Final answer:
Ahmed exhibits symptoms of anterograde amnesia, where he has significant impairment in forming new memories but can recall past memories, indicating damage to the hippocampus affecting memory consolidation.
Step-by-step explanation:
Ahmed's main memory issue, following a severe brain injury, is characterized by his difficulty in remembering new experiences while retaining most of his older memories. This condition is known as anterograde amnesia. Ahmed's ability to form new episodic and semantic memories is impaired, which suggests that the damage to his brain has impacted the process of transferring information from short-term to long-term memory, and thereby affecting memory consolidation. In well-documented cases such as that of patient H.M., similar symptoms were observed after damage to the hippocampus, indicating that the hippocampus plays a crucial role in the consolidation of new learning into explicit memory.