Neuroscience Research Methods and Neuroethics

Practice flashcards covering neuroanatomical techniques, lesion methods, ethical standards in human and animal research, and modern brain imaging and stimulation technologies based on lecture transcript notes.

Who invented the neuroanatomical technique that reveals the structure of individual neurons by staining them in their entirety?

Italian Physician Camilo Golgi

What is the primary function of Nissl staining?

It colors the cell bodies of Neurons within Brain tissues, allowing for the observation of Brain structure and identification of cell types.

What is the purpose of Neuroanatomical Tracing techniques?

They use markers such as dyes to label Neurons and follow their Pathways.

Distinguish between Anterograde and Retrograde tracing.

Anterograde involves labelling Neurons in a particular region starting at the cell body and following axons to their projections, while Retrograde is the opposite, starting at the axons and identifying the source Neuron.

What characterizes a Trans-synaptic Tracing technique?

It is a specialized technique using viruses to study connections between Neurons that are synthetically connected.

Define Histology in the context of Neuroscience.

Involving preparing thin sections of brain tissue, staining them, and examining them under a microscope to observe cellular details like Neurons and glial cells.

What are the three types of microscopy mentioned in the lecture notes?

Brightfield, Fluorescence (using specialized dyes or proteins), and Electron microscopy (atomic-level detail).

What does the technique of Brain slicing involve?

Cutting the Brain into thin sections using specialized equipment to reveal the organization of different Brain regions.

What are the disadvantages of Surgical lesions?

They are highly invasive, carry an infection risk, and cause permanent tissue loss.

How is tissue removed in an Aspiration lesion, and where is it typically used?

Tissue is removed using suction after opening the skull; it is mostly limited to the superficial cortex.

What is the mechanism of an Electrolytic lesion?

It uses an electrical current that destroys nearby tissue by causing heat and cell death, though it is less selective because it destroys both Neurons and fibers of passage.

Which brain regions are targeted using Radiofrequency lesions for Parkinson tremor treatment?

The Globus Pallidus (GP) and Subthalamic Nuclei (SN).

Name five common chemicals used for Chemical lesions.

Kainic acid, NMDA, ibotenic acid, Quinolinic, and $6-OHDA$.

What is the mechanism of a Cryogenic (cryogenic/cooling) lesion?

It involves using liquid Nitrogen or a cryoprobe to freeze tissue, causing ice crystal formation and cell death.

What is a Reversible lesion?

A technique that temporarily blocks activity without tissue damage, achieved through cooling, local anesthetics, or GABA agonists.

How do Neurochemical lesions manipulate specific neurotransmitter (NTM) systems?

By using receptor agonists or antagonists to temporarily suppress or selectively eliminate certain Neuron populations by activating inhibitory or blocking excitatory activity.

What is the purpose of Anterograde and Retrograde Degeneration techniques?

To study the effects of damage to specific Neural Pathways by disrupting connections and observing changes in behavior, function, and connectivity.

What is the role of the Institutional Review Board (IRB)?

To ensure the ethical treatment of human volunteers in research.

What occurred in the case of Havasupai Tribe v/s Arizona Board of Regents (2010)?

The case was settled with the return of biological samples and a payment of $700,000$.

In animal research, what do the '3Rs' represent?

Refinement (minimizing pain), Replacement (finding alternatives to animal testing), and Reduction (reducing the number of animals).

What is the IACUC and who are its typical members?

The Institutional Animal Care and Use Committee; it includes veterinarian scientists, nonscientist members, and community members not affiliated with the institution.

Name three alternative methods to animal testing mentioned in the notes.

In-vitro testing (cell tissues), Computer Modelling (In-silico), and Microfluidic organ-on-a-chip.

What mechanism does a CT (Computerized Tomography) scan use to create images?

It uses an X-ray tube and detector on opposite sides to scan the body from all angles; a computer then translates the data based on varying tissue densities into visual images.

How does MRI (Magnetic Resonance Imaging) differ from CT in terms of technology and safety?

MRI uses strong magnetic fields and Radio Frequency pulses with hydrogen atoms rather than radioactive X-rays, making it safer for repeated use and better for soft tissue evaluation.

What are the four 'axes' used to organize the field of brain scanning techniques?

1. Structural v/s Functional, 2. Spatial v/s Temporal, 3. Invasive v/s Non-Invasive, 4. Cost v/s Practicality.

What is Spatial Resolution versus Temporal Resolution?

Spatial Resolution is the precision regarding the dimension or 'where' activity occurs, while Temporal Resolution is the precision regarding 'when' activity occurs.

What provides the most direct non-invasive window into the online brain, according to the notes?

Electrophysiological methods like EEG and MEG.

Explain Neurovascular Coupling.

The principle that neural activity reliably leads to increased blood flow and Oxygen/Metabolism in the same region, which is the basis for hemodynamic techniques like fMRI and PET.

How does a Positron Emission Tomography (PET) scan work?

A radioactive tracer like fluro-deoxyglucose ($FDG$) is injected; as the isotope decays, it emits a positron ($B^+$) that annihilates with an electron ($B^-$), releasing two Gamma Rays ($\gamma$) in opposite directions detected by the scanner.

What defines the spatial and temporal resolution of PET scans?

It has moderate spatial resolution ($1-4-5\,min$ as per transcript, or $4-6\,mm$) and poor temporal resolution because measurements integrate over time.

What does EEG measure?

The Postsynaptic potentials of many thousands or millions of cells through electrodes attached to the scalp.

What is the function of SQUIDs in Magnetoencephalography (MEG)?

Superconducting Quantum Interference Devices are used to detect minute magnetic fields induced by electrical currents in the brain.

In optogenetics, what is the effect of blue light on Channelrhodopsin ($ChR2$)?

Blue light strikes the $ChR2$ ion channel, causing it to open and permit the flow of sodium ($Na^+$), potassium ($K^+$), and calcium ($Ca^{2+}$) ions, resulting in depolarization (excitation).

In optogenetics, what is the function of Halorhodopsin ($NpHR$) when activated by yellow light?

It moves chloride ($Cl^-$) into the cell, hyperpolarizing the membrane and causing inhibition.

How is light introduced into the brain for optogenetics if neurons are in the cerebral cortex?

Through a small hole drilled into the skull with LEDs attached above the hole.

Distinguish between Autoradiography and Immunohistochemistry for localizing receptors.

Autoradiography uses radioactive ligands to label receptors in brain slices, while Immunohistochemistry uses antibodies labeled with fluorescent dyes.

What is Deep Brain Stimulation (DBS) used for?

To treat neurological disorders like Parkinson's and OCD by implanting electrodes into brain structures to normalize activity.

What is Transcranial Magnetic Stimulation (TMS)?

A non-invasive technique that uses magnetic pulses delivered via a coil on the skull to temporarily disrupt or stimulate brain activity and test causality.