Researchers at Neuroscience Research Australia (NeuRA) have discovered that the region of the brain called the orbitofrontal cortex plays a key role in linking emotion and memories.
The finding comes from a new study, which demonstrates that patients with frontotemporal dementia (FTD) lose the “emotional content” of their memories.
While most people vividly remember events infused with emotion — such as a daughter’s wedding or a loved one’s funeral — patients with FTD have a “profound difficulty” understanding and expressing emotion, according to Dr. Olivier Piguet, the study’s lead author.
Formerly known as Pick’s Disease, FTD is the second most common degenerative disease that causes dementia in younger adults. The age of onset is typically in the 50s or 60s, but can be as young as 30, the researchers explain.
For the study, the research team showed images designed to prompt an emotional reaction in healthy people. They found that healthy control subjects and patients with Alzheimer’s disease remembered more emotional than neutral images. The FTD patients, however, did not.
“Up until now, we knew that emotional memories were supported by the amygdala, a brain region also involved with emotion regulation,” said Piguet.
“This study is the first to demonstrate the involvement of the orbitofrontal cortex in this process. This is an important development in how we understand the relations between emotions and memory and the disturbance of the emotional system in this type of dementia.”
The findings may help caregivers and family members better understand why people with FTD find personal interaction difficult, added researcher and doctoral student Fiona Kumfor.
“Imagine if you attended the wedding of your daughter, or met your grandchild for the first time, but this event was as memorable as doing the groceries,” she said. “We have discovered that this is what life is like for patients with FTD.”
Information gleaned from the study could help create new diagnostic tools, she noted.
It also could “change how we diagnose certain types of dementias and differentiate between them,” she said. “We have basically found the source of the deficit driving these impairments in patients, which brings us a step closer to understanding what it means to have FTD.”
The study was published in the journal Brain.
Source: Neuroscience Research Australia