Friday, March 21, 2025

Levy Things and Data Management

 

There's a whole bag of words referring to this one phenomenon we call foraging behavior. Animals poke around for food, poke, poke, poke, and then move to another spot, and poke, poke, poke. A big jump followed by a bunch of little jumps, followed by a big jump, etc. The explore-exploit heuristic it's also called. This behavior is found in many other places, from the way people look for a job to the way atoms move. That's called Brownian motion, or the Drunkard's Walk. It's found in the unconscious  uncontrollable way our eyes move when we look at things, and it's kind of even related to the way we choose baby names over decades. 

The following articles are mostly tangentially related to this phenomenon; they're about navigation and vision, and information theory in general. 
 
A new mechanism for animal food caching behavior discovered
Aug 2024, phys.org

Contrary to the long-held belief that scatter-hoarding animals rely on memory to retrieve cached food items, the researchers propose a static mechanism similar to hash functions used in computing. Hash functions in computing are algorithms that convert input data of any size into a fixed-size string of characters, which typically represents the data in a unique and efficient manner.

The researchers' mathematical model aligns with the activity of hippocampal spatial cells, which respond to an animal's positional attention. The remapping ensures that these cells activate consistently across subsequent visits to the same area but differ between areas.

This remapping, combined with unique cognitive maps, generates persistent hash functions that can aid both food caching and retrieval.

In other words: Both layers are arranged in a two-dimensional grid, with each cell corresponding to a specific location. The cache site is determined by the activity level of the output neurons, known as the cache score.

via Department of Cognition and Brain Sciences and The Department of Animal Sciences at Hebrew University of Jerusalem: Sharon Mordechay et al, A non-memory-based functional neural framework for animal caching behavior, Scientific Reports (2024). DOI: 10.1038/s41598-024-68003-8



Grid cells' rhythmic sweeps reshape understanding of brain's spatial navigation
Feb 2025, phys.org

Grid cells alternate between tracking an animal's real-time position and scanning the environment ahead in a highly regular pattern—sweeping 30 degrees to the right, then 30 degrees to the left—at a rapid pace of ten times per second.

These rhythmic sweeps create a more efficient way to anchor locations relative to one another, providing a richer and more adaptable navigation system than previously imagined.

So it's not exactly the eyes sweeping but the brain?

via Kavli Institute at the Norwegian University of Science and Technology: Abraham Z. Vollan et al, Left–right-alternating theta sweeps in entorhinal–hippocampal maps of space, Nature (2025). DOI: 10.1038/s41586-024-08527-1


How eye saccades enable mammals to simultaneously chase prey and navigate through complex environments
Feb 2025, phys.org

It's almost like we're not designed to look at static images:

Researchers reconstructed the visual fields of freely moving ferrets that were chasing a fleeing target and discovered that eye saccades (very rapid coordinated eye movements) align the world motion—and not the actual thing they are chasing—to the retina and retinal specializations used for high-acuity vision.

Saccades achieve this by countering head rotations to align the area of the sharpest vision with the direction of intended travel and the area of the least motion-induced blur. 

via Max Planck Institute for Neurobiology of Behavior and Max Planck Florida Institute for Neuroscience: Eye saccades align optic flow with retinal specializations during object pursuit in freely moving ferrets, Current Biology (2025). DOI: 10.1016/j.cub.2024.12.032.


No comments:

Post a Comment