An interface holding chamber for anatomical and physiological studies of living brain slices.

The popularity of infrared DIC videomicroscopy for a variety of anatomical and physiological studies in living brain slices has created a need for holding chambers to allow more than one slice to be examined during a single experiment. As is well known, the yield of experiments requiring living brain slices is severely limited by the conditions under which these slices are maintained prior to being examined. Previous electrophysiological and morphological studies have demonstrated that slices maintained submerged in solution deteriorate dramatically compared to those kept at the gas/fluid interface, even after only 1.5 hours and many recording chambers incorporate the interface principle in their design. However, to our knowledge, as obvious as it may seem, this principle has not been applied to the design of holding chambers, and those which are in current use are of the non-optimal, submerged type. We have designed a simple, but extremely effective holding chamber for incubation of brain slices floating at the gas-fluid interface. The slices held in this chamber have been maintained for at least 12 hours in excellent condition as shown here by rich labeling of their local axonal arbors. In addition, the chamber is designed to hold individual slices (up to 1 cm2 in size) in separate compartments for better preservation of brain slices from valuable species (e.g. animals subjected to experimental treatments, nonhuman primates and human biopsy tissue).