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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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Ocular Artifacts Compared to Delta Activity

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Dr. Rishabh Pathak

Ocular artifacts and delta activity in EEG recordings can share some similarities but also have key differences that help differentiate between the two.

Comparison:

o   Both isolated monomorphic frontal slow waves seen in ocular artifacts and frontal intermittent rhythmic delta activity (FIRDA) have similar wave duration and field distribution.

o  Ocular artifacts, including those from blinks, eye flutter, lateral gaze, and rapid eye movements, can resemble delta activity in terms of waveform characteristics and frequency range.

o  Repetitive blinks and blepharospasm can produce ocular artifacts that resemble delta activity but may have distinguishing features related to the nature and frequency of eye movements.

2.     Differentiation:

o  Ocular artifacts do not extend into the central region, unlike delta activity, which can be more widespread across the scalp.

o    The field of ocular artifacts is typically limited to the frontal regions, while delta activity may have a broader distribution across the scalp.

o Waveform differences, such as the contour and phase reversals between specific electrode channels, can help differentiate ocular artifacts from delta activity.

Understanding the similarities and differences between ocular artifacts and delta activity is essential for accurate EEG interpretation, as misinterpretation of ocular artifacts as pathological delta activity can lead to incorrect clinical conclusions.

 

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