Today in the lab I was dissecting a brain. The brain is kept in a red/pink solution called the 'dissection medium'. This is composed of essential nutrients to ensure that the cells in the tissue remain alive and healthy for the duration of the dissection, until they can be placed in an incubator to continue growing. The dissection medium also contains a buffer which keeps the pH at a physiological level.
The dissection is performed aseptically, to minimise the risk of contamination from bacteria or other organisms. Once the brain area that is required gets dissected out of the rest of the brain, it is cut into small pieces which are then broken down by enzymatic and mechanical methods to separate the tissue into single cells that can be cultured in an incubator.