Brain Entropy

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Concept

Video

Paper

1.Entropy from Thermodynamic to Brain Science

1.1 What is the Entropy

• Entropy is a scientific concept as well as a measurable physical property that is most commonly associated with a state of disorder, randomness, or uncertainty.

1.2 Entropy in Thermodynamic

• The second law of thermodynamics states that the total entropy of a system either increases or remains constant in any spontaneous process; it never decreases. An important implication of this law is that heat transfers energy spontaneously from higher- to lower-temperature objects, but never spontaneously in the reverse direction.

1.3 Entropy in Information Theory

• In information theory, the entropy of a random variable is the average level of “information”, “surprise”, or “uncertainty” inherent to the variable’s possible outcomes.

1.4 Entropy in Biological Signal Measure

• Pincus (1991) introduced Approximate Entropy (ApEn) , a set of measures of system complexity closely related to entropy, which is easily applied to clinical cardiovascular and other time series.

• Sample Entropy (SampEn) is a modification of approximate entropy (ApEn), used for assessing the complexity of physiological time-series signals, diagnosing diseased states.

2. Entropy Calculation

• Click Distance Measures to try Calculate different Distances including Euclidean Distance， Chebyshev Distance and Manhattan Distance.

• Click Calculate Entropy to try Calculate Shannon Entropy, Approximate Entropy, Sample Entropy.

3. fMRI-based Brain Entropy Mapping

• Dr. Ze Wang (2014) proposed a fMRI-based Brain Entropy Mapping for resting-state fMRI using sample entropy, you can find the original paper from Brain Entropy Mapping Using fMRI ,and he created a Brain Entropy Mapping Toolbox named BENtbx. You can download BENtbx from https://github.com/zewangnew/BENtbx or go to https://cfn.upenn.edu/zewang/BENtbx.php to download the sample data and matlab code.

4. fMRI-based Brain Entropy Research

4.1. Brain Entropy (BEN) and others measures in the resting brain

Brain entropy provides unique information that cannot be revealed by CBF and fALFF (Donghui Song et al., 2019b, Brain Imaging and Behavior). a. correlation of BEN and CBF; b. correlation of BEN and fALFF; c. correlation of CBF and fALFF

4.2. Brain Entropy and rTMS

Reduced Brain Entropy by rTMS on the left DLPFC in healthy young adults(Donghui Song et al., 2019a, Brain Imaging and Behavior). a. post-rTMS vs pre-rTMS; b. post-SHAM vs pre-SHAM; c. rTMS-SHAM

4.3. Brain Entropy and Fluid Intelligence

Association of brain entropy and fluid intelligence in the young adults brain from HCP (Ze Wang,2021,Neuroimage)

Association of brain entropy and fluid intelligence in the adolescence brain from ABCD study (Donghui Song et al.,2021,OHBM2021)

5. Acknowledgements

Wang Lab at University of Maryland School of Medicine