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Unveiling Hidden Neural Codes: SIMPL – A Scalable and Fast Approach for Optimizing Latent Variables and Tuning Curves in Neural Population Data

Dr. Rishabh Pathak
This research paper presents SIMPL (Scalable Iterative Maximization of Population-coded Latents), a novel, computationally efficient algorithm designed to refine the estimation of latent variables and tuning curves from neural population activity. Latent variables in neural data represent essential low-dimensional quantities encoding behavioral or cognitive states, which neuroscientists seek to identify to understand brain computations better. Background and Motivation Traditional approaches commonly assume the observed behavioral variable as the latent neural code. However, this assumption can lead to inaccuracies because neural activity sometimes encodes internal cognitive states differing subtly from observable behavior (e.g., anticipation, mental simulation). Existing latent variable models face challenges such as high computational cost, poor scalability to large datasets, limited expressiveness of tuning models, or difficulties interpreting complex neural network-based functio...
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What are the eight basic principles of brain plasticity?

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Dr. Rishabh Pathak

The eight basic principles of brain plasticity identified in the article are as follows:


1.     Experience-Dependent Changes: The brain changes in response to experiences, and these changes can occur at various levels of analysis.


2.     Synaptic Pruning and Formation: While synaptic pruning is important in brain development, synapses continue to form throughout life and are essential for learning and memory processes.


3. Experience-Expectant Synapses: Early forming synapses are "expecting" experiences, which then prune them back. These synapses are found diffusely throughout the cerebrum.


4.  Experience-Dependent Synapses: Later synapse formation is more focal and localized to regions involved in processing specific experiences.


5.   Selective Synapse Formation and Pruning: Specific experiences lead to both selective synapse formation and selective synaptic loss, changing neural networks by adding and pruning synapses.


6.     Plastic Changes in Brain Organization: Plastic changes in brain organization can be studied at various levels, with gene expression being the fundamental mechanism of synaptic change.


7.  Not All Plasticity is Beneficial: While plastic changes generally support improved motor and cognitive functions, they can also interfere with behavior, leading to maladaptive outcomes in conditions like drug addiction, pathological pain, epilepsy, schizophrenia, and dementia.


8.     Pathological Plasticity in Development: Examples of pathological plasticity in the developing brain include fetal alcohol spectrum disorder and the effects of severe prenatal stress, which can impact cognitive and motor functions in both development and adulthood.


These principles highlight the dynamic and complex nature of brain plasticity, emphasizing how experiences, synapse formation and pruning, and the potential for both beneficial and detrimental plastic changes play crucial roles in shaping brain development and function.

 

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