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Are worms more complex than humans?

Are worms more complex than humans?. Rodrigo Quian Quiroga Sloan-Swartz Center for Theoretical Neurobiology. Caltech. Complexity measures. Shannon information (entropy) Algorithmic complexity (length of the shortest code). Logical deep (time taken by the shortest code)

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Are worms more complex than humans?

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  1. Are worms more complex than humans? Rodrigo Quian Quiroga Sloan-Swartz Center for Theoretical Neurobiology. Caltech

  2. Complexity measures • Shannon information (entropy) • Algorithmic complexity (length of the shortest code). Logical deep (time taken by the shortest code) • Correlation dimension (topologic dimension of an attractor). Kolmogorov entropy. • Neural Complexity (functional clustering)

  3. X1(I) X1( 1 ) = 0.1 X2( 1 ) = 0.3 DO I = 1, N X1(I+1) = 1.4 - X1(I)**2 + 0.3 * X2(I) X2(I+1) = X1(I) END DO I Is it complex? 31 41 5 9 2653 …

  4. Claims: • There is no unique measure of complexity.

  5. Power spectra Phase space reconstruction Amplitude distributions Frequency Frequency Amplitude Amplitude Which one is more complex? Data points Data points

  6. Phase space reconstruction Amplitude distribution Power spectra Amplitudes Frequency Amplitudes Frequency Which one is more complex? Data points Data points

  7. Claims: • There is no unique measure of complexity. • Complexity depends on how we measure and represent the data.

  8. Complexity Disorder Which one is more complex? Adapted from P. Grassberger, ‘89

  9. Claims: • There is no unique measure of complexity. • Complexity depends on how we measure and represent the data. • Complexity is low both for order and randomness.

  10. Classical mechanics Classical mechanics Statistical mechanics V1 V3 V1 V4 V2 T ~ < V > Complexity Disorder Which one is more complex?

  11. Tossing a coin

  12. Claims: • There is no unique measure of complexity. • Complexity depends on how we measure and represent the data. • Complexity is low both for order and randomness. But randomness is relative! (it depends on measurements, analysis tools, computer power, etc.)

  13. Complexity of the brain Images from D. van Essen’s lab

  14. Oztia! The brain is simple, Just half a kilo of matter. Complexity of the brain

  15. Complexity of the brain Google: 374000 hits • Complexity  Evolution • Complexity  Behavior • Complexity  Consciousness Can we measure this from brain data?

  16. Complexity and consciousness

  17. Complexity Disorder Complexity and consciousness Seizure EEG Normal EEG

  18. Quian Quiroga et al, 2001

  19. Claims: • There is no unique measure of complexity. • Complexity depends on how we measure and represent the data. • Complexity is low both for order and randomness.(?!?!?!) • Is it useful?

  20. Awake Deep sleep Complexity and Behavior 30 sec EEG 30 sec EEG Frequency (Hz) Frequency (Hz)

  21. Thalamo-cortical networks Adapted from M. Steriade’s work They generate sleep spindles and spike wave discharges

  22. Why worms can be more complex than humans? • Ideally: • Background activity  random (functional) conectivity • Complex behavior  activation of a complex network • In practice: • A very complex network may look random, whereas a simpler one may show high complexity. • This depends on: measurement (# of neurons, noise, etc.), analysis tools, definition of complexity, etc.

  23. Claims: (open for discussion) • There is no unique measure of complexity. • Complexity depends on how we measure and represent the data. • Complexity is low both for order and randomness. (?!?!?!) • Is it useful?

  24. Which one is more complex?

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