Studies of the human brain include techniques that measure activity recorded during cognitive and affective processing. Results demonstrate systematic changes in the brain correlated with developments in behavior. Research shows changes in the brain due to age, and differences in the brain related to psychiatric and brain disorders.
Electroencephalography (EEG) is a technique for studying the development in infants and children; EEG analysis allows precision in the localization of neural generators. EEG measures include: regional activity recorded during cognitive and affective processing; measures of coherence and phase derived from distinct brain regions; and event-related potentials related to linguistic and cognitive processes. As a result of research, current hypotheses regarding patterns for brain and behavior include that major developmental changes include the coordination of components of brain and behavior into higher-order control systems. Connections of elements of these systems grow strong as coordination develops and in turn influence the shape of growth functions (Dawson & Fischer, 1994).
Systematic changes during childhood include myelination, synaptic density, dendritic branching, brain mass, pruning of neurons and synapses, and brain electrical activity. At the same time, the child's actions, speech, problem solving concepts, social interactions, and emotions also change systematically. Studies with rhesus monkeys chow that across large areas of the cerebral cortex, synapses grow and are pruned in parallel cycles closely related to broad cognitive changes. In humans, functioning cortical networks and connections, indexed by brain electrical activity in specific locations, shows developmental patterns that may relate to cognitive and language development. Regarding behavior, global correlations include that diverse knowledge domains develop in predictable correspondence, showing synchronies with age; ...