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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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The Role of Polysialylation in Brain Development

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Dr. Rishabh Pathak

Polysialylation, the addition of polysialic acid chains to glycoproteins like the Neural Cell Adhesion Molecule (NCAM), plays a crucial role in brain development. Here are key points outlining the significance of polysialylation in brain development:

1.      Neuronal Migration:

oPolysialylation of NCAM is essential for neuronal migration during brain development.

oPolysialic acid chains on NCAM reduce cell adhesion, allowing migrating neurons to detach from neighboring cells and move to their appropriate locations in the developing brain.

2.     Axon Guidance:

oPolysialylation of NCAM is involved in axon guidance, the process by which growing axons navigate to their target regions to establish neural circuits.

oPolysialic acid on NCAM modulates axon growth cone behavior, facilitating the extension of axons and their pathfinding to specific target areas.

3.     Synaptic Plasticity:

oPolysialylation of NCAM contributes to synaptic plasticity, the ability of synapses to strengthen or weaken in response to activity and experience.

oPolysialic acid on NCAM influences synaptic remodeling, synaptic connectivity, and the formation of new synaptic contacts during brain development.

4.    Neurite Outgrowth:

oPolysialylated NCAM promotes neurite outgrowth, the extension of neuronal processes such as axons and dendrites.

oPolysialic acid chains on NCAM reduce adhesion between neurites, allowing for increased exploratory behavior of growth cones and facilitating the extension of neuronal processes.

5.     Plasticity and Learning:

oPolysialylation of NCAM is associated with synaptic plasticity, learning, and memory formation in the brain.

o Dynamic regulation of polysialic acid levels on NCAM influences the adaptability of neural circuits, which is essential for learning and memory processes.

6.    Neurodevelopmental Disorders:

oDysregulation of polysialylation has been linked to neurodevelopmental disorders such as autism spectrum disorders, schizophrenia, and intellectual disabilities.

o Altered polysialylation of NCAM can disrupt neuronal migration, axon guidance, and synaptic connectivity, contributing to the pathogenesis of these disorders.

In summary, polysialylation of NCAM plays a critical role in brain development by regulating processes such as neuronal migration, axon guidance, synaptic plasticity, neurite outgrowth, and learning. The dynamic modulation of polysialic acid levels on NCAM is essential for the proper wiring of the developing brain and the establishment of functional neural circuits necessary for normal brain function and behavior.

 

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