Optogenetic Inactivation
Optogenetic Inactivation - Related Videos
01:58
X-Inactivation
0 Views •
2019
The human X chromosome contains over ten times the number of genes as in the Y chromosome. Since males have only one X chromosome, and females have two, one might expect females to produce twice as many of the proteins, with undesirable results. Instead, in order to avoid this potential issue, female mammalian cells inactivate nearly all the genes in one of their X chromosomes during early embryonic development. In the nuclear envelope surrounding the cell nucleus, the inactivated X chromosome...
01:58
X-inactivation
0 Views •
2021
The human X chromosome contains over ten times the number of genes as in the Y chromosome. Since males have only one X chromosome, and females have two, one might expect females to produce twice as many of the proteins, with undesirable results. Instead, in order to avoid this potential issue, female mammalian cells inactivate nearly all the genes in one of their X chromosomes during early embryonic development. In the nuclear envelope surrounding the cell nucleus, the inactivated X chromosome...
06:06
Optogenetic Functional MRI
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Cited by 15 •
2016
This protocol describes the steps and data analysis required to successfully perform optogenetic functional magnetic resonance imaging (ofMRI). ofMRI is a novel technique that combines high-field fMRI readout with optogenetic stimulation, allowing for cell type-specific mapping of functional neural circuits and their dynamics across the whole living brain.
01:22
Activation and Inactivation of G Proteins
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2023
Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high affinity and are together...
02:30
Optogenetic Control of Hippocampal Network Dynamics
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2025
This video demonstrates the method to use optogenetics to modulate hippocampal network dynamics by activating genetically modified light-sensitive interneurons in a mouse brain slice, enhancing theta oscillation synchronization and studying neural circuit behavior.
FAQs
When activated by light, inhibitory opsins alter ion movement across the neuronal membrane. This shifts the membrane toward a hyperpolarized state, making the cell less likely to generate action potentials. The resulting reduction in firing allows investigators to examine what changes when activity in a selected neural population is temporarily suppressed rather than left active.
Reversible suppression lets researchers compare neural function during inactivation with the same circuit operating without illumination. This within-experiment contrast supports stronger causal reasoning because behavioral or physiological changes can be linked to the temporary reduction in activity. It also helps distinguish a circuit's immediate contribution from effects that might follow permanent cellular disruption.
Halorhodopsin and archaerhodopsin serve as inhibitory opsins that can be expressed in selected neurons and activated with light. Their function in the experiment is to alter membrane ion movement and reduce action-potential firing. Choosing an inhibitory opsin provides the molecular means to suppress activity in the genetically targeted population during circuit investigations.
Genetic targeting restricts expression of the inhibitory opsin to the neuronal population selected for study. Light then acts on cells carrying that light-sensitive protein, while the optical fiber provides the localized delivery route. Together, these components connect cellular identity with experimental control, allowing investigators to test the contribution of defined neurons rather than treating the entire brain region as equivalent.
The workflow begins by expressing an inhibitory opsin in genetically selected neurons. Researchers then deliver light to those cells through an optical fiber, activating the opsin and reducing neuronal firing. They can compare neural or behavioral outcomes with and without this temporary suppression. This sequence links targeted molecular preparation, optical control, and functional measurement.
By suppressing defined neurons during an experiment, researchers can test their contribution to movement, sensation, learning, and decision-making. The same strategy supports studies of circuit organization and neurological disease. Observed changes in behavior or brain function indicate how the silenced population participates in the process being examined, helping establish circuit-level causal relationships.