I had the audacity to be curious about my brain and how it processes stuff. After all, I have to think before I can act. Gad zooks, the activation is complicated. My brain contains about 10 billion neurons. OK it appears to be working because I am acting – well I am typing symbols on a keyboard. Those neurons are connected to others in a massively parallel information processing system.

So different from my computer in which a single processor executes a single series of instructions. However my neurons operate at a rate of 100 Hz but my computer’s CPU can do several hundred million machine level operations per second. That appears incongruous in the face of how I am constantly bombarded with thoughts jumping into my consciousness.

Well my comparatively slow acting brain is nevertheless quite remarkable.

The neurons are connected by very specialized and complex structures called synapses. A synapse is the place where two neurons join in such a way that a signal can be transmitted from one to the other. Simply enough don’t you think? Remember I have somewhere in the neighborhood of 10 billion neurons to connect. A flurry of actions take place with a single thought.

The actions include chemical releases and physiological changes in the receiving neurons. Good thing those little pieces cooperate, isn’t it? There is depolarization of membranes and all sorts of changes that bring a thought to the forefront. How did this all come about? Research shows that all vertebrates share the same functions. The number and complexity of proteins in the synapse first exploded when multi-cellular animals emerged, some billion years ago. A second wave occurred with the appearance of vertebrates, perhaps 500 million years ago.

Most important for understanding of human thought, the expansion in proteins that occurred in vertebrates provided a pool of proteins that were used for making different parts of the brain into the specialized regions such as cortex, cerebellum and spinal cord.

The most mind boggling thought of all is the enormous length of time it took for those changes to happen and the hundreds if not thousands of mutations in perhaps hundreds or thousands of genes. It is nothing short of spectacular that so many mutations in so many genes were acquired during the mere 20-25 million years of time in the evolutionary lineage leading to humans. This means that selection worked "extra-hard" during human evolution to create the powerful brain.

Maybe the lesson here is that good things take a long time a’coming.

_______________________________________

Note: this information gleaned from the following sources -
Wellcome Trust, the Medical Research Council, GSK, Edinburgh University and the e-Science Institute, and the European Molecular Biology Organization.
Nature Neuroscience
Science Daily
The Howard Hughes Institute