Improving Accuracy in Stereotaxic Surgeries in Juvenile Rodents

Currently, the Paxinos Rat Brain Stereotaxic Atlas is used to obtain the optimal coordinates for targeting rat brain structures. However, this atlas is based on an average of mature male Wistar rats and is inadequate for targeting nuclei in young rats at ages postnatal days 14 through 21 (P14-21). The purpose of this study is to obtain accurate coordinates for the subthalamic and pedunculopontine tegmental nuclei in female and male rats in this age range.  First, we will confirm existing coordinates in mature Sprague-Dawley rats through injection of red dye beads, followed by histological analysis of their locations.  Then, we will make proportional modifications of the coordinates, using bregma to lambda distance.  The coordinates will be adjusted until reliable stereotaxic coordinates are developed for several regions within each nucleus.  These findings will allow us to analyze projections to and from sub-regions of the nuclei in virally-infected neuronal tissue marked with a fluorescent protein.  This experiment is partially supported by NIGMS RISE GM60655, and NIMH.