Hillel Chiel - US grants

9309691 Chiel In order to survive and reproduce, animals must pursue specific goals while continuously modifying their behavior in response to changing internal and environmental conditions. Over periods of hours or days, animals must choose among different mutually exclusive behaviors, such as feeding or mating. As they engage in a particular behavior over minutes or hours, they must select among different behavioral responses in order to continue to perform that behavior (e.g., rejecting an inedible piece of food in order to continue feeding). They must also rapidly alter their behavioral responses within seconds to cope with changes in the environment (e.g., biting harder on tough food). What are the neural mechanisms underlying the ability of animals to generate adaptive behavior? In order to address this question, the principal investigator proposes to study a behavioral switch in the marine mollusc Aplysia californica. Preliminary results indicate that Aplysia is capable of switching among different behavioral responses as environmental conditions change. Specifically, the animal can switch from ingestive to rejection responses if it attempts to ingest inedible material. The investigator proposes to use intracellular recording from nerve cells in vivo and in vitro (1) to identify and characterize the properties of premotor neurons and interneurons that cause the switch in the timing of the activity of these motor neurons, as well as (2) to identify and characterize the properties of sensory neurons that trigger these different patterns of activity. Using these data, he will (3) simulate and analyze the neural network responsible for the behavioral switch. These three specific aims will allow him to test different hypotheses about the neural organization of a behavioral switch: is it due to dedicated neural circuits, to a distributed neural circuit, or to circuits that have some shared and some distinct neural elements? It will also allow him to develop a more abstract description of behavioral switching, based on concepts from dynamical systems theory.***

EIA-0130773 Randall D. Beer-Case Western Reserve-Reconfigurable and Multifunctional Behavior Pattern Generators

We propose to develop new theories and models that extend current computational frameworks by understanding and implementing the dynamically reconfigurable and multifunctional information processing architectures of biological systems. We will address this challenge through a collaborative interdisciplinary research program focusing on multifunctional neuromechanical components and their reconfiguration into multiple behavioral patterns in animals. The ultimate goal of our proposed research is to abstract general design principles that can eventually be applied in a variety of other contexts. Specifically, we propose the following four closely intertwined experimental and modeling/theoretical projects:

1)We will undertake a detailed experimental analysis of the feeding system of the mollusk Aplysia California, which dynamically reconfigures its feeding behavior in response to changing environmental circumstances, and does so through the multifuntionality of its neuromechanics. First, we will characterize the conditions under which the animal switches between distant behavioral patterns. Second, we will examine the neural and mechanical basis of these switches.

2)We will create and analyze models of behavioral pattern switching as the basis for new design principles. First, we will construct interconnected semi-Markov models to capture behavioral pattern reconfiguration observed in biological systems. Second, we will pursue the development of a systematic design methodology for engineered systems, with potential applications to robotic assembly.

3)We will create and analyze models of multifunctional pattern generations in order to identify general design principles. First, we will use genetic algorithms to evolve multifunctional neural pattern generators that can switch between distinct behavioral patterns. Second, we will undertake a detailed study of the "design space" of these model pattern generators.

4)We will explore the implementation of multifunctional neural pattern generators in analog VLSI. First, we will develop compact, low-power pattern generators based on the experimental and theoretical work proposed above. Second, we will study the effects of noise and component mismatch on the performance of these networks.

DESCRIPTION (provided by applicant): Motor systems are multifunctional, i.e., the same peripheral structures can generate qualitatively different behaviors. Diseases of the nervous system, such as stroke, severely compromise multifunctionality. To treat such diseases, it is important to understand multifunctionality in the intact nervous system. Principles of multifunctionality could also be used to construct flexible prosthetic devices. This is the rationale for analyzing multifunctionality in the marine mollusk Aplysia californica, whose biomechanics and neural control can both be studied. Kinematic measurements in intact, behaving animals of Aplysia's feeding muscles using magnetic resonance imaging have clarified the biomechanical basis of multifunctionality. The kinematics of the muscles, and in vivo recordings of neural activity correlated with the kinematics, indicate how activity in motor pools controlling buccal mass muscles must be altered to generate different feeding responses. Furthermore, these data suggest that multifunctionality of feeding in Aplysia is mediated by differential activation of context dependent identified interneurons that cause some of the observed shifts in timing, intensity and duration of the motor neuronal pools controlling muscles of the buccal mass to generate appropriate movements for qualitatively different feeding responses. To test this hypothesis, three Specific Aims will be pursued. First, we will simultaneously characterize the in vivo activity of interneurons and selected motor neurons that control the buccal muscles. Second, we will study reduced preparations capable of generating feeding motor patterns, and examine the effect of hyperpolarizing or depolarizing interneurons on the resulting motor patterns. Third, we will test the hypothesis in vivo using a novel electrophysiological technique that will allow us to turn on or turn off the activity of different interneurons in intact, behaving animals. These studies will lead to a deeper understanding of the neuromechanical principles underlying multifunctionality.

Animals as simple as cockroaches and slugs and as complex as humans all possess similar ways to control how they walk, crawl, swim or fly through earth's many complex environments. Engineers have turned to these natural systems for inspiration in developing robots, hoping to attain the same ease of movement and ability to adapt to any environment on earth (or off of it). The goals of animal motion studies and robotics are clearly complementary and benefit greatly from extended interaction. Although many meetings have limited sessions dedicated to such discussions, the International Symposium on Adaptive Motion in Animals and Machines (AMAM) is uniquely dedicated to intense week long interaction among engineers and biologists. The funds from this proposal will be used to bring young U.S. scientists and engineers (especially female and underrepresented minorities) to AMAM 2008 this June 1-6 at Case Western Reserve University in Cleveland, Ohio. Funds will also be used to support web-based distribution of the meeting to members of the international community and educators who cannot attend the meeting in person. The potential impacts of this meeting include: 1) use of robots as hardware models to promote a greater understanding of how animals (including humans) control their movement through their complex worlds, 2) creation of new walking, crawling, swimming and flying robots that more closely capture properties of animals, and 3) introduction of young developing scientists and engineers to an area of research that relies heavily on collaboration of people with many different skills from many different areas for success. The ultimate goal of this work is to provide highly functional robotic devices to serve human needs, such as search and rescue, environmental monitoring, surveying and many others, as well as greater understanding of animal movement.

How can intelligent control be created for autonomous robots that will allow them to respond flexibly and adaptively to changing environments? In the animal world, relatively simple animals such as soft-bodied invertebrates, are capable of coordinating their many possible movements, flexibly shifting and sequencing multiple behaviors as conditions change, and learning to alter their behavior based on experience. For robots, however, this remains a challenge, which is addressed in this project using a novel control architecture that can produce sensory driven or cyclic movements.

Traditional control architectures for robotics have three layers: high level deliberative planning, low-level reactive control, and an intermediate level for sequencing and simple decision-making. Creating intermediate level controllers for intelligent behavior is particularly challenging, and a major obstacle to progress in autonomous robotics. This problem will be addressed using a novel neural-inspired control architecture, stable heteroclinic channels (SHCs) that can flexibly and robustly orchestrate multiple degrees of freedom for multifunctionality, and can readily handle behavioral hierarchies, temporal decision-making, and learning. Their properties also allow them to incorporate some of the best aspects of the two traditional approaches to robotic control: finite state machines and central pattern generator (limit cycle) controllers. SHC-based dynamical architectures underlying multifunctionality will be analyzed in a soft-bodied animal that is tractable to experimentation, and principles from these neurobiological architectures will be used to implement multifunctional behavior in a novel hyper-redundant, soft-bodied robot platform.

There are many possible applications for adaptive, flexibly-controlled soft-bodied, or hyper-redundant, robots that are able to coordinate their many degrees of freedom in varying ways to accomplish multiple functions. A multifunctional worm-like robot could crawl through pipes of varying diameter and at any angle with respect to gravity and make sharp turns at intersections. A hollow hyper-redundant robot could inspect water mains from the inside, without interrupting water flow. Such a robot could be used for oil and gas pipeline inspections to avoid costly and environmentally disastrous leaks. Smaller versions could be developed for endoscopic diagnosis of the gastrointestinal tract. The proposed work will lead to a single controller framework that can robustly coordinate multiple coupled actuated mechanisms within a robot, and describe the sequencing of distinct behaviors in both animals and robots.

Despite the apparent differences between animals and their behaviors, they all are subject to the same constraints. All animals use a nervous system to control their motions, which must follow the laws of physics. Therefore, this NeuroNex Research Network seeks to understand how animals move by studying animals of different sizes and with unique evolutionary histories: Vertebrates (mice, rats, and cats), mollusks (sea hares), and insects (fruit flies). The differences between these species will inform how physics and evolution have shaped the nervous system. Understanding motion across different organisms and scales may lead to robots with more graceful, coordinated motion. Additionally, this Network enhances the training of American engineers and scientists by exchanging post-doctoral trainees and students between laboratories, providing them opportunities to work with different model organisms, and broadening the trainees? education. The activities of this Network enrich existing outreach programs through interactions with international, interdisciplinary collaborators and allow for new, larger initiatives. Public demonstrations, day camps, and internships carried out as part of this project expose K-12 students to interdisciplinary research and international collaborators? ideas and culture. This Network also constructs exhibits at natural science museums in its major cities and develops an interactive website describing how very different animals solve similar problems.

Animals move to seek food, mates, and shelter. In the phyla Arthropoda, Mollusca, and Chordata, the nervous system cephalized towards a higher-level brain and lower-level sensorimotor network. The brain would not exist without a body, and yet little is understood about how the nervous system controls and coordinates distributed body parts. Many fundamental questions remain unanswered: How is neural information encoded and communicated? How does the system correct for environmental perturbations? How do passive biomechanics affect the neuronal control of behavior? This leads to the foundational question: How do nervous systems control and execute interactions with the environment? This international Network of interdisciplinary research groups consists of modelers, engineers, and experimentalists to explore the Communication, Coordination, and Control of Neuromechanical Systems (C3NS). This NeuroNex Network investigates a foundational question in model genera from three phyla: adult Drosophila from Arthropoda, Aplysia from Mollusca, and small mammals from Chordata. Each interdisciplinary research group studies the control of a behavior in which the body interacts with the environment. Investigators explore how higher-level command centers (HLCCs) generate descending commands to lower-level motor centers (LLMCs), how LLMCs control the body to produce desired behavior, and how LLMCs generate ascending signals back to HLCCs. The animal models of C3NS allow the investigation of these questions across degrees of nervous system complexity and ranges of dynamic scale (i.e., size and speed) using the same conceptual modeling framework. This effort will create a bottom-up theory for how nervous systems control movement during environmental interactions. This project is co-funded by Emerging Frontiers in the Directorate for Biological Sciences and Robust Intelligence in the Directorate for Computer and Information Science and Engineering.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.