Semantic memory is critical for episodic future thinking
Wednesday 23 May 2012
Researchers from Neuroscience Research Australia (NRA) have found that our ability to imagine and plan our future depends on brain regions that store general knowledge.
NRA's Dr. Muireann Irish found that people with dementia who no longer recall general knowledge - for example, the names of famous people or popular songs - are also unable to imagine themselves in the future.
"We already know that if memory of past events is compromised, as is the case in Alzheimer's disease, then the ability to imagine future scenarios is also impaired," she said. "We have now discovered that damage to parts of the brain that store knowledge of facts and meanings can also produce the same effect."
Thinking about the future is an important ability because it helps us to plan and anticipate the consequences of our actions. Dr. Irish explained: "A person with dementia may leave the oven on, partly because they forget the appropriate action, but also because they cannot project forward in time to anticipate the dangerous consequences this might have."
The research team used MRI to study people with Alzheimer's disease (where memories of past experiences are lost) as well as patients with semantic dementia who have lost the ability to remember facts (semantic memory) but have little problem remembering past experiences.
Results showed that the semantic dementia group was as impaired as the Alzheimer's group when imagining future events, even though their memory of past experiences was relatively intact.
Dr. Irish concluded: "This is an important finding, as it points to multiple regions in the brain that are responsible for our ability to imagine and plan for the future."