Symmetry Memory

In early memory formation and higher-level brain function, the symmetrical synaptic connections of neurons are achieved by neuron A forming a synapse on neuron B, which in turn forms a synapse on neuron A, and so on. This creates a two-way street for information flow or mutual influence. If two events (or representations) consistently occur, the neurons representing them might form reciprocal connections. Activating one neuron can then more easily activate the other, creating an association (a basic building block of memory). Reciprocal connections are fundamental to feedback loops. In the prefrontal cortex, these loops are crucial for working memory (holding information online), planning, and error correction. In the hippocampus, they're vital for memory consolidation and pattern completion (recalling a full memory from a partial cue). Symmetrical connections can support reverberating circuits where activity can persist even after the initial stimulus. This is important for short-term memory and the initial stages of long-term memory consolidation.



While not strictly a symmetrical connection between two specific neurons, this refers to a balance in the overall excitatory and inhibitory inputs a neuron or a local circuit receives. When two neurons are interconnected, their effects on each other may be balanced, or their plasticity mechanisms may be similar. A balance between excitation and inhibition prevents runaway excitation (leading to seizures) or excessive silencing, allowing for stable and precise neural representations. This balance is critical for sharpening signals, improving signal-to-noise ratio, and enabling complex computations required for reasoning. Brains maintain stability despite ongoing learning. If some connections strengthen, others might weaken, or inhibitory connections might adjust, maintaining an overall functional symmetry or balance.




Memories began to form from simple chemical reactions to light. An early, perhaps primitive form of learning where environmental stimuli (light) drive changes in neural connectivity. Reciprocal connections could arise from neurons consistently co-activated by such stimuli. Results of the reactions began to link together. Symmetric (or reciprocal) connections are associative processes in neurons. Neurologically, this is likely tied to the brain’s ability to form and strengthen connections in areas like the prefrontal cortex for reasoning and the hippocampus for memory. These foundational symmetrical principles scale up to support complex cognitive functions. The hippocampus relies heavily on reciprocal connectivity for associative memory, and the prefrontal cortex uses extensive recurrent (which includes reciprocal) connections for executive functions.





By emphasizing mutual influence, balanced interactions, and shared plasticity rules, symmetric synaptic connections provide a conceptual bridge from basic associative mechanisms to the complex, interconnected networks that underpin sophisticated cognitive abilities such as memory and reasoning. Reciprocal connections are the most direct neurological correlates.


 

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What is Hebbian Learning?
Hebbian Learning explains how neurons adapt and form stronger connections through repeated use. Each time a memory is recalled or an action is repeated, the neural pathways involved become more robust as they fire together, making that action or memory more intuitive or easy to reproduce.
https://thedecisionlab.com/reference-guide/neuroscience/hebbian-learning

Hebbian Learning - The Decision Lab

 



Symmetry energy in nuclei and neutron stars
https://www.sciencedirect.com/science/article/abs/pii/S0375947414000906

Scientists build largest maps to date of cells in human brain
https://www.nih.gov/news-events/nih-research-matters/scientists-build-largest-maps-date-cells-human-brain

Scientists build largest maps to date of cells in human brain

If a symmetry is preserved under a transformation it is said to be invariant. Symmetries in nature lead directly to conservation laws, something which is precisely formulated by Noether's theorem.
https://en.m.wikipedia.org/wiki/Time-translation_symmetry

Time-translation symmetry - Wikipedia