Describe some of the major changes in brain development that take place during middle childhood, and the effects these changes have on cognition.

Question

What will be an ideal response?

Answer 1

The weight of the brain increases by only 10 percent during middle childhood and adolescence. Nevertheless, considerable growth occurs in certain brain structures. White matter, consisting largely of myelinated nerve fibers, rises steadily throughout childhood and adolescence, especially in the prefrontal cortex (responsible for complex thought), in the parietal lobes (supporting spatial abilities), and in the corpus callosum (leading to more efficient communication between the two cortical hemispheres). Gray matter, consisting mostly of neurons and supportive material, peaks in middle childhood and then declines as synaptic pruning and death of surrounding neurons proceed. Pruning and accompanying reorganization of brain circuits lead to more optimized functioning of specific brain regions and, therefore, to more effective information processing. Additional brain development likely takes place at the level of neurotransmitters, chemicals that permit neurons to communicate across synapses. Over time, neurons may become increasingly selective, responding only to certain chemical messages. This change may contribute to school-age children's more efficient thinking.