Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Pachygyria ?
    ### Response:
    Pachygyria is a developmental condition due to abnormal migration of nerve cells (neurons) in the developing brain and nervous system. With pachygyria, there are few gyri (the ridges between the wrinkles in the brain), and they are usually broad and flat. The condition is also known as "incomplete lissencephaly.
    