NIMH Instrumentation Core Facility

Dold, George

Abstract

This past year, our Section had the unique opportunity to support the research of various Labs & Sections within NIMH, NINDS, NICHD, and NCCIH. During the past twelve months, investigators from these labs and branches requested 465 formal projects from our staff. Each of these requests was documented and the time recorded to complete the job. In addition to the formal requests we are available daily for numerous walk-in, phone call or e-mail requests for assistance. In general, our technical support this past year can be divided into the following research areas: Electrophysiology The Section on Instrumentation staff continuously strives to improve the utility of various components that comprise electrophysiology. We have continued to improve the engineering and fabrication of multiple-hole grid arrays that allow precise, repeatable placement of a single or multiple electrodes over a wide area. We have also continued to develop small single-electrode microdrives. Novel methods using 3D printing now allow for the production low-component count yet accurate and smooth microdrives. Single unit recording in behaving nonhuman primates is widely used to study the primate central nervous system. However, certain questions cannot be addressed without recording large numbers of neurons simultaneously. In collaboration with NIMH scientific staff, the Section on Instrumentation developed a method using 3D printing to include an individualized 3D-printed connector mounting platform, allowing for implanting and recording from 8 arrays of 96 electrodes. This technique doubles the number of arrays that have been successfully implanted in single animals. fMRI The Section on Instrumentation provides a wide range of support for fMRI-related research. Fabrication of devices for use in MRI environments is a specialized area of expertise, with great attention given to design without ferrous metals and minimization of all metal components. In addition, commercial industrial fiber optic components and systems are evaluated and integrated into many designs and devices we fabricate. The Section on Instrumentation supports the installation of new equipment in MRI suites, including custom mirror and projection assemblies used for stimulus presentation, and custom RF-shielded penetration panels used to route cabling. Non-Human Primate (NHP) Our group is responsible for providing a wide range of engineering and fabrication services to support non-human primate research. Many of the mechanical assemblies that are necessary for this type of research are engineered and fabricated in-house. Our group provides a diverse array of custom systems and components to many different investigators, such as custom primate chairs, high-strength restraints, MRI positioning systems, custom head coils, reward systems, data acquisition, analysis and optical response systems, plus a wide range of small mechanical components. Using the 3D print capabilities of our shop, the Section on Instrumentation is assisting neurological researchers within the NIMH and other institutes in improving their pre-surgery preparations. With data provided and converted from CT and MRI scans, our section is able to print custom and detailed models of the individual monkeys skull and brain. These skulls and brains allow the surgeon and researchers to complete some of the necessary modifications and planning before entering the operating room, reducing surgery times, decreasing risks of complications, and maintaining sterility. Human Human research requires the creation of many novel devices that are compatible with the high-magnetic field environment. When a new magnet is installed, we are consulted with and provide the necessary components for presenting visual stimuli in the bore of the magnet, including image periscopes, screens, and mirrors. These devices are designed and manufactured with specific space and material constraints. The Section on Instrumentation provides a substantial amount of engineering support to the Section on PET Radiopharmaceutical Sciences in the Molecular Imaging Branch (MIB) in the production of short-lived radiotracers for research studies in human subjects with positron emission tomography (PET). A bubble point test (BPT) on the sterilizing filter is required before release of a PET radiopharmaceutical. Data logging is an important aspect of quality assurance. The Section on Instrumentation fabricated an automated data-logging BPT instrument. The fabricated BPT instrument gives accurate, reliable and data-loggable BPT results. Behavioral Several different types of mazes are used to study spatial learning and memory in rats. These studies have been used to help understand general principles about learning that can be applied to humans, and to determine what effect different treatments affect learning and memory in mice. We continue to produce a variety of custom T and Y mazes for behavioral testing. When you pick up a phone, remember a phone number and dial it, you are using your working memory. Working memory is a cognitive process which maintains information for a relative short time, and is one of the most important cognitive process which is crucial to the functioning of the mind. The T-maze delayed alternation task is a classic method to assess working memory in rodents. The task consists of a sample trial, a holding period and a test trial. In the sample trial, the animal is guided into one of the two arms to get a reward. After the sample trial, the animal is kept in the holding area for several seconds. Then in the test trial, the animal needs to go to the arm which it has not been to in the sample phase to get a reward. In order to eliminate any environmental distractions such as the movement of the investigator, we fabricated an automated T-maze. It detects the position and movement of the mouse, and operates the doors and delivers rewards automatically. Imaging Two-photon excitation microscopy is a fluorescence imaging technique that allows imaging of living tissue up to about one millimeter in depth. Two-photon excitation can be a superior alternative to confocal microscopy due to its deeper tissue penetration, efficient light detection, and reduced phototoxicity. The Section on Instrumentation produces a variety of equipment that supports two-photon microscopy, such as faraday cages for electronic and light shielding and custom mirror mounts. In addition, behavioral testing equipment such as low-inertia mouse wheels are fabricated for use with two-photon microscopy. Clinical Our Section also supports a number of clinical based research requests under the broad areas of surgical, therapeutic and basic research. Moderate and deep pressure touch are commonly utilized in massage therapy and have been linked to reductions in stress, depression, and pain. Yet there is no understanding of how pressure exerts these affective benefits. We recently developed a custom novel device that administers repeatable mechanical compression. This apparatus was used to identify the most pleasant intensity, frequency, and location for pressure stimulation of the lower leg. This device allowed the testing of the subject while undergoing fMRI to determine the brain regions that correspond to the sensory stimulation. Technology By using the latest technology in advanced fabrication machinery, we are able to increase productivity and effectiveness while at the same time decreasing the amount of time needed to engineer and machine the components. Our waterjet cutter continues to increase our cutting and fabricating capabilities, especially with the multiple fiberglass parts we produce. With this system, we were able to drill a hole the approximate diameter of 4 human hairs through a ceramic screw.