effects on the tissue which are not yet understood. During recording, the tissue also "ages", degrading at a faster rate than in the intact animal. Finally, the artificial composition of the bathing solution means that the presence and relative concentrations of the necessary compounds may not be present. References Schurr, Avital, Brain Slice Preparation in Electrophysiology, Kopf Carrier, Vol 15 Neurophysiology Electrophysiology Laboratory techniques