Final answer:
The hippocampus is key in converting short-term memories to long-term memories, as evidenced by experiments and the study of Patient HM, who could form short-term but not long-term memories after losing his medial temporal lobe.
Step-by-step explanation:
Due to experimentation, it was discovered that the hippocampus is involved in the conversion of short-term memories to long-term memories. The hippocampus works together with related medial temporal structures to move or consolidate memories from the short-term memory storage in the prefrontal lobe to the long-term memory storage in the multimodal integration areas of the cerebral cortex.
Patient HM, who lost his medial temporal lobe but retained the ability to form new short-term memories, provided evidence that short-term memory is localized to the prefrontal lobe, whereas the consolidation of these memories to long-term storage is a function of the hippocampus.