16 Preliminaries
- The fundamental operational units of the brain’s information processing functionality are called
neurons^12. Neurons receive electrochemical signals from other neurons that are transmitted
through long fibers calledaxons^13 Neurotransmitters^14 are the actual chemicals responsible
for the triggered functioning of neurons and hence the neural network in the cortex that spans
the halves of the brain. - Parts of the cortex are devoted to the senses. These parts often contain amapof sorts of the
world as seen by the associated sense mechanism. For example, there exists a topographic map
in the brain that roughly corresponds to points in the retina, which inturn are stimulated by
an image of the outside world that is projected onto the retina by your eye’s lens in a way we
will learn about later in this course! There is thus arepresentation of your visual fieldlaid out
inside your brain! - Similar maps exist for the other senses, although sensations from the right side of your body
are generally processed in a laterally inverted way by theoppositehemisphere of the brain.
What your right eye sees, what your right hand touches, is ultimately transmitted to a sensory
area in your left brain hemisphere and vice versa, and volitional muscle control flows from
these brain halves the other way. - Neurotransmitters require biological resources to produce and consume bioenergy (provided
as glucose) in their operation. You canexhaustthe resources, andsaturatethe receptors for
the various neurotransmitters on the neurons by overstimulation. - You can also block neurotransmitters by chemical means, put neurotransmitter analogues into
your system, and alter the chemical trigger potentials of your neurons by taking various drugs,
poisons, or hormones. Thebiochemistry of your brainis extremely important to its function,
and (unfortunately) is not infrequently a bit “out of whack” for many individuals, resulting
in e.g. attention deficit or mood disorders that can greatly affect one’s ability to easily learn
while leaving one otherwise highly functional. - Intelligence^15 , learning ability, and problem solving capabilities are not fixed; they can vary
(often improving) over your whole lifetime! Your brain is highlyplasticand can sometimes
even reprogram itself to full functionality when it is e.g. damaged by astroke or accident.
On the other hand neither is it infinitely plastic – any given brain has a range of accessible
capabilities and can be improved only to a certain point. However, forpeople of supposedly
“normal” intelligence and above, it is by no means clear what that pointis! Note well that
intelligence is an extremely controversial subjectand you should not take things like your own
measured “IQ” too seriously. - Intelligence is not even fixed within a population over time. A phenomenon known as “the
Flynn effect”^16 (after its discoverer) suggests that IQ tests have increased almost six points a
decade, on average, over a timescale of tens of years, with most of the increases coming from
the lower half of the distribution of intelligence. This is an active area of research (as one might
well imagine) and some of that research has demonstrated fairly conclusively that individual
intelligences can be improved by five to ten points (a significant amount) by environmentally
correlated factors such as nutrition, education, complexity of environment. - The best time for the brain to learn is right before sleep. The process of sleep appears to
“fix” long term memories in the brain and things one studies right before going to bed are
retained much better than things studied first thing in the morning.Note that this conflicts
(^12) Wikipedia: http://www.wikipedia.org/wiki/Neurons.
(^13) Wikipedia: http://www.wikipedia.org/wiki/axon..
(^14) Wikipedia: http://www.wikipedia.org/wiki/neurotransmitters.
(^15) Wikipedia: http://www.wikipedia.org/wiki/intelligence.
(^16) Wikipedia: http://www.wikipedia.org/wiki/flynneffect.