Molecular Basis of Neurodevelopment and Circuit Assembly
Building the nervous system
Patterning and fate choice
Neurodevelopment is guided by morphogens, transcriptional cascades, cell adhesion molecules, guidance cues, and activity-dependent refinement. These processes ensure that cells acquire the right identities and connect with appropriate targets.
Developmental principle
The same signaling pathway can have different effects depending on timing, dosage, cellular context, and receptor composition.
Guidance and synapse formation
Axon guidance involves attractive and repulsive cues such as netrins, semaphorins, ephrins, and slits. Synaptogenesis requires adhesion molecules, scaffold proteins, and trans-synaptic signaling complexes that stabilize nascent contacts.
Which family of molecules is best known for axon guidance cues?
Semaphorins and ephrins are classic guidance cue families.
Correct answer: Semaphorins and ephrins
What is one role of cell adhesion molecules in neurodevelopment?
Adhesion molecules help neurons recognize, contact, and maintain appropriate partners.
Correct answer: Stabilize synaptic contacts
Developmental mechanisms
Morphogen signaling
- Patterns tissue fields
- Influences fate decisions
Guidance cues
- Direct axon pathfinding
- Shape circuit topology
Classic guidance molecules
Why can the same developmental cue have different effects in different neurons?
Ligand effects depend on receptor repertoire, timing, and intracellular context.
Correct answer: Because receptor context and developmental state differ
From gene to circuit
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Step 1: Define the developmental stage of interest.
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Step 2: Identify molecular markers of fate or migration.
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Step 3: Manipulate signaling pathways or adhesion molecules.
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Step 4: Quantify structural and connectivity outcomes.
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Step 5: Link circuit changes to function and behavior.