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Seminars at the NVRI

Prof. Shelley Fried, Department of Neurosurgery/Harvard Medical School Friday 15th Nov 2013

Title: Creating physiological patterns of neural activity with prosthetic stimulation

Abstract: In most neural prosthetic applications that target the CNS, the ability to create predictable and desirable patterns of neural activity remains quite limited. Often, the lack of good stimulation methods is directly correlated with sub-optimal clinical outcomes. For example, although electric stimulation of the retina in blind subjects consistently yields light percepts (phosphenes), eliciting more complex spatial patterns of vision has proven challenging. One of the most significant factors thought to underlie the limited quality of elicited vision is that the neural activity elicited by artificial stimulation is quite different from the physiological patterns of signaling generated by the healthy retina. As a basis for developing more effective stimulation methods, my lab studies how and why retinal neurons respond to electric stimulation. We use a combination of electrophysiology, modeling and immunochemistry – this approach has yielded several key insights into the activation process. For example, we have determined the relative sensitivity of different neuronal elements to stimulation and have shown how biological variations in each property influence the observed sensitivity across different types of neurons. This type of fundamental insight has led to new stimulation methods that allow more physiological-like patterns of neural activity to be created. The implications of this work for other types of neural prosthetics will be discussed as well.

Bio: Shelley Fried is in the Department of Neurosurgery at Massachusetts General Hospital / Harvard Medical School and Research Scientist at the Boston VA Medical Center in Boston, MA. Dr. Fried has a PhD in Vision Science from UC Berkeley where he studied the mechanisms by which the normal retina transforms light into neural signals. He did postdoctoral training at both UC Berkeley and at the Massachusetts General Hospital in Boston studying electric stimulation of the retina. His research explores how and why retinal neurons respond to electric stimulation with the goal of developing more effective methods of stimulation.

Professor Shelley Fried and Dr Shaun Cloherty