Modeling brain function : the world of attractor neural networks /
Saved in:
Author / Creator: | Amit, D. J., 1938-2007 |
---|---|
Imprint: | Cambridge [England] ; New York : Cambridge University Press, 1989. |
Description: | xvii, 504 p. : ill. ; 24 cm. |
Language: | English |
Subject: | |
Format: | Print Book |
URL for this record: | http://pi.lib.uchicago.edu/1001/cat/bib/1056039 |
Table of Contents:
- Preface
- 1. Introduction
- 1.1. Philosophy and Methodology
- 1.1.1. Reduction to physics and physics modeling analogues
- 1.1.2. Methods for mind and matter
- 1.1.3. Some methodological questions
- 1.2. Neurophysiological Background
- 1.2.1. Building blocks for neural networks
- 1.2.2. Dynamics of neurons and synapses
- 1.2.3. More complicated building blocks
- 1.2.4. From biology to information processing
- 1.3. Modeling Simplified Neurophysiological Information
- 1.3.1. Neuron as perceptron and formal neuron
- 1.3.2. Digression on formal neurons and perceptrons
- 1.3.3. Beyond the basic perceptron
- 1.3.4. Building blocks for attractor neural networks (ANN)
- 1.4. The Network and the World
- 1.4.1. Neural states, network states and state space
- 1.4.2. Digression on the relation between measures
- 1.4.3. Representations on network states
- 1.4.4. Thinking about output mechanism
- 1.5. Spontaneous Computation vs. Cognitive Processing
- 1.5.1. Input systems, transducers, transformers
- 1.5.2. ANN's as computing elements -- a position
- 1.5.3. ANN's and computation of mental representations
- Bibliography
- 2. The Basic Attractor Neural Network
- 2.1. Networks of Analog, Discrete, Noisy Neurons
- 2.1.1. Analog neurons, spike rates, two-state neural models
- 2.1.2. Binary representation of single neuron activity
- 2.1.3. Noisy dynamics of discrete two-state neurons
- 2.2. Dynamical Evolution of Network States
- 2.2.1. Network dynamics of discrete-neurons
- 2.2.2. Synchronous dynamics
- 2.2.3. Asynchronous dynamics
- 2.2.4. Sample trajectories and lessons about dynamics
- 2.2.5. Types of trajectories and possible interpretation - a summary
- 2.3. On Attractors
- 2.3.1. The landscape metaphor
- 2.3.2. Perception, recognition and recall
- 2.3.3. Perception errors due to spurious states - possible role of noise
- 2.3.4. Psychiatric speculations and images
- 2.3.5. The role of noise and simulated annealing
- 2.3.6. Frustration and diversity of attractors
- Bibliography
- 3. General Ideas Concerning Dynamics
- 3.1. The Stochastic Process, Ergodicity and Beyond
- 3.1.1. Stochastic equation and apparent ergodicity
- 3.1.2. Two ways of evading ergodicity
- 3.2. Cooperativity as an Emergent Property in Magnetic Analog
- 3.2.1. Ising model for a magnet - spin, field and interaction
- 3.2.2. Dynamics and equilibrium properties
- 3.2.3. Noiseless, short range ferromagnet
- 3.2.4. Fully connected Ising model: real non-ergodicity
- 3.3. From Dynamics to Landscapes - The Free Energy
- 3.3.1. Energy as Lyapunov function for noiseless dynamics
- 3.3.2. Parametrized attractor distributions with noise
- 3.3.3. Free-energy landscapes - a noisy Lyapunov function
- 3.3.4. Free-energy minima, non-ergodicity, order-parameters
- 3.4. Free-Energy of Fully Connected Ising Model
- 3.4.1. From minimization equation to the free-energy
- 3.4.2. The analytic way to the free-energy
- 3.4.3. Attractors at metastable states
- 3.5. Synaptic Symmetry and Landscapes
- 3.5.1. Noiseless asynchronous dynamics - energy
- 3.5.2. Detailed balance for noisy asynchronous dynamics
- 3.5.3. Noiseless synchronous dynamics - Lyapunov function
- 3.5.4. Detailed balance for noisy synchronous dynamics
- 3.6. Appendix: Technical Details for Stochastic Equations
- 3.6.1. The maximal eigen-value and the associated vector
- 3.6.2. Differential equation for mean magnetization
- 3.6.3. The minimization of the dynamical free-energy
- 3.6.4. Legendre transform for the free-energy
- Bibliography
- 4. Symmetric Neural Networks at Low Memory Loading
- 4.1. Motivations and List of Results
- 4.1.1. Simplifying assumptions and specific questions
- 4.1.2. Specific answers for low loading of random memories
- 4.1.3. Properties of the noiseless network
- 4.1.4. Properties of the network in the presence of fast noise
- 4.2. Explicit Construction of Synaptic Efficacies
- 4.2.1. Choice of memorized patterns
- 4.2.2. Storage prescription - "Hebb's rule"
- 4.2.3. A decorrelating (but nonlocal) storage prescription
- 4.3. Stability Considerations at Low Storage
- 4.3.1. Signal to noise analysis - memories, spurious states
- 4.3.2. Basins of attraction and retrieval times
- 4.3.3. Neurophysiological interpretation
- 4.4. Mean Field Approach to Attractors
- 4.4.1. Self-consistency and equations for attractors
- 4.4.2. Self-averaging and the final equations
- 4.4.3. Free-energy, extrema, stability
- 4.4.4. Mean-field and free-energy - synchronous dynamics
- 4.5. Retrieval States, Spurious States - Noiseless
- 4.5.1. Perfect retrieval of memorized patterns
- 4.5.2. Noiseless, symmetric spurious memories
- 4.5.3. Non-symmetric spurious states
- 4.5.4. Are spurious states a free lunch?
- 4.6. Role of Noise at Low Loading
- 4.6.1. Ergodicity at high noise levels - asynchronous
- 4.6.2. Just below the critical noise level
- 4.6.3. Positive role of noise and retrieval with no fixed points
- 4.7. Appendix: Technical Details for Low Storage
- 4.7.1. Free-energy at finite p - asynchronous
- 4.7.2. Free-energy and solutions - synchronous dynamics
- 4.7.3. Bound on magnitude of overlaps
- 4.7.4. Asymmetric spurious solution
- Bibliography
- 5. Storage and Retrieval of Temporal Sequences
- 5.1. Motivations: Introspective, Biological, Philosophical
- 5.1.1. The introspective motivation
- 5.1.2. The biological motivation
- 5.1.3. Philosophical motivations
- 5.2. Storing and Retrieving Temporal Sequences
- 5.2.1. Functional asymmetry
- 5.2.2. Early ideas for instant temporal sequences
- 5.3. Temporal Sequences by Delayed Synapses
- 5.3.1. A simple generalization and its motivation
- 5.3.2. Dynamics with fast and slow synapses
- 5.3.3. Simulation examples of sequence recall
- 5.3.4. Adiabatically varying energy landscapes
- 5.3.5. Bi-phasic oscillations and CPG's
- 5.4. Tentative Steps into Abstract Computation
- 5.4.1. The attempt to reintroduce structured operations
- 5.4.2. Ann counting chimes
- 5.4.3. Counting network - an exercise in connectionist programming
- 5.4.4. The network
- 5.4.5. Its dynamics
- 5.4.6. Simulations
- 5.4.7. Reflections on associated cognitive psychology
- 5.5. Sequences Without Synaptic Delays
- 5.5.1. Basic oscillator - origin of cognitive time scale
- 5.5.2. Behavior in the absence of noise
- 5.5.3. The role of noise
- 5.5.4. Synaptic structure and underlying dynamics
- 5.5.5. Network storing sequence with several patterns
- 5.6. Appendix: Elaborate Temporal Sequences
- 5.6.1. Temporal sequences by time averaged synaptic inputs
- 5.6.2. Temporal sequences without errors
- Bibliography
- 6. Storage Capacity of ANN's
- 6.1. Motivation and general considerations
- 6.1.1. Different measures of storage capacity
- 6.1.2. Storage capacity of human brains
- 6.1.3. Intrinsic interest in high storage
- 6.1.4. List of results
- 6.2. Statistical Estimates of Storage
- 6.2.1. Statistical signal to noise analysis
- 6.2.2. Absolute informational bounds on storage capacity
- 6.2.3. Coupling (synaptic efficacies) for optimal storage
- 6.3. Theory Near Memory Saturation
- 6.3.1. Mean-field equations with replica symmetry
- 6.3.2. Retrieval in the absence of fast noise
- 6.3.3. Analysis of the T = 0 equations
- 6.4. Memory Saturation with Noise and Fields
- 6.4.1. A tour in the T-[alpha] phase diagram
- 6.4.2. Effect of external fields - thresholds and PSP's
- 6.4.3. Fields coupled to several patterns
- 6.4.4. Some technical details related to phase diagrams
- 6.5. Balance Sheet for Standard ANN
- 6.5.1. Limiting framework and analytic consequences
- 6.5.2. Finite-size effects and basins of attraction: simulations
- 6.6. Beyond the Memory Blackout Catastrophe
- 6.6.1. Bounded synapses and palimpsest memory
- 6.6.2. The 7 [plus or minus] 2 rule and palimpsest memories
- 6.7. Appendix: Replica Symmetric Theory
- 6.7.1. The replica method
- 6.7.2. The free-energy and the mean-field equations
- 6.7.3. Marginal storage and palimpsests
- Bibliography
- 7. Robustness - Getting Closer to Biology
- 7.1. Synaptic Noise and Synaptic Dilution
- 7.1.1. Two meanings of robustness
- 7.1.2. Noise in synaptic efficacies
- 7.1.3. Random symmetric dilution of synapses
- 7.2. Non-Linear Synapses and Limited Analog Depth
- 7.2.1. Place and role of non-linear synapses
- 7.2.2. Properties of networks with clipped synapses
- 7.2.3. Non-linear storage and the noisy equivalent
- 7.2.4. Clipping at low storage level
- 7.3. Random vs. Functional Synaptic Asymmetry
- 7.3.1. Random asymmetry and performance quality
- 7.3.2. Asymmetry, noise and spin-glass suppression
- 7.3.3. Neuronal specificity of synapses - Dale's law
- 7.3.4. Extreme asymmetric dilution
- 7.3.5. Functional asymmetry
- 7.4. Effective Cortical Cycle Times
- 7.4.1. Slow bursts and relative refractory period
- 7.4.2. Neuronal memory and expanded scenario
- 7.4.3. Simplified scenario for relative refractory period
- 7.5. Appendix: Technical Details
- 7.5.1. Digression - the mean-field equations
- 7.5.2. Dilution requirement
- Bibliography
- 8. Memory Data Structures
- 8.1. Biological and Computational Motivation
- 8.1.1. Low mean activity level and background-foreground asymmetry
- 8.1.2. Hierarchies for biology and for computation
- 8.2. Local Treatment of Low Activity Patterns
- 8.2.1. Demise of naive standard model
- 8.2.2. Modified ANN and a plague of spurious states
- 8.2.3. Constrained dynamics - monitoring thresholds
- 8.2.4. Properties of the constrained biased network
- 8.2.5. Quantity of information in an ANN with low activity
- 8.2.6. More effective storage of low activity (sparse) patterns
- 8.3. Hierarchical Data Structures in a Single Network
- 8.3.1. Early proposals
- 8.3.2. Explicit construction of hierarchy in a single ANN
- 8.3.3. Properties of hierarchy in a single network
- 8.3.4. Prosopagnosia and learning class properties
- 8.3.5. Multy-ancestry with many generations
- 8.4. Hierarchies in Multi-ANN: Generalization First
- 8.4.1. Organization of the data and the networks
- 8.4.2. Hierarchical dynamics
- 8.4.3. Hierarchy for image vector quantization
- 8.5. Appendix: Technical Details for Biased Patterns
- 8.5.1. Noise estimates for biased patterns
- 8.5.2. Mean-field equations in noiseless biased network
- 8.5.3. Retrieval entropy in biased network
- 8.5.4. Mean-square noise in low activity network
- Bibliography
- 9. Learning
- 9.1. The Context of Learning
- 9.1.1. General Comments and a limited scope
- 9.1.2. Modes, time scales and other constraints
- 9.1.3. The need for learning modes
- 9.1.4. Results for learning in learning modes
- 9.2. Learning in Modes
- 9.2.1. Perceptron learning
- 9.2.2. ANN learning by perceptron algorithm
- 9.2.3. Local learning of the Kohonen synaptic matrix
- 9.3. Natural Learning - Double Dynamics
- 9.3.1. General features
- 9.3.2. Learning in a network of physiological neurons
- 9.3.3. Learning to form associations
- 9.3.4. Memory generation and maintenance
- 9.4. Technical Details in Learning Models
- 9.4.1. Local Iterative Construction of Projector Matrix
- 9.4.2. The free energy and the correlation function
- Bibliography
- 10. Hardware Implementations of Neural Networks
- 10.1. Situating Artificial Neural Networks
- 10.1.1. The role of hardware implementations
- 10.1.2. Motivations for different designs
- 10.2. The VLSI Neural Network
- 10.2.1. High density high speed integrated chip
- 10.2.2. Smaller, more flexible electronic ANN's
- 10.3. The Electro-Optical ANN
- 10.4. Shift Register (CCD) Implementation
- Bibliography
- Glossary
- Index