Glial Cells as Perceivers of Musicality
I have, for quite a long time, proposed that glial cells play a major role in the perception of music.
The rationale for this hypothesis is that:
- Two musical features are pitch scales and nested regular beat, and each of these features would be expected to cause certain patterns of activity in cortical maps, but in different maps in each case.
- These patterns of activity relate to the actual physical location of active and inactive neurons in a map, and this suggests the existence of some type of “meta-perception” of the activity of neurons as a function of their location.
- This suggestion is consistent with the role of glial cells, where glial cells interact with neurons as a function of their proximity to those neurons.
- That is, there are glial cells located in cortical maps that relate to the perception of musical sound, where those glial cells are responsible for “observing” the musicality of music as defined by the occurrence of these patterns of neural activity.
Glial Cells as Deciders to “Not Bother”
More recently, I have developed a hypothesis that our emotional response to song lyrics has two major aspects:
- Responding to the emotional consequences of a situation that a protagonist finds themselves in.
- Not bothering to try and think about how one might deal with such a situation.
At the time of developing this hypothesis, I was not particularly thinking to relate it to any hypothesis about glial cells.
However, I recently came upon this article from Quanta Magazine.
It described three different papers about the roles that astrocytes (one type of glial cell) play in the brain.
One paper was Glia Accumulate Evidence that Actions Are Futile and Suppress Unsuccessful Behavior, which reported an observation that glial cells are directly involved in decisions to “give up” when repeated attempts to do something fail.
I realised that this is similiar to, albeit not exactly the same as, my hypothesis about how the human brain responds to song lyrics.
The similarity is apparent if we describe both situations in terms of an individual “not bothering”.
In particular:
- As glial cells accumulate evidence that actions are futile, the individual animal will decide to give up, that is, not to bother trying anymore.
- According to my hypothesis about the response to song lyrics, the listener decides not to bother trying to think of how one might deal with the situation described in the lyrics.
The main difference between the two situations is that in the “giving up” example the individual eventually decides not to bother, whereas in the musical case the “not bothering” happens straight away.
Possible intra-glial cell communication involved in our response to music lyrics
But, if glial cells can be involved in deciding “not to bother”, and if glial cells are involved in the perception of musicality, then it is quite possible that the connection between these two things occurs directly within the glial cells themselves.
That is, something like:
- Neurons perceive music, and the features of music cause certain patterns of activity.
- Glial cells perceive these patterns of activity.
- Glial cells respond to the perception of these patterns by activating a “don’t bother” signal in relation to those parts of the brain involved in thinking about how to deal with a situation.
- Neurons that would otherwise think about how to deal with a situation are de-activated by that glial signal.
The glial cells in items 2 and 3 are necessarily not the same glial cells, because they have to be colocated with the relevant neurons in items 1 and 4, which are neurons with different functions, and therefore each will be located according to their respective functions. So if the two are linked, then there has to be some kind of glial-to-glial cell communication occurring over a certain distance.