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Uncertainty in Multiclass Classification

Dr. Rishabh Pathak
1. What is Uncertainty in Classification? Uncertainty refers to the model’s confidence or doubt in its predictions. Quantifying uncertainty is important to understand how reliable each prediction is. In multiclass classification , uncertainty estimates provide probabilities over multiple classes, reflecting how sure the model is about each possible class. 2. Methods to Estimate Uncertainty in Multiclass Classification Most multiclass classifiers provide methods such as: predict_proba: Returns a probability distribution across all classes. decision_function: Returns scores or margins for each class (sometimes called raw or uncalibrated confidence scores). The probability distribution from predict_proba captures the uncertainty by assigning a probability to each class. 3. Shape and Interpretation of predict_proba in Multiclass Output shape: (n_samples, n_classes) Each row corresponds to the probabilities of ...
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Gyrogenesis

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Dr. Rishabh Pathak

Gyrogenesis refers to the process of gyrus formation in the brain, specifically the development of the characteristic folds and grooves (gyri and sulci) on the surface of the cerebral cortex. This intricate process of cortical folding is essential for maximizing the surface area of the brain within the constraints of the skull, allowing for increased neuronal density and enhanced cognitive capabilities. Here is an overview of gyrogenesis and its significance in brain development:


1.  Timing of Gyrogenesis: Gyrogenesis begins around mid-gestation in human brain development, typically around week 23 of gestation. Primary sulci start to form, followed by the development of secondary and tertiary sulci as the brain continues to grow and mature. The process of gyrification continues throughout prenatal and postnatal development, shaping the convoluted surface of the cerebral cortex.


2.     Relationship to Neural Connectivity: Gyrogenesis is closely linked to neuronal connectivity and the establishment of functional neural circuits in the brain. The folding of the cortex allows for the spatial organization of different brain regions and facilitates efficient communication between neurons by reducing the distance over which signals need to travel. The convolutions created by gyrogenesis increase the surface area available for synaptic connections, supporting complex cognitive processes.


3. Regulation of Brain Function: The pattern of gyri and sulci formed during gyrogenesis is not random but follows a specific developmental trajectory that is influenced by genetic, environmental, and epigenetic factors. The unique folding patterns of individual brains contribute to variations in brain structure and function, including differences in cognitive abilities, sensory processing, and motor skills. Disruptions in gyrogenesis can impact brain connectivity and function, potentially leading to neurodevelopmental disorders.


4. Computational Modeling: Computational models have been developed to simulate the process of gyrogenesis and understand the underlying mechanisms that drive cortical folding. These models incorporate factors such as differential growth rates, mechanical forces, and genetic influences to predict the formation of gyri and sulci patterns observed in the human brain. By studying gyrogenesis computationally, researchers can gain insights into the complex interplay of biological and physical processes that shape brain morphology.


5. Clinical Implications: Abnormalities in gyrogenesis can manifest as cortical malformations, such as lissencephaly (smooth brain) or polymicrogyria (excessive small folds). These conditions are associated with developmental delays, intellectual disabilities, and epilepsy, highlighting the importance of proper cortical folding for normal brain function. Understanding the mechanisms of gyrogenesis and its disruptions is crucial for diagnosing and treating neurodevelopmental disorders.

In summary, gyrogenesis is a fundamental process in brain development that shapes the convoluted structure of the cerebral cortex, influencing neural connectivity, brain function, and cognitive abilities. The intricate folding patterns generated during gyrogenesis optimize the brain's capacity for information processing and are essential for normal brain development and function.
 

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