Closed-loop optogenetic manipulation of amygdalar network activity based on local gamma band oscillations
1 Neuronal Network and Behavior Research Group, Research Centre for Natural Sciences, Budapest, Hungary; 2Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary; 3Faculty of Electrical Engineering and Informatics, Budapest University of Technology and Economics, Budapest, Hungary; 4János Szentágothai School of Neurosciences, Semmelweis University, Budapest, Hungary; 5Department of Physiology, University of Szeged, Szeged, Hungary; 6Department of Anatomy and Histology, University of Veterinary Medicine, Budapest, Hungary.
Gamma band oscillations (30-80 Hz) are prominent in the amygdala and have an important role in fear memory processes. However, the precise means by which they are generated and modulated in fear behavior are largely unknown. In order to investigate this problem, we have started to develop a system which enables the real-time modulation of gamma oscillations using optogenetics. As a regulator mechanism of this stimulation system, we aim to use a closed-loop approach to optogenetically control amygdalar gamma activity based on their real time detection. To ensure the proper operation of this system, we need to overcome many limitations. The most important problems we have to solve are [a] to minimize the communicational delay between the components of the system (both hardware and software) and [b] to make sure that the algorithm doesn’t detect artifacts. The use of open-source equipment ensures high-level flexibility and adaptability in our system while maintaining cost efficiency. Although the system is still a work-in-progress, the results of our initial tests on pre-recorded datasets show promise in detecting gamma band oscillations and administering stimuli with a delay of less than 20 ms. In the future, we seek to use this system to identify the prerequisites for fear memory related amygdalar gamma activity in awake, behaving mice.