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Metastability and Eye Movements: A Dynamical‑Systems Interpretation

  1. Why metastability is a natural language for gaze behavior The idea that perception, attention, and neural activity evolve through transiently stable states has deep roots in cognitive science and neuroscience. Concepts such as attractors , basins , noise‑induced transitions , and escape times appear in work on perceptual switching, decision‑making, and neural population dynamics (Kelso, 1995; Rabinovich et al., 2008; Deco & Jirsa, 2012). Eye movements, especially the alternation between fixations and saccades ,   fit remarkably well into this metastable picture. The Freidlin–Wentzell theory of rare events (Freidlin & Wentzell, 2012) provides a rigorous mathematical language for these intuitions. 2. Fixations as metastable states  Consider the gaze position X t as the state of a stochastic dynamical system. During a fixation the  gaze remains confined to a small region, microsaccades and noise generate small fluctuations, and the gaze tends to return...

The Relationship Between Weighted Geometric Mean and Shannon's Entropy

The geometric mean is a type of average that is useful for comparing quantities that have different units or vary over a wide range. It is defined as the n-th root of the product of n numbers G M = ( ∏ i = 1 n x i ) 1 / n The geometric mean has some interesting properties that make it useful for certain applications. For instance, the geometric mean is always less than or equal to the arithmetic mean (the ordinary average), and it is always greater than or equal to the harmonic mean (another type of average that is useful for rates and ratios). The geometric mean also preserves the ratios of the data values, meaning that multiplying or dividing all the data values by a constant does not change their geometric mean, and it tends to be closer to the smaller values in the data set. This makes it more robust to outliers and skewed distributions. However, the geometric mean has a limitation: it assumes that all the values in the...

R function Kullback_Leibler

The  Kullback_Leibler()  function calculates the  Kullback-Leibler divergence  between two probability distributions  p  and  q . The function takes two arguments  p  and  q , which can be either discrete or continuous probability distributions. The type of distribution is specified using the  type  argument. The function first checks the type of distributions and their lengths. If the distributions are discrete, it checks that they have non-negative values and sum to one. If the distributions are continuous, it checks that they have positive values. The Kullback-Leibler divergence is then calculated using the formula  sum(p * log(p / q)) . The function also calculates a normalized version of the divergence by dividing it by the entropy of  p . The asymmetry of the divergence is checked by swapping  p  and  q . Finally, the function returns a list of results that includes the Kullback-Leibler divergence...

The Kullback-Leibler Divergence: a bridge between Probability Theory and Information Theory

1. Introduction Evaluating the difference between two probability distributions is an important task in many fields of statistics, machine learning, and data science. For example, we may want to compare the performance of different models, test hypotheses about the underlying data-generating process, or measure the divergence or similarity between two populations or groups. There are different ways to evaluate the difference between two probability distributions, depending on the type and nature of the data, the assumptions we make about the distributions, and the goal of the analysis. Some common methods are: ·          The Kolmogorov-Smirnov test : This is a non-parametric test that compares the empirical cumulative distribution functions (CDFs) of two samples and measures the maximum vertical distance between them. The test can be used to check if two samples come from the same distribution or if one distribution is stochastically larger th...

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