Bayesian%20Brain

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Bayesian Brain

• Presented by Nguyen Duc Thang

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Contents

• Introduction
• Bottom-up approach
• Top-down approach
• Vision recognition, brain computer interface
  (BCI), and artificial general intelligence (AGI)

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Introduction

• Old dream of all philosophers and more recently
  of AI
• understand how the brain works
• make intelligent machines

T. Poggio Visual recognition in primates and
machines, NIPS07 tutorial
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Bayes rule
K. Kording Decision Theory What "Should" the
Nervous System Do?, Science 26 Oct. 2007
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Bayes rule
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Free energy and brain
Any adaptive change in the brain will minimize
the free-energy, this is correspondent to
Bayesian inference process make prediction about
the world and update based on what it senses
Friston K., Stephan KE. Free energy and the
brain, Synthese, 2007
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Two approaches of Bayesian brain

• Bottom-up approach
• How the brain works?
• Top-down approach
• Machine intelligence
• When two approaches meet together?

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Bottom-up approach
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Bayesian population code
- Single neural the spike counts satisfy the
Poisson distribution - A group of neural decode
the stimulus by Gaussian distribution
Ma W.J.,Beck J., Latham P., Pouget A. Bayesian
inference with probabilistic population codes,
Nature Neuroscience, 2006
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Bayesian inference
Sum of two population codes is equivalent to
taking the product of their encoded distributions
Beck J., Ma W.J., Kiani R., Hanks T., Churchland
A.K., Roitman L. , Shadlen M.N., Latham P.,
Pouget A. Probabilistic population codes for
Bayesian decision making , Neuron, 2008
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Blue brain project
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Top-down approach

• Machine intelligence
• Is based on the Bayes theorem, build a
  probabilistic framework for one specific problem,
  and apply Bayesian inference to find solutions
• Bayesian inference belief propagation,
  variational method, and non-parametric method
• Some journals IJCV, PAMI, CVIU, JMLR

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Interesting results
Automatically discover structure form, ontology,
causal relationships
Kemp C., Tenenbaum J. B. The discovery of
structural form, PNAS 2008
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Related researches

• Vision recognition
• Brain computer interface (BCI)
• Artificial general intelligence (AGI)

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David Hunter Hubel (born February 27, 1926) was
co-recipient with Torsten Wiesel of the
1981 Nobel Prize in Physiology or Medicine, for
their discoveries concerning information
processing in the visual system
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Vision recognition
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Classify animal and non-animal
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Results
Serre T., Oliva A., Poggio T. A feedforward
architecture accounts for rapid categorization,
PNAS 2007
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What is next beyond the feedforward models
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Hierarchy Bayesian inference
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Brain-Computer interface (BCI)

• A braincomputer interface (BCI), sometimes
  called a direct neural interface or a
  brainmachine interface, is a direct
  communication pathway between a brain and an
  external devices
• Invasive BCI direct brain implants restore sight
  for blindness, hand-control for persons with
  paralysis
• Non-invasive BCI EEG, MEG, MRI
• Interesting results research developed in the
  Advanced Telecommunications (ATR) Computational
  Neuroscience LAB in Kyoto, Japan allowed the
  scientists to reconstruct images directly from
  the brain and display them on a computer.

Miyawaki Y., Decoding the minds eye-visual
image reconstruction from human brain activity
using a combination of multiscale local image
decoders, Neuron Dec.2008
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Artificial General Intelligence (Strong AI)

• Weak AI only claims that machines can act
  intelligently. Strong AI claims that a machine
  that acts intelligently also has mind and
  understands in the same sense people do
• More information on the AGI conference 2009
• Prediction singularity in 2045
• Two different opinions
• I, robot (2004) Eagle eye (2008)
• Cyborg girl (2008) Doraemon

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My opinion