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Neural Pathways

architecture

Neural circuits map perceptions to actions, stimuli to response, context to behaviour. We call these neural pathways, and they are stronger the more they're trained. The stronger they are, the more they determine our behaviour.

Nerve cells are responsible for taking in signals from our senses and transmitting them through the nervous system to produce the appropriate responses. They fundamentally map perceptions to actions. This can be simple, like a knee jerk response to someone tapping the kneecap. But it can be complex too, like determining the difference in response between seeing someone running towards you with a knife on TV, vs that same knife-wielder in the dark alley you're walking in.

Of course, these signals don't pass through the brain magically. They travel along pathways defined by which neurons are connected to which others (and how). The way neurons are wired together determines an enormous proportion of our behaviour. This is why the idea of neural 'pathways' is so popular, because it really is the best way to think about how neurons (indeed, all nerve cells) work.

Those pathways are given to you by evolution, and then developed by you as you go through life. The more you train a pathway, the more likely it is that certain sensory inputs will produce the response it's connected to.

The strongest pathways are the ones you have trained the most and, since you can't control the electrical firing of your neurons directly, means that there's only so much you can do to change the pathways that you're using in the moment.

There is a rhythm of practice and consolidation at work here: co‑activation strengthens a pathway between stimulus and response, so that the response tends to run first when the stimulus is presented again. For a deeper look at the speed‑versus‑flexibility trade‑off (and why adolescents are often more flexible while adults are more efficient), see Plasticity & Stability.

So, a good way to think about neurons are pathways. All grouped together, they're the information highways of the brain and body, running messages about what perceptions should go to what actions. If we zoomed out from these pathways, both the heavily constructed highways and the lighter animal trails that comprise our perception-action mappings, we'd have exactly that---a map. Our nervous system, and particularly our brain, is a big map of which perceptions should be mapped to which actions. A map of the statistical structure of the world, and our actions within it.

How can you think with this?

These heuristics help you apply this neural system:

Ways to think with this

Practical ways to use this neural mechanism in understanding behaviour

Think inputs-to-outputs
Heuristic: input-output-machine

The neural pathways concept is most useful when you think of the brain as an input-output machine: sensory cues (inputs) automatically trigger responses (outputs) along pathways you've trained. The stronger the pathway---the more you've practised that particular mapping---the more automatic the response becomes.

So what can you do? When you want to change behaviour, don't fight the output directly (like 'don't eat the biscuit'). Instead, change the input. If you don't want to eat biscuits, don't keep them on your desk where seeing them activates the eating pathway. The input implies the output, so controlling the context (the inputs) is far more effective than trying to suppress a trained response that's already been triggered. You're working with the pathways, not against them.

WIP: Stronger paths win by default
Heuristic: Bias vs Noise Bias trades flexibility for precision; noise trades precision for flexibility. Brains tune this trade‑off by context, stress, and uncertainty.

The more you train a pathway, the stronger it becomes, and the stronger it is, the more it determines your behaviour. This means there's an asymmetry at work: well-trained pathways run automatically and reliably, while less-trained alternatives need active support to fire at all. The system defaults to what it knows, treating the familiar as signal and the novel as noise.

So what can you do? When you're trying to establish a new behaviour, recognise that you're fighting against the statistical weight of history. The old pathway isn't wrong---it's just been trained more. You need to practise the new route enough times that it becomes competitive, and you need to do it in contexts where the old pathway isn't automatically triggered. Don't expect the new option to feel natural until it's had time to consolidate.

WIP: Your map reflects your history
Heuristic: Everything is Ideology The brain maps perceptions to actions through frames that highlight some meanings and sacrifice others. We don't choose between truth and ideology---we choose between ideologies.

Neural pathways are maps of the statistical structure of the world you've lived in---which perceptions have led to which actions, which contexts have meant what. This means your nervous system is an ideology in the sense that it filters the world according to patterns you've experienced, necessarily highlighting some relationships and obscuring others. The map is never the territory, and your pathways reflect your particular history of being in the world, not some objective truth about it.

So what can you do? Understand that your automatic responses aren't revealing the truth of a situation; they're revealing what has been true for you historically. If a pathway keeps producing outcomes you don't want, the issue isn't that you're broken---it's that the map was drawn under different conditions. You can redraw it, but you need to acknowledge that the old map made sense given where it came from.

WIP: Predictions run on the same rails
Heuristic: Prediction Engine The brain predicts what should happen next---in the world and in the body. When predictions fail, you feel something, attention pivots, and behaviour updates.

The pathways that connect perceptions to actions are the same pathways that generate predictions about what will happen next. This is why anticipating something activates much of the same neural machinery as experiencing it---the pathway runs either way. It also means that context cues can trigger a response before the thing you're responding to has even arrived, because the prediction loads the action automatically.

So what can you do? If you want to change a habitual response, pay attention to the cues that precede it. The pathway is already loading the response as soon as the context appears, which is why trying to intervene at the moment of action feels so difficult---you're catching it too late. Either change the cues so the old pathway doesn't load, or practise an alternative response to the same cues until that becomes the predicted action.

WIP: Context determines which route runs
Heuristic: top-down-bottom-up

Sensory signals travel up neural pathways, but predictions and goals also travel down them, biasing which routes are active and which features get attended to. This top-down influence means that the same bottom-up input can produce different outputs depending on what the system is expecting or trying to achieve. Context---both external and internal---determines which pathway wins.

So what can you do? You can't always control the bottom-up signals, but you can often shape the top-down ones. Set the goal before the cue arrives, so the right pathway is already primed. Or change the external context so the cues themselves are different, which shifts which bottom-up signals arrive in the first place. The pathway that fires is the one where bottom-up and top-down converge, so you have leverage at both ends.

Referenced by

Sources

  • analects/what-are-neurons.md
  • neurotypica/content/archive/anatomy-neurons.md
  • neurotypica/content/archive/anatomy-nervous-system.md
  • analects/brain-structures-and-behaviour.md
  • analects/brain-regions-to-networks.md
  • analects/frontal-lobe-development.md