[About] [Members] [Joining] [Meetings] [Spring 2002] [Winter 2002/3]
The CMCC is a small group of active researchers that meet periodically at the
Department of Electrical Engineering
in the Technion and discuss current
research in this field. The wide range of topics include: Biological Motor Control, Brain Theory (Neuroscience), Learning Theory, Control Theory, Artificial Neural Networks, Man-Machine Interfaces,
April 27, 2003: Bayes meets Bellman:
The Gaussian Process Approach to Temporal Difference Learning
June 8, 2003: Adaptation in a genetic
(*) Some of the meetings consist of a formal talk and discussion in the club. The formal talk is published in the Technion bulletin and is open to any interested person.
The purpose of the club is to conduct deep discussions that would generate new research ideas and collaborations. Therefore the members are asked to come regularly, be prepared for the meetings and occasionally to present a topic from their field of interest. If you are an active researcher in this field (e.g., faculty member, graduate student) and wish to commit yourself to participate regularly and to contribute to our discussions, please contact Amir Karniel or any other member for details about the next meeting. You would be asked to introduce yourself shortly at the first meeting you attend. (*)
October 20, 2002: (*) Does
the Brain Use Clocks, Counters, or Switches During Motor Adaptation?
Amir Karniel, 11:00am, EE building 1061
The first meeting is self-contained and is open to every interested person.
11:00-11:50 Formal presentation
Jordan and Wolpert 1999. (Review)
Miall 2002 (Research news)
Mechsner et al. 2001
Karniel and Mussa-Ivaldi 2002
November 3, 2002: Discuss the work of
Maass Natschlager and Markram (2002) A fresh look at
real-time computation in generic recurrent neural circuits
Maass et al. 2002
November 17, 2002: Dynamic Approach to
Jirsa Fuchs & Kelso.
December 8, 2002: (*) Planning and execution of arm movements in normal humans
and in neglect patients [abstract]
Assaf Dvorkin, Interdisciplinary Center for Neural Computation (ICNC), The Hebrew University of Jerusalem, and Dept. of Applied Math. and Computer Science, The Weizmann Institute of Science
December 22,2002: Computer analysis of the
handwriting of proficient and poor handwriters
The discussion would be about possible control mechanisms that might underlie these results.
April 7, 2002: Bernstein (Victor Yosef)
The book: Dexterity and Its Development (Resources for Ecological Psychology)
by Mark L. Latash (Editor), Michael T. Turvey (Editor) 1996 (Link to Amazon)
May 12, 2002: Evidence for cortical activity during adaptation (Elad Yom-Tov)
Yom-Tov, Grossman and Inbar 2001
May 26, 2002: Highlights from recent conferences
12th annual meetings of the Neural Control of Movement society (Naples, Florida, April 2002)
IEEE World Congress on computational intelligence (Honolulu, Hawaii, May 2002)
From the dawn of cybernetics, the search for artificial
intelligence was a salient driving force. In
the forties, numerical calculations were a daunting task; a decade ago, playing
the game of chess was considered the ultimate test. Modern computer easily beat any person in these tasks.
Nevertheless modern robots are far behind the motor abilities of a five
years old child. Beside the
scientific interest, understanding the biological motor control system has great
potential in promoting future applications to help the physically disabled and
to build intelligent robots and computers.
In this talk I will describe a series of psychophysical
experiments along with computational models that challenge some common theories
and analogies between the computer and the brain.
Studies of arm movements have shown that subjects learn to
compensate for predictable mechanical perturbations by developing a
representation of the relation between the state of motion of the arm and the
perturbing forces. We tested the
hypothesis that subjects can employ clocks, counters or switches in order to
construct this internal representation.
Our findings suggest that in contrast to standard computers
and robots, the biological motor control system may not use the equivalent of
clocks, counters or switches in order to adapt to time-varying environment.
Instead, the biological system tends to build an internal dynamic model
that is usually based on a state mapping.
This research was performed in collaboration with
Ferdinando A. Mussa-Ivaldi. The
experiments were performed at the robotics lab of the Rehabilitation Institute
Prof. Eytan Ruppin, Tel-Aviv University
How does one aim to "understand" the processing of a system?
A classical, good point to start is to find the ``contributions'', i.e., the relative importance of the different elements that compose that system.
In this talk I shall present some novel methods to address this question, employing concepts ranging from function minimization to information theory and game theory. Their workings will be demonstrated in the analysis of neurocontrollers of evolved autonomous agents and on biological data of reversible inactivation experiments.
Developed initially for the study of neurocontrollers, this kind of localization analysis may have a broad array of potential applications in the field of functional genomics and drug design, and, more generally, to solving cost allocation problems.
-- Joint work with Ranit Aharonov, Lior Segev, Alon Keinan and Isaac Meilijson --
Assaf, ICNC, Hebrew Univ., Jerusalem; Dept. CS & Appl. Math., Weizmann
Reaching toward a visual target involves the transformation of visual information into motor commands, using multiple spatial reference frames (RF). The origin of these RF may be shoulder-, hand-, or eye-centered.
In an attempt to identify which RF are used to represent target position, we measured constant and variable errors in a double-step (DS) paradigm, while subjects (Ss) reached toward visual targets, located in a horizontal plane. Moreover, in this study we investigated the spatial and temporal characteristics of the attentional deficit in unilateral neglect patients during reaching.
Results from young Ss showed that in pointing movements, the major axes of the confidence ellipses co-aligned with the average movement direction. This may suggest a hand-centered RF. In contrast, in DS movements various orientations were found, suggesting that endpoint variability may also reflect motion planning rather than mere execution.
The recorded movements in both young and elderly normal Ss included averaged/non-averaged and direct trajectories. In contrast, results from two neglect patients showed no averaged modified trajectories. These findings suggest that the patients were unable to perform on-line motor corrections. Furthermore, a higher proportion of direct trajectories was observed, for movements that were initially directed toward the left side of space. In addition, whereas in elderly subjects and patients, some of the DS movements contained a pause, the patients displayed significantly longer pauses, especially when the first target appeared ipsilesionally. These findings reflect the existence of a competitive bias in favor of ipsilesional stimuli.
Results from a perceptual control experiment demonstrated
the existence of a spatial perception deficit in both patients.
This research was done under the supervision of Flash Tamar and Bentin Shlomo, and in collaboration with Behrmann Marlene and Soroker Nachum.