Stereotaxic instrument

In establishing the stereotaxic coordinate system for this atlas we studied sections from over 100 rats. To prepare these sections, we positioned the skull in a standard way (the flat-skull position) and marked the vertical and horizontal planes with needle tracks. We placed anesthetized rats in a Kopf small-animal stereotaxic instrument, and the incisor bar was adjusted until the heights of lambda and bregma were equal. This flat-skull position was achieved when the incisor bar was lowered 3.3 0.4 mm below horizontal zero (Table 1). 

We thank David Kopf for providing us with his extremely accurate stereotaxic instrument. 

Use of the David Kopf Stereotaxic Instrument and Brain Blocker... 

In our work on this and other stereotaxic atlases we found the David Kopf Small Animal Stereotaxic instrument of high precision. However, no atlas or stereotaxic instrument will compensate for using bregma and lambdoid points inappropriately. These reference skull marks are the midpoints of the curve of best fit along the coronal and the lambdoid suture, respectively. They are not necessarily the points of intersection of these sutures with the midline suture. 

The stereotaxic method is used for the insertion of electrodes into the deep structures of the brain. Atlases of the brains of different animals have been published describing the position of each point of the brain as determined by three orthogonal coordinates By means of a stereotaxic instrument the electrode is inserted into the brain nucleus being tested in accordance with the prescribed coordinates... 

For lentivirus injection into the cerebellum, mice are anesthetized and fixed to the stereotaxic instrument as described above. A small cranial window is formed on the occipital bone with an electrical drill (for adult mice) or a 27-G needle (for pups), and the surface of cerebellar lobules VI-VII is exposed. A glass pipette filled with lentivirus solution is then inserted into the cerebellum. Two weeks later, mice are transcardially perfused with 4 % PFA. 

Stereotaxic alignment system base with mouse adaptor (David Kopf Instruments, Tujunga, CA, Model 1900). 

The microdialysis probe is the heart of the method, as a chromatographic column is the heart of the HPLC instrument. Rigid CMA probes, Models 10, 11, and 12, are used for stereotaxic implantations into the brain, where the probe can be fixed (cemented) to the skull. A flexible probe design (CMA 20) allows the placement of such a catheter into the moving tissues (muscle) or peripheral organs for studies in freely moving animals. The technical difficulties of microdialysis experiments impose requirements for precise liquid delivery, minimized dead volumes, and the capability of handling small sample volumes. 

The Brain Blocker Designed taproduce the plane of section of The Rat Brain in Stereotaxic Coordinates (PA 001 David Kopf Instruments, P.O. Box 636, Tujunga, CA 91043). 

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