A population of PPTN neurons exhibited a fixational saccade-related phasic increase in activity, Inhibitor Library and the majority of them also showed activity modulation with large targeting saccades. In addition, a group of these neurons showed a task-related tonic increase in activity during the fixation period, and half of them relayed the saccade signal only when the neuron exhibited higher tonic activity during the task execution period. Thus, fixational saccade-related signals
of PPTN neurons overlap with tonic task-related signals, and might contribute to the cognitive modulation of fixational saccades. “
“We examined whether elevating levels of neurotrophin-3 (NT-3) in the spinal cord and dorsal
root ganglion (DRG) would alter connections made by muscle spindle afferent http://www.selleckchem.com/products/epacadostat-incb024360.html fibers on motoneurons. Adeno-associated virus (AAV) serotypes AAV1, AAV2 and AAV5, selected for their tropism profile, were engineered with the NT-3 gene and administered to the medial gastrocnemius muscle in adult rats. ELISA studies in muscle, DRG and spinal cord revealed that NT-3 concentration in all tissues peaked about 3 months after a single viral injection; after 6 months NT-3 concentration returned to normal values. Intracellular recording in triceps surae motoneurons revealed complex electrophysiological changes. Moderate
elevation in cord NT-3 resulted in diminished segmental excitatory postsynaptic potential Casein kinase 1 (EPSP) amplitude, perhaps as a result of the observed decrease in motoneuron input resistance. With further elevation in NT-3 expression, the decline in EPSP amplitude was reversed, indicating that NT-3 at higher concentration could increase EPSP amplitude. No correlation was observed between EPSP amplitude and NT-3 concentration in the DRG. Treatment with control viruses could elevate NT-3 levels minimally resulting in measurable electrophysiological effects, perhaps as a result of inflammation associated with injection. EPSPs elicited by stimulation of the ventrolateral funiculus underwent a consistent decline in amplitude independent of NT-3 level. These novel correlations between modified NT-3 expression and single-cell electrophysiological parameters indicate that intramuscular administration of AAV(NT-3) can exert long-lasting effects on synaptic transmission to motoneurons. This approach to neurotrophin delivery could be useful in modifying spinal function after injury. “
“The two histopathological hallmarks of Alzheimer’s disease (AD) are amyloid plaques containing multiple forms of amyloid beta (Aβ) and neurofibrillary tangles containing phosphorylated tau proteins.