The article reviews recent advances in neuroimaging studies of brain development, focusing on cortical and subcortical changes in healthy children and abnormal developmental changes in disorders such as schizophrenia, fetal alcohol syndrome, ADHD, and Williams syndrome. It discusses how structural changes relate to cellular processes and cognitive development. The brain matures through a complex, lifelong process, with early development involving cell proliferation, migration, and maturation. The human brain has about 100 billion neurons at birth but continues to grow and specialize. Synaptic density increases in early development, followed by pruning, leading to more efficient connections. Myelination, which increases conduction speed, continues into adolescence. MRI has enabled longitudinal studies of brain development, revealing regional variations in maturation. Cortical thickness changes are linked to cognitive development, with thinning in certain areas correlating with improved cognitive performance. Subcortical structures also undergo development, with the caudate showing volume loss during puberty. Brain imaging has identified structural differences in developmental disorders, such as reduced gray matter in schizophrenia and increased gray matter in ADHD and Williams syndrome. Genetic factors influence brain development, as shown by twin studies. Despite these advances, limitations in MRI resolution and sample size remain. The study highlights the importance of brain imaging in understanding normal and abnormal development, and its potential in clinical applications.The article reviews recent advances in neuroimaging studies of brain development, focusing on cortical and subcortical changes in healthy children and abnormal developmental changes in disorders such as schizophrenia, fetal alcohol syndrome, ADHD, and Williams syndrome. It discusses how structural changes relate to cellular processes and cognitive development. The brain matures through a complex, lifelong process, with early development involving cell proliferation, migration, and maturation. The human brain has about 100 billion neurons at birth but continues to grow and specialize. Synaptic density increases in early development, followed by pruning, leading to more efficient connections. Myelination, which increases conduction speed, continues into adolescence. MRI has enabled longitudinal studies of brain development, revealing regional variations in maturation. Cortical thickness changes are linked to cognitive development, with thinning in certain areas correlating with improved cognitive performance. Subcortical structures also undergo development, with the caudate showing volume loss during puberty. Brain imaging has identified structural differences in developmental disorders, such as reduced gray matter in schizophrenia and increased gray matter in ADHD and Williams syndrome. Genetic factors influence brain development, as shown by twin studies. Despite these advances, limitations in MRI resolution and sample size remain. The study highlights the importance of brain imaging in understanding normal and abnormal development, and its potential in clinical applications.