are worms more complex than humans?
DESCRIPTION
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) - PowerPoint PPT PresentationTRANSCRIPT
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)
• Correlation dimension (topologic dimension of an attractor). Kolmogorov entropy.
• Neural Complexity (functional clustering)
Is it complex?
3 1 4 1 5 9 2 6 5 3 …
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
X1(I)
I
Claims:
1. There is no unique measure of complexity.
Amplitude distributions
Amplitude Amplitude
Which one is more complex?
Data points Data points
Frequency Frequency
Power spectraPhase space reconstruction
Which one is more complex?
Data points Data points
Amplitude distribution
Amplitudes AmplitudesFrequency Frequency
Power spectraPhase space reconstruction
Claims:
1. There is no unique measure of complexity.
2. Complexity depends on how we measure and represent the data.
Which one is more complex?
Complexity
Disorder
Adapted from P. Grassberger, ‘89
Claims:
1. There is no unique measure of complexity.
2. Complexity depends on how we measure and represent the data.
3. Complexity is low both for order and randomness.
Which one is more complex?
Complexity
Disorder
V1 V4
V3
T ~ < V >
V1
V2
Classical mechanics
Classical mechanics
Statistical mechanics
Tossing a coin
Claims:
1. There is no unique measure of complexity.
2. Complexity depends on how we measure and represent the data.
3. Complexity is low both for order and randomness.
But randomness is relative!(it depends on measurements, analysis
tools, computer power, etc.)
Complexity of the brain
Images from D. van Essen’s lab
Complexity of the brain
Oztia! The brain is simple, Just half a kilo of matter.
• Complexity Evolution
• Complexity Behavior
• Complexity Consciousness
Complexity of the brainGoogle: 374000 hits
Can we measure this from brain data?
Complexity and consciousness
Complexity
Disorder
Seizure EEG
Normal EEG
Complexity and consciousness
Quian Quiroga et al, 2001
Claims:
1. There is no unique measure of complexity.
2. Complexity depends on how we measure and represent the data.
3. Complexity is low both for order and randomness. (?!?!?!)
4. Is it useful?
30 sec EEG 30 sec EEG
Frequency (Hz) Frequency (Hz)
Complexity and Behavior
Awake Deep sleep
Thalamo-cortical networks
They generate sleep spindles and spike wave discharges
Adapted from M. Steriade’s work
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.
Claims: (open for discussion)
1. There is no unique measure of complexity.
2. Complexity depends on how we measure and represent the data.
3. Complexity is low both for order and randomness. (?!?!?!)
4. Is it useful?
Which one is more complex?