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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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Role Of PIP2 Metabolism At The Neuronal Synapse

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Dr. Rishabh Pathak

Phosphatidylinositol 4,5-bisphosphate (PIP2) metabolism plays a crucial role at the neuronal synapse, influencing various aspects of synaptic function and neurotransmission. Here is an overview of the role of PIP2 metabolism at the neuronal synapse:


1.      Regulation of Ion Channels:

o Ion Channel Modulation: PIP2 interacts with ion channels, including potassium and calcium channels, regulating their activity and membrane localization.

o    Neuronal Excitability: By modulating ion channel function, PIP2 metabolism influences neuronal excitability and action potential firing at the synapse.

2.     Actin Cytoskeleton Dynamics:

o Actin Binding Proteins: PIP2 interacts with actin-binding proteins, such as profilin and gelsolin, regulating actin polymerization and cytoskeletal dynamics.

o Synaptic Structure: PIP2 metabolism contributes to the organization of the actin cytoskeleton at the synapse, influencing synaptic structure and plasticity.

3.     Regulation of Synaptic Vesicle Cycling:

o    Vesicle Trafficking: PIP2 is involved in regulating synaptic vesicle trafficking, docking, and fusion at the presynaptic terminal.

o  Exocytosis and Endocytosis: PIP2 metabolism modulates the dynamics of vesicle exocytosis and endocytosis, impacting neurotransmitter release and synaptic vesicle recycling.

4.    Interaction with Synaptic Proteins:

o    SNARE Complex: PIP2 interacts with SNARE proteins and other synaptic proteins involved in vesicle fusion and neurotransmitter release.

o    Priming Vesicle Fusion: PIP2 metabolism influences the priming of synaptic vesicles for fusion by regulating the assembly and function of the SNARE complex.

5.     Neuromodulation and Plasticity:

o Neurotransmitter Receptors: PIP2 modulates the activity of neurotransmitter receptors, including G protein-coupled receptors and ionotropic receptors.

o    Synaptic Plasticity: Changes in PIP2 levels can impact synaptic plasticity mechanisms, such as long-term potentiation (LTP) and long-term depression (LTD), affecting synaptic strength and connectivity.

6.    Signal Transduction Pathways:

o    Second Messenger Production: PIP2 serves as a precursor for second messengers, such as inositol trisphosphate (IP3) and diacylglycerol (DAG), involved in intracellular signaling cascades.

o Neuronal Signaling: PIP2 metabolism influences signal transduction pathways that regulate synaptic transmission, neuronal excitability, and synaptic plasticity.

Understanding the role of PIP2 metabolism at the neuronal synapse provides insights into the molecular mechanisms governing synaptic function and communication. Dysregulation of PIP2 signaling pathways can impact synaptic transmission and contribute to neurological disorders characterized by synaptic dysfunction. Studying the dynamic regulation of PIP2 metabolism offers potential therapeutic targets for modulating synaptic activity and restoring proper neuronal function in health and disease.

 

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