Final Report Summary - TRANSMEM (Fast transformation between episodic and semantic memories: Interactions between the hippocampal formation and related regions and their breakdown in Alzheimer’s disease)
Our memories define who we are. When we recall a memory it is usually thought to be one of two types; “episodic memories” are memories of specific events, whereas “semantic memories” are facts or more general knowledge. Scientists have typically thought of these two types of memories as being separate from each other, such that, for example, brain damage might affect one type of memory system but not the other. The TRANSMEM project tested a new idea – that these memory systems are highly interactive. The TRANSMEM model made a number of predictions about when and why events and information can be remembered better, as well as the brain regions that support memory and how memory is affected by Alzheimer’s disease.
During the project we tested our different predictions experimentally. We developed new techniques to investigate memory for life-like events by using short videos and we combined this with functional MRI to measure which brain regions were activate when experiencing events and when remembering them later. We found that events have their own “signature” pattern of brain activity and that these signature activity patterns can be measured in the brain whenever that event is recalled. Remarkably, these signature patterns of brain activity are similar across different individuals – if two people are thinking about the same event, their pattern of brain activity looks similar too. Further work showed that this similarity across individuals is not apparent in people with memory problems caused by Alzheimer’s disease. Nevertheless, we found that people with Alzheimer’s disease could be helped to create better memories for events by described what they had just seen immediately afterwards – and this was a better memory aid than simply re-watching the video for a second time. Lastly, we found that when people try and remember names of several unknown objects that are shown repeatedly in groups (mimicking word learning in everyday situations), they tend to make guesses about which words and objects go together and test these guesses out when they see the same objects again. Perhaps because of this reliance on explicit memory processes, we found that adults with Alzheimer’s disease found it difficult to learn word-object associations irrespective of what learning regime was used.
Overall, the project delivered, (1) important new experimental findings that are important for advancing our understanding of how memory operates, (2) insights into how individuals with memory impairment might compensate for their difficulties, and (3) novel research tools that have been enthusiastically taken up by other researchers of memory and cognition.
During the project we tested our different predictions experimentally. We developed new techniques to investigate memory for life-like events by using short videos and we combined this with functional MRI to measure which brain regions were activate when experiencing events and when remembering them later. We found that events have their own “signature” pattern of brain activity and that these signature activity patterns can be measured in the brain whenever that event is recalled. Remarkably, these signature patterns of brain activity are similar across different individuals – if two people are thinking about the same event, their pattern of brain activity looks similar too. Further work showed that this similarity across individuals is not apparent in people with memory problems caused by Alzheimer’s disease. Nevertheless, we found that people with Alzheimer’s disease could be helped to create better memories for events by described what they had just seen immediately afterwards – and this was a better memory aid than simply re-watching the video for a second time. Lastly, we found that when people try and remember names of several unknown objects that are shown repeatedly in groups (mimicking word learning in everyday situations), they tend to make guesses about which words and objects go together and test these guesses out when they see the same objects again. Perhaps because of this reliance on explicit memory processes, we found that adults with Alzheimer’s disease found it difficult to learn word-object associations irrespective of what learning regime was used.
Overall, the project delivered, (1) important new experimental findings that are important for advancing our understanding of how memory operates, (2) insights into how individuals with memory impairment might compensate for their difficulties, and (3) novel research tools that have been enthusiastically taken up by other researchers of memory and cognition.