Scientists find way to map brain's complexity | Reuters

Scientists find way to map brain's complexity | Reuters

Mapping synaptic connections sounds like a job for Google! We have Gooogle Earth. How about Google Brain?

Location might correlate to the function of a neuron. I read this weekend in the textbook and on the computerized study guide for Psychology 231 that three distinct sections of the brain, fore, mid, and hind sections begin to emerge from the top portion of the neural tube, followed by the spinal cord at day 22 after conception. Thus begins a period of neurogenesis (brain cell creation).

The three distinct areas of the brain are fully in place by week 8, the beginning of the fetal period. Immature neurons (brain cells) travel from inner to outer sections of the brain, guided to their destinations along a scaffolding of glial cells. After reaching their destinations, neurons differentiate. They sprout two kinds of extensions, short branch-like dendrites for receiving signals, and long trunk-like axons for transmitting signals. Synaptic connections form at junctions between an axon of one neuron and a dendrite of another. Neural impulses transmitted along the axon of one neuron trigger the release of chemical neurotransmitters at the the synapse, which migrate to the dendrite of the other neuron, causing it to fire.

Two major processes begin during weeks 8-26, exuberant synaptogenesis, where new connections are formed, and synaptic pruning, where unused connections are removed and others are strengthened through a competitive process. The brain increases 6 times in size during this period.

Exuberant synaptogenesis occurs throughout the 1st year as the child bonds with the mother and its environment. Synaptic pruning is a use-it or lose-it proposition, where synapses that wire together fire together, while unused or weak synapses are subject to death and removal. Brain development is a dynamic process, both responsive to external stimuli, and shaped by genetic factors.

Around week 28, the cerebral cortex, which first emerged from the forebrain, begins to wrinkle and fold, increasing its surface area, vastly increasing the number of synaptic connections. A fully developed normal human brain has about 100 trillion synaptic connections.

Futurists like Ray Kurzweill argue that the reverse-engineering of the human brain will be completed sooner than most people realize.