Possible Confirmations of the Super-Stimulus Theory
My super-stimulus theory of music makes a number of radical claims about what music perception represents and how it occurs. Unfortunately it won't get much respect in the world of science until some confirming evidence appears, such as one of the following:
- A generative mathematical formula which successfully composes music;
- A predictive mathematical formula which accurately judges the quality of music (or non-music, as the case may be);
- Observation of constant activity patterns in cortical maps of a person listening to music;
- Discovery of "musicality-detecting" brain cells. (By this I mean brain cells whose activity corresponds exactly to the perception of music which is considered "musical" by the person listening to it.)
The problem with trying to develop a generative or predictive formula is that the super-stimulus theory is not complete enough for me to achieve this. What is missing from the theory, which is required to determine such a formula, is a complete description of the representation of information in all cortical maps which play a role in perceiving speech which might be relevant to the perception of musicality. This requirement is equivalent to completely determining the functionality and operation of a considerable portion of the human brain, and I don't think that is going to happen any time soon.
Detection of constant activity patterns is probably beyond the capabilities of current brain imaging technologies, although there might be some specific statistical techniques that could be used together with current imaging technologies, to indirectly detect increase constancy of activity patterns when music is perceived by a listener compared to when music is not perceived.
Which leaves the last option: discovery of musicality-detecting brain cells.
Shouldn't that be Musicality Neurons?
I was originally going to title this article "Please Help Me Find the Musicality Neurons", and in my book (What is Music? Solving a Scientific Mystery), I do assume that they must be neurons, since neurons are the brain cells that are believed to be responsible for most if not all of the information processing that occurs in the brain, and a basic assumption of the theory is that perception of musicality is a type of information processing (as is any other form of "perception").
However, as I planned how I was going to write this article, I started thinking about what characteristics a musicality neuron might have, and how it could detect musicality, and how it might propagate information about the detection of musicality, and various possibilities involving inhibition and excitation, and it occurred to me that non-neuronal brain cells might actually have information processing capabilities more relevant to the detection of musicality than those of neurons.
Non-neuronal brain cells are called glial cells. One function of glial cells is to maintain a suitable operating environment for the neurons, and for each glial cell this involves restorative functions which depend on the degree of activity of neurons in and around the location of that glial cell.
Given that my theory of music proposes that musicality is detected according to the occurrence of fixed patterns of neural activity, with well-defined edges between active and inactive regions of a cortical map, it is not beyond the bounds of possibility that some type of glial cell has evolved into a specialised cell capable of detecting these "edges". There would still need to be some way for these musical glial cells to communicate information about the edges back into the neural networks of the brain, but this could happen via some special neurotransmitter which is released into the brain medium and then acts on some further set of neurons which implement the emotional and other effects of music.
Since musicality is a property that melody and rhythm have over an extended period of time (and it does not change suddenly from moment to moment), and since it also appears to be a one-dimensional value, there is no necessity for anything more complicated than the release of a single specific chemical messenger to communicate this information, and, in particular, there is no requirement for the high "bandwidth" that is available in the connections between neurons and other neurons.
However, although this model of a specialised glial cell is plausible, I would still not rule out the possibility that musicality detection is carried out by some specialised type of neuron, so I will leave the question stated in terms of "brain cells".
Expected Properties
Whether or not the musicality-detectors are neurons or other brain cells, we can list the properties that such cells would be expected to have, based on the assumptions of the super-stimulus theory:
- The musicality-detector which detected a particular activity "edge" would be slowly excited by activity from neurons on one side of the edge, and rapidly inhibited by activity from neurons on the other side of the edge.
- The same type of cell will be found across those regions of the brain involved in the perception of those aspects of speech which are found in an exaggerated form in music. These regions would include regions involved in the perception of visual aspects of speech, such as gestures, since my theory predicts that dance is a visual super-stimulus for the perception of musicality from these aspects of speech.
Possible Detection Methods
The most straightforward way to discover a candidate for a musicality-detecting brain cell will be to discover some particular type of cell which occurs across regions involved in the relevant aspects of speech perception. (One complication in my theory is the split map hypothesis, which states that some aspects of musicality perception may occur in maps which are evolved analogues of corresponding cortical maps involved in speech perception, and this possibility might have to be taken into account.)
Another way to detect the occurrence of a particular cell type in particular brain areas might be to detect some gene which is expressed in those areas and only in those areas. I was recently interested to read about the Brain Gene Expression Map, however when I read the fine print I discovered that it was a map of gene expression in mouse brains, and unfortunately mice are not very musical (and my theory predicts that humans are the only musical animal). Furthermore, the methods employed to generate the expression map for mice were not easily or ethically applicable to human beings. (In contrast, I assume that identifying brain cells visually is something that can be practically and ethically done on human brains, in those cases where people who die have willed their bodies to the cause of science.)
Can the Reader Help?
So, can you help me? Ways that you could help might include the following:
- You know of some type of brain cell (glial or neuronal) already identified, which is an obvious candidate for a musicality-detecting brain cell based on the criteria specified here.
- You know some other way to identify particular populations of cells in the brain.
If you have any ideas or suggestions, you can contact me at (the slightly spam-proofed email address) web at 1729.com.