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dcyphr | Utah Optrode Array Customization Using Stereotactic Brain Atlases and 3-D CAD Modeling for Optogenetic Neocortical Interrogation in Small Rodents and Nonhuman Primates

Abstract 

    This study creates a device that is known as an optrode array. Optrode is referring to an optical electrode. This means that the electrodes are able to send signals to the neurons that are stimulated when flashing a light. Several versions were completed with the first causing extensive damage to the brain cortex. The following models were inserted into mice and were shown to cause minimal damage while allowing for long-term (6 month) tolerability.  

Introduction

    Previous optrodes are individually inserted, which is not space, time, or resource efficient. Previous designs hinder the exploration into brain regions of interest. The goal of this study is to develop an optrode array by using a modeling software that can be inserted into a virtual brain. This procedure will then be transferred to live animals. 

Methods 

    The first iteration of the device caused significant damage to a monkey cortex and was thus reengineered. A goal of the redesign was to target a smaller area to minimize the contact surface. 

Results 

    The second optrode array showed significantly decreased neural tissue and vessel damage. The improved design also allowed for the electrodes to send optic signals to the correct layer of the brain's cortex. The significantly decreased size of the electrodes and array led to less tissue compression and damage. The improved design was able to be implanted into two mice without any serious infection issues or complications for 6 months. 

Conclusion

    This study shows that this optrode array design can be optimized using computer modeling for specific areas of the brain on monkeys and mice. A major difference between the two models was the improved models electrode shape. The electrodes were smaller, slender, and bullet shaped. This provided the design to have a smaller footprint and reduce the amount of optrodes per array. The method of optimization of the optrode array design on a computer model dramatically increases the efficiency and plausibility of using a system like this.