A middle-aged woman comes to her physician's office with complaints of visual difficulties. A review of systems and physical examination are unremarkable except for her eye exam. When a light is shined in her right eye, there is no pupillary response in either eye. However, upon shining a light in her left eye, both ipsilateral and contralateral pupillary responses are apparent. Her extraocular movements are intact. What is the MOST likely location of her lesion?