Page 40 - Mind Games The Aging Brain and How to Keep it Healthy

24 • Chapter 2

Dendrite

Message
Pathway

Axon

Figure 2-1 Connections between brain cells

neuron out its axon, is transmitted over the synapse, and
travels up one of the dendrites of another neuron on its way
to its destination. The message may be passed from neuron
to neuron until it reaches the final destination. On the other
hand, the neurotransmitters released into the synapse may
alert multiple neurons at the same time. These message path-
ways are called connections.

connections—message pathways in the brain

Also present in the spaces between the neurons are tril-
lions of glial cells, from the Greek word for glue. These cells
support, sustain, and safeguard the neurons and may have
a communications system of their own.

glial—glue-like cells that form a support for the neurons

The neurotransmitter performs a critical function in the cre-
ation of these communications connections. Each time a mes-
sage is transmitted between cells, the chemical that is released
into the synapse physically changes the receptor dendrite.
Bristly spikes build on the dendrite as a result of the interaction
of the chemical neurotransmitter and the dendrite. It is the rep-
etition of this chemical reaction along the message route that
strengthens the connection. You will learn in Chapter 4, “De-
velop a Brawny Brain,” how to use rehearsal to make a mem-
ory stronger. (Visit the Web site www.mentalagility.com
to view an animation of this phenomenon.)