A 62-year-old man with a history of poorly controlled hypertension and diabetes presents with sudden onset of weakness. His blood pressure is 200/115 mm Hg, and his pulse is 80 per minute. An X-ray film of the chest demonstrates cardiomegaly and pulmonary edema. A CT scan of the brain reveals intra-parenchymal hemorrhage. The patient becomes unresponsive and eventually expires. Which of the following was the most likely site for cerebral hemorrhage in this patient?