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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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White Matter (WM)

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Dr. Rishabh Pathak

White matter (WM) is one of the two main types of tissue in the brain, along with gray matter. Here is an overview of white matter in the brain:


1.      Composition:

oWhite matter consists primarily of myelinated nerve fibers, which are long extensions of nerve cells (neurons) that form connections between different brain regions.

o The white appearance of this tissue is due to the high concentration of myelin, a fatty substance that insulates and protects the nerve fibers, facilitating the rapid transmission of electrical signals between neurons.

2.     Function:

oWhite matter plays a crucial role in facilitating communication between different regions of the brain by transmitting electrical impulses along the nerve fibers.

oIt forms the neural pathways that connect various brain areas, allowing for coordinated functioning of different brain regions involved in sensory processing, motor control, cognition, and other functions.

3.     Structure:

oWhite matter is located deep within the brain and spinal cord, surrounding the gray matter regions.

oIt is organized into bundles of nerve fibers called tracts, which can be classified based on their function and the brain regions they connect.

oWhite matter tracts can be visualized using neuroimaging techniques such as diffusion tensor imaging (DTI), which measures the diffusion of water molecules along the nerve fibers to map the structural connectivity of the brain.

4.    Role in Brain Health:

oHealthy white matter is essential for efficient neural communication and cognitive functioning. Disruptions in white matter integrity, such as demyelination or axonal damage, can impair signal transmission and lead to neurological deficits.

oWhite matter abnormalities have been implicated in various neurological conditions, including multiple sclerosis, Alzheimer's disease, stroke, and psychiatric disorders like schizophrenia.

5.     Plasticity:

oWhile white matter was traditionally viewed as a static component of the brain, research has shown that it exhibits structural and functional plasticity in response to learning, experience, and environmental stimuli.

oWhite matter plasticity involves changes in the organization and connectivity of neural pathways, reflecting the brain's ability to adapt and rewire in response to new challenges or experiences.

6.    Research and Clinical Applications:

oStudying white matter structure and connectivity is crucial for understanding brain development, aging, and neurological disorders.

oAdvances in neuroimaging techniques have enabled researchers and clinicians to investigate white matter integrity, connectivity patterns, and their implications for brain function and dysfunction.

In summary, white matter plays a vital role in facilitating communication between different brain regions, supporting cognitive functions, and maintaining overall brain health. Understanding the structure, function, and plasticity of white matter is essential for unraveling the complexities of brain connectivity and neurological disorders.

 

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