Scientists/radiologists who are interested in interventional surgeries with robotic control, e.g. deep brain stimulation.The multi-model neuroimaging methodologies on animal models are crucial for better understanding brain function¹. The neuron-glia-vessel (NGV) network is one of the most challenging areas given the multifaceted requirements of signal acquisition from the brain^2,3. By using fiber optics, it is possible to target certain brain regions to deliver light pulse for photo-activation or acquiring cell-specific calcium signal simultaneously with fMRI^{4, 5}. These existing methodologies provide us the possible platform to better characterize the NGV network activity upon brain activation. A key challenge of the fiber optic-mediated multi-model fMRI methodologies is how to locate fiber tips accurately and precisely to target the deep brain nuclei with the size of only a few hundred microns. The development of MRI-guided insertion by a robotic arm should significantly reduce the position error of fiber tips. Meanwhile, an optimized fiber insertion trajectory in the brain is required in order to investigate the effectiveness, safety and feasibility of deep brain nuclei targeting for translational application. The goal of this study is to create a multiple degree-of-freedom robotic controlling system to target brain nuclei in the rat brain inside the high field MRI scanner.With the use of step motors, we have developed a high-field 14.1T MRI-guided multi degree of freedom robotic arm for fiber placement. The head part of the robotic arm drives the fiber insertion into the brain with an insertion angle. This study tested the robotic arm movement to target centrolateral thalamic nucleus(CL) and internal capsule(ic) in a perfused rat (250g) brain. The rat brain was fixed in soft agar which contained manganese and was placed on a custom-designed MRI-compatible cradle to simulate a real rat experiment. A 24mm-diameter custom-designed transmit/receive surface coil was located on the brain while the fiber could be inserted into the brain through the hole of the coil driven by the robotic arm. In this configuration, the cradle with the rat brain was placed into the iso-center of the 26cm horizontal bore magnet while the robot controller and power supply for motor controls were placed in the scanner room at approximately 4.7 meters distance from the scanner’s bore to avoid the electromagnetic interference. MRI scans were performed using 2D rapid acquisition with relaxation enhancement (RARE) sequence: TR, 1500ms, TE, 23.9ms, 192X144 matrix, 0.1X0.1X0.4 mm3 spatial resolution. The fiber’s diameter was 200um. After the first image was transfered into the navigation workstation, the operator defined a target for fiber insertion on MRI image transfered from the scanner and calculated the steps for fiber insertion. The step motor drove the head part to make the fiber move 100um into the rat brain at each step and then started the next scan automatically.In this study, we demonstrated a MRI-compatible rotobic fiber placement in the MRI scanner, such as targeting ic, as illustrated in Fig.1. The capability to place the fiber with different depth is particularly useful to target multiple sites along the insertion path. Fig.2 A shows the targeting position in the rat brain atlas with the Bregma and Interaural position: -3.48mm and 5.52mm, respectively. Fig.2 B shows the fiber location in the targeted brain region, centrolateral thalamic nucleus, which is illustrated in Fig.2 D. Fig.3 shows three images with two motor steps to clarify the precision of the robotic arm. At each step, the fiber was one line of voxel deeper. Meanwhile, this distance difference was maintained through the whole fiber insertion procedure.We developed a compact, MRI-compatible robotic arm inside the MRI scanner to provide a flexible fiber location for simultaneous fMRI and fiber-optic recording of fluorescent calcium signal in rat brain. This work would provide a reliable, efficient multi-modal fMRI platform to study the neurovascular coupling in real rat model. The MgRA system can be translated to support human intervention surgical procedures, e.g. deep brain stimulation, in multiple brain targeting tasks.