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Synergy and Redundancy among Brain Cells of Behaving Monkeys
Determining the relationship between the activity of a single nerve cell to that of an entire population is a fundamental question that bears on the basic neural computation paradigms. In this paper we apply an information theoretic approach to quantify the level of cooperative activity among cells in a behavioral context. It is possible to discriminate between synergetic activity of the cells vs. redundant activity, depending on the difference between the information they provide when measured jointly and the information they provide independently. We define a synergy value that is positive in the first case and negative in the second and show that the synergy value can be measured by detecting the behavioral mode of the animal from simultaneously recorded activity of the cells. We observe that among cortical cells positive synergy can be found, while cells from the basal ganglia, active during the same task, do not exhibit similar synergetic activity.
Viewing Classifier Systems as Model Free Learning in POMDPs
Hayashi, Akira, Suematsu, Nobuo
Classifier systems are now viewed disappointing because of their problems such as the rule strength vs rule set performance problem and the credit assignment problem. In order to solve the problems, we have developed a hybrid classifier system: GLS (Generalization Learning System). In designing GLS, we view CSs as model free learning in POMDPs and take a hybrid approach to finding the best generalization, given the total number of rules. GLS uses the policy improvement procedure by Jaakkola et al. for an locally optimal stochastic policy when a set of rule conditions is given. GLS uses GA to search for the best set of rule conditions. 1 INTRODUCTION Classifier systems (CSs) (Holland 1986) have been among the most used in reinforcement learning.
Multi-Electrode Spike Sorting by Clustering Transfer Functions
Rinberg, Dmitry, Davidowitz, Hanan, Tishby, Naftali
Since every electrode is in a different position it will measure a different contribution from each of the different neurons. Simply stated, the problem is this: how can these complex signals be untangled to determine when each individual cell fired? This problem is difficult because, a) the objects being classified are very similar and often noisy, b) spikes coming from the same cell can ·Permanent address: Institute of Computer Science and Center for Neural Computation, The Hebrew University, Jerusalem, Israel.
Multiple Paired Forward-Inverse Models for Human Motor Learning and Control
Haruno, Masahiko, Wolpert, Daniel M., Kawato, Mitsuo
Humans demonstrate a remarkable ability to generate accurate and appropriate motor behavior under many different and oftpn uncprtain environmental conditions. This paper describes a new modular approach to human motor learning and control, baspd on multiple pairs of inverse (controller) and forward (prpdictor) models. This architecture simultaneously learns the multiple inverse models necessary for control as well as how to select the inverse models appropriate for a given em'ironm0nt. Simulations of object manipulation demonstrates the ability to learn mUltiple objects, appropriate generalization to novel objects and the inappropriate activation of motor programs based on visual cues, followed by online correction, seen in the "size-weight illusion".
Multiple Paired Forward-Inverse Models for Human Motor Learning and Control
Haruno, Masahiko, Wolpert, Daniel M., Kawato, Mitsuo
Humans demonstrate a remarkable ability to generate accurate and appropriate motor behavior under many different and oftpn uncprtain environmental conditions. This paper describes a new modular approach tohuman motor learning and control, baspd on multiple pairs of inverse (controller) and forward (prpdictor) models. This architecture simultaneously learns the multiple inverse models necessary for control as well as how to select the inverse models appropriate for a given em'ironm0nt. Simulationsof object manipulation demonstrates the ability to learn mUltiple objects, appropriate generalization to novel objects and the inappropriate activation of motor programs based on visual cues, followed by online correction, seen in the "size-weight illusion".
Reinforcement Learning Based on On-Line EM Algorithm
The actor and the critic are approximated by Normalized Gaussian Networks (NGnet), which are networks of local linear regression units. The NGnet is trained by the online EM algorithm proposed in our previous paper.We apply our RL method to the task of swinging-up and stabilizing a single pendulum and the task of balancing a double pendulumnear the upright position.
Unsupervised and Supervised Clustering: The Mutual Information between Parameters and Observations
Herschkowitz, Didier, Nadal, Jean-Pierre
Recent works in parameter estimation and neural coding have demonstrated that optimal performance are related to the mutual information between parameters and data. We consider the mutual information in the case where the dependency in the parameter (a vector 8) of the conditional p.d.f. of each observation (a vector
The Distributed Data-Mining Worksho
Kargupta, Hillol, Chan, Philip
Victor Lesser (University of Massachusetts at Amherst) gave an invited talk on distributed interpretation and its of Hong Kong Polytechnic University, possible implication in DDM. Mining, brought interested researchers (Brigham Young University) and Salvatore The paper sessions ended with two and practitioners together and created Stolfo (Columbia University) working paper presentations by Billy an environment for crystallizing the presented the effects of class distribution Wallace and Juan Botia, Marcedes Garijo, fast-growing field of DDM. The concluding session was the panel Lawrence Hall, Nitesh Chawla, and 40 participants attended the workshop. Stolfo, George Cybenko Kevin W. Bowyer (all of University of The workshop had 13 presentations, Stolfo stressed suggested different techniques for Cybenko of Dartmouth University. Organizers sincerely hope that the session.
A New Technique Enables Dynamic Replanning and Rescheduling of Aeromedical Evacuation
Kott, Alexander, Saks, Victor, Mercer, Albert
We describe an application of a dynamic replanning technique in a highly dynamic and complex domain: the military aeromedical evacuation of patients to medical treatment facilities. U.S. Transportation Command (USTRANSCOM) is the U.S. Department of Defense (DoD) agency responsible for evacuating patients during wartime and peace. Doctrinally, patients requiring extended treatment must be evacuated by air to a suitable medical treatment facility. The Persian Gulf War was the first significant armed conflict in which this concept was put to a serious test. The results were far from satisfactory -- about 60 percent of the patients ended up at the wrong destinations. In early 1993, the DoD tasked USTRANSCOM to consolidate the command and control of medical regulation and aeromedical evacuation operations. The ensuing analysis led to TRAC2ES (TRANSCOM regulating and command and control evacuation system), a decision support system for planning and scheduling medical evacuation operations. Probably the most challenging aspect of the problem has to do with the dynamics of a domain in which requirements and constraints continuously change over time. Continuous dynamic replanning is a key capability of TRAC2ES. This article describes the application and the AI approach we took in providing this capability.