"I will remember until they die?
is running a course over the matter offered in the Ph.D., which is "Introduction to Cognitive Neuroscience." As we now have this blog, because students take the opportunity to make their first steps in popularizing science. That is why in the next installment of the blog will place the contributions of students to be You, my dear readers, judges of the work (with one or two corrections of styles to fit the format of the blog). Maybe in this way have a taste of what intellectual work is to expose to public scrutiny. Begin raising the contribution of Arafat Angulo.
"I will remember until they die?
memories that will stay
There are moments in the life of any organism that is stored for a long time, it might involve relevant (aggressive event to be avoided), repetition (daily event : how to brush teeth) or they are so related to other episodes in the life of the body which are widely distributed in many other memory traces, which leads you to that memory trace of an event or whatever you say about Rome, which can be reached by many paths. In the case of man, a very complex organism, and in many of these phenomena simply unique, a memory and its duration can be measured in many ways. Likewise, the amnesia and its temporal extension can be studied in patients with retrograde or anterograde amnesia, concepts that refer to the preferential direction in which memory is being affected: Retrograde amnesia for old memory or amnesia, to create new memories .
A historical review. What kind of memories are those that endure? This is a question that most of us have done one way or another, though some have gone further. Lynn Nadel & Morris Moscovitch looked at what was known (until 1997, they published their review in Current opionion in Neurobiology) on how to keep a long memory, how memories are affected and saved and what structures are involved in it. In the end, especially the two main points:
1. There is a standard theory suggests that memory for a store permanently (Consolidated) must pass by so many years, possibly in this case most of the memories would not be bound to die, that is, would likely be lost. The explanation they gave was based on data obtained from people suffering from amnesia, which showed a graduation of his memoirs, that is, the more recent traumatic event or injury, was more easily affected their memory trace and retrieval of the same , then, noting that they saw a graduation condition, directly determined by the temporal proximity to the injury, and indirectly by the time that memory had consolidated, if it was little was labile, if it was much less susceptible.
2. There are certain specific structures and regions involved. The hippocampal complex, par excellence, is called as the "trainer" or encoder memory in which information coming from the cortex and other regions, reporting on the spatial characteristics in turn (space and time), is manipulated, encoded and preserved, all for a period of decades. In the end, the information that lasts (for different reasons), will be stored permanently in neocortex. This last pillar of the standard theory was mainly supported by data patients with temporal lesions showed no retrograde amnesia (RA), arguing that this is because the memories had already been consolidated and not depend on the hippocampus.
Its contribution.
All of the above sounded interesting, but it was not until two researchers rethink the theory and propose a new approach, with new data that allowed them to generate new ideas as to why, how and where it is carrying out perpetuation of a memory emerged.
To begin there are new elements in the scene that Nadel and Moscovitch raised. One was based on the concept that there are different types of memory. They focused on a few to answer the first question: are there types of reports that are more easily stored?. Another element was to clarify the extent of AR after a lesion in the temporal lobe, that to know how many years of memories can be affected by damaging the hippocampal complex and at the same time, identify if there are memories that no longer depend on the structure. It also sought to identify whether the AR was always graded (had levels of involvement) according to the proximity to the traumatic event or injury. Finally, the last item that was questioned was the relationship between RA and anterograde amnesia (AA), which seems trivial, but if you think it is not necessarily when the hippocampus is affected and the memories they already had too, just as all future events will be impossible to keep, what implies an assumption that is a necessary correlation between these two types of amnesia, as if it functioned well.
His perspective.
With the data obtained at the time of this revision, we have laid the foundation for several current models of memory formation and the famous role of the hippocampus in this issue. First things first: yes there are memories that are affected or remain (as do the thing like it) in different proportions. To our surprise most susceptible are the memories of autobiographical episodes (for example, where I spent Christmas Party Paty, when I went to the beach), these memories may be affected in RA for 25 or 40 years or any life, depending on the degree of injury. Secondly, there were the memories of public events and personalities (the year he died Saramago, who won the Nobel Medicine last year, in what year was signed the San Andrés accords), these traces of memory are less affected by injuries, however, when the information was very transient (the actress who announced soap than in the year 99), the memories were equally affected in the previous case, and therefore not even had a graduation from amnesia, as it was absolute. Finally, they found that semantic memories-personal (date of birth, names of schools) and semantic-general (which is a fruit-world data), are the least affected after an injury to the hippocampal complex. With these findings simultaneously answered the second question: the extent of AR after the injury, and as already stated, the years "erased" depend on the extent of injury and the type of memory that is being evaluated (such as autobiographical can succumb to death.)
The gradient of Amnesia. With regard to the temporal gradient of damage to the reports, found that when they are injured hippocampal complex, is not it remarkable autobiographical memories in general are affected, however, this phenomenon could be distinguished more memories public events (you remember more than more distantly data and increasingly less as they approach the time of injury). Finally, they found that although there is some relationship between the presence of RA and AA (if you have AR, hippocampal injury, there may be some degree of AA), there is a proportion. This is very important because although the AA has a visible boundary (may or may not form new memories), RA can be affected in different sizes (5, 20, 50 or for life).
Having been through all this, the phrase will take you to the grave, is it better to say it to a concept that an episode life wonderful?, Now may think they are among the memories that go easily. But we intuitively know that this is not entirely true when we think not in subjects with amnesia or temporary injuries, but our grandparents or people "bigger" than we know, saying, I just remember when I met your grandfather. This idea had also Nadel and Moscovitch and was the culminating this study, they argued that the older memories (including autobiographical) endured more naturally because they were interconnected with many memories, and as I said initially, is much easier to remember, as there are more ways to reach it, a classic example: an apple, remember as a flavoring, fruit, food, a taste, one or more colors, the first time we tested, the dessert apple of her grandmother, a texture, typically, etc. Which would generate several memory traces of the apple through time and experiences that progressively accumulate in relation to it, will ensure their survival, because now not only depends on a group of neurons in the hippocampus but many other groups of neurons (assemblies) distributed in various parts of the cortex involved in other paths. And so it was claimed the role of the hippocampus, not only as a generator of memories, which is "forgotten" memories already consolidated, but as a structure for life involved in the formation and retrieval of autobiographical memories (remember ?, most affected after injury), that is, each and every one of the episodes of our life, and the bark, for its part, as an equally important and constantly required, but preferred their own information (type of episode, as general semantic information).
Thus, the multiple trace theory (as they called it), leaves us satisfied with our favorite memories, ready to take to the grave until the hippocampus the part.
