Dr. Patric Meyer
Central Institute of Mental Health, Mannheim
Interview of June 24, 2010 with Dr. Birgit Teichmann
That is an absolute important sentence and it would be disastrous for us, if we actually would remember everything we encounter during the day, during our life. Milliseconds decide what is important and what not. What isn’t relevant is blanked out. What actually exceeds a certain level of importance- often emotional information- is passed onto other brain areas, is processed there and then obtains a level of consciousness.
What is understood to be memory and how can one imagine it?
Until the middle of the last century, it was assumed that memory is one entity. A process in which the brain as a whole is involved. That’s why they did not hesitate to undergo a certain kind of surgery on patients with untreatable epilepsy. An operation in which for example the hippocampus –whose calcification is often a cause for epilepsy-was removed and in the worst case of the famous patient H.M., where both hippocampi were removed. As it was believed that the whole brain is responsible for memory, it should only have small consequences if we remove a small part of the brain. It was then discovered, that the patients developed such deep amnesia, that they could not remember anything over 10 minutes. Although there were memories on events before the operation, but as of the time of the operation, it was not possible to store new information. Only in the middle of the last century it was eventually noticed, that there are specific brain structures that are responsible for specific memory processes. But it does not mean that nevertheless, large parts of the brain are involved in different memory processes.
Now you already mentioned, that we can remember some things for a long time, and some not. What is the difference between short-term- and long-term memory?
Through these findings in such patients as I have just described, it was noticed that you can actually differentiate memory in short- and long-term memory. With these patients only the long-term memory was deficit. Short-term memory, e.g. how it is expressed in a normal communication like the one between us, was intact. As soon as the attention was shifted from the ongoing activity, this information was lost, if it was not repeated over a certain amount of time. In a healthy brain it is like this: If the information is interrupted through any other process, we are able to draw information from our long-term memory and get back to the actual topic. That means, it is obvious that for short-term memory other brain structures are responsible than for long-term memory. The central structure for the long-term memory is the hippocampus. This brain structure is responsible for solidifying short-term memory information through a so called consolidation process, so they can then be retrieved again. That applies to the section of declarative long-term memory. But there is a form of long-term memory that has nothing to do with consciousness. Conditioning or procedural learning, e.g. how to learn riding a bike, how to play golf or reading mirror writing. Even though he had no hippocampi, which are responsible for conscious long-term memory, H.M. was able to learn this new skill. But he could not acquire new facts- except a few exceptions-, nothing that is really verbally retrievable.
Do we memorize more pleasant or unpleasant things?
It depends. It does not remain the same throughout our lifespan. In principal you can say, that we mostly remember the unpleasant things. Evolutionary it makes sense because it can be more important to remember unpleasant things. It is relatively important to remember a snake, that I met once in the jungle, biting me. If I come across a tiger a few times and it did not hurt me, it is less important to remember. At old age however, there is the so called “positivity effect”. Thereby it is assumed that we rather remember positive things and those also become greatly relevant. Why it actually is like that, cannot be exactly explained.
There is the theory, that at old age we sugarcoat some things that happened to us in the past. How prone is our memory for falsification?
Memory is relatively prone for falsification. One can image it like this: Every time when I strongly remember an episode from the past, the memory trace becomes fragile and unstable. In the moment of remembering, subsequently the memory itself is newly stored. At this point, when I newly store the retrieved information, I can modify it in a certain direction. And if I do that often enough, then at a later point, the memory becomes a totally different coloration than maybe at the beginning.
At the beginning you mention that something must happen, so things will be passed on to long-term memory. Does this knowledge help with learning, meaning can I compose a certain learn strategy that especially supports this?
There is a difference between superficial- and intensive learning. Intensive learning involves the hippocampus and therefore has a bigger chance of being remembered. And of course, a personal analysis of what was learned, is of crucial importance, so it becomes a certain emotional salience. Furthermore, repetition is a very important aspect. If I repeat information often enough, the possibility that it will be passed onto long-term memory is much higher as if I, for example, see a vocabulary only once.
How about mnemonics? Why are they so useful if simple repetition would be enough?
Mnemonics are valuable to remember rows of numbers, names or very abstract information. Especially when you have to remember a lot of things that have no correlation, memory often has problems. Mnemonics avoid this fact by summarizing single information- for example into a sentence or rhyme. In this way you only have to remember one thing- the essential information is hidden within. Instead of the actual circumstances, we memorize a slogan or a picture. Funny or unusual mnemonics are especially easy to remember.
How does memory change at old age? Does learning become slower or is it in general more difficult to keep something in long-term memory?
Memory, especially declarative, episodic long-term memory as well as prospective memory are the first functions that also decrease in healthy age. And apparently, that has something to do with the hippocampus being impaired in its functionality. The same goes for the prefrontal cortex, both are eminently pivotal for memory storing and recalling. Prospective memory is something like: I memorize that tomorrow a certain appointment is taking place, so remembering something that is in the future. The episodic memory is the detailed, spatiotemporal context memory. At old age, things from the past remain retrievable but rather with a semantic character. I know I was on vacation last year but I cannot remember every detail.
Until the 1990’s, the dogma existed, that new nerve cells cannot develop in the brain of adults. Until Thomas Björk Eriksson substantiated the formation of new nerve cells. Since then, there have been continuous reports of, for example, sports helping the growth of nerve cells or E. Altenmüller showing that 20 minutes of playing the piano helps. Can you imagine that it will have an impact on future research? That we know, there is still something going to happen? That maybe one day, there will be medication, that will also help the elderly to improve learning?
It will surely go into that direction. In the end, we don’t know, from an ethical point of view, if we can support it or not. However, there are more simple and non-prescriptive methods to prompt the hippocampus at old age, because the functionality is mainly controlled by Dopamine. There are findings that show that initially, it was not the impaired integrity of the hippocampus that causes the disturbance of memory but more likely problems in the basal ganglia or substantia nigra- which produces Dopamin- because Dopamine modulates the functionality of the hippocampus. That means, if Dopamine decreases, one becomes a little more lethargic, less interested in things, is not so much into new things anymore. Ultimately, we will experience less new, so the hippocampus is less stimulated to store and learn new things. But if one tries to actively keep the desire for the new, going to the theatre more often, going on vacation, be excited about it, prepare for it, learn new things, maybe a new language, so that the system is going to stay stable for a longer period of time. But even those circumstances will not halt dementia if it threatens us one day. It can delay it for some time, but in the end, when it happens, it will not help anymore.
Glossar (Source: Wikipedia)
Declarative memory
Declarative memory (sometimes referred to as Explicit memory) is one of two types of long term human memory. It refers to memories which can be consciously recalled such as facts and events. Its counterpart is known as non-declarative or Procedural memory, which refers to unconscious memories such as skills (e.g. learning to ride a bicycle). Declarative memory can be divided into two distinct categories:
- Semantic memories are those that store general factual knowledge that is independent of personal experience. Examples include types of food, capital cities, lexical knowledge (vocabulary), etc.
Procedural memory
Procedural memory is our memory for how to do things. When needed, procedural memories are automatically retrieved and utilized for the execution of the step-by-step procedures involved in both cognitive and motor skills; from tying your shoes to flying an airplane. This process occurs without the need for conscious control or attention. Procedural memory is a type of long-term memory and more specifically a type of implicit memory.
Personal Data
Patric Meyer was born in 1976 in Völklingen. He studied Psychology at the University of the
