Equipotentiality refers to the idea that one part of the cortex can take over the function of another part;
within a functional area of the brain, any tissue within that area can perform its associated function.
Therefore, to destroy a function, all the tissue within a functional area must be destroyed.
If the area is not destroyed then the cortex can take over another part.
These two principles grew out of Lashley’s research on the cortical basis of learning and discrimination.