Furthermore, representational drift observes that a biological single neuron's output given activation is not stable over time; which implies that there is greater emergent complexity than is modeled with ANNs (which have stable outputs given training, NN topology parameters, and activation functions that effectively weight training samples (which are usually also noise))

/? Representational drift brain https://www.google.com/search?q=representational+drift+brain ...

"Causes and consequences of representational drift" (2019)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7385530/

> The nervous system learns new associations while maintaining memories over long periods, exhibiting a balance between flexibility and stability. Recent experiments reveal that neuronal representations of learned sensorimotor tasks continually change over days and weeks, even after animals have achieved expert behavioral performance. How is learned information stored to allow consistent behavior despite ongoing changes in neuronal activity? What functions could ongoing reconfiguration serve? We highlight recent experimental evidence for such representational drift in sensorimotor systems, and discuss how this fits into a framework of distributed population codes. We identify recent theoretical work that suggests computational roles for drift and argue that the recurrent and distributed nature of sensorimotor representations permits drift while limiting disruptive effects. We propose that representational drift may create error signals between interconnected brain regions that can be used to keep neural codes consistent in the presence of continual change. These concepts suggest experimental and theoretical approaches to studying both learning and maintenance of distributed and adaptive population codes.

"The geometry of representational drift in natural and artificial neural networks" (2022)
https://journals.plos.org/ploscompbiol/article?id=10.1371/jo... :

> [...] We examine stimulus representations from fluorescence recordings across hundreds of neurons in the visual cortex using in vivo two-photon calcium imaging and we corroborate previous studies finding that such representations change as experimental trials are repeated across days. This phenomenon has been termed “representational drift”. In this study we geometrically characterize the properties of representational drift in the primary visual cortex [...]

> The features we observe in the neural data are similar to properties of artificial neural networks where representations are updated by continual learning in the presence of dropout, i.e. a random masking of nodes/weights, but not other types of noise. Therefore, we conclude that a potential reason for the representational drift in biological networks is driven by an underlying dropout-like noise while continuously learning and that such a mechanism may be computational advantageous for the brain in the same way it is for artificial neural networks, e.g. preventing overfitting.

"Neurons are fickle: Electric fields are more reliable for information" (2022) https://www.sciencedaily.com/releases/2022/03/220311115326.h... :

> [...] And when the scientists trained software called a "decoder" to guess which direction the animals were holding in mind, the decoder was relatively better able to do it based on the electric fields than based on the neural activity.

> This is not to say that the variations among individual neurons is meaningless noise, Miller said. The thoughts and sensations of people and animals experience, even as they repeat the same tasks, can change minute by minute, leading to different neurons behaving differently than they just did. The important thing for the sake of accomplishing the memory task is that the overall field remains consistent in its representation.

> "This stuff that we call representational drift or noise may be real computations the brain is doing, but the point is that at that next level up of electric fields, you can get rid of that drift and just have the signal," Miller said.

> The researchers hypothesize that the field even appears to be a means the brain can employ to sculpt information flow to ensure the desired result. By imposing that a particular field emerge, it directs the activity of the participating neurons.

> Indeed, that's one of the next questions the scientists are investigating: Could electric fields be a means of controlling neurons?

/? representational drift site:github.com
https://www.google.com/search?q=representational+drift+site%...