Bio: Rhonda Dzakpasu received a B.S. in Computer Science from The City College of New York. After working as a research assistant in a semiconductor laboratory, she entered the PhD program at the University of Michigan where she completed a PhD in experimental optical physics. Her thesis work resulted in the development of an optical technique that images dynamically scattered light fluctuation decay rates.  She remained at the University of Michigan for her postdoctoral training where she performed computational modeling to study how architecture influences the dynamics within networks of coupled non-linear oscillators. As part of her postdoctoral training, she also participated in two intensive neuroscience summer courses at the Marine Biological Laboratory (MBL) in Woods Hole, MA: SPINES and Neurobiology. Prof. Dzakpasu joined the faculty in the Department of Physics as well as the Department of Pharmacology and Physiology at Georgetown University in 2008. Her current research incorporates experimental in vitro as well as computational techniques to probe the dynamical patterns that arise from the interactions within networks of neurons.

What can we learn from neurochemical and cellular perturbations of in vitro neuronal network dynamics?

Probing neural systems is essential to understanding the circuitry that underlies complex neuronal dynamics. Tools such as pharmacological assays are widely employed to assess differences between healthy and pathological states of a network and to elucidate biochemical mechanisms of a variety of cognitive processes. Manipulating the cellular composition of neural systems can also provide insights into the basic interactions between the constituent partners within the neural circuit.
I will discuss results from two studies. In the first study, we use neuromodulation to perturb the excitatory/inhibitory balance within a network of hippocampal neurons using pharmacological agents. Neuromodulation impacts oscillatory activity within cortical and hippocampal circuits and these oscillations have been shown to be important for cognitive processes such as working memory and attention. The oscillatory states are indicative of information transmission within the neural circuit and to examine changes in information transmission, we perform extracellular recordings of action potentials from cultured hippocampal neuronal networks using an array of microelectrodes. We show a time-dependent effect on bursting dynamics after application of one of these agents and will discuss two possible mechanisms that may be involved.
In the second study, I will present results from a new tissue co-culture system designed to investigate the network effects due to APOE, the strongest genetic risk factor for Alzheimer’s disease. While the pathogenesis of Alzheimer’s is not well understood, neural seizure-like activity has been shown to influence disease progression. Recent research suggests a link between Alzheimer’s disease and seizure-like brain activity. However, little is known about how APOE affects activity across networks of neurons. I will discuss how APOE genotype impacts spiking dynamics of developing in vitro neuronal networks and its impact on the basic biophysical properties of the extracellular network voltage.

Prof. Dzakpasu is being hosted by Prof. Zochowski (Physics & Biophysics). If you would like to meet with her during her visit, please send an email to [email protected]. If you are an MICDE students, or a Physics graduate student and would like to join Prof. Dzakpasu for lunch, please sign up here.