A new study into how different parts of memory work in the brain has shown that the same brain areas are involved in retrieving different types of information, the findings could redefine how memory is understood and studied.
Researchers from the School of Psychology at the University of Nottingham and the Cognition and Brain Sciences Unit at the University of Cambridge have examined episodic and semantic memory, combining task based and fMRI data and have shown that there is no difference in neural activity between successful semantic and episodic retrieval. The findings have been published today in Nature Human Behaviour.
Episodic memory refers to the ability to remember a past event that occurred in a particular spatial and temporal context. This type of memory supports the human capacity to re-experience events from our past, as a form of "mental time travel". Semantic memory, on the other hand, refers to the ability to remember facts and general knowledge about the world that are retrieved independently from their original spatial or temporal context.
In this research the team examined how information associated with successful episodic and semantic memory is processed and stored, using tasks that are more closely matched. 40 participants recalled pairings between logos and brand names, where the pairings corresponded to real-world knowledge (semantic task), or were learned in an initial study phase (episodic task).
fMRI (Functional Magnetic Resonance Imaging) scanning was used whilst participants were asked to recall details about the associated brand from their prior knowledge in the semantic task, or details about the pairing in the study phase in the episodic task.
fMRI is a non-invasive brain imaging technique that maps brain activity by detecting changes in blood flow, showing which areas are active during tasks like speaking, moving, or thinking. It works by sensing increased oxygen-rich blood flow to active neurons, creating dynamic 3D maps that help doctors and researchers understand brain function, plan surgeries, and study neurological conditions.
Dr Roni Tibon, Assistant Professor in the School of Psychology led the study, she said: "We were very surprised by the results of this study as a long-standing research tradition suggested there would be differences in brain activity with episodic and semantic retrieval. But when we used neuroimaging to investigate this alongside the task based study we found that the distinction didn't exist and that there is considerable overlap in the brain regions involved in semantic and episodic retrieval.
"These findings could help to better understand diseases like, dementia and Alzheimer's as we can begin to see that the whole brain is involved in the different types of memory so interventions could be developed to support this view."
Because, for many years, episodic and semantic memories were considered to be distinct entities, a research tradition had developed in which they are explored separately. The consequence of this is a lack of within-study designs that tap into both systems.
Dr Tibon continues: "Based on what we already knew from previous research in this area we really expected to see stark differences in brain activity but any difference we did see was very subtle, I think these results should change the direction of travel for this area of research and hopefully open up new interest in looking at both sides of memory and how they work together."
