Cours : Cell Migration in Nervous System Development

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which type of neuron is responsible for the formation of excitatory pyramidal neurons in the cerebral cortex?

Pyramidal neuron (correct)

Granule cell

Stellate cell

Purkinje cell

What is the primary mode of migration for inhibitory interneurons into the cerebral cortex?

Somal translocation

Tangential migration (correct)

Radial migration

Glial guided locomotion

Which type of neuron migrates radially during cerebellar development?

Purkinje cell (correct)

Granule cell

Stellate cell

Basket cell

Which of the following is NOT a layer of the cerebellum?

Pyramidal layer (B) Signup and view all the answers

Which type of cell is responsible for guiding the migration of neuronal precursor cells along radial glia?

Radial glia (B) Signup and view all the answers

What type of cells are specifically referred to in the example of developmental processes?

SST+ Martinotti cells (B) Signup and view all the answers

Which region is NOT associated with the development of SST+ Martinotti cells?

Pulvinar nucleus (A) Signup and view all the answers

Which mutated gene is primarily associated with Periventricular Heterotopia?

filamin A (FLNA) (D) Signup and view all the answers

Which of the following human disorders is linked to abnormalities in cortical migration due to genetic mutations?

Lissencephaly (B) Signup and view all the answers

What is the function of the gene Arfgef2 mentioned in the context of cortical migration defects?

Vesicle trafficking (A) Signup and view all the answers

What disorder is associated with mutations in the POMT1, POMGnT1, and Fukutin genes?

Cobblestone Lissencephaly (D) Signup and view all the answers

Which of the following accurately describes the migration pattern of granule neuron precursors in the developing cerebellum?

They stop dividing in the inner EGL before migrating. (B) Signup and view all the answers

What is the main function of Sema6A in granule cell precursors?

To initiate migration towards the inner granule cell layer (A) Signup and view all the answers

When does cerebellar development complete in mice?

Three weeks after birth (A) Signup and view all the answers

What is the origin of the cerebellum in the developing brain?

Rhombic lip (D) Signup and view all the answers

What role do neural crest cells play in the development of the nervous system?

They give rise to various components of the peripheral nervous system. (D) Signup and view all the answers

What process allows neural crest cells to migrate from their origin?

Epithelial to mesenchymal transition (B) Signup and view all the answers

Which of the following structures is formed by radial glia cells?

Cortex layers (C) Signup and view all the answers

What is the key function of Cajal Retzius cells in the nervous system development?

They release reelin to provide stop signals for migrating precursors. (A) Signup and view all the answers

What type of neurons do enteric neural crest cells primarily differentiate into?

Enteric neurons (A) Signup and view all the answers

What primarily determines the formation of neurons versus glial cells during neural development?

Time in the developmental process (B) Signup and view all the answers

In which part of the nervous system do precursor cells migrate long distances?

Central nervous system (D) Signup and view all the answers

What is the primary consequence of aberrant development in the nervous system?

Increased risk of disease (C) Signup and view all the answers

What role do basal radial glia cells play in the outer subventricular zone?

They contribute to the increased neuronal cell number. (C) Signup and view all the answers

Which statement about corticogenesis is accurate?

The basic principles of corticogenesis are conserved across species. (C) Signup and view all the answers

What aspect of cortical development has increased in complexity as evolution progressed?

The timing and complexity of cell types. (B) Signup and view all the answers

Where do interneurons originate in the developing brain?

The medial and lateral ganglionic eminence. (C) Signup and view all the answers

What guides the migration of interneurons in the telencephalon?

Guidance cues. (A) Signup and view all the answers

What is a noted characteristic of thalamocortical pathways in cortical areas?

They show preserved arrangement across species. (A) Signup and view all the answers

What is the significance of ventricle-directed migration for interneurons?

It precedes layer-specific targeting. (A) Signup and view all the answers

Which of the following types of interneurons are known to form synapses with excitatory neurons?

Somatostatin interneurons. (B) Signup and view all the answers

Study Notes

Cell Migration in the Developing Nervous System

Cell migration is a crucial process in nervous system development.
Different types of cells migrate in the developing nervous system, including neural crest cells and CNS precursor cells.
Neural crest cells contribute to the peripheral nervous system (PNS).
These cells undergo epithelial-mesenchymal transition (EMT) before migrating.
Neural crest cells differentiate into various cell types, including neurons, glia, and melanocytes.
Cranial neural crest cells differentiate into bone, cartilage, and connective tissues (e.g., teeth, eyes, ears).
Vagal neural crest cells differentiate into enteric neurons, sensory neurons, glia, melanocytes, smooth and cardiac muscles.
Trunk neural crest cells differentiate into autonomic neurons, chromaffin cells (adrenal medulla), and melanocytes.
In the central nervous system (CNS), precursor cells migrate long distances to reach their final destinations.
An example is the migration of precursor cells to different layers of the cerebral cortex.

Stages of Development

Proliferation: Initial cell division.
Differentiation: Cells specialize into different types.
Cell Migration: Cells move to their appropriate locations, often guided by specific signals.
Axonal pathfinding: Axons grow toward their targets.
Synapse formation: Connections form between neurons.
Circuit formation: Networks of neurons develop and function together.
Cell death (apoptosis): Removal of unnecessary or aberrant cells.
Maturation: Refinement and optimization of connections.
Pruning: Elimination of unwanted or inefficient neural connections.

Mechanisms for Neural Crest Cells

Neural plate border specification: Cells at the border differentiate into the neural crest.
Neural crest specification: Specification of the neural crest into various cell types happens next.
Neural crest epithelial to mesenchymal transition (EMT) or delamination: Transition from sheet form to individual cells
Neural crest migration: Cells move to their final destinations.

Structure and Function of Cells

Radial glia cells: These act as stem cells and guide neurons during their migration.
Cajal-Retzius cells: Cajal-Retzius cells form and produce Reelin, a key guidance cue that signals for migration, and regulate the formation of the cortical layers.
Interneurons: Interneurons form synapses with various parts of excitatory neurons and have a central role in the function of neural circuits. They display remarkable diversity in terms of their subtypes and the projection patterns they develop, and their locations of origin.

Development of Cerebral Cortex

The cerebral cortex develops in an inside-out manner.
The ventricular zone(VZ) is the origin of progenitor cells in the cortex.
Progenitor cells migrate tangential to the ventricular surface, forming the intermediate zone (IZ), then the subventricular zone (SVZ), cortical plate.
The migration to form specific layers is also guided by specific signals.
The production and timing of different cell types are crucial for cortical development.

Time and Formation

Embryonic stages determine neuronal versus glial cell production.
Temporal differences in the formation of neurons and glial cells.
Asymmetric divisions of apical progenitors or radial glia cells are important for self-renewal and precursor cell production.

Birthdating

Birthdating with [3H]-thymidine allows tracing the origin of cells in the cortex.
This technique uses radioactive thymidine to mark cells born at particular times during development.
Birthdates can be determined by autoradiography. This reveals where the cells are in the cortex.
Birthdating studies reveal that cortical neurons are generated in an inside-out fashion, meaning that cells born earlier migrate to deeper layers.

Evolutionary Aspects

Lissencephalic vs. gyrencephalic species development show variations in cortical layers.
Conservation of basic principles of corticogenesis is consistent even with the emergence of gyrencephaly.
Key cell types and patterns of migration are conserved across different species.
Timing of events and cell-type complexity have increased during evolution. Cortical regions are preserved in evolutionary terms, but the species show variations in development.

Defects and Disorders

Specific genes (e.g., Reelin, POMT1; Dcx, Lis1) play important roles in proper migration steps.
Mutations in these genes can cause various cortical migration defects, resulting in different disorders.
These disorders are associated with structural abnormalities in the brain, such as lissencephaly, or cobblestone lissencephaly.
Periventricular heterotopia is another disorder.

Cerebellum Development

The cerebellum originates from the rhombic lip, a structure at the wall of the fourth ventricle.
Granule cell precursors migrate to the internal granule layer, guided by Bergmann glia fibers.
Granule cells generate parallel fibers before migrating
- They downregulate Sema6A to begin radial migration.
Cerebellar development takes 3 weeks post-birth in mice.

Neuronal Connections

Interneurons originate in the medial, caudal, or lateral ganglionic eminence and have a crucial involvement in establishing inhibitory circuits in the cortex.
Diversity in GABAergic interneurons in the neocortex is essential for cortical function.
Different kinds of interneurons target various locations in the cortex, contributing to the complexity of neural circuits.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz explores the vital process of cell migration during the development of the nervous system. It covers the various types of migrating cells, such as neural crest and CNS precursor cells, and their differentiation into specialized cell types. Learn about the roles these cells play in forming structures within the peripheral and central nervous systems.