When we don’t sleep, we can lose sensory and cognitive coherence. Mild visual hallucinations begin and reality can start slipping.
Sleep itself is characterized by coherent neural activity— the large number of brain regions with synchronized neural activity. The slow waves where huge numbers are all firing close together in a rhythm. Low frequency and high amplitude delta brainwaves (1-2 hertz).
Complex adaptive brain activity requires more complex firing than a simple rhythmic frequency. So, in a way, the complex activity must be stopped in order to support global synchrony.
Why would our neurons want to all fire synchronously? Well, it is healthy for neurons to fire together in a causal manner— neurons release growth hormones then. That neural growth during synchronized firing is the basis of “neurons that fire together wire together.” And it doesn’t seem coincidental that a successfully predicted model feels good, as in the case of successfully throw a ball in a basket. Neurons are trying to predict other neuron firing and respond to it. If they are unable to effectively, they may become like the 1/3 of our baby neurons in the cortex — they will be pruned and die.
Good feelings is positive reinforcement—behaviors leading to good feelings get reinforcement. The feeling of harmony or harmonization, where we have to balance a broad set of internal neural impulses, feels good when we do it well. We feel harmony in music — and in our own internal sensory resonance to the world.
Hypothesis 1: the harmonization of neural activity might cause conscious feelings due to the convergence of the activity to platonic forms (see Platonic Representation Hypothesis in LLM research).
Returning to sleep — this is a proposal for why sleep feels good. Synchronization might intrinsically feel good. But because the sleep also disrupts your working memory contextual attunements (ie, whatever your day was about) - taking your brain into deep synchrony — it strengthens the overall dendritic connections between the synchronizing neurons.
And, because it wears off the edges of your previous experiences — you can return refreshed.
In this way, sleep seems to contribute to the overall integrity of the operation of our intelligence. Without it, we lose integrity and internal harmony.
And yet, not sleeping is one of my favorite drugs. Can be a major performance enhancer, even if it is variable.
Hypothesis 2: Not sleeping increases the (statistical) temperature of the brain.