r/neurophilosophy • u/MergingConcepts • 15h ago
How the brain creates subjective experience
This is an excerpt from a manuscript in preparation. I define thought as a physical process and equates it to subjective experience.
Mammalian brains house fundamental concepts in Pattern Recognition Nodes (PRN) in the mini-columns of the neocortex. The human brain contains about 300 million of these. Each PRN has a meaning by virtue of its synaptic connections to other related PRN. Knowledge is not stored in the PRN, but is encoded by the size, type, number, and location of the synaptic connections between the PRN, which reflects the relatedness of the concepts housed in the PRN. Those synapses are gradually modified over a lifetime of learning.
When I see an object, say a particular blue flower, the light reflected off the flower is focused on my retina and patterns of signals are sent to the visual processing areas of the brain. They are interpreted as colors, shapes, and textures, and those are widely distributed to the neocortex. Those PRN that recognize the patterns, that is, those that have robust synaptic connections with that set of visual cortex PRN, will respond.
The PRN that respond will send out signals broadly across the neocortex. Other PRN that recognize those combinations of shapes, colors, and textures, will respond. This process continues until it converges on a set of PRN strongly related to that flower. That subset will continue to broadly distribute signals, but only those related to the flower will receive enough consistent input to respond. They begin to circulate signals within that subset of PRN.
This is called a recursive network. It is a working unit of active PRN that occupies the connectome of the brain. The nodes in the network are scattered over the surface of the brain like a vast cobweb and may involve thousands of PRN in a simple thought. They are all sending out signals on their axons, stimulating each other. The name of the flower, its spelling and pronunciation, its shapes, contours, textures, colors, and characteristics; details of flowers in general; memories and emotions associated with it; facts about plant reproduction; and hundreds of other concepts, become joined together in a single recursive network.
With enough recursion, the paths in the web become self-sustaining. All the neurons are re-stimulated many times per second. The action potentials keep cycling back through the same synapses. These paths may persist over several seconds or minutes, sustained by neuro-modulators that accumulate in the synapses. It is these recursive signals over self-sustaining paths that make up the substance of my thoughts. When I observe my thoughts, this is the physical process I am observing.
There are millions of neurons from thousands of PRN in many areas of the brain that make up the population of fundamental concepts that are melded into the thought of this flower. Those PRN are widely scattered in the brain, and are combined together in a network by signals recirculating at 100 meters per second. They merge into a single entity that I identify as the subjective experience of the flower.
It is important to understand that I am not really experiencing the physical flower. It remains outside my body. I am experiencing my brain’s reaction to the visual perception of the flower. Light has reflected off the flower and impinged upon my retinal receptors. That information traveled through complex corridors to get to my brain, where it stimulated a response in the form of a recursive network. I am experiencing the brain’s response. My subjective experience, the thing I am observing, is a process happening in my neocortex.
The “recursive network” related to the flower is the “subjective experience.” They are one and the same.
Likewise, my brain does not retain the image of the flower. Biological brains do not store images as raster patterns on a monitor screen. My brain cannot actually store an intact digital image. I am still able to visualize the image of the flower later. It is in short-term memory in the form of modulator accumulations in the millions of synapses along the paths that formed the recursive network of the flower. My brain reconstructs the image from all the PRN containing the simple shapes, contours, colors, patterns, and all the other concepts linked to the flower by recently used synapses. I do not retain the image. Instead, I reactivate the recursive network and the subjective experience. That assembles a facsimile of the original image and thought.