81–88 of 88 posts
Maybe one day we'll have pills to have total recall for a few hours, wouldn't that be cool for exams and learning languages ? I much prefer that than a chip in my head which the silicon valley seems super keen on selling me.
Total recall would be quite bad, every little irrelevant detail would be stored.
Earlier quoted context omitted.
I have a background in both. Both are implemented in physical mediums. The gating and current flow are similarly physical as are magnetic field changes on disk mediums. There is a greater diversity in the brain which uses field effects ala hormones, ion movement, transmitter diffusion, and direct electrical connection. The physical/informational duality is present in both so I would suggest that the building out of t…
> The physical/informational duality is present in both A very important distinction is that a computer has clean separation between physical data representation (magnetic bits) and physical device implementation (transistors & etc). As an analogy to a biological system I'd suggest an FPGA running a self modifying program that's also reconfiguring the FPGA on the fly. No sane engineer would design such a system (I ho…
For ion flow through dendrites and axons, the separation of information transmission from the protein assemblies of neurons is similarly separated.
For neurotransmitters the particles are literally packed into bundles and separated from the ionic transmission that causes their release and cell boundaries at the synapse until re-up take.
For electric transmission, the electricity is definitely separate from the axon and junction.
I think the distinction is a little more in how a single computer's hardware is constrained to a (relatively) small set of finite states outside of outside modification. The brain can expand and contract the set of states that it's physical parts can enter on top of being, for better and worse, less discrete. If our computers could grow their silicon wafers and lay new circuits then we would have something similar.
Please please don't take away from this that there are "memory cells" that "encode memories." The article is so badly written it seems to imply that. Memory is a whole brain phenomenon, and memory formation involves connections being formed and lost constantly between all types of neurons everywhere in the brain. One small aspect of memory (episodic memory) relies more heavily on hippocampal neurons during consolidat…
Surely there must be a better way to conduct this experiment than to terrorize innocent mice.
Why can't they
Earlier quoted context omitted.
> The physical/informational duality is present in both A very important distinction is that a computer has clean separation between physical data representation (magnetic bits) and physical device implementation (transistors & etc). As an analogy to a biological system I'd suggest an FPGA running a self modifying program that's also reconfiguring the FPGA on the fly. No sane engineer would design such a system (I ho…
Self modifying programs have totally been a thing. :D They were hard to reason about so fell by the wayside but still... For ion flow through dendrites and axons, the separation of information transmission from the protein assemblies of neurons is similarly separated. For neurotransmitters the particles are literally packed into bundles and separated from the ionic transmission that causes their release and cell boun…
> If our computers could grow their silicon wafers and lay new circuits then we would have something similar.
Yes, that's why my analogy included reconfiguring the FPGA (ie hardware) that's running the program on the fly. You highlight a number of examples where a reasonably clear line between the biological "hardware" and "software" can be drawn at a given point in time. However, you fail to explicitly mention any of the biological mechanisms involved in reconfiguration, some of which I would consider to blur those lines!
The addition and removal of synapses over time is an obvious but fairly slow and boring example. The software is very slowly modifying the hardware by small amounts, but the two are still clearly separate.
Epigenetics is more interesting. Any number of convoluted signalling pathways feeding back on the machinery that controls gene expression, with (in some cases) heritable effects. The distinction here remains fairly clear to me at any given point in time. The proteins are the hardware, the DNA the storage, and the program is manipulating the storage so as to modify the synthesis of future hardware components. Easy enough.
... or is it? Often the quantity of some component that gets synthesized is itself used as a signal. Does synthesis being used in this manner mean that the hardware has become part of the software? How far do things have to go before the hardware can be considered to be part of the software? But things get even weirder!
> the separation of information transmission from the protein assemblies of neurons is similarly separated
Not always! Ever come across GPCR heteromerization? This happens at your synapses (among other places), more or less in real time, in response to various convoluted signalling pathways. It can change how the receptor responds to a given ligand, or even allow it to respond to entirely different ligands. So in some cases, an important part of the "logic" for the neurotransmitter response is being played out by the physical configuration of the receptors. From my perspective, it looks decidedly as though the receptor (ie hardware) has become an integral part of the software.
Other examples abound, but this comment has gotten quite lengthy so I digress.
Original article here (paywalled): https://www.nature.com/articles/s41593-020-00717-0
Just reading the abstract, is it me, or did the authors revel in spewing a ridiculous amount of jargon instead of using the opportunity to give a simple and clear statement of the fundamental finding of the work to a general scientific audience? "The epigenome and three-dimensional (3D) genomic architecture are emerging as key factors in the dynamic regulation of different transcriptional programs required for neuron…
One concrete example: "Our work shows" would work just as well as "our work elucidates".
It's ultimately up to the author, but that kind of word choice really doesn't add anything and makes the paper less accessible to non-native speakers.
Please please don't take away from this that there are "memory cells" that "encode memories." The article is so badly written it seems to imply that. Memory is a whole brain phenomenon, and memory formation involves connections being formed and lost constantly between all types of neurons everywhere in the brain. One small aspect of memory (episodic memory) relies more heavily on hippocampal neurons during consolidat…
Open loop systems are simple...the effects of one block can be understood in isolation. Closed loop control systems with feedback have nonlinear responses to stimuli that can cause ripple effects across the system.
By analogy, on a modern cpu with good power management, and shared memory caches, if a program heavily writes to computer memory, the effects will be on the whole computer. Not only will memory power increase, but cache use will too (causing threads on other cpus to slow down) and the chip will heat up, causing every part of the chip to throttle.
Earlier quoted context omitted.
There's no single concept of nature that's understood completely. For example, there are a lot of things still understood pretty vaguely about milk. Or apples. So you can say that about pretty much anything.
>There's no single concept of nature that's understood completely. For example, there are a lot of things still understood pretty vaguely about milk. Or apples. So you can say that about pretty much anything. But that is practically untrue (I'm not just saying there are corner cases, but that the main topic is still very poorly understood) and a cop-out. And yet I can speak concretely about a hydrogen atom. Or even p…
Memory shares a property with holograms or with lenses/mirrors. If you draw a spot with a marker on one and looks at/through it, you don’t see the spot rather you see a slight loss of image quality across the image.
If you wipe out a bit of brain your memories degrade a bit. Somehow the encoding of memory is holographic.
We just need a different set of mathematical skills/tools to understand this property. From the point of view of traditional scientists it’s not something they know how to tackle.
Personally I think we should look at the brain (and DNA) with a signal processing lens. How data is encoded in the brain is something engineers could answer. Neural networks too are analog computers and spike signals are encoded with a variety of modulation schemes. If we understand those we don’t need to model neutrons the way we do (which is very inefficient, using floating point etc.) but by custom single-transistor analog circuits. That might help advance computation in general...once we understand how the brain is doing it.
Earlier quoted context omitted.
Self modifying programs have totally been a thing. :D They were hard to reason about so fell by the wayside but still... For ion flow through dendrites and axons, the separation of information transmission from the protein assemblies of neurons is similarly separated. For neurotransmitters the particles are literally packed into bundles and separated from the ionic transmission that causes their release and cell boun…
Self modifying programs exist , sure, but (as you note) aren't much used. Meanwhile the "software" layer in biology is a tangled mess. > If our computers could grow their silicon wafers and lay new circuits then we would have something similar. Yes, that's why my analogy included reconfiguring the FPGA (ie hardware) that's running the program on the fly. You highlight a number of examples where a reasonably clear lin…
Gene expression, signaling proteins, and protein synthesis or epigenetics in general are excellent examples both of the duality but some circumstances where the distinction gets fuzzier, particularly depending on the context and perspective you take.
I had not heard of GPCR heteromerization and will be reading more. I ended up going down the complexity and theory path more heavily and assigning my brain into business software so my knowledge of the concrete mechanisms is shallower than I'd like.
I definitely enjoyed thinking about about where to more specifically pin the difference in this context so thank you for being gracious with my making that attempt to offer a formulation. I think there's another interesting question to ask whether the duality divide matters but perhaps another day.
Thank you for the conversation.