Neurohacking Tutorial 5 - Improving & Augmenting N1 & N2 - Cells That Fire Together Wire Together |
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Автор: NHA | |||
18.11.2009 01:01 | |||
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Stretching & relaxing brain networks
How do you 'stretch' a network? The same way that you stretch a muscle -you give it something to do that is new suitable input for its natural functions, something just a little different, and maybe difficult, but that it can get the hang of with practice. The mental ‘stretching’ takes place when we encounter new or unknown challenges, and the ‘relaxing’ takes place when that thing becomes known, familiar and automatic. These events are marked chemically by the release of different transmitters in the brain and physiologically by changes in the actual networks themselves, making them more efficient at transferring and processing information, improving the speed and acuity of your mental abilities. When we relax and assimilate new information, the brain restructures itself to store and co-associate our newfound knowledge.
Hebb combined up-to-date data about behavior and the mind into a single theory. His theory became known as Hebbian Theory and the models which follow this theory are said to exhibit Hebbian learning. This method of learning is best expressed by this quote from his book “The Organization of Behavior”:
"When an axon of cell A is near enough to excite cell B and repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells such that A's efficiency, as one of the cells firing B, is increased.”
This is often paraphrased as "Neurons that fire together wire together" and is commonly referred to as Hebb's Law. Hebb's law explains how plasticity works. Put simply, it means that the brain uses coincidence for association; that is to say, events that occur at the same time as each other are assumed to be connected and so are associated in memory, and this association of ideas causes different networks to fire in synchrony even if only one network is receiving input. We introduced plasticity in tutorial 1, as one of the most important processes of developing intelligence. If you have read previous tutorials you will know that plasticity affects ability and function (software), as well as brain cells (hardware) and also the genome. Plasticity enables learning and memory, and is usable in NH for changing habits. You will also know that anxiety prevents plasticity, because plasticity usually takes place via epigenetics; interaction between genes and signals from their environment. Researchers distinguish between 'functional' and 'structural' plasticity. Functional plasticity refers to neuronal activity; functions enabled, and communication in the brain, while structural plasticity refers to the physical shape, connectivity and density of the brain and cells themselves. These changes are not only proven but measurable. There are marked changes measurable by Diffusion Imaging MRI in the characteristics of brain microstructure showing structural plasticity happening in only two hours, and this discovery in particular has been pivotal to the way scientists view the effect of learning and memory on the brain (7) (Scientists used to believe that the brain took days or weeks to change its microstructure.) “Cells that fire together wire together” describes the mechanism of neural plasticity, and it means: each time a group of neurons fires together and makes a pattern, their tendency to fire in the same pattern again is increased –because they pay closer attention to their associated neighbors. Synchronous firing is triggered by association (events happening at the same time as each other.) The more cells fire together, the more connections they build between each other. Eventually, repeated synchronous firing creates multiple connections between neurons so that the slightest activity on one will trigger all those that have become associated with it to fire, too. A long term memory, set of associations and habit of thought have been formed. When cells are firing, this is the 'stretching' half of learning. In the 'relax' half, new connections are being built as association defragments the new information and stores it in long term memory alongside other connected information. If you look at the neurotransmitters connected with stress/relaxation you'll see that we use more dopamine when paying attention and more serotonin when assimilating information. The transmitters are essential for easy learning, and they can only be triggered by motivation. This is why learning under coercion cannot trigger long term memory. We recognize there is a dark side to the brain’s plasticity, because its nature makes it vulnerable to problems caused by the wrong sort of habits (wronguse and nonuse become habitual through plasticity), but we also know how to use plasticity as intended; using networks in the right way and practising helpful habits of thought triggers the signals for epigenetic changes towards optimal development. Rather than dismissing ourselves as unchangeable creatures of habit, we now know that we can instead direct our own change by consciously developing new habits. In fact, the more new things we try — the more we step outside of what is 'known' into the unknown —and return safely to the 'known', the more inherently intelligent we become.
From this point on you are no longer an observer. You are a participator. You recognize yourself as Captain and as in control. The impact of this responsibility cannot be understated. To return to our starship analogy, if you have not been in control up until now you will have been drifting; your course through life and whatever you have believed to be real and true may have been strongly influenced or even totally determined by others, all sorts of people will have been trying to pull you in to their own orbits for their own purposes, many of which are not in the interests of your wellbeing. In retrospect you may realize that now.
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