Fig. 6. Comparison of pyramidal neurons in early versus late stages of degeneration after exposure to isoflurane. (A ) The typical appearance of a relatively well-preserved activated caspase-3-positive pyramidal neuron in an early stage of degeneration. Note that the shaft of the apical dendrite is straight and does not seem dysmorphic. (B , C , and D ) are from layer V of the primary visual cortex and illustrate a later stage of degeneration when the apical dendrite has begun to shrivel and assume a corkscrew-like configuration. (E , F , and G ) are from the deep layers of the temporal cortex and show neurons in a later stage of degeneration with shriveled apical dendrites that are beginning to undergo fragmentation. Compare these dysmorphic neuronal profiles with those in fig. 5Bthat are in an earlier stage of degeneration.