Lashley initially believed that the changes were specific and localized. He found that there was no part of the cerebral cortex that was required for retention of complex long-term memories. Ie, a maze-trained rat could still run the maze after any piece of its cortex was surgically removed. Lashley concluded that memory is distributed in the brain. He observed changes in a small part of the cerebellum.
Memory appears to be both localized and distributed.
PET scans confirm that memory tasks require the involvement of a range of brain areas. Neuronal Correlates of Long-Term Memory Memory seems to involve changes in both the function and the structure of neurons. If you give the snail a slight shock following a squirt of water, the snail soon begins to withdraw its gill flap in response to the squirt alone. The amount of neurotransmitter released by the neurons increases. The number of branches on the dendrites and the number of synaptic connections increases.