Neuron Anatomy and Development Quiz

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Questions and Answers

What is the primary function of dendrites in a neuron?

To receive electrochemical input signals from other neurons (correct)

To transmit signals away from the neuron cell body

To form synapses with target neurons

To connect neurons over long distances

What term is used to describe collections of dendrites?

Dendritic cones

Dendritic trunks

Dendritic arbors (correct)

Dendritic roots

What structure at the distal tip of an axon guides it to the targeted brain regions?

Neural progenitor

Dendritic arbor

Growth cone (correct)

Synapse

Where do synapses form in the structure of neurons?

Between the axon and the target neuron Signup and view all the answers

What do axons primarily do in the nervous system?

Connect with other neurons over long distances Signup and view all the answers

Which part of the neuron is responsible for the transmission of signals?

Axon Signup and view all the answers

What characterizes the appearance of dendrites?

They are like the branches of a tree Signup and view all the answers

In the context of neuron structure, what does the term 'neocortex' refer to?

The thin outer layer of the brain Signup and view all the answers

What is the significance of the primitive node during embryonic development?

It serves as a molecular signaling center for neural development. Signup and view all the answers

What event marks the beginning of neural tube development?

The appearance of two ridges along the neural plate. Signup and view all the answers

What happens to the ridges that form during neural plate development?

They rise, fold inward, and fuse to form a hollow tube. Signup and view all the answers

How is gene expression in migrating cells triggered during neural development?

Through a protein signal secreted by the primitive node. Signup and view all the answers

Where does fusion of the neural tube begin during development?

In the center of the developing neural tube. Signup and view all the answers

What shape does the hollow center of the developed neural tube resemble?

A cylindrical straw. Signup and view all the answers

What ultimately forms as the brain becomes larger and more complex?

The ventricular system of the brain. Signup and view all the answers

Which cell populations are involved in the differentiation of neural progenitor cells?

Cells of the node, migrating cells, and epiblast cells. Signup and view all the answers

What is the process by which the earliest produced neurons migrate by extending a long basal process?

Somal translocation Signup and view all the answers

Which type of migration is characterized by the neuron traversing long distances along the pial surface?

Tangential migration Signup and view all the answers

Where is the second proliferative zone located during embryonic development?

Ventral telencephalon Signup and view all the answers

What significant class of interneurons is derived from the compartments of the ganglionic eminences?

Inhibitory cortical interneurons Signup and view all the answers

What morphological change occurs to the nucleus during somal translocation?

It becomes thicker and shorter Signup and view all the answers

What do the terms medial, lateral, and caudal refer to in the context of the ganglionic eminences?

Compartmental regions Signup and view all the answers

What happens to the pial process as the nucleus migrates during somal translocation?

It shortens and thickens Signup and view all the answers

Which statement is true about the distances neurons must traverse during migration from the ventral zone?

They must traverse short distances Signup and view all the answers

What does the extrapolation from species such as rodents suggest regarding human development?

It leads to uncertainty about the temporal extent of neurodevelopment. Signup and view all the answers

Which of the following roles are suggested for oligodendrocyte precursor cells (OPCs)?

They participate in excitatory and inhibitory signaling. Signup and view all the answers

What is indicated about transient connections during early brain development?

They do not exist in adults. Signup and view all the answers

How does the late maturation of glial populations likely affect brain function?

It carries widespread functional implications. Signup and view all the answers

Which brain pathways have been documented for exuberant connectivity during development?

Pathways such as the corpus callosum and thalamocortical pathways. Signup and view all the answers

What plays a significant role in the retention or elimination of neural pathways?

Neurotrophic factors as competitive resources. Signup and view all the answers

What is a common characteristic of brain development mentioned regarding glial cells?

There is typically an overproduction of glial cells. Signup and view all the answers

What is the significance of molecular interactions between neurons and glial cells?

They have implications for the late maturation of glial populations. Signup and view all the answers

What is the main observation about proton diffusion in the cerebral white matter of human newborns?

It is high and exhibits low anisotropy. Signup and view all the answers

How does the directionality of diffusion in fiber bundles behave compared to gray matter voxels?

Diffusion is higher along the long axis of the fibers. Signup and view all the answers

What key relationship is suggested between cortical thinning and fiber tract myelination?

Cortical thinning may relate to nearby myelination levels. Signup and view all the answers

Which method is mentioned for measuring directional diffusion in the brain?

Fractional anisotropy (FA). Signup and view all the answers

What happens to proton diffusion and anisotropy as fiber tracts mature?

Proton diffusion declines and anisotropy increases. Signup and view all the answers

Which factor influences the change of fractional anisotropy during development?

Changes in all three tensor eigenvalues. Signup and view all the answers

What is indicated by isotropic diffusion in specific brain areas?

Random diffusion with no preferred direction. Signup and view all the answers

What is a potential outcome of maturation of fiber tracts as mentioned in the content?

Increased cortical activity stimulating myelination. Signup and view all the answers

Study Notes

Neuron Anatomy

Dendrites are the short branches of a neuron that receive signals from other neurons. They form complex arrays called dendritic arbors.
Axons are long fibers that transmit signals from the neuron.
The synapse is a point of connection between axons and dendrites, transmitting signals via electrochemical mechanisms.

Neural Tube Development

The neural plate is a region of the embryo that contains neural progenitor cells which will develop into neurons.
Two ridges appear on the neural plate (approximately E21) and fuse together to form a hollow tube. The fusion starts in the center and proceeds towards both ends.
The anterior neuropore at the rostral (head) end closes on E25, and the posterior neuropore at the caudal (tail) end closes on E27.

Neuron Migration

Early neurons use somal translocation to migrate. This process involves the neuron extending a long basal process towards the outer surface of the brain (pial surface). The nucleus of the cell then moves up the basal process and migrates out of the ventricular zone (VZ).
Later, as the brain grows, neurons use tangential migration to move. This mode of migration is observed in neurons originating from the ganglionic eminences, which contribute to the formation of inhibitory cortical interneurons.

Postnatal Development

Glial precursor proliferation and differentiation, including astrocytes and oligodendrocytes, primarily occur postnatally, and play a significant role in the functional maturation of neural circuits.
There is evidence that neurons, oligodendrocytes, and astrocytes interact and influence each other.

Regressive Events in Postnatal Period

The brain overproduces neurons and glial cells, neural processes, and synapses during development.
Subsequent removal of excess components is a crucial part of development. This process is driven by factors like competition for resources, activity-dependent pruning, and specific molecular signals.
The abundance of transient connections in the early stages of development is known as exuberant connectivity. This phenomenon has been documented in many brain pathways.
The competition for resources, such as neurotrophic factors, plays a role in the retention or elimination of pathways.

Myelination and Diffusion Tensor Imaging

Myelination, the process of wrapping axons in myelin, increases the speed of signal transmission.
Myelination is a gradual process during development.
Diffusion tensor imaging (DTI) is a technique used to study the directionality of water diffusion in the brain.
DTI reveals that proton diffusion in the cerebral white matter is high and isotropic (non-directional) in newborns.
As myelination progresses, diffusion declines, and anisotropy (FA) increases, indicating a more directional flow of water along the myelinated axons.

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Description

Test your knowledge on the anatomy of neurons, including dendrites, axons, and synapses. Additionally, explore the stages of neural tube development and the processes involved in neuron migration. This quiz covers crucial concepts in neuroscience and developmental biology.