by sema4hacker | 2025-08-20 00:33:11+00:00
About a dozen years ago I thought up this (probably very naive) theory of why we sleep:

1 - Neural activity generates and deposits electrochemical "trail markers". The more a given neural path is used, the greater the accumulation of markers along that path. Markers might be inside and/or outside neurons. Markers might be electrical charge, a molecule, or some other convenient entity.

2 - Accumulated markers cause the sprouting, growth, and reinforcement of permanent neural connections. New connections will tend to form between any unconnected paths having the highest concentration of accumulated markers. More connections will tend to form between areas, even if already connected, when both areas have high concentrations of accumulated markers.

3 - Short-term memory is the temporary accumulation of markers that reinforce and emphasize the recollection and repetition of recently used neural pathways. As the markers cause the creation of permanent neural connections over time, short-term memory is effectively converted to long-term memory.

4 - Normally, markers are accumulated during the day, and processed and reduced during sleep. Without sleep, the brain can only tolerate the continuous accumulation of markers for a few days. After days without sleep, total marker levels are so high on so many different neural paths that proper brain functioning can no longer be guaranteed (because too many neural paths end up marked as important, the brain starts using paths it shouldn't, and our perception of reality begins to distort), so sleep is forced upon the brain so marker levels can be reduced to safe levels.

5 - Dreaming is simply a side-effect of the processing and reduction of accumulated markers. Sleep is the period when markers are converted to permanent brain "improvements", and markers are eventually "flushed" from the brain. (Flushing might be the actual disposal or transformation of markers, or simply reducing their levels below a cutoff threshold.) The processing and disposal of markers accumulated in the brain causes the triggering of neural activity that we perceive as dreams. If we were awake, the dreams would be hallucinations. (Hearing voices and other "psychotic" experiences happens when the body wrongly attempts to process markers and induce dream states while the brain is still awake instead of asleep.)

6 - Neurons are connected in a highly associative way. Activity in the brain for one purpose inevitably leads down paths of associated connections that may or may not be important to the activity at hand. As our neural activity concentrates on the important paths, those paths accumulate the greatest level of markers, although a number of unimportant connected paths also accumulate lesser levels of markers. During sleep, the processing and removal of unimportant markers that tag unimportant associations (because marker levels failed to reach a sufficient threshold along those unimportant fringe neural paths) nevertheless triggers activity along those unimportant associations, sometimes resulting in strange dreams that don't appear to have a direct association to our day's activities. Usually, dreams will have at least one obvious connection with something that happened during our recent conscious hours. But no matter how strange and unconnected a dream may appear, the dream is a result of previously triggered activity along actual neural connections where markers accumulated during our conscious hours.

7 - Since it is unpredictable what dream associations will be triggered by the accumulated markers, sleep (with the lockdown of muscles) is the mechanism by which the brain can allow markers to be processed or flushed without us actually acting upon the neural activity they cause.

8 - Newborns require a lot of sleep because markers quickly accumulate beyond the sleep-inducing threshold, primarily because there are relatively few neural pathways among which the markers can be dispersed. A newborn eyeball and an adult eyeball (to name just one source of neural input) have essentially the same bandwidth, and will attempt to generate the same quantity of neural activity and associated markers. But the newborn brain, having fewer pathways and thereby being a smaller cup to fill, will more quickly saturate with markers, and so require sleep sooner.

9 - A network of neurons is a multidimensional canvas. The firing of neurons are brushstrokes throughout the canvas. The accumulation of markers along those brushstrokes is like paint building up on repeated brushstrokes. Heavy, accumulated brushstrokes are important to the picture; they are frequently revisited and repainted. Light, rarely-visited brushstrokes are less important, and may even fade away.

10 - The general development and maintenance technique for the brain is (CONNECT:) make lots of connections, even if some may be "wrong", (USE:) use the connections, allowing lots of free associations to occur, (MARK:) mark which connections get used repeatedly and are therefore important, (GROW:) grow new connections along heavily marked paths, (REPEAT:) continuously repeat the above CONNECT-USE-MARK-GROW steps.