In general, the participants' ability to recall any given news event decreased in relation to the amount of time that had passed since the event had occurred. As expected, they were better able to recollect more recent events than older ones. The researchers also found that the participants' memory of the questions they had been asked, and of the content of each news event, was independent of how long ago the events had occurred. The richness of the participants' memories was also unrelated to when a particular event occurred; the memories of events that occurred in the distant past were often as rich as those of more recent events.
In their analyses, the researchers used only those fMRI data from the questions that had been answered correctly. This data set showed that medial temporal lobe structures (the hippocampus and amygdala) exhibited gradually decreasing activity as the participants recalled progressively older memories. This drop in activity was true for memories of news events that occurred up to 12 years before, but the recollection of events that took place longer than 12 years was associated with a constant level of activity in those areas. The opposite activation pattern was observed in areas of the frontal, parietal and lateral temporal lobes: activity in these areas increased with the age of the news event being recalled, but remained constant during the recollection of more recent events.
File Cabinets in the Brain
This study therefore provides anatomical and functional evidence supporting the findings obtained from brain-damaged patients with memory impairments. Patients such as H.M., who have lesions in the hippocampus on both sides of the brain, not only lose the ability to form new memories, but also lose memories for events that occurred in the years preceding the onset of their amnesia. The memories of events that took place in the distant past remain intact, whereas those that occurred at intermediate times are lost in a graded manner. This finding suggests that, with time, the hippocampus becomes less important for a given memory, and the frontal cortex more so.
Lashley's theory of memory was not right, but neither was it completely wrong. Why, then, might old memories be transferred from the hippocampus to the frontal cortex? It may be because retrieving older memories requires stronger associations and increased effort—memory encoding in the frontal cortex is more complex than in the hippocampus, and involves a widely distributed network with a greater number of connections. The frontal cortex may therefore be better suited to the task of retrieving memories that were encoded in the distant past.
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9 Comments
Add CommentI think so
Reply | Report Abuse | Link to thisMy father had Glioblastoma Grade IV. primary brain tumor in his Left Medial Lobe. Based on the videos compared to the MRI scans of progression from month to month it supports the fact that the short term memories became almost absent as the lesion progressed. However, the long term memories were still there in most cases except word associations. This is common with the hipp/region medial. When the tumor was shrunk at times and the swelling was decreased the short term memory would appear for short periods of time only to leave as the symptoms occured of the swelling and tumor growth.
Reply | Report Abuse | Link to thisMemory is so mysterious!
Reply | Report Abuse | Link to thishow can the frontal areas operate without the hippocampus at all?
Reply | Report Abuse | Link to thisor is that the stem-
Does this show where memory is stored or where it is processed?
Reply | Report Abuse | Link to thisWhy has nobody come up with the idea that the biggest part of the memory is located in the body to which tge brain is connected? Tge skin has a perfect connection with the brain and every touch activates memory. Without this associated touch the memory does not work.
Reply | Report Abuse | Link to thisThe brain is a perfect connection maker. Not the memory itself.
So all this theories and research in the brain will never bring the solution. I suggest to start research on the theory that the body is one big memory with a huge capacity to store events and reproduce them via the brain connections.
Cees de Vrieze, Bloemendaal, The Netherlands.
I have found that the longer the period of time I am given to remember or retrieve an old memory, the more detail comes to me. If I think of an old memory for a week or two, details start filling in as time goes by. Eventually, I can recall much more detail than I originally thought I could. Why is that?
Reply | Report Abuse | Link to thisThis isn't really on topic with the article, but I'm hoping someone can point me in the right direction for something I have been thinking about.
Reply | Report Abuse | Link to thisDoes anyone know of any books or articles dealing with the development in humans of the ability to conceptualize the future? Animals, as far as I know, have no concept of the future, operating instinctually through hardwired fixed action patterns. Yet, somewhere in our evolutionary history humans developed the ability to imagine events in the future, and consequently to plan, dream, and hope.
I don't know if the ability to image the future is linked to our ability to remember the past and/or our general concept of time, but perhaps someone is familiar with this idea and might know of someone who has written about it.
The hippocampus and amygdala ??? Storing of memories??? All this may be just silliness.... that anything, including any memory, is stored in a mass of blood, veins, tissue, and synapses. The brain acts like a computer, downloading from Divine Intelligence, pictures and memories that are stored everywhere in the invisible energy field of the universe. I believe it is possible that the brain stores nothing, in fact, it may not have the ability to store any memories. In a computer, the memory is stored in a metal box, called a hard drive, and then downloaded. In the brain, through the engine of thought, data is pulled from the Oneness of Infinite Divine Intelligence, which is everywhere and in everything, and re-creates the imagery and memory of the past. Actually, I believe that the physical body, including the brain, is a manifestation of the Mind of IDI. (what some call, God)
Reply | Report Abuse | Link to thisMaybe it is this force, (God IDI) along with us, that is looking out through our eyes, hearing with our ears, smelling, tasting and touching. I think it is what the founders of all major religions were trying to say.
"The Kingdom of God is within." The Father and I are One."
It's all vibrational energy, everything vibrating at different frequency levels.
For a glimpse of more about all this, see: SacredEternalPresence.com Noble