Final answer:
Patients with Korsakoff's syndrome mainly experience anterograde amnesia, which is the inability to form new memories after the onset of the syndrome, while they usually retain the ability to recall past events.
Step-by-step explanation:
Patients with Korsakoff's syndrome predominantly suffer from anterograde amnesia. This condition is characterized by a patient's inability to form new memories after the onset of the syndrome. The hippocampus, a part of the brain critical for memory consolidation, is typically affected in anterograde amnesia. As a result, individuals with this condition can recall past events and information from before the injury but have difficulty creating new episodic memories following the trauma.
In contrast, retrograde amnesia, another type of amnesia, involves a loss of memories from before a particular event. However, Korsakoff's syndrome primarily impacts the formation of new memories. Famous case studies like patient H.M. have largely informed our understanding of anterograde amnesia, as H.M. was able to retain short-term memories and long-term memories from before his surgery, but he could not form new long-term episodic memories.