses...

Morphological alterations and the course of changes in motoneuron counts were studied by light microscopy (cresyl violet staining) in the L2/L3 region of the spinal cord of hemizygotic transgenic rats carrying the amyotrophic lateral sclerosis-associated mutant human gene for Cu,Zn superoxide dismutase (hSOD1G93A) and of their non-transgenic littermates. In 60-day old transgenic rats, a few isc...

The activity of motoneurons during lateral turns was studied in a lower vertebrate, the lamprey, to investigate how a supraspinal command for the change of direction during locomotion is transmitted from the brain stem and integrated with the activity of the spinal locomotor pattern generator. Three types of experiments were performed. 1) The muscular activity during lateral turns in freely swi...

Motoneurons establish a critical link between the CNS and muscles. If motoneurons do not develop correctly, they cannot form the required connections, resulting in movement defects or paralysis. Compromised development can also lead to degeneration because the motoneuron is not set up to function properly. Little is known, however, regarding the mechanisms that control vertebrate motoneuron dev...

-In this work we examine the behaviour of a complex physiological system (muscle spindle) by using spectral analysis techniques of stationary point processes. In particular, we investigate the effect of a gamma motoneuron on the complex system when (a) there is no other stimulus present, and (b) there is an alpha motoneuron present. It is shown that the presence of an alpha motoneuron reduces t...