Contents

• Contents
• List of Figures
• 1 Introduction
• 2 Related Work
  • 2.1 Anatomy and physiology of the visual system
  • 2.2 Experimental data on the TAE
    • 2.2.1 Measuring the TAE in humans
    • 2.2.2 Human psychophysical data
  • 2.3 Proposed theories
    • 2.3.1 Gibson normalization
    • 2.3.2 Satiation
    • 2.3.3 Feature-detector fatigue
    • 2.3.4 Modifiable lateral inhibition
      • Direct effect
      • Indirect effect
  • 2.4 Computational and mathematical models
    • 2.4.1 Previous models of orientation maps
    • 2.4.2 Previous models of tilt illusions and aftereffects
  • 2.5 Conclusion
• 3 The RF-LISSOM Model
  • 3.1 Introduction
  • 3.2 The RF-LISSOM Architecture
  • 3.3 Previous work with the RF-LISSOM model
  • 3.4 Sparseness and decorrelation
  • 3.5 Biological basis of the model
  • 3.6 Long-range inhibitory connections
  • 3.7 Environmental versus genetic factors in development
    • 3.7.1 Evolutionary and developmental constraints
    • 3.7.2 Two-stage model for development
    • 3.7.3 Overlapping model for development using pattern generation
    • 3.7.4 Pattern-generated development in mammals
      • Retinal waves
      • PGO waves
    • 3.7.5 Pattern-generated development in self-organizing models
  • 3.8 Conclusion
• 4 Training the Orientation Map
  • 4.1 Training inputs
  • 4.2 Training parameters
  • 4.3 Receptive fields and orientation maps
  • 4.4 Self-organization of lateral connections
  • 4.5 Orientation encoding
  • 4.6 Conclusion
• 5 Aftereffect Experiments
  • 5.1 Experimental setup
  • 5.2 Angular function of the tilt aftereffect
  • 5.3 Changes in the patterns of connection strength
  • 5.4 Changes in the response to test lines
    • 5.4.1 Sharpening of the response to the adaptation line
    • 5.4.2 Expansion of small angles (direct effect)
    • 5.4.3 Contraction of large angles (indirect effect)
  • 5.5 Time course of the tilt aftereffect
  • 5.6 Conclusion
• 6 Discussion and Future Work
  • 6.1 Psychophysical evidence relating to the TAE
  • 6.2 Biological mechanisms underlying the TAE
    • 6.2.1 Is the TAE due to synaptic plasticity or to accumulation of inhibition?
    • 6.2.2 Contribution of afferent and excitatory plasticity
    • 6.2.3 Biophysical mechanisms of inhibitory plasticity in development and in adulthood
    • 6.2.4 Biophysical mechanisms of the indirect effect
  • 6.3 Specific predictions for experimental verification
  • 6.4 Future work
    • 6.4.1 Tilt illusions
    • 6.4.2 Effect of test grating
    • 6.4.3 Contrast effects
    • 6.4.4 Masking phenomena
    • 6.4.5 Aftereffects in visual hierarchies
    • 6.4.6 Hyperacuity
    • 6.4.7 Other visual aftereffects
  • 6.5 Conclusion
• 7 Conclusion
  • 7.1 Summary of the thesis
  • 7.2 Conclusion
• References