Any studies looking for a quantum bump in human photoreceptors?

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Looking for material related to Quantum Bumps as it relates to humans.
Has there been a study looking for a quantum bump in human photoreceptors. I've done some searching and haven't crossed anything as of yet.
 

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berkeman
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Summary:: Looking for material related to Quantum Bumps as it relates to humans.

Has there been a study looking for a quantum bump in human photoreceptors. I've done some searching and haven't crossed anything as of yet.
Welcome to PhysicsForums. :smile:

What is a "quantum bump" in this context?
 
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jim mcnamara
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Photoreceptors of Drosophila compound eye employ a G protein-mediated signaling pathway that transduces single photons into transient electrical responses called “quantum bumps”
https://www.pnas.org/content/105/30/10354

And no, I do not see anything with quick search in terms of human vision. What prompted this question?
 
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BillTre
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This looks like it probably is addressing "quantal release" of neurotransmitter at synapses to me.
Many neurotransmitters are packaged in small vesicles in a pre-synaptic ending ready to be released when a Ca++ enters the pre-synaptic ending, which is evoked by action potentials or other membrane potential changes.
The neurotransmitter diffuses across the synaptic cleft (between the pre-synaptic cell and the post-synaptic cell) where the neuurotransmitter interacts with membrane receptors. Many kinds of receptors than open channels for ions to enter the cell for a short period of time, causing a small short lived change in the post-synaptic cell's membrane potential. these events are often called miniature end plate potentials, but I could understand someone calling them quantal bumps.
The quantal part refers to it being the smallest amount of transmitter released and smallest membrane response to a synaptic activity. Has nothing to do with quantum physics however.
 
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atyy
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https://www.pnas.org/content/105/30/10354

And no, I do not see anything with quick search in terms of human vision. What prompted this question?

I had not heard of the term "quantum bump" before, but given that the paper is about the transduction of "single photons", corresponding papers about human photoreceptors follow below. The term "single photon" means different things in both papers, with the review by Pugh (2018) using to the term to refer to work such as that by Hecht (1942), and stricter criteria used to define the term in the paper by Tinsley et al (2016).
Pugh (2018): The discovery of the ability of rod photoreceptors to signal single photons
Tinsley et al (2016): Direct detection of a single photon by humans
 
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jim mcnamara
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That answers the original question. Good google foo, @atyy
 
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It's a transient electrical response, in this case triggered by a single photon into a photo receptor, which passes through a cellular membrane. The only studies I've found are using Drosophilla.
 
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This looks like it probably is addressing "quantal release" of neurotransmitter at synapses to me.
Many neurotransmitters are packaged in small vesicles in a pre-synaptic ending ready to be released when a Ca++ enters the pre-synaptic ending, which is evoked by action potentials or other membrane potential changes.
The neurotransmitter diffuses across the synaptic cleft (between the pre-synaptic cell and the post-synaptic cell) where the neuurotransmitter interacts with membrane receptors. Many kinds of receptors than open channels for ions to enter the cell for a short period of time, causing a small short lived change in the post-synaptic cell's membrane potential. these events are often called miniature end plate potentials, but I could understand someone calling them quantal bumps.
The quantal part refers to it being the smallest amount of transmitter released and smallest membrane response to a synaptic activity. Has nothing to do with quantum physics however.



I thought the name was a bit quirky too but I am trying to look at it with an eye toward information theory and considering this as a good place to get a strong number for bits into a system. Might not be what I end with but I gotta exhaust it first.
 
  • #11
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I had not heard of the term "quantum bump" before, but given that the paper is about the transduction of "single photons", corresponding papers about human photoreceptors follow below. The term "single photon" means different things in both papers, with the review by Pugh (2018) using to the term to refer to work such as that by Hecht (1942), and stricter criteria used to define the term in the paper by Tinsley et al (2016).
Pugh (2018): The discovery of the ability of rod photoreceptors to signal single photons
Tinsley et al (2016): Direct detection of a single photon by humans

Most excellent! Many thanks!
 

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