Bruker 4.7T vertical bore scanner was installed in the spring of 2004, and became fully functional in summer of 2005. The system has a 33 cm diameter bore equipped with the elevator for positioning the animal. Specially-designed vertical chairs provide convenient sitting position of the animals, facilitating rigorous behavioral training and scanning procedures.
At the moment, the system is equipped with two RF coils (Bruker): linear transmitter-receiver birdcage coil that allows for the whole head homogeneous coverage, and the quadrature two-loop surface coil that provides improved SNR in occipital and parieto-temporal regions.
The software packages include ParaVision 4.0 platform for MR image acquisition (Bruker), integrated LabVIEW (National Instruments) RealTime based system for online behavioral control, synchronized visual stimulus presentation using OpenGL custom software and MATLAB, and data acquisition OmniLab for continuous recording of triggers from the scanner, timing, stimulus and behavioral signals. Visual stimuli are delivered via LCD goggles (800x600@60 Hz, Resonance Technology), and eye position is monitored with IR-sensitive miniature video camera (60 Hz, Arrington Research). Body and jaw motions are monitored with IR-sensitive video cameras coupled to motion detection circuitry.
The methods for scanning awake and behaving animals in this scanner were developed by the Andersen lab MRI group. Current research focuses on elucidating neural correlates of cognitive functions such as working memory, movement planning, and decision-making. These questions are addressed using a time-resolved event-related design, the technique that enables attributing fMRI activity to specific epochs in the task and delineation of BOLD signal time-courses. A new line of experiments also investigates neural substrates of visual awareness by means of reversible pharmacological inactivation during scanning. All these studies contribute to a comparison of brain functions in humans and animal species, and provide valuable insights into hemodynamic coupling and the neuronal basis of fMRI activity. Application of similar experimental paradigms in humans (in Siemens Trio 3T scanner) and animals (in Bruker 4.7T scanner) establishes a comprehensive approach to investigation of goal-directed behavior.
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