When the now-famous neurological patient Henry Molaison had his brain’s hippocampus surgically sectioned to treat seizures in 1953, science’s understanding of memory inadvertently received perhaps its biggest boost ever. Molaison lost the ability to form new memories of events, and his recollection of anything that had happened during the preceding year was severely impaired. Other types of memory such as learning physical skills were unaffected, suggesting the hippocampus specifically handles the recall of events—known as “episodic” memories.
