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[00:05.75]Last month, scientists announced that they recorded the first detailed maps

[00:13.06]of the development of a child's brain between the ages of three and fifteen.

[00:19.98]Scientists at the University of California at Los Angeles School of Medicine led the group of scientists.

[00:29.68]The study appeared in the magazine "Nature".

[00:34.01]The researchers say their study provides new information

[00:39.42]about what areas of the brain are used in learning at different ages.

[00:45.22]The scientists at the University of California invented a process

[00:52.17]that let them map brain growth in greater detail than ever before.

[00:57.31]They used a machine called an M-R-I to take a picture of the brain of each child in the study.

[01:06.14]Using a computer the scientists identified millions of areas of each brain.

[01:13.64]They took more pictures of each child's brain during the fouryear study.

[01:20.61]Then they mapped the changes in position as the brain developed.

[01:25.03]The scientists mainly observed growth in the area of complex nerve tissue called the corpus callosom,

[01:34.75]This area sends information between the two halves of the brain.

[01:40.28]They say they found that a child's brain experiences two main periods of growth.

[01:48.09]The first takes place between the ages of three and six.

[01:53.53]The greatest growth appears in an area of the corpus callosom in the front of the brain.

[02:00.76]This area is involved in learning new skills,planning and organizing new actions and working on an activity.

[02:09.78]The second period of brain growth takes place in the middle and back areas of the corpus callosom from age six to twelve.

[02:20.77]The most growth was in the areas of a child's brain involved in language skills and understanding relations in space.

[02:30.54]The scientists say it is during these quick growth periods that the brain is best able to learn.

[02:39.11]Scientists say the brain overproduces some cells when it grows.

[02:45.38]The new cells organize into networks based on the connections that are used in mental or physical activity.

[02:55.96]Cells and pathways used often form strong permanent connections.

[03:02.67]Those used least die out as the brain returns to its normal size.

[03:09.86]Scientists have known that such periods of growth and shrinkage happen before birth and in very early childhood.

[03:20.91]And, they knew that the brain network connections continued to change until about the age of five.

[03:29.97]But this study and two similar studies released late last year are the first to suggest the process continue to adulthood.

[03:40.71]The scientists say their study may explain why the ability to learn new languages generally decreases after the age of twelve.