Comment by ltbarcly3 | Hacker News Reader

Comment by ltbarcly3 | Hacker News Reader

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I appreciate what you are saying, but it may be that it's premature to try to list things necessary to understand something when it's not understood by anyone.

In fact, I think you're probably dead wrong. Certainly hormone interactions and feedback loops in the body have some consequence on an organism, but these things take time. Lets say that some feedback loop is extremely fast, say 10 seconds. It seems reasonable to assume that you can't have a complex feedback loop with the body much faster than that, just because it takes time for chemicals to physically move. Cognition is much, much faster than that. There are many situations where you can learn, and then apply that learning in less than a second. Now if we were instead talking about what it takes to build a complex organism that can satisfy it's own needs, then certainly these complex hormonal feedback loops are essential. You can't have an organism survive when it doesn't look for food when it's body is out of fuel or keeps eating poisonous berries because it's body can't send the reasonable feedback to it's brain, and you can forget about dropping everything and competing for mates at the correct time without some kind of behavior modifying hormonal signals!

I would say that your assertion is not significantly different from saying "you can't understand the workings of the brain without considering the complex interactions of the brain with the lungs, since without oxygen the brain can't work". So while I agree that the brain exists as part of the body, I don't see why you would automatically assume that the hormonal feedback loops with the body are at all necessary for cognition rather than a way to tell the brain when it's necessary to find food, when it's adaptive to conserve energy and be lethargic, or what have you.

My point is that we may or may not find that there is some critical ingredient of cognition hiding in this place or that, and you can't very well tell us where that will be if nobody knows if it's there.

Well neurotransmitters are a kind of hormone and they certainly play a direct role in the computational processes of neurons.

Neurotransmitters are not hormones. Some neurotransmitters are also hormones.

Yes, you're right. That was phrased a bit haphazardly.

My point was that we can't just determine the typical time constant for a hormone's effect and run home with it since there are chemicals which have significantly lower time constants and some of them act as endocrine hormones as well.

Furthermore, an immediate feedback loop isn't the only possible way the body could play a role in cognition, though I suppose the OP is aware of this and was talking about moment-by-moment interaction with the body on purpose.

Well sure. My point was that there’s countless additional factors to consider, beyond just physical structure. Those feedback loops may be slow, but there’s plenty of evidence that they influence aspects of cognition quite strongly. On the flip side, a lot of current research about brain function is built on fMRI scans which monitor blood flow changes to exact locations in the brain, but necessarily at a long temporal distance from the actual “decisions” being made.

So yes I think we agree that it’s all more complicated than anyone can even comprehend just yet.

> My point is that we may or may not find that there is some critical ingredient of cognition hiding in this place or that, and you can't very well tell us where that will be if nobody knows if it's there.

It's like the parable of the Drunken man looking for his lost keys under the street-lamp. He only looks under the lamp for his keys because that's the only place the light is.

Similarly, in neuroscience, we only have a few tools to look at the brain. By some miracle, the brain happens to be electrically active to a degree that we can shove wires into it and pick up signals. So, dutifully, grad students across the world have been shoving needles into brains and trying to pick up signals and then tell advisers what that means.

Another miracle is that blood has a ferromagnet in it and the brain has a fair bit of blood in it. So, after a lot of trial and error, we've been able to build very complicated fMRI machines that can give grad students an idea of the usage of blood in the brain. This is then correlated with other measurements to find out what is happening in the brain.

Recently, we've been able to combine two different little miracles together. One is opto-genetics, a little serendipity we pulled out of the chromatic hot-pools in Yellowstone. Essentially, when you shine light on a little bacteria, it's cell wall opens up and you can squeak certain ions through the hole. The other little miracle is CRISPR-CAS9. Here, you can again use some tricks bacteria have made up to more easily copy-paste in the genetic code. Using these tricks and a lot of help from post-docs, yet more grad students have been able to report results in lab meetings to their advisers.

More techniques exist, of course, but my point is that the vast majority of neuroscience is still in the dark, away from the drunken man searching for his keys in the light.

Look at astrocytes. These guys make up ~50% of the brain. Very recent research says that they play something of a role in the synapse, moving NMDA receptors around the cleft, recycling, phospho-tagging recpetor, etc. It's super recent work. But also super important. Before, we thought that only the neurons were involved in the synapse, but now we have good evidence that other, action-potential lacking, cells are also deeply involved.

That vein of research is also really hard to do and preform experiments in. As such, most grad students are wise not to do their work in that kinda lab. It's hard and has a high potential of failure, and therefore no degree.

So, wait and see. Our understanding of the brain is still very much in it's infancy. We've not really even got a good accounting of all the cell types and connections in the brain yet.

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