Deepa Rajan
@deeparajan.bsky.social
MD/PhD candidate at UCSF researching the intelligence of single cells
research summary: https://www.youtube.com/watch?v=Noq8wtqZKWY
research summary: https://www.youtube.com/watch?v=Noq8wtqZKWY
I'm leading a program at the Exploratorium @exploratorium.bsky.social this weekend! Come check out "Mini Microbe Missions", an opportunity for kids (and adults) to do citizen science using the single cell Stentor coeruleus, supported by our Stentor in Every School initiative t.co/VX8r9BHxsJ
April 11, 2025 at 11:49 PM
I'm leading a program at the Exploratorium @exploratorium.bsky.social this weekend! Come check out "Mini Microbe Missions", an opportunity for kids (and adults) to do citizen science using the single cell Stentor coeruleus, supported by our Stentor in Every School initiative t.co/VX8r9BHxsJ
channeled my inner Joan Baez at the Stand Up for Science protest today
March 8, 2025 at 12:23 AM
channeled my inner Joan Baez at the Stand Up for Science protest today
I brought live Stentor cells with me on the train and have regaled a few fellow passengers with tales of this mysterious giant cell that can learn #scicomm
January 13, 2025 at 12:54 AM
I brought live Stentor cells with me on the train and have regaled a few fellow passengers with tales of this mysterious giant cell that can learn #scicomm
after a week in Chicago for the Biological Systems that Learn workshop @nitmb.bsky.social, I've been traveling back to SF via train over ~55 hours. Today is Day 3 on Amtrak for me and I've never experienced more scenic backdrops for working on a manuscript
January 13, 2025 at 12:54 AM
after a week in Chicago for the Biological Systems that Learn workshop @nitmb.bsky.social, I've been traveling back to SF via train over ~55 hours. Today is Day 3 on Amtrak for me and I've never experienced more scenic backdrops for working on a manuscript
I also brought some live Stentor with me on the plane along with a portable microscope if you want to see them up close! Stentor plushie made by lab mate Connie Yan
December 17, 2024 at 6:15 PM
I also brought some live Stentor with me on the plane along with a portable microscope if you want to see them up close! Stentor plushie made by lab mate Connie Yan
but for actual mating/conjugation, it's been reported that micronuclei do get exchanged (after the macronucleus breaks up)!
And thank you for reading our paper!! I have tried training Stentor while they're mating and indeed they do learn in sync! here's my favorite Stentor mating video:
And thank you for reading our paper!! I have tried training Stentor while they're mating and indeed they do learn in sync! here's my favorite Stentor mating video:
December 10, 2024 at 1:15 AM
but for actual mating/conjugation, it's been reported that micronuclei do get exchanged (after the macronucleus breaks up)!
And thank you for reading our paper!! I have tried training Stentor while they're mating and indeed they do learn in sync! here's my favorite Stentor mating video:
And thank you for reading our paper!! I have tried training Stentor while they're mating and indeed they do learn in sync! here's my favorite Stentor mating video:
found 2 stentor cells fused together!
December 8, 2024 at 4:41 AM
found 2 stentor cells fused together!
While we’ve uncovered some important features of cell learning, so many mysteries persist! A burning question: which molecules drive cell learning? Stay tuned for our next paper! By researching how a single cell learns, we can begin to unravel the origins of intelligence 13/n
November 25, 2024 at 5:46 AM
While we’ve uncovered some important features of cell learning, so many mysteries persist! A burning question: which molecules drive cell learning? Stay tuned for our next paper! By researching how a single cell learns, we can begin to unravel the origins of intelligence 13/n
Rate-sensitivity: in other organisms, habituation to high-frequency stimuli leads to faster forgetting. Interestingly, our experiments/model don’t show evidence of this in Stentor cells – perhaps there’s something unique about cell learning 12/n
November 25, 2024 at 5:46 AM
Rate-sensitivity: in other organisms, habituation to high-frequency stimuli leads to faster forgetting. Interestingly, our experiments/model don’t show evidence of this in Stentor cells – perhaps there’s something unique about cell learning 12/n
Potentiation: if you’ve ever studied for an exam, you’ll know that spaced repetition, or repeated bouts of studying with breaks in between, beats cramming any day. Our experiments/model show that Stentor cells are the same – they learn faster with each bout of training 11/n
November 25, 2024 at 5:46 AM
Potentiation: if you’ve ever studied for an exam, you’ll know that spaced repetition, or repeated bouts of studying with breaks in between, beats cramming any day. Our experiments/model show that Stentor cells are the same – they learn faster with each bout of training 11/n
Over-training: any musician/dancer/etc knows that even when you have a routine 100% down, extra practice means you’ll remember it longer. Likewise, we show that Stentor memory improves when cells undergo extra training even after reaching 100% habituation (0% contraction) 10/n
November 25, 2024 at 5:46 AM
Over-training: any musician/dancer/etc knows that even when you have a routine 100% down, extra practice means you’ll remember it longer. Likewise, we show that Stentor memory improves when cells undergo extra training even after reaching 100% habituation (0% contraction) 10/n
“Train hard, fight easy”: our experiments/model show that training with strong stimuli improves memory retention (i.e. lower contraction fraction) when the cells are subsequently exposed to weak stimuli 9/n
November 25, 2024 at 5:46 AM
“Train hard, fight easy”: our experiments/model show that training with strong stimuli improves memory retention (i.e. lower contraction fraction) when the cells are subsequently exposed to weak stimuli 9/n
Dishabituation: if you habituate to the sound of a ticking clock, but then hear a loud alarm, you will likely start paying attention to the ticking again. But our experiments/model show that Stentor cells, unlike us, actually exhibit better habituation after strong stimuli 8/n
November 25, 2024 at 5:46 AM
Dishabituation: if you habituate to the sound of a ticking clock, but then hear a loud alarm, you will likely start paying attention to the ticking again. But our experiments/model show that Stentor cells, unlike us, actually exhibit better habituation after strong stimuli 8/n
Habituation depends on the frequency and intensity of stimuli, and our model recapitulates this. It also accounts for the step-like habituation response of individual cells. We investigated these phenomena in our previous paper: bit.ly/40VCuug 7/n
November 25, 2024 at 5:46 AM
Habituation depends on the frequency and intensity of stimuli, and our model recapitulates this. It also accounts for the step-like habituation response of individual cells. We investigated these phenomena in our previous paper: bit.ly/40VCuug 7/n
Our receptor-inactivation model can account for this habituation + subsequent forgetting: mechanoreceptor senses the stimulus ➡️ channel opening changes membrane potential ➡️ action potential drives contraction ➡️ internalization of activated receptors 6/n
November 25, 2024 at 5:46 AM
Our receptor-inactivation model can account for this habituation + subsequent forgetting: mechanoreceptor senses the stimulus ➡️ channel opening changes membrane potential ➡️ action potential drives contraction ➡️ internalization of activated receptors 6/n
When Stentor receive repeated weak mechanical stimulation, however, they habituate and thus stop contracting and remain in their elongated state. Below is a video of Stentor that have become habituated after an hour of repeated stimulation. 5/n
November 25, 2024 at 5:46 AM
When Stentor receive repeated weak mechanical stimulation, however, they habituate and thus stop contracting and remain in their elongated state. Below is a video of Stentor that have become habituated after an hour of repeated stimulation. 5/n
When Stentor experience a mechanical stimulus, they contract into a ball-like shape – presumably to escape from predators lurking in the pond. 4/n
November 25, 2024 at 5:46 AM
When Stentor experience a mechanical stimulus, they contract into a ball-like shape – presumably to escape from predators lurking in the pond. 4/n
Habituation is the gradual decrease in response after repeated stimulation. Humans do this, too! For example, we learn to ignore the feeling of clothes on our skin after wearing them all day. However, we have 86 billion neurons to help us learn while Stentor is a single cell! 3/n
November 25, 2024 at 5:46 AM
Habituation is the gradual decrease in response after repeated stimulation. Humans do this, too! For example, we learn to ignore the feeling of clothes on our skin after wearing them all day. However, we have 86 billion neurons to help us learn while Stentor is a single cell! 3/n
If you scoop up some water from a local pond and stick it under a microscope, you might just encounter Stentor coeruleus, a unicellular organism that is capable of a type of learning called habituation. 2/n
November 25, 2024 at 5:46 AM
If you scoop up some water from a local pond and stick it under a microscope, you might just encounter Stentor coeruleus, a unicellular organism that is capable of a type of learning called habituation. 2/n
How can a single cell learn without a brain or nervous system? We explore this in our new preprint with
@wallaceucsf.bsky.social! We discovered that central features of learning in single cells can be accounted for by a model based on receptor inactivation bit.ly/3CDukfS 🧵 1/n
@wallaceucsf.bsky.social! We discovered that central features of learning in single cells can be accounted for by a model based on receptor inactivation bit.ly/3CDukfS 🧵 1/n
November 25, 2024 at 5:46 AM
How can a single cell learn without a brain or nervous system? We explore this in our new preprint with
@wallaceucsf.bsky.social! We discovered that central features of learning in single cells can be accounted for by a model based on receptor inactivation bit.ly/3CDukfS 🧵 1/n
@wallaceucsf.bsky.social! We discovered that central features of learning in single cells can be accounted for by a model based on receptor inactivation bit.ly/3CDukfS 🧵 1/n