A) Viral expression of green fluorescent protein in a hippocampal slice. Sindbis virus encoding green fluorescent protein was injected into the CA1 region of an acute hippocampal slice. This image was taken 24 hours after infection. This technique allows expression of proteins of interest in acute hippocampal slices suitable for electrophysiology studies on synaptic function.

B) Barrels in a thalamocortical slice prepared from a 5 day old mouse pup. Barrels, the anatomical substrate for the topographical map of the rodent whisker pad in the primary somatosensory cortex, can be easily visualized in live thin slices. In this case we use DIC optics combined with infra-red illumination and a micrometer objective in a 500 micrometer thick slice. The barrels appear as light patches separated by dark boundaries. A recording electrode (left) is also shown.