Mental disorder. Coloured Magnetic Resonance Imaging (MRI) brain scan depicting a mental state of instability, nervous breakdown or Parkinson's disease. Multiple images may represent loss of mental control or consciousness, or hallucination. They may also represent body tremor typical of Parkinson's disease. The slice" through the head reveals the brain inside. Parkinson's disease is caused by a degeneration of nerve tissue within the brain's basal ganglia. These areas control body movement, and in this disease muscles are prevented from relaxing. As a result there is body tremor and a slow shuffling movement. Parkinson's disease mainly affects the elderly."