Does the brain's architecture change while growing up?

Question

If we are somehow able to record and store all the neural connection in the brain of a child and also the brain of the same individual when he is old will there be difference between the two ?

Is the brain capable to destroy and create neural networks (neurons) on its own, namely to store, process and retrieve memories? Or does it uses a fixed network instead, i.e., the network which each individual is born with )?

If the brain does create new networks, can you please provide a link to the resource where I can read this from ?

Answer 1

Short answer
The brain is a highly dynamic organ that changes constantly through life. During adulthood, there is a general decline in the number of cells. Memory formation is generally thought to be regulated through synaptic connections rather than at the whole-neuron level.

Background
First of all, aging results in a steady decline of the number of nerve cells, so the 'architecture' of the brain changes dramatically regardless its function.

Secondly, memories and other dynamic processes in the brain are typically controlled by altering synaptic connectivity and not so much at the level of the whole-neuron.

Thirdly, neuronal regeneration is confined to but a few areas in the brain, for example the hippocampus where it may, or may not be directly involved in memory formation.

But yes, the brain does dynamically control the synaptic connectivity and notably the synaptic strength of synapses. As Fizz here correctly states, that is called neuroplasticity. Intensive use of certain synaptic connections may result in synaptic strengthening,for example by long-term potentiation (Lynch, 2004). Reversely, abandoned connections may be downregulated through long-term depression.

A general reference work best suited for your basic question would really be a general Neuroscience text book, such as the following online work:

- Purves et al. (eds). Neuroscience. 2^nd ed. Sunderland (MA): Sinauer Associates; 2001.

Or for something more up-to-date, yet not online, the bible of Neuroscience:

- Kandel et al. (eds.). Principles of Neural Science

<sub>Reference
- Lynch, Physiol Rev (2004); 84(1): 87-136</sub>

Answer 2

The brain continues to reorganize throughout life. The process is called neuroplasticity. Among other things (and as proof) it is what allows people to recover from stroke (or traumatic brain injury). Neuroplasticity does slow down in the really old age, which also makes recovery from stroke more difficult for the elderly.

For even more details (than the prvious link) see "Old Dogs Learning New Tricks: Neuroplasticity Beyond the Juvenile Period"