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As promised, I am reblogging this post from about a year ago in which I covered many of the basics of brain function. I prefer to describe brain function in terms of:
Clearly "Output" and "Control" could be thought of as the same thing,
but I will clarify that in my classification scheme, "Output" results in
an action of the body, while "Control" results in a change to the
body's internal workings.
Now, what are the "Inputs"? Vision, Hearing, Smell, Taste and Touch.
Those are the five basic senses. In addition, there are special cases:
"Proprioception," the sense of body and limb position is a special case
of "Touch," although the receptors are in the joints and muscles and
not the skin. Balance is tightly associated with the sense of hearing,
but is controlled mostly by proprioceptors, pressure sensors on the
feet, and the proprioceptor-like neurons of the semicircular canals.
Smell and Taste are essentially the same sense - what we sometimes call
"Chemoreception" - and there are special instances of chemoreception
through skin receptors. This brings us to pain. The sense of Pain is
closely intermingled with all of the senses, each can signal a painful
stimulus, but for the most part it is organized with, and associated
with the sense of touch.
Outputs: The commonly considered outputs of the brain are speech and
muscle movement. In truth there are many more outputs, but most of them
fall into regulating the various physiological systems of the body, and
are more appropriately considered "Control" functions. In addition,
muscle movement is not just moving the limbs, but also includes eye
blinks, pupil dilation and constriction, "scanning" movements,
adjustments of the ear drum, swallowing, breathing, and piloerection
Processing is the function that involves the largest percentage of the
brain. Once a sensory neuron reports to the appropriate part of the
brain, that information is *represented* then *associate*. Smell gets
associated with taste, and we decide which foods we like. Sound and
vision are associated, and we can track a moving car, bird, airplane, or
that baseball flying toward us at 75-80 mph. Vision, touch (vibration)
and proprioception are associated, and we are certain we've *hit* that
baseball out of the park. Vision, hearing, and proprioception are
associated to give us the power of speech and reading.
To reiterate from a previous blog, the diagram of the various "lobes" of
the brain at right also serve to divide up functions as well. If one
were to draw a line directly downward from the point marked "Central
Sulcus," most Input functions would be to the right and Output to the
left. Red (Frontal), Orange (Cerebellum), and light Blue (Brainstem)
are Control areas. Blue (Parietal) and Yellow (Temporal) are Processing
areas, although there are also some processing in the Frontal lobe.
Over the next several blogs, we will continue to discuss diseases and disorders of the brain. This organization is important to being able to understand many of the "central" brain disorders such as Alzheimer's disease, and the "A's" as posted last week. It's been long enough since the original post that I thought it worth repeating both for new and continuing readers.
In the meantime, protect your brain it's the only brain you've got!