Lecture 6 NROB60 Question And Answer

A comprehensive set of flashcards based on the lecture notes covering various techniques and concepts related to visualizing the nervous system, including methods of imaging, tracing neural connectivity, and genetics in neuroscience.

What is histology?

Histology is the scientific study of the composition of tissues at a microscopic level.

What is the goal of histology?

To understand the structure of tissues and how this structure relates to function.

What technique does electron microscopy rely on?

Electron microscopy uses a focused beam of electrons instead of photons.

What is the magnification ability of electron microscopy?

Up to 1,000,000 times.

What does transmission electron microscopy (TEM) provide?

TEM allows for subcellular resolution.

What is a limitation of electron microscopy?

It is extremely labor-intensive and cannot image live cells.

What does scanning electron microscopy (SEM) create?

A detailed 3D image of the specimen's surface.

What is one major use of electron microscopy in neuroanatomy?

To examine subcellular morphology of neurons, including synaptic contacts.

What are dark gray areas in electron micrographs indicative of?

Electron dense tissue.

What colors are used to represent different neuron parts in colored micrographs?

Blue for dendrites, green for axon terminals, yellow for astrocytes, grey for dendritic spines, uncolored for axon profiles.

What type of synapses are asymmetric synapses?

Excitatory synapses characterized by a thick postsynaptic density.

What percentage of synapses are asymmetric (Type I)?

About 80%.

What are symmetric synapses associated with?

Inhibitory function and similar width presynaptic and postsynaptic densities.

What does the term 'vesicle' refer to in neural context?

A small membrane-bound compartment that holds neurotransmitters.

What are dendritic spines primarily associated with?

Postsynaptic sites for many excitatory synapses.

What significant discovery did electron micrographs help establish about synaptic transmission?

Chemical synaptic transmission results from the discrete discharge of neurotransmitters from synaptic vesicles.

What is the primary neurotransmitter involved in the circuitry of the VTA-NAc reward circuit?

Dopamine.

What does the acronym HRP stand for in neuroanatomical tracing?

Horseradish peroxidase.

What do microtubules provide for axonal transport?

The 'roads' for transporting substances between the soma and axon terminal.

What are the two directions of axonal transport?

Anterograde (forward) and retrograde (backward) transport.

What is a characteristic of motor proteins like kinesin?

They transport cargo toward the plus-end of the microtubules.

How does the Cre-lox system help in genetic research?

It allows for conditional mutations that can be activated in specific cell types.

What is the benefit of using transgenic animals in brain studies?

They allow the introduction of genetic modifications to observe changes in function.

What key feature is characteristic of cholinergic neurons?

They release acetylcholine as their neurotransmitter.

What is the outcome of using viral vector methods in neuroscience?

To deliver transgenes to specific brain regions for study.

What does AAV stand for, and why is it used?

Adeno-associated Virus, used for its ability to effectively deliver genetic material with low pathogenicity.

How does the Cre-lox system control gene expression in specific cells?

By allowing recombination only in cells that express Cre recombinase.

What is done to the stop sequence in a floxed transgene when Cre recombinase is present?

It is removed, allowing transcription of the transgene to proceed.

What is the purpose of using a floxed stop sequence in transgenic research?

To ensure that gene expression is tightly controlled and specific to certain cell types.

Why are specific promoters important in gene expression studies?

They help determine expression exclusively in desired cell types.

In neuronal tracing, what is anterograde labeling intended to show?

The pathways from the cell body to its axon terminal.

What kind of information does Diffusion Tensor Imaging (DTI) provide?

It visualizes the major axon pathways in the brain.

What role do astrocytes play in the nervous system?

They support neurons and maintain the blood-brain barrier.

What results when a tracer is injected into the synapse?

It can label neurons that are directly connected or make synaptic contacts.

What is the significance of rabies virus in neuroscience research?

It can trace neural circuits due to its ability to jump across synapses.

What type of imaging can detect brain lesions effectively?

Computed Tomography (CT) imaging.

What key advancement did MRI provide in brain imaging?

Detailed spatial images using atomic motion physics.

How does MRI differentiate between tissues?

By detecting changes in the distribution of water molecules.

What is the major neurotransmitter involved in excitatory synapses?

Glutamate.

What does the term 'cell-type specificity' refer to?

The ability to target specific populations of neurons during genetic manipulation.

What is an unexpected feature of rabies virus in tracing experiments?

It can transsynaptically label afferent circuits.

What technological advance improved the specificity of neuronal tracing?

The use of viral vectors in combination with Cre-lox systems.

Why is genetic tracing important in neuroscience?

It allows researchers to map specific populations of neurons and their connections.

What is the significance of using promotor sequences in transgenic mice?

They dictate where and when genes are expressed in the organism.

How are fluorescent proteins like GFP used in neuroscience research?

To visualize cells and their projections due to their ability to fluoresce.

What approach uses viral vectors for fast delivery of transgenes?

Viral-mediated gene delivery.

What is the advantage of using a mixed population of neurons in research?

It allows for the study of interactions between different neurotransmitter systems.

What are transgenic lines in genetic research?

Organisms that have had a foreign gene deliberately inserted into their genome.

How do electrophysiological techniques complement imaging methods?

They provide functional information about neuronal activity correlated with structure.

What does the term tracers refer to in neuroanatomy?

Substances injected to label and map neuronal connections.

What do the terms 'afferent' and 'efferent' describe in neuroanatomy?

Afferent refers to input to a neuron, while efferent refers to output from a neuron.

How does selective gene expression improve functional studies in neurons?

It facilitates the examination of specific neuronal pathways and functions.

What is the neural circuit path from the motor cortex to the substantia nigra?

Corticostriatal projection neurons extend from the cortex to the striatum and then to the substantia nigra.

What type of synaptic density suggests excitatory function in synaptic junctions?

A thickened postsynaptic density.

What discovery enhanced our understanding of synaptic transmission dynamics?

The observation of vesicle fusion at presynaptic terminals.

Why are certain genetic modifications used in developing animal models of human diseases?

To investigate the effects of those modifications and mimic human pathology.

What role does the axon terminal play in neurotransmission?

It releases neurotransmitters into the synaptic cleft.

How does cranial imaging assist in clinical applications?

It aids in diagnosing conditions such as strokes or brain tumors.

What type of neurons release GABA as their neurotransmitter?

GABAergic neurons.

How does the body generate white and gray matter distinctions in brain imaging?

These tissues are distinguished based on their density and electromagnetic properties.

What are some common examples of retrograde tracers?

Fluorogold, CTB, and PRV.

What methodological advances have revolutionized neural circuit mapping?

Combining viral tracing techniques with genetic modifications.

What can alterations in dendritic spine morphology indicate?

Potential changes in synaptic function and plasticity.

What is the outcome of using tract tracers in neuroscience research?

They define the connections and pathways between specific brain regions.

What does the term 'neuronal connectivity' encompass?

The patterns and pathways by which neurons communicate with one another.

What does a dark area on an electron micrograph indicate?

High electron density in tissue.

What does the presence of myelinated axons indicate in imaging?

Faster conduction velocities in neural pathways.

What aspect of brain structure does magnetic resonance imaging primarily visualize?

The distribution of water across different brain tissues.

What does the term 'neuroanatomical tracing' refer to?

Mapping the connections between different regions of the nervous system.

How can the viral vector technique improve the study of neurotransmitter function?

By enabling specific gene expressions only in relevant neuronal populations.

What factors influence the resolution of imaging techniques?

The technology used and the properties of the tissues being imaged.

What discovery helped clarify the excitatory nature of a synapse?

The visual evidence of receptor proteins in the postsynaptic density.

What role do interneurons play in neural circuits?

They modulate and integrate signals between other neurons.

What does 'cell-type specific transgene' imply in genetic studies?

The transgene is expressed only in a certain cell type and not others.

Why is it important to use conditional mutant mice in research?

To study the effects of genes in specific tissues or developmental stages.

What defines the seminal work of Cajal in neural studies?

His detailed drawings and classification of neural components, including various spine types.

What role do viral vectors serve in experimental neuroscience?

To introduce genetic material into specific cells rapidly for experimental analysis.

What is the significant function of the Nucleus Accumbens (NAc)?

Involved in reward learning and motivated behaviors.

In tracing techniques, what does it mean for a tracer to be retrogradely transported?

The tracer moves from an axon terminal back to the cell body.

What cellular structures are crucial for supporting the movement of motor proteins?

Microtubules.

What distinguishes Type II synapses from Type I synapses?

Type II synapses have a similar width in pre- and postsynaptic densities.

What technique is frequently used to label neuronal projections?

Tract tracing with fluorescent markers.

How is neuronal circuitry often represented in studies?

Through detailed anatomical maps showing input and output connections.

What information can be gleaned from colored staining in electron micrographs?

Anatomical organization and structural specialization of neurons.

What research advancement resulted from the study of cholinergic neurons?

Understanding the specific functions and connections they form within neural circuits.

What challenge do researchers face when applying AAVs for gene delivery?

The size limitation of the genetic material that can be packaged into AAVs.

How can gene expression be visually confirmed in transgenic studies?

Using fluorescence microscopy to detect fluorescent markers on specific cells.

What major microscopy technique allows for real-time imaging of live neurons?

Fluorescence microscopy with genetically encoded indicators.

What does neuroplasticity refer to in neuroscience?

The brain's ability to reorganize itself by forming new neural connections.

What role do sensory neurons play in the nervous system?

They transmit sensory information from the body to the central nervous system.

What do micrographs reveal about synaptic vesicle distribution?

The presence and location of vesicles in presynaptic terminals.

Why is monitoring cell type-specific expression important in neuroscience?

It enables targeted interventions and studies of neuronal function.

What is the challenge of using conventional tracers in brain mapping?

Identifying complete neuronal pathways without missing connections.

What distinguishes specific neuronal populations in molecular terms?

The unique neurotransmitters they produce and receptors they express.

What aspects of nervous system function are affected by neurodegenerative diseases?

Cellular structure, synaptic integrity, and signal transmission.

How do experiences influence the morphology of dendritic spines?

They can induce structural changes that contribute to learning and memory.

What is the advantage of using genetically modified animals in behavioral studies?

To connect genetic factors with behavioral outcomes effectively.

What does the concept of neural circuit dynamics encompass?

The changes in signaling and connectivity in response to activity and experience.

What can variations in neuron morphology indicate?

Potential alterations in function and synaptic connectivity.

What type of cellular diversity exists within specific brain regions?

Neurons that differ in neurotransmitter type, morphology, and connectivity.