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2. MJ, what is your reaction to the brain's 10-90 use-disuse concept after my response?
Some more on what I found on how brain functions : ). I agree to your understanding that 10% usage is a myth. -
What does it mean to "use only 10% of your brain?" Does this statement imply that only 10% of the brain's neurons is active at any one time? If so, how could this be measured? Does the statement assume that only 10% of the brain is firing action potentials at one time? Even if this was true, the discharge of action potentials is not the only function of neurons. Neurons receive a constant barrage of signals from other neurons that result in postsynaptic potentials. Postsynaptic potentials do not always result in the generation of action potentials. Nevertheless, these neurons, even in the absence of generating action potentials, are active.
If all neurons of the brain were generating action potentials at the same time, it is highly likely to result in dysfunction. In fact, some neurotransmitters, such as GABA, act to inhibit the activity of neurons and reduce the probability that an action potential will be produced. Massive excitation of neurons in the cerebral cortex may result in seizures such as those that occur during epilepsy. Inhibition of neuronal activity is a normal and important function of the brain. In other words, some areas of the brain keep other areas quiet.
It is also important to keep in mind that neurons are not the only type of brain cell. Although there are an estimated 100 billion neurons in the human brain, there are another ten to fifty times that number of glial cells in the brain. Glial cells do not generate action potentials. Glial cells function to:
* support the brain structurally
* insulate axons
* clean up cellular debris around neurons
* regulate the chemical composition of the extracellular space
Would we behave normally without 90 billion neurons and billions of glial cells? Would we be just fine if 90% of our brains was removed? If the average human brain weighs 1,400 grams (about 3 lb) and 90% of it was removed, that would leave 140 grams (about 0.3 lb) of brain tissue. That's about the size of a sheep's brain. Clinical evidence indicates that damage to even a small area of the brain, such as that caused by a stroke, may have devastating effects. Some neurological disorders (e.g., Parkinson's disease) also affect only specific areas of the brain. Disabilities may arise after damage to far less 90% of any particular brain area. Because removal of small essential brain areas may have severe functional consequences, neurosurgeons must map the brain carefully before removing brain tissue during operations for epilepsy or brain tumors.
Apart from that, in our brain, there are redundant pathways that serve similar functions. This redundancy may be a type of "safety mechanism" should one pathway for a specific function fail. Still, functional brain imaging studies show that all parts of the brain function. Even during sleep, the brain is active. The brain is still being "used"; it is just in a different active state.
From a developmental perspective, the 10% of the brain statement also fails. The adage "use it or lose it" seems to apply to the developing nervous system. During development, many new synapses in the brain are formed. After birth, many synapses are eliminated later on in development. This period of synaptic development and elimination goes on to "fine tune" the wiring of the nervous system. It appears that correct input is required to maintain a synapse. If input to a particular neural system is eliminated, then neurons in this system may not function properly.
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3. Does the brain have ability to sense
Please explain the Question. Brain can feel the physical pain or it also has the capability of thought. What senses are we talking about here?
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4. Finally, do you agree that evolution is a currently ongoing process?
Human evolution is directly linked to evolution of their brains. In so many centuries, we have become capable of archiving and using the information, but not exactlyt learnt to put it in our brain. Most of it still needs to be learnt. Also, the ability to learn more has not changed, which suggests that over brain has not significantly evolved. OR maybe I do not know of the differences and so not in a position to comment.
It would be nice if you could point out some specific examples, what kind of information is already available now to us upon birth.
Look at the chart above I posted... it indicates, we are still quite young. So yes, we will grow, but how and where, dont know.