Lecture 7 -- Neurodevelopment Flashcards
(36 cards)
What are the six stages of neural development?
Neurogenesis
Cell migration
Cell differentiation, Synaptogenesis
Neuronal cell death
Synapse rearrangement
What occurs during neurogenesis?
The mitotic division of non-neuronal progenitor cells to produce neurons occurs in the ventricular zone of the neural tube.
What happens during cell migration?
Neurons or their precursors move to establish distinct nerve cell populations (e.g., layers of the cortex).
What is cell differentiation?
The process by which cells become specialized as neurons or glial cells, guided by gene expression and local cell-cell interactions.
What is synaptogenesis?
The formation of synaptic connections between neurons as axons and dendrites grow.
What is neuronal cell death (apoptosis), and why is it important?
The selective, programmed death of neurons; crucial for refining neural circuits and preventing overgrowth.
What happens during synapse rearrangement?
Synaptic connections are refined—some are lost and others are strengthened—throughout life.
What two phases of brain development involve loss of structures?
Neuronal cell death, Synapse rearrangement
What guides a developing neuron to take on the right structure and function?
Cell-cell interactions that influence gene expression and chemical signaling from neighboring cells.
What are stem cells, and why are they important in brain development?
Undifferentiated cells that can become neurons or glial cells; they may integrate into damaged regions of the brain and replace lost functions.
Why is adult neurogenesis significant?
It contributes to learning and memory, particularly in the hippocampus; influenced by factors like exercise and enriched environments.
Where in the adult brain does neurogenesis primarily occur?
In the dentate gyrus of the hippocampus.
What are neurotrophic factors?
Chemicals released by target structures that promote neuron survival by supporting those that make successful synaptic connections.
What happens to neurons that don’t receive enough neurotrophic factors?
They undergo apoptosis and die.
What is apoptosis?
Programmed cell death, an essential process for shaping the nervous system and eliminating excess neurons.
When does the nervous system begin to form during development?
Shortly after fertilization, from the ectoderm layer, forming the neural groove and then the neural tube.
What are the three initial subdivisions of the brain in the neural tube?
Forebrain (cortex, thalamus, hypothalamus), midbrain, and hindbrain (cerebellum, pons, medulla).
What is synapse rearrangement (synaptic remodeling)?
A developmental process in which some synapses formed early are lost and many new ones are formed, typically after the period of neuronal cell death.
When does synapse rearrangement occur during development?
After the period of naturally occurring neuronal cell death.
What drives which synapses are retained and which are eliminated?
Neural activity and competition for neurotrophic factors; active synapses are stabilized, while inactive ones are pruned.
How does cortical gray matter change during adolescence?
It thins due to pruning of dendrites and axon terminals, with changes proceeding from back (caudal) to front (rostral); the prefrontal cortex matures last. It thins for adult-level cognitive and emotional functioning.
What is the functional benefit of synapse pruning?
It refines neural circuits, improving efficiency and cognitive function. Excess synapses can impair intellectual development.
What condition demonstrates the negative effects of insufficient synapse pruning?
Fragile X syndrome; individuals have too many immature dendritic spines, which may contribute to intellectual disability.
What does fragile X syndrome reveal about synaptic development?
That failure to eliminate excess synapses can impair normal brain function and cognitive development.
