Bruce P. Graham

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Short-term facilitation and depression have a profound influence on transmission at many glutamatergic synapses, particularly during trains of stimuli. A major component of these processes is postsynaptic receptor desensitization. Both presynaptic and postsynaptic mechanisms can contribute to synaptic efficacy, but it is often difficult to define their(More)
Presynaptic group III metabotropic glutamate receptor (mGluR) activation by exogenous agonists (such as L-2-amino-4-phosphonobutyrate (L-AP4)) potently inhibit transmitter release, but their autoreceptor function has been questioned because endogenous activation during high-frequency stimulation appears to have little impact on synaptic amplitude. We(More)
It has been proposed that the hippocampal theta rhythm (4-7 Hz) can contribute to memory formation by separating encoding (storage) and retrieval of memories into different functional half-cycles (Hasselmo et al. (2002) Neural Comput 14:793-817). We investigate, via computer simulations, the biophysical mechanisms by which storage and recall of(More)
The vestibulo-ocular reflex (VOR) is characterized by a short-latency, high-fidelity eye movement response to head rotations at frequencies up to 20 Hz. Electrophysiological studies of medial vestibular nucleus (MVN) neurons, however, show that their response to sinusoidal currents above 10 to 12 Hz is highly nonlinear and distorted by aliasing for all but(More)
An average-response model of depression at the calyx of Held, a giant glutamatergic synapse in the mammalian auditory pathway, is presented. The model is 2t to experimentally recorded EPSC amplitudes resulting from 10 to 100 Hz presynaptic stimulation for 1 s. This data exhibits a strong depression of the EPSC amplitude. The model best 2ts the time course(More)
Sustained activity at most central synapses is accompanied by a number of short-term changes in synaptic strength which act over a range of time scales. Here we examine experimental data and develop a model of synaptic depression at the calyx of Held synaptic terminal that combines many of these mechanisms (acting at differing sites and across a range of(More)
Neurite outgrowth (dendrites and axons) should be a stable, but easily regulated process to enable a neuron to make its appropriate network connections during development. We explore the dynamics of outgrowth in a mathematical continuum model of neurite elongation. The model describes the construction of the internal microtubule cytoskeleton, which results(More)
Neuronal nitric oxide synthase (nNOS) is broadly expressed in the brain and associated with synaptic plasticity through NMDAR-mediated calcium influx. However, its physiological activation and the mechanisms by which nitric oxide (NO) influences synaptic transmission have proved elusive. Here, we exploit the unique input-specificity of the calyx of Held to(More)
Mathematical modeling and computer simulation are valuable tools in unravelling the complexities underlying the morphological development of neurons. In this chapter, we consider biologically plausible mathematical models of neurite initiation, elongation, and branching. These models attempt to describe the intraand extracellular environments of a(More)