are spidery structures that have a cell body and thousands of appendages that can either receive (dendrites)2 or send (axons)3 electro-chemical impulses to and from other nerve cells across the synaptic gaps4. The interconnectivity between brain cells is the power that allows us to make new
associations and continually add to them all our lives. Our thoughts and actions are the traffic of these signals between
cells. While healthy brains lose some cells as they age, the loss is not dramatic and is limited to very specific areas (Goldman,
1996). So inevitable loss of brain capacity with age is greatly overstated. In fact, rather than losing brain cells as we
get older we can usually extend our neural connections as long as we stay healthy and intellectually active.
also Mature Minds page.
Click here to read more about brain plasticity -
The Brain from Top to Bottom - McGill University. '
'Learning depends on the plasticity of the circuits in the brain - the ability of the neurons to make
lasting changes in the efficiency of their synaptic transmission.'
birds, reptiles and mammals have the same basic brain cells as humans, with the only difference being their number and organisation. However
wildlife has a range of different and amazing capabilities. A bee can communicate, dance, learn, defend its community, adapt
to gravitational forces and detect the difference between millions of scents. Computer analysis of a skylark's song reveals
that it composes as many as twenty different Mozart-like symphonies in a day. Mammals have complex social systems, have
emotions, have reasoning powers and a range of intricate communication systems. We often forget that an anthropocentric view5 of the natural world is a very limiting one.
The Cerebral Cortex
The key to the
brain's amazing power lies in the most evolutionary advanced part of our brain - the cerebral cortex - the 2mm wrinkled
outer coating which, spread out flat, would cover approximately four A4 sheets of paper. The bulkiness of the brain comes
from the myelin sheathes on the axons that speeds up communication between cells.
of ‘wisdom’ is dependent on the axons – the long string-like extensions of the cells or ‘cables’
that allow neurons to link up to other cells in different parts of the brain. Myelin production peaks around 50 but continues
more slowly till the end of life. It is this ongoing ‘superhighway’ construction that creates better co-ordination
between different brain regions, better integrated use of the left and right hemispheres and supports neurogenesis and wisdom
in the second half of life.
See the Brain Shapers page.
carry our evolution inside us, within the different structures of the brain, structures built in different eras.... each one
designed to maintain stability in its organism as animals moved from the sea to land, to the trees, to the savannahs of Eastern
Africa, to Fifth Avenue.' Ornstein and Sobel