Brain & Behavior Quiz 2

Neurogenesis

mitotic division of nonneuronal cells to produce neurons

cell migration

Movement of newly generated cells to create distinct populations in the developing nervous system.

Differentiation

Transformation of cells into neurons and glial cells with specific forms and functions after reaching definition.

Synaptogenesis

Formation of synaptic connections as axons and dendrites grow.

Apoptosis

Programmed neuronal cell death; a normal and important part of neural development.

Synaptic rearrangement

Pruning and development of synapses; helps refine neural connections.

Neural tube

Developing structure that gives rise to the central nervous system.

Ventricular Zone (VZ)

Layer of cells along the inner surface of the neural tube containing neural progenitor cells where neurogenesis occurs.

Marginal Zone (MZ)

An additional zone formed as cells leave the ventricular zone during development.

Neural progenitor cells

Developing cells that can give rise to neurons and glial cells.

Radial glia

Major cell type in the developing neural tube that guides neuronal migration (monorail) from birth (VZ) to final destination (cortex). Also divide and become neurons/glia. HELP MIGRATION AND BECOME NEURONS/GLIA

Younger neurons

reside in deeper layers of cortex

Inside-out migration

Pattern in which newer waves of neurons migrate past older neurons to form progressively more superficial cortical layers.

Pial surface

Outer surface toward which developing neurons migrate.

Guidance molecules

Extracellular molecules that help direct the movement of developing neurons. Chemoattractants and chemorepellents.

Chemoattractants

Chemical signals that attract developing cells/axons toward them.

Chemorepellents

Chemical signals that repel developing cells/axons.

Cell adhesion molecules (CAMs)

Proteins on cell surfaces that help guide cell migration.

Cellular stages of neurodevelopment

1. Neurogenesis

2. Cell migration

3. Differentiation

4. Synaptogenesis

5. Apoptosis

6. Synaptic Rearrangement

Sonic hedgehog

Protein secreted by the notochord that acts as a signal influencing differentiation of developing spinal cord neurons into MOTOR NEURONS.

PLACE

matters for differentiation, defines gene expression and therefore specific proteins and functions

TIME

neurons adapt different characteristics according to their birthday

Notochord

Structure that provides signals, including Sonic hedgehog, to nearby developing neural cells.

Growth cone

Growing tip of an axon or dendrite that detects external guidance signals and directs growth.

Actin

Protein concentrated in the growth cone that acts as the "engine" for movement.

Filipodia

Small outgrowths from growth cones that detect guidance molecules and help steer the growing process.

Nerve Growth Factor (NGF)

Neurotrophic factor that guides growth cones and axonal branching and supports neuronal survival as axons take up NGF to survive.

Neurotrophic factors (NFs)

Target cells make these which neurons compete for to survive. They also influence gene expression + development

BDNF

Similar to NGF, produced by target cells and taken up by neurons

Why is apoptosis useful?

Sculpts the nervous system + housekeeping (eliminate cells/synaptic connections that aren’t functional)

Neurons compete for

Synaptic sites and neurotrophic factors from target cells

Activity-dependent synaptic remodeling

Electrical activity influence which synapses are strengthened or eliminated. If activity blocked, remodeling inhibited (fuzzy map)

Fetal Alcohol Syndrome (FAS)

Developmental disorder caused by maternal alcohol ingestion that can produce anatomical, physiological, and behavioral impairments.

Microcephaly

Abnormally small head/brain size; listed as one consequence associated with FAS in the presentation.

Fragile X Syndrome

Developmental disorder: excess small, immature dendritic spines and abnormal elimination of synapses after birth. Modified facial features and cognitive deficits.