NIMH Instrumentation Core Facility

Dold, George

Abstract

This past year, our Section had the unique opportunity to support the research from various Labs & Sections within NIMH, NINDS, NICHD, and NCCIH. During the past twelve months, investigators from these labs and branches requested 527 formal projects from our staff. Each of these requests was documented and the time to complete the job recorded. In addition to the formal requests we are available daily for numerous walk-in, phone call or e-mail requests for assistance. (Note: 33 jobs were CGMP Hot-Cell related). In general, our technical support this past year can be divided into the following research areas: Electrophysiology The Section on Instrumentation (SI) 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. This has been made possible by the use of our new 3D printer. Noise is a major concern when recording with electrodes. Shielding and grounding are used to minimize noise, but this can be a black art where different techniques are empirically tried. We recently fabricated another novel system to shield a multiple electrode positioning system over a primate head, using 3D plastic printed parts that were plated with nickel. The shield allowed for enhanced access to the regions of interest, and the noise attenuation was significant. 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. This past year we fabricated a custom lick sensor for use in magnetic environments. This was difficult due to the requester wanting to know the relative amount of licking done by a primate in a repeatable and measurable system that was completely non-metallic. We also continued our support for the human, primate and rodent magnet imaging facilities. 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, restraints, MRI positioning systems, custom head coils, reward systems, data acquisition, analysis and optical response systems, plus a wide range of small mechanical components. We have become experts in many different types of force and load cells and the integration of these into working research tools. Restraining the monkeys head for scans in the MRI has been difficult, since all parts associated with these systems have to be non-metallic, and are more susceptible to movement. In addition, a constraint is that the head holding system must be as small as possible to allow electrode placement over a larger area of the head. Our group is developing a novel MRI-compatible head post system to allow for more robust positioning and securing of the NHP head. 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. Histology of human brains can be difficult. Sectioning the brain methodically with accurate and parallel slices has always been problematic, due to the plasticity of the brain. With our SLA 3D printer we were able to fabricate a custom matrix that allows for precise sectioning of brains. This method is being adopted immediately for Multiple Sclerosis studies and for the NIH Brain bank. We continue to provide a variety of custom head coils, cradles, and phantom holders for various fMRI applications. These cradles allow for precise placement of imaging coils in the scanner, enabling higher-resolution scanning. 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. In addition, we have designed and fabricated numerous testing boxes for social interaction studies. Imaging The addition of small secondary coils at specific regional sites enhances the resolution of MRI images at those sites. By exploiting the capabilities of our 3D rapid prototyping systems, we are able to fabricate custom coil holders for these specific sites. In collaboration with NINDS physicists, a plethora of such devices have been designed and implemented. Also, various means to minimize radio frequency noise introduced by the associated cabling for the coils have been collaboratively designed and fabricated. Currently, NIMH produces virtually all of its short-lived radiotracers for research studies in human subjects with positron emission tomography (PET) from its own laboratory suite. A new laboratory has been created in the Clinical PET Center to produce all radiotracers for PET studies in human subjects on the NIH campus according to a high common standard in compliance with regulatory needs. The Section on Instrumentation is providing a substantial amount of engineering support to the Section on PET Radiopharmaceutical Sciences in the Molecular Imaging Branch (MIB) to implement the new facility. In collaboration with MIB staff, SI will be responsible for installation of all components in the hot-cell, including the design and fabrication of a variety of custom mechanical systems, the fabrication of electrical distribution panels for electronics inside the hot-cell, the construction of wiring for all equipment inside the hot-cell, and interfacing with an external custom automated radiochemistry system. Clinical Our Section also supports a number of clinical based research requests under the broad areas of surgical, therapeutic and basic research. This FY we developed a sensorimotor task to test the behavioral phenomenon known as the sequence effect in Parkinsons disease. It is the gradual decrement in speed and/or amplitude of movement. This was tested using a static grip force and it measured the gradual decline in force over 20-second blocks. Visual feedback is known to reverse the sequence effect; therefore, subjects were tested without and with visual feedback on their performance. These applications are programmed with Labview, a high-level software package. Millisecond timing of visual stimulation and recording of operator feedback are critical. Technology By using the latest technology in CAD/CAM programming, Rapid Prototyping techniques, and reverse engineering, SI is able to increase productivity and effectiveness while at the same time decreasing the amount of time needed to engineer and machine the components. 3D printing is considered to be the next technological revolution. This past year we acquired a state-of-the-art SLA printer (3D Systems Project 6000) which has greatly expanded our capabilities and has continued to transform and advance our prototyping process.