Neurodevelopment Quiz

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Questions and Answers

What is the primary structure that forms the basis of the brain and spinal cord during neurulation?

The neural tube forms the basis of the brain and spinal cord.

At what rate are neurons added during early embryonic life?

Neurons are added at a rate of 250,000 neurons per minute.

During which stage of neurodevelopment do progenitor cells primarily undergo mitosis?

During neurogenesis, progenitor cells divide primarily through mitosis.

What happens to the neural tube during the third week of embryonic life?

By the third week, the neural tube develops three chambers that eventually become the ventricles. Signup and view all the answers

What average number of other cells does a single neuron interact with?

A single neuron interacts with an average of 15,000 other cells. Signup and view all the answers

What is the peak period for neural migration during brain development?

The peak period for neural migration is between 8 to 16 weeks after conception. Signup and view all the answers

How are newly-formed neurons guided into position during neural migration?

Newly-formed neurons are guided into position by radial glia cells. Signup and view all the answers

What happens to the migration of neurons after the peak period?

Migration slows down until around 25 weeks gestation. Signup and view all the answers

What occurs after immature neurons reach their positions?

They differentiate into different types of specialized neurons. Signup and view all the answers

What is the significance of the laminar structure formed in the cortex?

The laminar structure is crucial for the organization and function of the cortex. Signup and view all the answers

What is the main process of over-production of synapses that occurs mainly postnatally?

Synaptogenesis Signup and view all the answers

At what gestational age does myelination typically begin in the visual system?

28 weeks after conception Signup and view all the answers

What process involves the programmed death of neurons that do not establish connections?

Apoptosis Signup and view all the answers

During which developmental stage does synaptic reorganization primarily occur?

From birth until 14 years old Signup and view all the answers

What type of glial cell is responsible for the production of myelin?

Oligodendrocytes Signup and view all the answers

Which two processes are involved in the competitive elimination of neurons during neurodevelopment?

Apoptosis and synaptic pruning Signup and view all the answers

What is the significance of dendritic and axonal arborisation during neurodevelopment?

It facilitates the formation of synapses and enhances neuronal connectivity. Signup and view all the answers

What stage of brain development follows neurogenesis and is characterized by maximum growth?

Synaptogenesis Signup and view all the answers

Study Notes

Neurodevelopment

The adult brain contains approximately 80 billion neurons, 15 times more than the global human population.
During early embryonic development, neurons are generated at a rate of 250,000 per minute.
Almost all brain structures are present at birth.
Brain growth reaches roughly 80% of its adult size by age 2.
A single neuron typically interacts with an average of 15,000 other cells.

Stages of Neurodevelopment

Neurogenesis (Mitosis): Stem cells in the neural tube divide through mitosis to create more progenitor cells (early in development; symmetrical cell division). Later progenitor cells divide asymmetrically creating one progenitor cell and one neuron/glial cell. This process is most prominent during weeks 8-16 of development.
Neural Migration: Newly formed neurons from the ventricular zone are guided to their correct location by radial glial cells. A wave-like process, with earlier migrating neurons setting the position for later migrations. Brain region development relies on precise spatial relationships among neurons. This is heavy during weeks 8-16 and then slows until around 25 weeks after conception.
Neural Differentiation: Immature neurons, once in their proper positions, mature into specific neuron types. This differentiation process leads to the distinctive layers of the cerebral cortex.
Synaptogenesis: Overproduction of synapses. Begins around 17 weeks post-conception and mostly occurs after birth. This period is characterized by synapse redundancy.
Apoptosis (Cell Death): Neurons whose axons do not find their targets undergo programmed cell death (apoptosis) which is genetically driven -different from necrosis. This process occurs from around 16 weeks post-conception, to after birth.
Synapse Rearrangement: Synaptic connections are reorganized and refined, leading to more precise and efficient neuronal circuits. This process extends from approximately 26 weeks after conception until after birth or even into adolescence.
Myelination: Oligodendrocytes produce myelin which coats axons. Myelination plays a crucial role in facilitating efficient nerve impulse transmission. It starts in the visual system before birth and extends to other sensory systems. Sensory systems are myelinated earlier than motor systems. All white matter tracts are myelinated by 2 years.

Time Course of Neurodevelopment

The images show how neurodevelopment is a protracted process that continues after birth.
The stages occur during specific time periods. This is helpful in understanding what may harm a developing fetus.

Summary of Critical Period Stages

The stages of early brain development are influenced by critical periods. The first 2 weeks of embryonic development, critical periods for creating systems, and for the sensory systems following these critical periods.
Critical periods are related to neural activity and their relationships, as well as synaptic and/or dendritic connections and arborisations, during specific time periods.

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Description

Test your knowledge on the stages and facts of neurodevelopment. Learn about the number of neurons, their generation rate, and the growth of the brain during early development. This quiz covers key concepts from neurogenesis to neural migration.