Source 1review2016Methods in molecular biology
Toolkit/Chronos
Chronos
Taxonomy: Mechanism Branch / Component. Workflows sit above the mechanism and technique branches rather than replacing them.
Summary
Chronos is a channelrhodopsin construct used for optical excitation of neurons. In the cited 2014 Nature Methods work, it is presented with Chrimson as a complementary optogenetic pair for two-color activation of distinct neural populations, enabling independent spiking and downstream synaptic transmission in mouse brain slice without detectable cross-talk.
Usefulness & Problems
Why this is useful
Chronos is useful as an optogenetic actuator for driving neuronal spiking with light and, in combination with Chrimson, for separating control of two neural populations by color. The cited work also describes Chronos as having faster kinetics than previous channelrhodopsins while remaining effectively more light sensitive.
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Chronos is a channelrhodopsin described for optical excitation of neurons. In the abstract it is highlighted as having faster kinetics than previous channelrhodopsins while remaining effectively more light sensitive.
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optical activation of neural populations
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two-color activation experiments
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situations requiring fast channelrhodopsin kinetics
Problem solved
This tool helps address the need for optical excitation of neurons with improved temporal performance relative to prior channelrhodopsins. In paired use with Chrimson, it helps solve the specific problem of independently activating distinct neural populations without detectable cross-talk in mouse brain slice.
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It helps address the need for independent activation of distinct neural populations. Its fast kinetics and light sensitivity are presented as advantages over previous channelrhodopsins.
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provides a channelrhodopsin with faster kinetics than previous channelrhodopsins
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supports independent optical control when paired with Chrimson
Published Workflows
Objective: Discover and characterize channelrhodopsins that enable independent optical excitation of distinct neural populations.
Why it works: The abstract states that opsins from over 100 algal species were sequenced and physiologically characterized, yielding Chronos and Chrimson with complementary properties for two-color excitation.
red-shifted optical excitationfast channelrhodopsin gating kineticsindependent activation of distinct neural populationssequencingphysiological characterization
Stages
- 1.Opsin sequencing across algal diversity(library_design)
This stage expands the search space for discovering channelrhodopsins with useful spectral and kinetic properties.
Selection: Survey opsins from over 100 species of alga to identify candidate channelrhodopsins.
- 2.Physiological characterization of opsin candidates(functional_characterization)
This stage identifies candidates with complementary functional properties needed for independent optical control.
Selection: Identify channelrhodopsins with red-shifted excitation, fast kinetics, and effective light sensitivity.
- 3.Application testing in behavioral and slice preparations(confirmatory_validation)
This stage tests whether the candidate opsins retain their desired properties in relevant biological applications.
Selection: Confirm that selected reagents reduce behavioral interference and permit independent two-color activation without detectable cross-talk.
Taxonomy & Function
Primary hierarchy
Mechanism Branch
Component: A low-level protein part used inside a larger architecture that realizes a mechanism.
Techniques
Selection / EnrichmentTarget processes
selectionInput: Light
Implementation Constraints
Use requires expression of the opsin in neural populations and optical stimulation hardware. Two-color experiments additionally require pairing Chronos with Chrimson in a separate population; the provided evidence does not specify promoter choice, trafficking elements, or cofactor supplementation.
The supplied evidence does not define Chronos spectral properties, photocurrent magnitude, or construct architecture in detail. The cross-talk-free dual-population result is supported for the Chronos-Chrimson pair in mouse brain slice, but the provided evidence does not establish that Chronos alone solves population separation or broadly validates in vivo performance limits.
Validation
Cell-freeBacteriaMammalianMouseHumanTherapeuticIndep. Replication
Supporting Sources
Source 2review2025MED
Source 3primary paper2014Nature Methods
Source 4review2020EMBO Molecular Medicine
Ranked Claims
A key milestone described by the review is partial vision restoration in a human patient using ChrimsonR with light-amplifying goggles.
Red-shifted opsins including ReaChR and ChrimsonR reduce phototoxicity by enabling activation under longer wavelengths.
Chronos provides superior temporal kinetics for dynamic visual tracking.
MCO1 optimized opsin performance under ambient light, helping bridge optogenetic vision restoration toward real-world applications.
CatCh, Chronos, and Chrimson-family opsins are presented in the supplied summary as relevant component classes for spiral ganglion neuron and optical cochlear implant performance.
High-signal enrichment leads found around this anchor cluster into ... opsin-engineering papers explicitly tied to SGN/oCI performance, especially CatCh, Chronos, and red-shifted Chrimson-family work.
Implant-oriented LED and μLED cochlear hardware platforms are relevant adjacent tools in the translational path toward optical cochlear implants.
Many engineered channelrhodopsin variants have advantages compared with wild-type variants.
Demand for more application-specific channelrhodopsin variants drove engineering of improved variants.
Channelrhodopsin variants in the review are described by mechanistic and operational properties including expression, kinetics, ion selectivity, and wavelength responsivity.
The review covers new channelrhodopsin variants whose efficacy has been proven in neurophysiological experiments or that are likely to extend the optogenetic toolbox.
Channelrhodopsins have become widely accepted as a tool to control the membrane potential of excitable cells via illumination.
The large number of new channelrhodopsin variants and their perplexing names can alienate users.
Chronos and Chrimson together enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Together these two reagents enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Chronos and Chrimson together enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Together these two reagents enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Chronos and Chrimson together enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Together these two reagents enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Chronos and Chrimson together enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Together these two reagents enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Chronos and Chrimson together enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Together these two reagents enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Chronos and Chrimson together enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Together these two reagents enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Chronos and Chrimson together enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Together these two reagents enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Chronos and Chrimson together enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Together these two reagents enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Chronos and Chrimson together enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Together these two reagents enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Using Chrimson in Drosophila melanogaster neurobehavioral studies showed minimal visual system-mediated behavioral interference.
We show minimal visual system-mediated behavioral interference when using Chrimson in neurobehavioral studies in Drosophila melanogaster.
Using Chrimson in Drosophila melanogaster neurobehavioral studies showed minimal visual system-mediated behavioral interference.
We show minimal visual system-mediated behavioral interference when using Chrimson in neurobehavioral studies in Drosophila melanogaster.
Using Chrimson in Drosophila melanogaster neurobehavioral studies showed minimal visual system-mediated behavioral interference.
We show minimal visual system-mediated behavioral interference when using Chrimson in neurobehavioral studies in Drosophila melanogaster.
Using Chrimson in Drosophila melanogaster neurobehavioral studies showed minimal visual system-mediated behavioral interference.
We show minimal visual system-mediated behavioral interference when using Chrimson in neurobehavioral studies in Drosophila melanogaster.
Using Chrimson in Drosophila melanogaster neurobehavioral studies showed minimal visual system-mediated behavioral interference.
We show minimal visual system-mediated behavioral interference when using Chrimson in neurobehavioral studies in Drosophila melanogaster.
Using Chrimson in Drosophila melanogaster neurobehavioral studies showed minimal visual system-mediated behavioral interference.
We show minimal visual system-mediated behavioral interference when using Chrimson in neurobehavioral studies in Drosophila melanogaster.
Using Chrimson in Drosophila melanogaster neurobehavioral studies showed minimal visual system-mediated behavioral interference.
We show minimal visual system-mediated behavioral interference when using Chrimson in neurobehavioral studies in Drosophila melanogaster.
Using Chrimson in Drosophila melanogaster neurobehavioral studies showed minimal visual system-mediated behavioral interference.
We show minimal visual system-mediated behavioral interference when using Chrimson in neurobehavioral studies in Drosophila melanogaster.
Using Chrimson in Drosophila melanogaster neurobehavioral studies showed minimal visual system-mediated behavioral interference.
We show minimal visual system-mediated behavioral interference when using Chrimson in neurobehavioral studies in Drosophila melanogaster.
Chrimson has an excitation spectrum red shifted by 45 nm relative to previous channelrhodopsins.
Chrimson's excitation spectrum is red shifted by 45 nm relative to previous channelrhodopsins
excitation spectrum red shift relative to previous channelrhodopsins 45 nm
Chrimson has an excitation spectrum red shifted by 45 nm relative to previous channelrhodopsins.
Chrimson's excitation spectrum is red shifted by 45 nm relative to previous channelrhodopsins
excitation spectrum red shift relative to previous channelrhodopsins 45 nm
Chrimson has an excitation spectrum red shifted by 45 nm relative to previous channelrhodopsins.
Chrimson's excitation spectrum is red shifted by 45 nm relative to previous channelrhodopsins
excitation spectrum red shift relative to previous channelrhodopsins 45 nm
Chrimson has an excitation spectrum red shifted by 45 nm relative to previous channelrhodopsins.
Chrimson's excitation spectrum is red shifted by 45 nm relative to previous channelrhodopsins
excitation spectrum red shift relative to previous channelrhodopsins 45 nm
Chrimson has an excitation spectrum red shifted by 45 nm relative to previous channelrhodopsins.
Chrimson's excitation spectrum is red shifted by 45 nm relative to previous channelrhodopsins
excitation spectrum red shift relative to previous channelrhodopsins 45 nm
Chrimson has an excitation spectrum red shifted by 45 nm relative to previous channelrhodopsins.
Chrimson's excitation spectrum is red shifted by 45 nm relative to previous channelrhodopsins
excitation spectrum red shift relative to previous channelrhodopsins 45 nm
Chrimson has an excitation spectrum red shifted by 45 nm relative to previous channelrhodopsins.
Chrimson's excitation spectrum is red shifted by 45 nm relative to previous channelrhodopsins
excitation spectrum red shift relative to previous channelrhodopsins 45 nm
Chrimson has an excitation spectrum red shifted by 45 nm relative to previous channelrhodopsins.
Chrimson's excitation spectrum is red shifted by 45 nm relative to previous channelrhodopsins
excitation spectrum red shift relative to previous channelrhodopsins 45 nm
Chrimson has an excitation spectrum red shifted by 45 nm relative to previous channelrhodopsins.
Chrimson's excitation spectrum is red shifted by 45 nm relative to previous channelrhodopsins
excitation spectrum red shift relative to previous channelrhodopsins 45 nm
Chronos has faster kinetics than previous channelrhodopsins and is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins yet is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins and is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins yet is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins and is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins yet is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins and is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins yet is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins and is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins yet is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins and is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins yet is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins and is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins yet is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins and is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins yet is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins and is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins yet is effectively more light sensitive.
Approval Evidence
4 sources4 linked approval claimsfirst-pass slug chronos
Chronos introduced superior temporal kinetics for dynamic visual tracking.
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High-signal enrichment leads found around this anchor cluster into ... opsin-engineering papers explicitly tied to SGN/oCI performance, especially CatCh, Chronos, and red-shifted Chrimson-family work.
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Explicitly supported variant/tool name recovered in the supplied web research summary as a directly relevant channelrhodopsin variant discussed in review-era literature.
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Here we describe two channelrhodopsins, Chronos and Chrimson
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performance summarysupports
Chronos provides superior temporal kinetics for dynamic visual tracking.
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component relevancesupports
CatCh, Chronos, and Chrimson-family opsins are presented in the supplied summary as relevant component classes for spiral ganglion neuron and optical cochlear implant performance.
High-signal enrichment leads found around this anchor cluster into ... opsin-engineering papers explicitly tied to SGN/oCI performance, especially CatCh, Chronos, and red-shifted Chrimson-family work.
Source:
application capabilitysupports
Chronos and Chrimson together enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
Together these two reagents enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.
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tool propertysupports
Chronos has faster kinetics than previous channelrhodopsins and is effectively more light sensitive.
Chronos has faster kinetics than previous channelrhodopsins yet is effectively more light sensitive.
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Comparisons
Source-backed strengths
The cited study reports that Chronos and Chrimson together support two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice. The extraction notes also state that Chronos was highlighted as faster than previous channelrhodopsins while remaining effectively more light sensitive.
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faster kinetics than previous channelrhodopsins
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effectively more light sensitive
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enables two-color activation with Chrimson without detectable cross-talk in mouse brain slice
Ranked Citations
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