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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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Interictal Epileptiform Patterns in Different Neurological Conditions

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Dr. Rishabh Pathak


Interictal epileptiform patterns (IEDs) can be observed in various neurological conditions beyond epilepsy. Their presence and characteristics can provide insights into the underlying pathology and help differentiate between different neurological disorders.

. Epilepsy

  • Primary Role: IEDs are most commonly associated with epilepsy, serving as a key diagnostic criterion. They indicate the presence of abnormal electrical activity in the brain that can lead to seizures.
  • Types of IEDs: Different types of IEDs (e.g., spikes, sharp waves) can correlate with specific epilepsy syndromes, such as temporal lobe epilepsy or focal cortical dysplasia.

2. Cerebral Dysgenesis and Malformations

  • Cortical Dysplasia: IEDs, particularly focal polyspikes, are often linked to cortical dysplasia, a condition where the brain's structure is abnormal due to developmental issues. This can lead to a higher likelihood of seizures.
  • Other Malformations: Conditions like polymicrogyria or lissencephaly may also present with IEDs, reflecting the underlying structural abnormalities in the brain.

3. Intellectual Disability

  • Association with IEDs: IEDs are frequently observed in individuals with intellectual disabilities, particularly when these disabilities are related to metabolic or chromosomal abnormalities. The presence of IEDs in this population often correlates with more severe cognitive impairment.

4. Traumatic Brain Injury (TBI)

  • Post-TBI Changes: Patients with a history of TBI may exhibit IEDs on EEG, which can indicate ongoing cortical irritability or damage. The presence of IEDs in this context may suggest a higher risk of developing post-traumatic epilepsy.

5. Neurodegenerative Disorders

  • Alzheimer’s Disease and Other Dementias: IEDs can occasionally be seen in patients with neurodegenerative conditions, such as Alzheimer’s disease. Their presence may reflect underlying cortical dysfunction and could be associated with cognitive decline.
  • Frontotemporal Dementia: Similar to Alzheimer’s, IEDs may appear in frontotemporal dementia, indicating abnormal electrical activity in the affected brain regions.

6. Psychiatric Disorders

  • Schizophrenia and Other Psychoses: Some studies have reported the presence of IEDs in patients with schizophrenia or other psychotic disorders. The clinical significance of these findings is still under investigation, but they may reflect underlying neurobiological changes.

7. Metabolic Disorders

  • Metabolic Encephalopathies: Conditions such as hepatic encephalopathy or uremic encephalopathy can lead to the appearance of IEDs on EEG. These patterns may indicate the brain's response to metabolic derangements.

Conclusion

Interictal epileptiform patterns are not exclusive to epilepsy and can be observed in a variety of neurological conditions. Their presence can provide valuable diagnostic information and insights into the underlying pathology. Understanding the context in which IEDs occur is essential for accurate diagnosis and management of patients with neurological disorders.

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