Neural Induction, Patterning, and Developmental Neurobiology

Vocabulary flashcards covering neural induction, morphogen gradients, patterning mechanisms, clinical neural tube defects, and key model organisms in developmental neurobiology.

Blastula

An early stage of embryonic development where cells create a hollow ball prior to gastrulation.

Gastrulation

The embryonic rearrangement of cells into primary germ layers: outer ectoderm, inner endoderm, and middle mesoderm.

Ectoderm

The outer germ layer formed during gastrulation that gives rise to the neural plate and epidermis.

Endoderm

The inner germ layer generated during embryonic gastrulation.

Mesoderm

The middle germ layer generated between the endoderm and ectoderm during gastrulation.

Neural Plate

A structure formed from the ectoderm that bends during development to generate the neural tube and neural crest cells.

Spemann-Mangold Organizer

A specialized cluster of cells in the dorsal lip of the blastopore that secretes growth factor antagonists to direct uncommitted cells, pattern the body plan, and induce the central nervous system.

Chordin and Noggin

Organizer-secreted antagonist proteins that block ventralizing signals to trigger neural induction in adjacent ectoderm cells.

Bone Morphogenetic Proteins (BMPs)

Powerful signaling molecules antagonized by Chordin that direct embryonic nervous system layout, maintain adult brain stability, aid axon regeneration, and regulate neural stem cell niches.

Morphogen

A signaling molecule that establishes a concentration gradient across a developmental field, providing positional information to direct cell fates based on concentration thresholds.

Sonic Hedgehog (Shh)

A morphogen secreted from the ventral spinal cord that operates in gradient opposition to dorsal BMPs to specify dorsal-ventral spinal cord patterning.

Spina Bifida Occulta

The mildest form of spina bifida characterized by a small gap in the vertebrae without protrusion of the spinal cord.

Meningocele

A form of spina bifida in which the meninges push out through a vertebral opening, typically causing few or no long-term neurological symptoms.

Myelomeningocele

The most severe form of open spina bifida, where the spinal canal remains open, allowing the spinal cord and meninges to protrude in a sac and cause permanent nerve damage.

Immunohistochemistry

An experimental technique that involves tissue fixation, slicing, blocking, permeabilization, and primary and secondary antibody binding to visualize specific target proteins using fluorophores.

C. elegans

A nematode model organism (~$1\,mm$ in length) featuring $302$ mapped neurons, an invariant cell lineage, and a ~$3\,day$ life cycle at $20\,^\circ\text{C}$.

Drosophila

A fruit fly model organism (~$2\text{--}3\,mm$ in length) with ~$100{,}000$ neurons, a ~$10\,day$ life cycle at $25\,^\circ\text{C}$, and advanced genetic tools such as GAL4/UAS.

Zebrafish

A vertebrate model organism with optically transparent larvae containing ~$100{,}000$ neurons, external fertilization, rapid embryonic development within $24\text{--}48\,hours$, and strong CNS regeneration abilities.

Mouse Model

A mammalian model organism (~$7\text{--}10\,cm$ body length) with ~$71\,million$ neurons, providing high biological relevance to human brain structures and genetic tools such as Cre-lox.

Soma

The cell body of a neuron containing the nucleus, cytoplasm, and mitochondria.

Dendrites

External neuronal projections that receive incoming signals from other cells across synaptic connections.

Axon

A specialized neuronal extension that conducts electrical signals generated at the axon hillock toward the axon terminal.

Growth Cone

A motile structure composed of actin and microtubules at the axon tip that senses environmental cues to guide axon navigation.