John R. Cressman

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1 Department of Physics & Astronomy and The Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, 22030, USA, 2 Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA, 3 Department of Biology and Biochemistry, The University of Houston, Houston,(More)
We describe a simple conductance-based model neuron that includes intra- and extracellular ion concentration dynamics and show that this model exhibits periodic bursting. The bursting arises as the fast-spiking behavior of the neuron is modulated by the slow oscillatory behavior in the ion concentration variables and vice versa. By separating these time(More)
Excitatory and inhibitory (EI) interactions shape network activity. However, little is known about the EI interactions in pathological conditions such as epilepsy. To investigate EI interactions during seizure-like events (SLEs), we performed simultaneous dual and triple whole cell and extracellular recordings in pyramidal cells and oriens interneurons in(More)
Precisely timed and dynamically balanced excitatory (E) and inhibitory (I) conductances underlie the basis of neural network activity. Normal E/I balance is often shifted in epilepsy, resulting in neuronal network hyperexcitability and recurrent seizures. However, dynamics of the actual excitatory and inhibitory synaptic conductances (ge and gi,(More)
In these companion papers, we study how the interrelated dynamics of sodium and potassium affect the excitability of neurons, the occurrence of seizures, and the stability of persistent states of activity. We seek to study these dynamics with respect to the following compartments: neurons, glia, and extracellular space. We are particularly interested in the(More)
In these companion papers, we study how the interrelated dynamics of sodium and potassium affect the excitability of neurons, the occurrence of seizures, and the stability of persistent states of activity. In this first paper, we construct a mathematical model consisting of a single conductance-based neuron together with intra- and extracellular ion(More)
We utilized a novel ratiometric nanoquantum dot fluorescence resonance energy transfer (NQD-FRET) optical sensor to quantitatively measure oxygen dynamics from single cell microdomains during hypoxic episodes as well as during 4-aminopyridine (4-AP)-induced spontaneous seizure-like events in rat hippocampal slices. Coupling oxygen sensing with electrical(More)
Ion concentration homeostasis is essential for normal neuronal functions and its changes can underlie different pathological conditions including seizures. However the mechanisms of these processes are poorly understood. Studying the dynamical and biophysical mechanisms of regulation of neuronal intraand extra-cellular ion concentrations is important for(More)
22 We utilized a novel ratiometric nano quantum dot fluorescence resonance energy transfer (NQD-FRET) 23 optical sensor to quantitatively measure oxygen dynamics from single cell microdomains during hypoxic 24 episodes as well as during 4-aminopyridine (4AP) induced spontaneous seizure-like events in rat hip25 pocampal slices. Coupling oxygen sensing with(More)
Oscillations in the β-band (8-30 Hz) that emerge in the output nuclei of the basal ganglia during Parkinson's disease, along with an imbalanced activation of the direct and indirect pathways, have been linked to the hypokinetic motor output associated with the disease. Although dopamine depletion causes a change in cellular and network properties in the(More)