TheMillerCircle.org

Who would argue that of all nature’s creatures, the evolutionary process of natural selection achieved its most stunning success when it brought Homo sapiens onto the world stage, about 200,000 years ago. You can imagine nature’s pride as she announced,  “here is my best work, 7 million years in the making” (the first human (hominin) ancestor in the fossil record is Australophithecus afarensis, who walked erect, but lived in trees, ate fruit and nuts and was preyed upon by the numerous predators of that era, like giant hyenas, saber-tooth tigers and many others. A. afarensis was an edge species, the size of a small ape, who  lived in the trees and on the ground. Perhaps 6-10 per cent of A. afarensis fell victim to these large, fast predators, based on the fossil record of  A. afarensis showing predator skull punctures and tooth marks on other bones). The guiding light for evolutionary change is natural selection operating on mutations that result in improved means of survival and procreation.

As humans, there is much that we can celebrate about ourselves. While we don’t have the greatest body plans and we are not the fastest or the most agile or the strongest species, we do have a brain worth bragging about, a modern marvel, and perhaps the pinnacle of the evolutionary process. Although big brains per se may be worth noting, it is far more important to understand what part of our brains have evolved in such a way that we manage to dwarf the achievements of all other species with our rich linguistic skills, a powerful sense of logic, a prolonged period of social learning  and the creation of a vast culture that has led to a sea change in the earth around us.  Our  language facility  keeps our social evolution on a continuous staircase of change and adaptation, one in which each new generation adds its own cultural layer on top of those of its predecessors.The central question is whether we can continue on the staircase we are currently on or whether we need to backup and start over on a new trajectory. As far as I know, there is no evidence in the fossil record that suggests Homo sapiens was ever confronted with something as threatening as what we might face with global climate change and its potential impact on our culture. Are we smart enough to make the kind of adaptation that may be required to meet this new uncertain future?

Cortical surface of human, cat and rat brain (NEUROSCIENCE: EXPLORING THE BRAIN, Bear et al, Fig 7-27; not to scale)

The figure above illustrates the cortical surface of thee different mammalian brains, including human, cat and rat. These are not drawn to scale, but magnified as required to illustrate how different regions of each brain are functionally divided into visual, auditory, motor and somatic sensory partitions (the olfactory bulb in humans is  tucked under the frontal lobes of brain and can’t be seen using this view). Most of us understand that the cerebral cortex (neocortex), the outer, undulated surface  of our brains, is the real envy of the neighborhood. It’s what has our competitors swooning. This convoluted outer surface of our brain is so vast that it has to be folded into peaks  (gyri) and valleys (sulci) to squeeze  its huge surface area into  our skull; within the skull, the brain is suspended in a fluid-filled shock absorber system, surrounded by cerebrospinal fluid (CSF) and suspended by strands and layers of concentric, fibrous collagen, through which blood vessels penetrate to nourish and oxygenate the brain: an impressive engineering marvel with natural selection at the control center. You can appreciate that the cortex of the rat has very few folds, whereas the number and complexity of them increase as one moves from cat to human.

The three pound universe that resides in our skulls, constitutes  a small percentage of our body weight, but requires 25% of the oxygen we consume. Our brains do not store energy, so blood supplied glucose provides the main nutrient and must be continuously available.  Every region of the brain is within 90 µm of a capillary, reflecting this supreme dependency on continuous access to oxygen and nutritional support. Our brains have created a miraculous way of regulating their own blood supply: the blood flow within the brain is not uniform, but varies according to the tissue demands. Brain regions where neuronal activity is high receive more blood flow compared to brain areas which have lower levels of activity. So, blood traffic in the brain is under neighborhood regulation. It’s like the street gets wider if the traffic gets heavier.  It is the change in blood flow, based on neuronal activity (maybe glial cells too (see below)), that serves as the signal detection basis  for the technique of functional Magnetic Resonance Imaging or fMRI. The cellular  mechanisms which regulate this regional blood flow  are still poorly understood, but appear to involve glial cells, the non-neuronal cells that were once thought to merely be the “glue” that keeps the neurons together.

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Millennial Support for Obama 2008 (Center for American Progress)

The Center for American Progress has released a poll showing the voting patterns and behavioral preferences of the Millennial generation, those born between 1978 and the year 2000. This analysis includes in-depth evaluation of the their voting preferences for the 2008 election, for which they played a major role in pushing through Obama’s impressive victory and further establishing Democratic majorities in the House and Senate. The 2008 election was the first in which the entire pool of the 18-29 year old voters were all from the Millennial generation.  This group is increasingly important in our electoral process and by the year 2020, the first presidential election will occur when all of the Millennial generation will be of voting age. In that year an estimated 90 million Millennial voters will constitute nearly 40% of the electorate. Increasingly their influence on our elections will be profound because, if they continue to vote in a manner consistent with the current polling data, and,  as expressed in the election of 2008, they will help transform American politics, perhaps more so than any other generation has achieved. When you look at their voting pattern for the 2008 presidential election and realize that their influence will only grow, you can see how some of the more progressive ideas kicking around today, like a single payer health care system, which doesn’t seem to get much traction at the moment, will become something of a no-brainer (see below) as the Millennial generation increasingly impacts on our elections and policy-making decisions.  We still have too many corporatist Democrats to get the kinds of legislation  passed that the majority of Americans view as important and appropriate for  government intervention. It may be that true reform of our political system, including restoration of our social contract and reconstructing our social safety net can only be done by reforming campaign financing and eliminating the influence that wealthy corporations have on our political decisions.

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