Cortical barrelfields in organotypic slice cultures from rat somatosensory cortex

We are attempting to determine the factors that influence both the formation and maintenance of barrels in the rodent somatosensory cortex. Cytochrome oxidase histochemistry and Nissl staining were used to identify the presence of barrels in slice cultures of rat cortex. Barrels were observed in sagittally cut slices, in cortical layer IV, from animals aged postnatal day 5-10 that were cultured for at least 10 days. No differences were observed in the barrel pattern from animals at different postnatal ages, or from cortex that was cultured for different lengths of time. In contrast, cortical barrels in tangentially cut sections from similarly aged animals were clearly visible after one day in culture, but they disappeared after two days in culture. These results suggest that intact connections within cortical columns are sufficient to sustain the functional architecture of the somatosensory cortex in vitro.