Scientists have discovered that people who have a larger part of the brain that plays an important role in long-term memory may actually be protected from the classic symptoms of Alzheimer’s disease, even after they have contracted the illness.

Researchers at the Oregon Health and Science University of Portland studied the brains in autopsies of 12 people who had sharp memories and thinking skills at the time of death, but who also showed a high amount of Alzheimer’s plaques. Their brains were compared to those of 23 people who had the same amount of plaques, but had been diagnosed with Alzheimer’s before death.

The autopsies revealed that the volume of the hippocampus part of the brain was 20 percent greater in the cognitively-intact group, compared with the Alzheimer’s group with dementia.

The hippocampus, which is crucial to long-term memory, is located in the limbic system and is one of the first regions of the brain to suffer the ravages of Alzheimer’s.

The lead researcher said, “Hopefully this will lead us eventually to prevention strategies.”