★ DEJA VU : FEELING OF SEEN BEFORE ★ The scientific explanation is that it has to do with memory processes. Ill make it as simple as I can here. The basic idea is that there are portions of the brain that are specialized for the past, the present and the future. In general, the frontal lobes are concerned with the future, the temporal lobes are concerned with the past, and the underlying, intermediate portions (the limbic system) are concerned with the present. When these are all doing their normal thing, in normal states of consciousness, the feeling that something is going to happen will only come up when we are thinking about the future, worrying about it, anticipating it or making plans for it. The sense of the past will only come up when our memories have been triggered in some way. The structure that overwhelms our consciousness when we are in the present are being here now is the amygdala. It assigns an emotional tone to our perceptions. When you step into the street and see a car speeding towards you, and you instantly freeze in terror and jump out of the way, that terror is the amygdala at work. Present. Here and now. The amygdala also recognizes expressions the expressions on peoples faces. When we are talking to someone, we can recognize their expressions and change the way we are talking to them just as quickly as we recognize danger. Words can often seem dangerous to the one hearing them. were thinking of letting you go. Ive been thinking that our relationship is holding me back. You are under arrest. Phrases like these need instant, appropriate responses, and the amygdala is specialized to provide them. For example, one function it participates in, the maintenance of the sense of self, is repeated 40 times per second. Each instance of the self is able to manifest a new emotional response, but only if circumstances have changed. Every 25 milliseconds. In fact, the duration of the present in neurological terms is so brief that we dont experience it so much as remember it. The next level could be called being around here-just about now. Short term-memory deals in periods of a few minutes. Its mostly based in the hippocampus. We know this because problems with the hippocampus. often lead to severe short-term memory problems. It helps us to stay oriented in time. There have been a few people who have lost all hippocampal functions, and they are unable to remember anything that happened after their brain problems began. Humans are a linguistic species, and an intensely social one. We relate to each other through words. We have conversations. In order to do this, we have to be able to remember what people say to us. We also have to be to think about it long enough to be able to respond to it. We have to remember what we have just finished doing in order not to have to do it again. Then there is long-term memory. Its seated in the surface of the brain, along the bottom of the temporal lobes. The area has been called the parahippocampal cortex, and its very closely connected to the hippocampus. Ordinarily, there is a fairly seamless integration of the past, present and the future. In simple terms, we experience something in the present, compare it to similar experiences in the past, and decide how we will respond. The time frame can be very brief; even a few seconds. Once in a while, though, there can be too much communication between short-term and long-term memories. When this happens, then the present can feel like the past. If perceptions from the present are shunted through the parts of the brain that process memories from the past, those perceptions will feel like they are memories, and the person will feel that they are re-living a moment stored in long-term memory. There is another experience worth mentioning; Jamais Vu. Its the opposite of deja vu. Instead of feeling extra familiar, thing seem totally unfamiliar. In this case there is too little connection between long-term memory and perceptions from the present. When a person is in this state, nothing they experience seems to have anything to do with the past. They might be talking to a person they know well and suddenly they person seems totally unfamiliar. Their sense of knowing the person, and knowing how to relate to them simply vanishes. A room in which they spend a lot of time suddenly becomes totally novel; everything seems new. Details they will have seen a thousand times suddenly become engaging. Jamais Vu is not so common as deja vu, but it can be just as compelling.
Posted on: Mon, 25 Aug 2014 14:49:24 +0000