methods of research in cellular neuroscience lecture 4
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methods of research in cellular neuroscience lecture 4

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Questions and Answers

What is the giant squid axon?

  • A part of the giant squid's nervous system that is used in research (correct)
  • A specialized type of muscle fiber in squids
  • An underwater creature native to the Pacific Ocean
  • A cell type found only in cephalopods
  • What is the voltage clamp technique used for?

  • To measure ion channel conductance (correct)
  • To directly manipulate ion concentrations
  • To record action potentials in living tissues
  • To isolate muscle contractions
  • What are we recording in a voltage clamp experiment?

  • The membrane potential of a cell
  • The ionic currents flowing through the membrane (correct)
  • The action potentials generated by the cell
  • The extracellular fluid composition
  • What is the capacitive current in neuroscience in the voltage clamp technique?

    <p>The current that charges the membrane capacitance</p> Signup and view all the answers

    What is the main difference between current and voltage?

    <p>Current is the flow of electric charge, while voltage is the potential difference that drives current.</p> Signup and view all the answers

    What is a current clamp?

    <p>Not changing the current but just recording the voltage</p> Signup and view all the answers

    What is a patch clamp?

    <p>A technique used to study single ion channels in isolated living cells</p> Signup and view all the answers

    What is optogenetics?

    <p>A technique that uses light to control neurons.</p> Signup and view all the answers

    How can neurons be controlled by genetically modifying them in optogenetics?

    <p>By inserting light-sensitive proteins into the neurons</p> Signup and view all the answers

    Which light-sensitive ion channels are commonly expressed in optogenetics?

    <p>Excitatory- Channelrhodopsins</p> Signup and view all the answers

    What do inhibitory light-sensitive ions do in optogenetics?

    <p>Pump a single ion across the membrane for every photon it absorbs</p> Signup and view all the answers

    What color light does channelrhodopsin absorb?

    <p>Blue</p> Signup and view all the answers

    What color light do inhibitory pumps in optogenetics absorb?

    <p>Yellow</p> Signup and view all the answers

    What is the purpose of optogenetics?

    <p>To control neurons using light</p> Signup and view all the answers

    What are DREADDs?

    <p>Designer Receptors Exclusively Activated by Designer Drugs</p> Signup and view all the answers

    What are examples of DREADDs?

    <p>Human muscarinic M3 DREADD</p> Signup and view all the answers

    What does the human M3 muscarinic DREADD do?

    <p>Activates neuronal activity</p> Signup and view all the answers

    What do human M4 muscarinic DREADDs do?

    <p>Inhibit neuronal activity in specific brain regions</p> Signup and view all the answers

    What is a brainbow?

    <p>A technique used to fluorescently label neurons using multiple colors</p> Signup and view all the answers

    What is calcium imaging used for?

    <p>Monitoring neuronal activity as when a neuron fires an AP there is a flood of Ca2+</p> Signup and view all the answers

    What are the functions of calcium in the body? (Select all that apply)

    <p>Cell division and death</p> Signup and view all the answers

    What is two-photon microscopy?

    <p>A technique that utilizes two photons to excite fluorophores for imaging.</p> Signup and view all the answers

    What does two-photon microscopy allow the imaging of?

    <p>Deep living tissue</p> Signup and view all the answers

    Which technique is used to fix the voltage at different levels?

    <p>Voltage clamp</p> Signup and view all the answers

    The Hodgkin and Huxley papers won a Nobel Prize in 1963.

    <p>True</p> Signup and view all the answers

    What type of conductance is referred to as 'active' or 'non-linear'?

    <p>Voltage-dependent conductance</p> Signup and view all the answers

    ___ is the technique that allows for imaging deep into living tissue.

    <p>2-photon microscopy</p> Signup and view all the answers

    What does the current clamp technique analyze?

    <p>Firing patterns of neurons</p> Signup and view all the answers

    What is DREADD an acronym for?

    <p>Designer Receptor Exclusively Activated by Designer Drugs</p> Signup and view all the answers

    Match the following optogenetic tools with their functions:

    <p>Channelrhodopsin ChR = Excitatory, non-specific cation channel Halorhodopsin NpHR = Inhibitory, electrogenic Cl- pump Archaerhodopsin Arch = Inhibitory, electrogenic H+ pump</p> Signup and view all the answers

    Which ion is commonly discussed in relation to multiple neuronal functions?

    <p>Ca2+</p> Signup and view all the answers

    Study Notes

    Methods of Research in Cellular Neuroscience

    • Key figures: Hodgkin & Huxley, awarded the Nobel Prize in 1963 for work on voltage clamp techniques revealing voltage-dependent currents.
    • The voltage clamp technique enables the analysis of how voltage influences membrane conductance by fixing the voltage at set levels.
    • Two main electrophysiology techniques:
      • Voltage clamp: Identifies voltage-dependent conductances, also termed "active" or "non-linear" conductance.
      • Current clamp: Simulates normal neuronal behavior for analyzing firing patterns.
    • Patch clamping, pioneered by Sakmann and Neher, allows the study of single ion channels by measuring currents in response to voltage changes.
    • Barbiturates and benzodiazepines modulate GABA receptor functions differently but enhance GABA's effect.

    Electrophysiological Techniques

    • Extracellular recordings: Used to measure electrical activity in neuronal networks, reflecting combined activity from multiple cells.
    • Research shows how extracellular fields and currents relate to EEG, ECoG, and local field potentials (LFPs).
    • Advances in calcium (Ca²+) imaging allow for real-time visualization of neuronal activity at single-cell resolution.

    Imaging Techniques

    • Two-photon microscopy: Facilitates deep tissue imaging, revealing cellular processes in live organisms.
    • Optogenetics: Allows precise control of neuronal activity using light.
      • Excitatory channelrhodopsins (ChR) promote action potentials in neurons.
      • Inhibitory halorhodopsins (NpHR) and archaerhodopsins (Arch) can suppress neuronal activity by altering ion flow.

    Innovations in Neuroscience

    • Chemogenetics (DREADDs): Designer receptors activated exclusively by designer drugs enable control over specific neuronal populations.
      • Human M3 muscarinic DREADD stimulates neurons (excitatory) while M4 muscarinic DREADD silences neurons (inhibitory).
    • Cell-specific targeting relies on distinct gene expression patterns in various neuron types, allowing for precise manipulation of neuronal activity.

    Summary of Techniques and Considerations

    • Neurons communicate through electrical impulses, a foundational concept in neuroscience.
    • Each experimental technique offers unique advantages, making the selection of methods crucial based on specific research questions.
    • Recent advancements enable non-invasive recording and stimulation, opening new avenues for neuroscience research.
    • Optimal experimental designs consider accessibility, temporal and spatial resolution for targeted neuronal studies.

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    Description

    This quiz explores the structure and function of the giant squid axon, a key topic in neurobiology. Discover its significance in scientific research and its role in understanding neural conductivity. Test your knowledge about its unique features and contributions to neuroscience.

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