Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the symptoms of Periventricular heterotopia ?
    ### Response:
    What are the signs and symptoms of periventricular nodular heterotopia? The condition is first noticed when seizures appear, often during the teenage years. The nodules around the ventricles are then typically discovered when magnetic resonance imaging (MRI) studies are done.
    