Isolated Brain

Isolated brain refers to keeping a brain alive in-vitro. This is done either by perfusion by a blood substitute, often an oxygenated solution of various salts, or by submerging the brain in oxygenated artificial cerebrospinal fluid(Bohlen, Halbach). It is the biological counterpart of brain in a vat. A related concept, attaching the brain or head to the circulatory system of another organism, is called a head transplant. An isolated brain however is more typically attached to an artificial perfusion device rather than a biological body.
The brains of many different organisms have been kept alive in-vitro for hours, or in some cases days. The central nervous system of invertebrate animals is often easily maintained as they need less oxygen and to a larger extent get their oxygen from CSF, for this reason the brains are more easily maintained without perfusion (Luksch, Walkowiak). Mammalian brains on the other hand have a much lesser degree of survival without perfusion and an artificial blood perfusate is usually used.
Most research on isolating mammalian brains has been done on guinea pigs.