This is the return of ends and odds.

New McFadden Site

Philosopher Eric, who has been a frequent commenter on this blog, has created a McFadden oriented website.

Consciousness as an Electromagnetic Field A site for exploring Johnjoe McFadden’s cemi field theory

He already has some posts up.

If you are unfamiliar with McFadden, you should know his core argument is effectively that the electromagnetic field generated by neurons is consciousness.

The more I read about neurons the more I discover new (to me) ways that they communicate. I read recently an article that says neurons emit photons and that possibly the photons could transmit information to other neurons. We have the well-known electrochemical communication. Then there is the possibilities that neurons also used electromagnetic fields to communicate with each other. If nature finds something useful, it will tend to use it, so I wouldn’t be surprised that neurons would use electromagnetic fields. Likely any or all of these methods could be related to consciousness, but it isn’t as clear whether one or a combination is more greatly involved.

Imaginative Rats

Rats are more imaginative than you might believe. Through some clever experimental methods researchers have found that rats navigate toward a goal only in brain activity. In other words, they are imagining themselves taking a path to a location different from where they are at to get a reward.

There are a lot of articles on the internet about this. Here is an explanation from one:

To explore whether rats can do the same, and unpick a possible mechanism, researchers employed a brain-machine interface in which electrodes were surgically implanted into the rats’ brains. The rats were then placed on a treadmill ball within a 360-degree immersive virtual reality (VR) arena, and presented with an on-screen goal to run towards.

As the rats moved, and the treadmill ball turned, the animal’s apparent location within the VR environment updated on screen – as if the rat was running through a real environment. When the rats reached the goal, they received a treat and the goal was moved within the VR environment. The process was then repeated.

During this initial phase, the team recorded the activity within the animals’ hippocampus. They then used a computer system to translate this neural activity to specific locations within the VR environment.

In the next step, the researchers decoupled the treadmill from the VR system. This meant the rats could not reach the goal by running on the treadmill. Instead, they could only use their brain activity to navigate through the VR environment.

By analysing the activity in rats’ hippocampus in real time during the task, the team were able to update the screen every 100 milliseconds with the animals’ current location in the VR environment, based on what was happening in their brain.

The results reveal the rats could indeed navigate to the goal using just their brain activity.

https://www.theguardian.com/science/2023/nov/02/rats-may-have-power-imagination-research

Perhaps this isn’t surprising. If one of the main roles of the brain is prediction, then the ability to imagine alternative outcomes and different ways to accomplish a task might be an inevitable consequence.This would extend to imagining steps involved in a task such as navigating to a reward.

Other research has show navigation in rats, perhaps most mammals, may be accomplished in grid cells in the hippocampus.

Mammals are able to navigate to hidden goal locations by direct routes that may traverse previously unvisited terrain. Empirical evidence suggests that this “vector navigation” relies on an internal representation of space provided by the hippocampal formation. The periodic spatial firing patterns of grid cells in the hippocampal formation offer a compact combinatorial code for location within large-scale space.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4534384/

This is evidence that, in some brain functions, the geometric arrangement of neurons may be critical to conscious content. We might speculate that, if each neuron had its own unique electromagnetic signature, the geometric arrangement of multiple neurons might create an unique combined “picture” composed of the individual signature of each neuron.

Bats Too

Bats have grid cells too and may use the same grid cells for spatial and social navigation.

In short, the bats’ navigation system appeared to do double duty as a social map. The mammals weren’t just moving around their home — they were also using the exact same brain cells to track who was on the premises.

In that sense, Forli said, the hippocampus may be like a powerful graphics card in a computer, which can have many uses, from rendering graphics for video games to performing machine learning computations. The hippocampus may be great at particular kinds of computations and may have the ability to be modified or programmed by evolution.

https://www.quantamagazine.org/bats-use-the-same-brain-cells-to-map-physical-and-social-worlds-20231031

I’m not especially fond of the “computation” metaphor in the quote, because it becomes associated with digital computation in the mind of many. Whatever form of “computation” is occurring hardly seems like digital computation, especially if the geometric arrangement of computing elements is part of the “computation.”

Grid Cells, Memory, Hexagonal Patterns

Brain’s Positioning System Linked to Memory is a fascinating article in Quanta from a number of years ago. It probably would be a great one to update.

The article is about special neurons called place cells, which fire whenever an animal is in a certain location and grid cells, which are like a dead-reckoning system, telling the animal its location independent of external cues.

Apparently these type of neurons and patterns are widespread in mammalian brains, including those of humans. The firing patterns for grid cells seems to have a hexagonal geometric pattern.

The hexagonal pattern of grid cell activity is repeated all over nature, from honeycombs to the benzene ring to a tightly packed crate of oranges. It’s a highly efficient arrangement; bees use hexagons in their combs to minimize their use of wax. In the grid-cell system, the hexagon isn’t a physical object. Rather, it’s the organization of space that encodes information most efficiently. “It’s the most efficient way to compress data,” said Marianne Hafting Fyhn, a neuroscientist at the University of Oslo in Norway and a former student of the Mosers. Researchers aren’t sure why grid cells use hexagons, but the hexagonal organizing principle has attracted attention from computational biologists, who are trying to figure out how the grid is generated.

Apparently it is not simply physical space and location that is maintained with grid cells. The grid contains abstract properties such as the social map mentioned about bats earlier.

The article concludes:

Many researchers believe that memory and space are even more intricately linked. In a popular trick for remembering speeches, dating back to ancient Greece, the orator calls to mind a familiar path through a city and attaches a segment of the speech to each location along the path. This mnemonic may unwittingly exploit the fact that the hippocampus encodes both location information and autobiographical memories. “It just happens that space is a good way of organizing experiences,” Wilson said.