Development of the brain in the first 3 years of life is genetically programmed but occurs in response to environmental stimuli. The brain is organized “from the bottom up,” that is, from simpler to more complex structures and functions, so the experiences and environment that shape early development have consequences that reach far into the future. This entry describes the ontogeny and processes of fetal and infant brain development, as well as major risks to early brain development (during pregnancy and after birth), with emphasis on the factors seen in social-work practice. Neuroscience research is changing social work practice, and understanding early brain development and the contributors to poor development is critical for social workers in medical, mental health, child welfare, and other practice settings.
