Brain study suggests adolescence may last for decades

adolescence: A transitional stage of physical and psychological development that begins at the onset of puberty, typically between the ages of 11 and 13, and ends with adulthood. People undergoing this transition are known as adolescents.

adolescent: Someone in that transitional stage of physical and psychological development that begins at the onset of puberty, typically between the ages of 11 and 13, and ends with adulthood.

axon: The long, tail-like extension of a neuron that conducts electrical signals away from the cell.

behavior: The way something (often a person or other organism) conducts itself or acts towards others.

brain scan: A technique to view structures inside the brain, typically with X-rays or a magnetic resonance imaging (or MRI) machine. With MRI technology — especially the type known as functional MRI (or fMRI) — the activity of different brain regions can be viewed during an event, such as viewing pictures, computing sums or listening to music.

circuit: A network that transmits electrical signals. In the body, nerve cells create circuits that relay electrical signals to the brain. In electronics, wires typically route those signals to activate some mechanical, computational or other function.

cognitive: A term that relates to mental activities, such as thinking, learning, remembering and solving puzzles.

development: (in biology) The growth of an organism from conception through adulthood, often undergoing changes in chemistry, size and sometimes even shape.

epoch: A span of time over which some dramatic changes have occurred.

function: The specific role some structure or device plays. (in math) A relationship between two or more variables in which one variable (the dependent one) is exactly determined by the value of the other variables.

gray matter: One of two main types of tissue found in the brain and spinal cord. It consists mainly of nerve cell bodies.

host: (in biology and medicine) The organism (or environment) in which some other thing resides. Humans may be a temporary host for food-poisoning germs or other infective agents.

information: (as opposed to data) Facts provided or trends learned about something or

mature: (adj.) Connoting an adult individual or full-grown and fully developed (non-juvenile) form of something. (verb) To develop toward — or into — a more complex and full-grown form of something, be it a living thing, a technology or an idea.

mental health: A term for someone’s emotional, psychological and social well-being. It refers to how people behave on their own and how they interact with others. It includes how people make choices, handle stress and manage fear or anxiety. Poor mental health can be triggered by disease or might reflect a short-term response to life’s challenges. It can occur in people of any age, from babies to the elderly.

nerve: A long, delicate fiber that transmits signals across the body of an animal. An animal’s backbone contains many nerves, some of which control the movement of its legs or fins, and some of which convey sensations such as hot, cold or pain.

neuron: The main cell type of the nervous system — the brain, spinal column and nerves. These specialized cells transmit information by producing, receiving and conducting electrical signals. Neurons also can transmit signals to other cells with chemical messengers.

neuroscientist: Someone who studies the structure or function of the brain and other parts of the nervous system.

society: An integrated group of people or animals that generally cooperate and support one another for the greater good of them all.

transition: The boundary where one thing (paragraphs, ecosystems, life stage, state of matter) changes or converts into another. Some transitions are sharp or abrupt. Others slowly or gradually morph from one condition or environment to another.

white matter: One of the two main tissue types found in the brain and spinal cord. It consists mainly of bundles of nerve fibers.