I read this article: https://news.mit.edu/2019/neurons-dendrite-role-computation-0606

My question is about this: “One hypothesis is that dendritic activity will actually sharpen up for representing features of a task you taught the animals, and all the other dendritic activity, and all the other somatic activity, is going to get dampened down in the rest of the cortical cells that are not involved,” Harnett says.

How exactly are neurons that are involved in a task chosen and how exactly is it decided which neurons are then supposed to be dampened?

Probably not a question that can be easily answered, but I wanted to ask it anyway.


I think our best understanding of this (that I can think of) is Hebb's law: Neurons that fire together wire together. Basically, maybe you can think of it like a bit of information is saved in a physical space neurally. So one idea, like your grandmas face, is a combination of many of these bits being activated (This is in reference to the language of thought theory https://plato.stanford.edu/entries/language-thought/). When trying to make sense of something, the more common connections will activate first and then less common ones, until an answer has been found or the task has been deemed not possible/unimportant.

As for how neurons are chosen, I would say in relation to what is already there. And dendritic connections are dampened the longer they go without linking. To the best of my knowledge, it's still contested exactly how we encode new information. There is a lot of evidence that certain tasks can be associated to general areas of the neocortex, from neural mapping experiments.

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    $\begingroup$ it's interesting that you mention faces cause to my knowledge, face recognition is done in fusiform face area and damage to it can result in prosopagnosia which means you can no longer recognize them and presumably neither can you relearn to recognize them. Hebb's law of "neurons that fire together wire together" is nice of course but how do complex cells then learn to respond to lines oriented in a certain direction if they receive firing from other cells as well? This is mostly what had me confused. It's not just about coincidence detection and there's a lot more to it as it seems $\endgroup$ – Anonymous Apr 29 at 1:56
  • $\begingroup$ Ah, okay. Just as a heads up I'm just an undergrad haha, but I love learning and discussing. Although it's not strictly the neuro-cortex responsible for thinking, I believe neuronal distribution is the densest there, and then that differs between white and grey matter? And depending on the type of neuron, each cell has around 7000 connections on average I believe. $\endgroup$ – M. Erickson May 3 at 2:00
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    $\begingroup$ So the fusiform gyrus is around/in the occipital lobe but is part of the cortex and isn't activated completely locally but in conjunction with many other areas, depending on the task (although I'm not sure if that's what you were meaning when you brought it up). So I just can't really imagine a system where it's not similar to coincidence detection, perhaps there is some piece of it though that is a gap I'm not making the connection on. $\endgroup$ – M. Erickson May 3 at 2:00
  • $\begingroup$ Some areas I'd imagine would relate to the question are language acquisition, where we are unsure if there are some physical/cognitive language modules that help children to acquire complex syntactic structures without explicitly defining what they are. Or machine learning and ANN's (artificial neural networks) where the processes are learned after lots and lots of training, which become really hard to trace the exact best path for executing tasks because it is similar to the human brain and new nodes are made and connections tested at random. $\endgroup$ – M. Erickson May 3 at 2:00
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    $\begingroup$ it does make sense, no worries. just a few side notes, even though many parts of the brain are activated together, they still have a specific role that they play which is why parts like the fusiform face area eventually have this name assigned to them. For example, even though frontal eye field, parietal cortex and the inferior frontal junction are activated whenever you're looking for something, they all play specific roles in what you do whenever you find it, this lecture probably explains it better than me: youtube.com/… $\endgroup$ – Anonymous May 3 at 14:10

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