The isolated mammalian brain: an in vivo preparation suitable for pathway tracing

An in vitro preparation of complete brain is presented which allows success ful tracing with fast axonal tracers for at least 2 days after in vitro pre paration. A simple procedure is used, by which the isolated brain is submer ged in oxygenated artificial cerebrospinal fluid, enabling maintenance of a dequate integrity without perfusion the vascular system. The use of an isol ated brain has many advantages: virtually all brain areas are easily access ible; tracer applications are possible without problems of animal survival; and the tracers are be translocated by blood circulation. The viability of this isolated brain preparation was validated by successful recording of e xtracellular field potentials 1 day later.