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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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Synaptic Deficits In Psychiatric Disorders

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Dr. Rishabh Pathak

Synaptic deficits are a common feature observed in various psychiatric disorders, contributing to the pathophysiology and symptoms associated with these conditions. Here are key insights into synaptic deficits in psychiatric disorders:


1.      Schizophrenia:

o Hypoconnectivity: Schizophrenia is characterized by synaptic hypoconnectivity, involving deficits in synaptic density, dendritic spine morphology, and synaptic protein expression in brain regions like the prefrontal cortex and hippocampus.

oGlutamatergic Dysfunction: Alterations in glutamatergic neurotransmission, including NMDA receptor hypofunction and disrupted synaptic plasticity, are implicated in schizophrenia pathogenesis.

o Synaptic Pruning Abnormalities: Dysregulation of synaptic pruning processes during neurodevelopment contributes to aberrant synaptic connectivity and cognitive impairments in schizophrenia.

2.     Depression:

o    Synaptic Atrophy: Depression is associated with synaptic atrophy, reduced synaptic density, and impaired synaptic plasticity in regions like the prefrontal cortex and hippocampus, affecting mood regulation and cognitive functions.

o    Neurotransmitter Imbalance: Dysregulation of monoaminergic neurotransmitters, such as serotonin and dopamine, can lead to synaptic deficits and altered synaptic transmission in depression.

oStress-Induced Changes: Chronic stress and elevated glucocorticoid levels associated with depression can impact synaptic structure and function, contributing to neuronal atrophy and synaptic loss.

3.     Bipolar Disorder:

o  Synaptic Dysfunction: Bipolar disorder is characterized by synaptic dysfunction, including alterations in synaptic plasticity mechanisms, neurotransmitter release, and dendritic spine morphology in brain regions like the amygdala and prefrontal cortex.

o    Excitatory/Inhibitory Imbalance: Imbalance between excitatory and inhibitory synaptic transmission, involving disruptions in glutamatergic and GABAergic signaling, is implicated in the pathophysiology of bipolar disorder.

o Circadian Rhythm Disruption: Dysregulation of circadian rhythms and clock genes can impact synaptic function and neuronal connectivity in individuals with bipolar disorder.

4.    Therapeutic Implications:

o  Targeting synaptic deficits through pharmacological interventions, cognitive-behavioral therapies, and neuromodulation techniques is a key focus in the treatment of psychiatric disorders.

o Strategies aimed at restoring synaptic plasticity, rebalancing neurotransmitter systems, and promoting neuroplasticity are being explored for their therapeutic potential in managing symptoms associated with synaptic deficits in psychiatric conditions.

By elucidating the synaptic deficits present in psychiatric disorders, researchers aim to develop novel treatment approaches that target specific synaptic pathways to restore normal synaptic function, improve neural connectivity, and alleviate symptoms in affected individuals.

 

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