Obtaining Horizontal Mouse Hippocampal Brain Slices

Take the mouse brain hemispheres in a high-sucrose solution. Secure the hemispheres with their ventral side facing up on a vibratome specimen plate using an adhesive.

Transfer the specimen plate into the slicing chamber.

Add a semi-frozen high-sucrose solution to maintain the tissue's physiological conditions and solidify the adhesive.

Supply a carbon dioxide-oxygen mixture to maintain tissue oxygenation.

Using set parameters, obtain the initial slices and remove them. Further, obtain horizontal hippocampal slices.

Carefully transfer these brain slices into a chamber containing ACSF for tissue recovery.

The horizontal hippocampal slices are ready for further experimentation.

Place both hemispheres on the freshly-cut dorsal side with the ventral part of the brain facing up, and place a drop of superglue onto a specimen plate. Use a pipette tip to spread the glue into a big area to accommodate both pieces of tissue, and touch a piece of filter paper strap to the ventral side of one hemisphere. Use another filter paper strap to carefully semi-dry the dorsal side of the brain, and position the hemisphere dorsal side down onto the glue on the specimen plate.

Use two additional filter paper straps to position the second hemisphere onto the glue as just demonstrated, and place the specimen plate into the slicing chamber. Then, quickly but carefully, cover the plate with ice-cold high-sucrose slice solution slush. To acquire sections of the brain tissue, position the vibratome blade in front of the medial side of the hemispheres, and lift the vibratome table so that the blade is on the same height as the ventral sides of the hemispheres, which are now facing up.

Use the vibratome control to lower the blade 600 microns further in the dorsal direction, and slice the tissue until the first two slices are completely separated from the two hemispheres. When the first two tissue slices have been obtained, reverse the cutting direction, and lower the blade another 300 microns before slicing again. When the hippocampus becomes visible, use a widened plastic Pasteur pipette to collect and transfer the slices into the recovery chamber in the water bath.