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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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Theta Burst Stimulation (TBS)

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Dr. Rishabh Pathak

Theta Burst Stimulation (TBS) is a form of repetitive transcranial magnetic stimulation (rTMS) that has gained attention in neuroscience and clinical research for its ability to modulate cortical excitability and induce lasting effects on brain function. Here is an overview of Theta Burst Stimulation (TBS):


1.      Definition:

oTheta Burst Stimulation (TBS) is a patterned form of repetitive transcranial magnetic stimulation (rTMS) that involves delivering bursts of magnetic pulses at a specific frequency (typically theta frequency, around 5 Hz) to targeted regions of the brain.

2.     Types of TBS:

o    There are two main types of Theta Burst Stimulation:

§ Continuous Theta Burst Stimulation (cTBS): Involves continuous bursts of stimulation over a period of time, typically leading to inhibitory effects on cortical excitability.

§Intermittent Theta Burst Stimulation (iTBS): Involves intermittent bursts of stimulation with short breaks in between, often resulting in facilitatory effects on cortical excitability.

3.     Effects on Cortical Excitability:

oTBS protocols have been shown to induce changes in cortical excitability that outlast the stimulation period. Inhibitory TBS can lead to long-term depression (LTD) of synaptic activity, while facilitatory TBS can induce long-term potentiation (LTP), resembling mechanisms of synaptic plasticity.

4.    Research and Therapeutic Applications:

oTBS has been widely used in research settings to investigate neural plasticity, motor learning, and cognitive functions. It is also being explored as a potential therapeutic tool for various neurological and psychiatric conditions.

5.     Clinical Applications:

oTBS has shown promise in the treatment of neurological and psychiatric disorders, including depression, schizophrenia, chronic pain, stroke rehabilitation, and movement disorders like Parkinson's disease. It is being studied as a non-invasive neuromodulation technique with potential therapeutic benefits.

6.    Targeted Brain Regions:

oTBS can be applied to specific brain regions based on the research or clinical objectives. Common targets include the primary motor cortex (M1), dorsolateral prefrontal cortex (DLPFC), cerebellum, and other areas implicated in motor control, mood regulation, and cognitive functions.

7.     Safety and Efficacy:

oTBS is generally considered safe when administered by trained professionals following established protocols. It is non-invasive and well-tolerated by most individuals. However, individual responses to TBS may vary, and its long-term effects are still being studied.

In summary, Theta Burst Stimulation (TBS) is a specialized form of repetitive transcranial magnetic stimulation that can modulate cortical excitability and induce lasting changes in brain function. Its potential applications in research and clinical settings make it a valuable tool for studying neural plasticity and exploring therapeutic interventions for various neurological and psychiatric conditions.

 

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