Episode 146: Gaurav Venkataraman discusses memory in DNA and RNA

03/30/23 • 39 min

In this episode, Matt sits down with Gaurav Vankataraman (Trisk Bio) to talk about how human memory is physically realized.

Where do your memories live? In the brain, right? They’re, like, imprinted there somehow? We often think of memories as analogous with recordings, like when you do an audio recording and the air vibrations get translated into an electrical signal which reorients the magnetic particles on some tape. But is that really how it works? Is the brain some tape waiting to get recorded to, or a hard drive waiting to get data written to it? We don’t exactly have definitive answers to those questions, but in this episode, our distinguished guest discusses a line of research into whether memories could be stored outside the brain, in RNA. He then notes that there is also a lot of RNA in the human brain itself, which means that a similar mechanism for storing memories could exist there as well.

This research, as it turns out, originated in some rather astonishing scientific work from the 1950s involving planarian flatworms. Planarian flatworms have the extraordinary ability to regenerate: if you cut one in half, each of the two halves can actually grow back into a new worm. At that time, there was some preliminary evidence to suggest that if a planarian flatworm learned something, and you cut it in half, when the half that didn’t have a brain grew back, it still retained what the original worm had learned. What the what? It could remember something even though it had a brand new brain? Those initial studies went through a period of being discredited, but in recent years a number of researchers have been exploring new, more rigorous evidence that something of this nature could be going on. Perhaps the flatworms could actually be storing some of their memories in their RNA or DNA, and perhaps RNA has the ability to preserve some of that information both in and outside of the brain.

In this episode, Gaurav Venkataraman argues that the RNA in the brain not responsible for making proteins (called non-coding RNA) has a specific type of mathematical structure that is particularly well-suited for transmitting information both fast and accurately. Not only that, but entities with that kind of structure transmit information more accurately the faster they transmit it. So the fact that RNA in the brain is structurally arranged in the way it is actually makes it a viable candidate for being sort of like the brain’s “software” for storing and manipulating memories.

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In this episode, Matt sits down with Gaurav Vankataraman (Trisk Bio) to talk about how human memory is physically realized.

Hosted on Acast. See acast.com/privacy for more information.

Previous Episode

Episode 145: Andrew Sepielli discusses quietism and metaethics

This episode, Matt and Joseph sit down with Andrew Sepielli (University of Toronto) to talk about metaethical quietism. His new book on the topic, Pragmatist Quietism, is out now from Oxford University Press. Click here to listen to episode 145 of Elucidations.

Metaethical quietism is the view that ethical statements—or anyway, a large portion of the ethical statements we’re usually interested in—can’t be justified or disproved by statements from outside of ethics. There’s something autonomous about the topic of ethics (or rather, about a lot of ethics). Consider the question: in the scenario where a trolley is barreling down the track, on its way to clobber five people, and you have the ability to divert it to the other track where it will only clobber one, should you do so? According to quietists such as our guest, you can’t answer this question by asking metaphysicians or logicians for help. It won’t do to investigate whether moral facts are part of the furniture of the universe, or to study the grammar of words like ought. The only way you can answer a question like that is, well, whatever we usually do to answer ethical questions.

Why are philosophers often tempted to think we can turn to metaphysics, logic, or the philosophy of language to help answer ethical questions? Andrew Sepielli thinks it’s because we conflate two different kinds of ethical statements: the statements he calls deep and the statements he calls superficial. A deep statement is one such that, if you believe it, that belief can impact your mental picture of how things are laid out in the world and guide your action. The fancy word for this mental picture of how the world is laid out is non-conceptual representation. A superficial statement is one belief in which does not influence your non-conpceptual representation of the world. The questions that moral philosophers often write about—such as whether one should divert the trolley, or whether utilitarianism is true—are superficial, which is part of why you can only answer them from within ethics. But there are also deep moral questions, such as: will the party we’re thinking of going to be attended by a bunch of jackasses? When you ask that question, you’re deploying moral language—jackass, specifically, so it is definitely a moral question—but you’re also trying to find out which individuals are going to be at the party. And which individuals happen to be at the party is part of the information in your non-conceptual mental map.

In this episode, Sepielli argues that keeping track of when we’re having a superficial debate vs. when we’re having a deep debate can make it seem less mysterious how ethics could be its own autonomous area of inquiry. Tune in to see why he thinks this is the case!

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Next Episode

Episode 147: Gabriella Gonzalez discusses the intersection of algebra and programming

In this episode, Matt talks to Gabriella Gonzalez about how basic concepts from the branch of math known as abstract algebra can help us simplify our

computer programs and organize our thoughts.

Algebra. That thing they make us do in school. What was that again? Oh yeah, that’s right; it’s where you get to manipulate equations containing variables. Like, if I have an equation that looks like this:

2⋅x = 16

Then I can divide both sides by two and get a new version where x stands alone, i.e. solve for x:

(2⋅x) / 2 = 16 / 2

x = 8

If you took algebra in school, you might remember learning a bunch of tricks for pushing parts of equations around to get one of the variables to appear only on one side and thus solve for it. Being able to solve for variables in equations proves useful for lots of things: like, if you can translate a word problem into one of those equations, finding the answer is often as simple as tinkering with the equation in some obvious way.

Abstract algebra is somewhat similar in that it also involves manipulating equations containing variables, except the twist is that now you aren’t necessarily manipulating numbers anymore. The variables can stand for something else, and there are more general versions of plus-like, times-like, etc. operations that you can do on these other things. You might be wondering: what on earth could a variable in an equation stand for other than a number? Well, in this episode, Gabriella Gonzalez gives a bunch of examples. You can have equations for cooking recipes, for computer programs, for transactions performed on databases, and for regular expressions. (A regular expression is a special type of computer program for identifying strings that fit a particular pattern and pulling information out of them.)

Gonzalez then goes on to argue that the point of all this is to avoid re-inventing the wheel. Often, when you write a computer program to add some numbers, though this isn’t necessariy obvious at the time of writing, you aren’t actually drawing meaningfully on the fact that they’re numbers. If that’s the case, then what you can often do is make your code that adds things abstract so you only have to write your program once, but then you can re-use it on all these different other kinds of entities other than numbers.

The overall payoff of all that, according to this month’s distinguished guest, is that by following algebra-driven design, you can keep your code simple and easy to understand, while still having it do fancy things. This is particularly important today, when our software just seems to keep getting fancier and fancier, but the usual ways of accomplishing that goal make it unreliable and well nigh impossible to keep up to date.

Join us as Gabriella Gonzalez gives us the tour through various algebraic systems that occur all over the place in computer science, philosophy, and linguistics!

Matt Teichman

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