Final answer:
To study nervous system disorders, a biopsychologist would need to obtain training in neurophysiology or neurobiology, which are interdisciplinary fields within the broader field of neuroscience.
Step-by-step explanation:
A biopsychologist interested in studying nervous system disorders would need to obtain training in neurophysiology or neurobiology. Neurophysiology focuses on the functioning of the nervous system, while neurobiology studies the biology of the nervous system. Both fields are considered interdisciplinary and fall under the broader field of neuroscience.