Complex systems and Biological physics seminar [before December 2013]

Designing optimal stimuli to control neuronal spike timing

by Yashar Ahmadian (Columbia U.)

Europe/Stockholm
122:026

122:026

Description
Recent advances in experimental stimulation methods have raised the following important computational question: how can we choose a stimulus that will drive a neuron to output a target spike train with optimal precision, given physiological constraints? I will present my work on this problem, where we adopt an approach based on models which describe how a stimulating agent (such as an injected electrical current, or a laser light interacting with caged neurotransmitters or photosensitive ion channels) affect the spiking activity of neurons. Based on these models, we solve the reverse problem of finding the best time-dependent modulation of the input, subject to hardware limitations as well as physiologically inspired safety measures, that causes the neuron to emit a spike train which with highest probability will be close to a target spike train. We adopt fast convex constrained optimization methods to solve this problem. I will explain how we can carry out the optimization in computational time that scales linearly with the temporal duration of the spike train, allowing for implementation in real time. I will also explain how in certain situations we can use approximate optimization algorithms whose computational time scales linearly also with the number of controlled cells. These properties make the method suitable for neural prosthesis applications. I will also present simualted and experimental tests of the method.