Dissecting the cortical and subcortical pathways of innate visual fear in the common marmoset

2021 Fiscal Year Research-status Report

• Project/Area Number: 20K22684
• Research Institution: Kyoto University
• Principal Investigator: CHEN Chih・Yang 京都大学, 高等研究院, 特定助教 (30884689)
• Project Period (FY): 2020-09-11 – 2023-03-31
• Keywords: Innate fear / Marmoset / Electrophysiology / Optogenetics

Outline of Annual Research Achievements

Innate fear is a type of negative emotion that even if one did not learn or experience before, one is afraid of it. For animals, this is related to survival, because they have to know their predators before experiencing to be captured. Until now, the neuronal mechanisms of innate fear in primate are still largely unknown.With the support of Kakenhi research start-up funding, I am performing a series of experiments trying to reveal the origin of visual innate fear and the potential neural networks with full hemifield ECoG recording in a small new world monkey, the common marmoset. I am also developing optogenetic manipulation method to preturb the network for causality measurments.I expect that I can clarify the neuronal networks and brain regions that are related to visual innate fear.

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

I have trained 3 marmosets perform the innate fear task and found differential pupillary resposes for fear vs non-fear pictures. I have also successfully implanted full hemifield ECoG in 1 marmoset and recorded the brain activities during the task. Clear differences in the visual, temporal, and parietal cortices have observed during the task. Brain phace analysis also showed syncronized activities in these brain regions while viewing fear related pictures only. The virus for optogenetic manipulation was also tested successfully in the marmoset. After specific brain areas are identified with the second marmoset, the virus will be injected to the marmosets and start with network perturbation. I am also preparing to publish the behavior results now.

Strategy for Future Research Activity

ll the current experiments demonstrated that the technics I proposed are feasible. This year, I will apply for new KAKENHI funding and expend the
current experiments with transcranial alternating electrical stimulations to have even stronger and faster control with the cortical network in order to perturb the brain more effectively. At the mean time, I will continue with the second marmoset's experiment and publish the curret behavior and physiological results. I believe with my research, I will clarify the innate fear network and try to understand the subconscious related fear response. This will help to reveal possible brain network related to anxiety and phobia and the potential treatment for these diseases.

Causes of Carryover

Due to the pandamic, ECoG purchase was delayed. I will order 1 set of ECoG the next fiscal year and also buy training reward for the marmosets.