Ancient Computers

Cerebral cortexes are cool and all, but the "dumber" parts of the brain have a lot of good secrets in there too.

Lost fish find their way, thanks to their 'ancient brain'

Dec 2022, phys.org

https://phys.org/news/2022-12-lost-fish-ancient-brain.html

They put tiny translucent zebrafish, barely half a centimeter in length, in a virtual reality environment that simulates water currents.

The researchers expected to see activation in the forebrain -- where the hippocampus, which contains a "cognitive map" of an animal's environment, is located. To their surprise, they saw activation in several regions of the medulla, where information about the animal's location was being transmitted from a newly identified circuit via a hindbrain structure called the inferior olive to the motor circuits in the cerebellum that enable the fish to move. When these pathways were blocked, the fish was unable to navigate back to its original location.

These findings suggest that areas of the brainstem remember a zebrafish's original location and generate an error signal based on its current and past locations. This information is relayed to the cerebellum, allowing the fish to swim back to its starting point. This research reveals a new function for the inferior olive and the cerebellum, which were known to be involved in actions like reaching and locomotion, but not this type of navigation.

via Howard Hughes Medical Institute: Misha B. Ahrens, A brainstem integrator for self-location memory and positional homeostasis in zebrafish, Cell (2022). DOI: 10.1016/j.cell.2022.11.022

https://dx.doi.org/10.1016/j.cell.2022.11.022

Image credit: Homotopical Topology by Fomenko and Fuchs

The Brain That Wouldn't Die

Film still from "The Brain That Wouldn't Die", Sterling Productions 

The flatworm can regenerate its entire brain in only a few days, and so scientists decapitate them, but the worms retain memory of a previous experiment, despite having lost their head, and how this works is unexplained, although it implies that information is stored somewhere else besides the head.

Smells are encoded into memory via the limbic system, and this means recording body-states along with the smells. Our body remembers the way it felt the last time that smell was received. We know that a phantom limb remains in the brain, despite its having been amputated, but does a memory remain in the body despite having lost its head? It should be interesting to note here that odor receptors are all over the body, in organs and even in muscle tissue.

-source:

Flatworms lose their heads but not their memories: Study finds memories stored outside the brain

phys.org, August 2013

"An automated training paradigm reveals long-term memory in planaria and its persistence through head regeneration" Journal of Experimental Biology jeb.087809 First posted online July 2, 2013, DOI: 10.1242/jeb.087809

Revisiting the Motor Cortex

All of the images here represent your somatosensory cortex, the part of your brain that senses and controls the corresponding parts of your body. The goofy image that is forever paired with this concept was illustrated by Dr. Wilder Penfield, and never changed thereafter, until, of course, Joe Scordo did it for Hidden Scents, see below.

The 'Homunculus' illustrated by Joe Scordo for Hidden Scents

Penfield's image is perhaps the most well known in representing the motor cortex. Because of the success of the image, he is confused as having discovered it. It was, in fact, discovered decades earlier.

The Penfield map has changed little in the years since its release. Whether or not scientific diagrams should be updated to withstand current aesthetic considerations is beside the point. The 'Homunculus' illustrated by Joe Scordo for Hidden Scents is another step in the sequence of representation and seriality.

On Our Way to the Organic Internet

Embodied cognition, image via Synthetic Zero

Scientists develop brain-inspired memory material

phys.org, July 2016

I don't know about you, but this sounds like a brain in a box if I ever heard of one. There is a world out there that can't be accessed via words. It's a world of feelings and memories and experiences, not of knowledge and raw data. We live in this world, but our technology does not. One day, perhaps, we will no longer be soggy meatbodies. Until then, it's nice to think how close we can get our technologies to this thing, the Organic Internet.