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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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Distinguishing Features of Fourteen and Six Per Second Positive Bursts (Ctenoids)

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Dr. Rishabh Pathak


 

The distinguishing features of Fourteen and Six Per Second Positive Bursts, also known as Ctenoids, help differentiate them from other EEG patterns and epileptiform activities. 


1.     Frequency and Duration:

o Ctenoids typically exhibit rhythmic activity at frequencies ranging from 6 to 14 Hz, with bursts lasting for about 1 second.

2.   Amplitude:

o The amplitude of Ctenoids is usually low, rarely exceeding 150 μV, with more common amplitudes around 75 μV.

3.   Spatial Distribution:

o Ctenoids have a broad and uniformly distributed field, often best recorded with long interelectrode distances to capture the pattern accurately.

4.   Electrode Montages:

o Contralateral ear reference montages provide maximal amplitude waves for Ctenoids, while ipsilateral ear reference montages may misrepresent the localization of the activity.

5.    Waveform Appearance:

o Ctenoids present as arciform repetitions with an arc-like shape in EEG channels, often showing sharply contoured components pointing downward, termed "positive".

6.   Benign Nature:

o  Ctenoids are considered benign epileptiform variants and are typically not associated with pathological conditions or epileptic seizures.

7.    Prevalence:

o  Ctenoids are relatively common in EEG recordings of healthy individuals and may not require specific medical intervention or treatment.

8.   Differential Diagnosis:

o Distinguishing Ctenoids from pathological epileptiform discharges is crucial to avoid misinterpretation and unnecessary medical interventions.

9.   Research and Studies:

o Various studies have focused on the electroencephalographic characteristics, prevalence, and clinical correlates of Ctenoids to differentiate them from epileptic activities.

By recognizing these distinguishing features of Fourteen and Six Per Second Positive Bursts (Ctenoids), healthcare providers and EEG interpreters can accurately identify and differentiate this benign EEG pattern from pathological findings, ensuring appropriate clinical management and avoiding unnecessary alarm or intervention in individuals with these characteristic waveforms.


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