Project acronym ANYONIC
Project Statistics of Exotic Fractional Hall States
Researcher (PI) Mordehai HEIBLUM
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Call Details Advanced Grant (AdG), PE3, ERC-2018-ADG
Summary Since their discovery, Quantum Hall Effects have unfolded intriguing avenues of research, exhibiting a multitude of unexpected exotic states: accurate quantized conductance states; particle-like and hole-conjugate fractional states; counter-propagating charge and neutral edge modes; and fractionally charged quasiparticles - abelian and (predicted) non-abelian. Since the sought-after anyonic statistics of fractional states is yet to be verified, I propose to launch a thorough search for it employing new means. I believe that our studies will serve the expanding field of the emerging family of topological materials.
Our on-going attempts to observe quasiparticles (qp’s) interference, in order to uncover their exchange statistics (under ERC), taught us that spontaneous, non-topological, ‘neutral edge modes’ are the main culprit responsible for qp’s dephasing. In an effort to quench the neutral modes, we plan to develop a new class of micro-size interferometers, based on synthetically engineered fractional modes. Flowing away from the fixed physical edge, their local environment can be controlled, making it less hospitable for the neutral modes.
Having at hand our synthetized helical-type fractional modes, it is highly tempting to employ them to form localize para-fermions, which will extend the family of exotic states. This can be done by proximitizing them to a superconductor, or gapping them via inter-mode coupling.
The less familiar thermal conductance measurements, which we recently developed (under ERC), will be applied throughout our work to identify ‘topological orders’ of exotic states; namely, distinguishing between abelian and non-abelian fractional states.
The proposal is based on an intensive and continuous MBE effort, aimed at developing extremely high purity, GaAs based, structures. Among them, structures that support our new synthetic modes that are amenable to manipulation, and others that host rare exotic states, such as v=5/2, 12/5, 19/8, and 35/16.
Summary
Since their discovery, Quantum Hall Effects have unfolded intriguing avenues of research, exhibiting a multitude of unexpected exotic states: accurate quantized conductance states; particle-like and hole-conjugate fractional states; counter-propagating charge and neutral edge modes; and fractionally charged quasiparticles - abelian and (predicted) non-abelian. Since the sought-after anyonic statistics of fractional states is yet to be verified, I propose to launch a thorough search for it employing new means. I believe that our studies will serve the expanding field of the emerging family of topological materials.
Our on-going attempts to observe quasiparticles (qp’s) interference, in order to uncover their exchange statistics (under ERC), taught us that spontaneous, non-topological, ‘neutral edge modes’ are the main culprit responsible for qp’s dephasing. In an effort to quench the neutral modes, we plan to develop a new class of micro-size interferometers, based on synthetically engineered fractional modes. Flowing away from the fixed physical edge, their local environment can be controlled, making it less hospitable for the neutral modes.
Having at hand our synthetized helical-type fractional modes, it is highly tempting to employ them to form localize para-fermions, which will extend the family of exotic states. This can be done by proximitizing them to a superconductor, or gapping them via inter-mode coupling.
The less familiar thermal conductance measurements, which we recently developed (under ERC), will be applied throughout our work to identify ‘topological orders’ of exotic states; namely, distinguishing between abelian and non-abelian fractional states.
The proposal is based on an intensive and continuous MBE effort, aimed at developing extremely high purity, GaAs based, structures. Among them, structures that support our new synthetic modes that are amenable to manipulation, and others that host rare exotic states, such as v=5/2, 12/5, 19/8, and 35/16.
Max ERC Funding
1 801 094 €
Duration
Start date: 2019-05-01, End date: 2024-04-30
Project acronym BRAIN2BRAIN
Project Towards two-person neuroscience
Researcher (PI) Riitta Kyllikki Hari
Host Institution (HI) AALTO KORKEAKOULUSAATIO SR
Call Details Advanced Grant (AdG), LS5, ERC-2008-AdG
Summary Humans interact with other people throughout their lives. This project aims to demonstrate that the complex social shaping of the human brain can be adequately tackled only by taking a leap from the conven-tional single-person neuroscience to two-person neuroscience. We will (1) develop a conceptual framework and experimental setups for two-person neuroscience, (2) apply time-sensitive methods for studies of two interacting persons, monitoring both brain and autonomic nervous activity to also cover the brain body connection, (3) use gaze as an index of subject s attention to simplify signal analysis in natural environments, and (4) apply insights from two-person neuroscience into disorders of social interaction. Brain activity will be recorded with millisecond-accurate whole-scalp (306-channel) magnetoencepha-lography (MEG), associated with EEG, and with the millimeter-accurate 3-tesla functional magnetic reso-nance imaging (fMRI). Heart rate, respiration, galvanic skin response, and pupil diameter inform about body function. A new psychophysiological interaction setting will be built, comprising a two-person eye-tracking system. Novel analysis methods will be developed to follow the interaction and possible synchronization of the two persons signals. This uncoventional approach crosses borders of neuroscience, social psychology, psychophysiology, psychiatry, medical imaging, and signal analysis, with intriguing connections to old philosophical questions, such as intersubjectivity and emphatic attunement. The results could open an unprecedented window into human human, instead of just brain brain, interactions, helping to understand also social disorders, such as autism and schizophrenia. Further applications include master apprentice and patient therapist relationships. Advancing from studies of single persons towards two-person neuroscience shows promise of a break-through in understanding the dynamic social shaping of human brain and mind.
Summary
Humans interact with other people throughout their lives. This project aims to demonstrate that the complex social shaping of the human brain can be adequately tackled only by taking a leap from the conven-tional single-person neuroscience to two-person neuroscience. We will (1) develop a conceptual framework and experimental setups for two-person neuroscience, (2) apply time-sensitive methods for studies of two interacting persons, monitoring both brain and autonomic nervous activity to also cover the brain body connection, (3) use gaze as an index of subject s attention to simplify signal analysis in natural environments, and (4) apply insights from two-person neuroscience into disorders of social interaction. Brain activity will be recorded with millisecond-accurate whole-scalp (306-channel) magnetoencepha-lography (MEG), associated with EEG, and with the millimeter-accurate 3-tesla functional magnetic reso-nance imaging (fMRI). Heart rate, respiration, galvanic skin response, and pupil diameter inform about body function. A new psychophysiological interaction setting will be built, comprising a two-person eye-tracking system. Novel analysis methods will be developed to follow the interaction and possible synchronization of the two persons signals. This uncoventional approach crosses borders of neuroscience, social psychology, psychophysiology, psychiatry, medical imaging, and signal analysis, with intriguing connections to old philosophical questions, such as intersubjectivity and emphatic attunement. The results could open an unprecedented window into human human, instead of just brain brain, interactions, helping to understand also social disorders, such as autism and schizophrenia. Further applications include master apprentice and patient therapist relationships. Advancing from studies of single persons towards two-person neuroscience shows promise of a break-through in understanding the dynamic social shaping of human brain and mind.
Max ERC Funding
2 489 643 €
Duration
Start date: 2009-01-01, End date: 2014-12-31
Project acronym FQHE
Project Statistics of Fractionally Charged Quasi-Particles
Researcher (PI) Mordehai (Moty) Heiblum
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Call Details Advanced Grant (AdG), PE3, ERC-2008-AdG
Summary The discovery of the fractional quantum Hall effect created a revolution in solid state research by introducing a new state of matter resulting from strong electron interactions. The new state is characterized by excitations (quasi-particles) that carry fractional charge, which are expected to obey fractional statistics. While odd denominator fractional states are expected to have an abelian statistics, the newly discovered 5/2 even denominator fractional state is expected to have a non-abelian statistics. Moreover, a large number of emerging proposals predict that the latter state can be employed for topological quantum computing ( Station Q was founded by Microsoft Corp. in order to pursue this goal). This proposal aims at studying the abelian and non-abelian fractional charges, and in particular to observe their peculiar statistics. While charges are preferably determined by measuring quantum shot noise, their statistics must be determined via interference experiments, where one particle goes around another. The experiments are very demanding since the even denominator fractions turn to be very fragile and thus can be observed only in the purest possible two dimensional electron gas and at the lowest temperatures. While until very recently such high quality samples were available only by a single grower (in the USA), we have the capability now to grow extremely pure samples with profound even denominator states. As will be detailed in the proposal, we have all the necessary tools to study charge and statistics of these fascinating excitations, due to our experience in crystal growth, shot noise and interferometry measurements.
Summary
The discovery of the fractional quantum Hall effect created a revolution in solid state research by introducing a new state of matter resulting from strong electron interactions. The new state is characterized by excitations (quasi-particles) that carry fractional charge, which are expected to obey fractional statistics. While odd denominator fractional states are expected to have an abelian statistics, the newly discovered 5/2 even denominator fractional state is expected to have a non-abelian statistics. Moreover, a large number of emerging proposals predict that the latter state can be employed for topological quantum computing ( Station Q was founded by Microsoft Corp. in order to pursue this goal). This proposal aims at studying the abelian and non-abelian fractional charges, and in particular to observe their peculiar statistics. While charges are preferably determined by measuring quantum shot noise, their statistics must be determined via interference experiments, where one particle goes around another. The experiments are very demanding since the even denominator fractions turn to be very fragile and thus can be observed only in the purest possible two dimensional electron gas and at the lowest temperatures. While until very recently such high quality samples were available only by a single grower (in the USA), we have the capability now to grow extremely pure samples with profound even denominator states. As will be detailed in the proposal, we have all the necessary tools to study charge and statistics of these fascinating excitations, due to our experience in crystal growth, shot noise and interferometry measurements.
Max ERC Funding
2 000 000 €
Duration
Start date: 2009-01-01, End date: 2013-12-31
Project acronym HQMAT
Project New Horizons in Quantum Matter: From Critical Fluids to High Temperature Superconductivity
Researcher (PI) Erez BERG
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Call Details Consolidator Grant (CoG), PE3, ERC-2018-COG
Summary Understanding the low-temperature behavior of quantum correlated materials has long been one of the central challenges in condensed matter physics. Such materials exhibit a number of interesting phenomena, such as anomalous transport behavior, complex phase diagrams, and high-temperature superconductivity. However, their understanding has been hindered by the lack of suitable theoretical tools to handle such strongly interacting quantum ``liquids.''
Recent years have witnessed a wave of renewed interest in this long-standing, deep problem, both from condensed matter, high energy, and quantum information physicists. The goal of this research program is to exploit the recent progress on these problems to open new ways of understanding strongly-coupled unconventional quantum fluids. We will perform large-scale, sign problem-free QMC simulations of metals close to quantum critical points, focusing on new regimes beyond the traditional paradigms. New ways to diagnose transport from QMC data will be developed. Exotic phase transitions between an ordinary and a topologically-ordered, fractionalized metal will be studied. In addition, insights will be gained from analytical studies of strongly coupled lattice models, starting from the tractable limit of a large number of degrees of freedom per unit cell. The thermodynamic and transport properties of these models will be studied. These solvable examples will be used to provide a new window into the properties of strongly coupled quantum matter. We will seek ``organizing principles'' to describe such matter, such as emergent local quantum critical behavior and a hydrodynamic description of electron flow. Connections will be made with the ideas of universal bounds on transport and on the rate of spread of quantum information, as well as with insights from other techniques. While our study will mostly focus on generic, universal features of quantum fluids, implications for specific materials will also be studied.
Summary
Understanding the low-temperature behavior of quantum correlated materials has long been one of the central challenges in condensed matter physics. Such materials exhibit a number of interesting phenomena, such as anomalous transport behavior, complex phase diagrams, and high-temperature superconductivity. However, their understanding has been hindered by the lack of suitable theoretical tools to handle such strongly interacting quantum ``liquids.''
Recent years have witnessed a wave of renewed interest in this long-standing, deep problem, both from condensed matter, high energy, and quantum information physicists. The goal of this research program is to exploit the recent progress on these problems to open new ways of understanding strongly-coupled unconventional quantum fluids. We will perform large-scale, sign problem-free QMC simulations of metals close to quantum critical points, focusing on new regimes beyond the traditional paradigms. New ways to diagnose transport from QMC data will be developed. Exotic phase transitions between an ordinary and a topologically-ordered, fractionalized metal will be studied. In addition, insights will be gained from analytical studies of strongly coupled lattice models, starting from the tractable limit of a large number of degrees of freedom per unit cell. The thermodynamic and transport properties of these models will be studied. These solvable examples will be used to provide a new window into the properties of strongly coupled quantum matter. We will seek ``organizing principles'' to describe such matter, such as emergent local quantum critical behavior and a hydrodynamic description of electron flow. Connections will be made with the ideas of universal bounds on transport and on the rate of spread of quantum information, as well as with insights from other techniques. While our study will mostly focus on generic, universal features of quantum fluids, implications for specific materials will also be studied.
Max ERC Funding
1 515 400 €
Duration
Start date: 2019-01-01, End date: 2023-12-31
Project acronym HydraMechanics
Project Mechanical Aspects of Hydra Morphogenesis
Researcher (PI) Kinneret Magda KEREN
Host Institution (HI) TECHNION - ISRAEL INSTITUTE OF TECHNOLOGY
Call Details Consolidator Grant (CoG), PE3, ERC-2018-COG
Summary Morphogenesis is one of the most remarkable examples of biological pattern formation. Despite substantial progress in the field, we still do not understand the organizational principles responsible for the robust convergence of the morphogenesis process, across scales, to form viable organisms under variable conditions. We focus here on the less-studied mechanical aspects of this problem, and aim to uncover how mechanical forces and feedback contribute to the formation and stabilization of the body plan. Regenerating Hydra offer a powerful platform to explore this direction, thanks to their simple body plan, extraordinary regeneration capabilities, and the accessibility and flexibility of their tissues. We propose to follow the regeneration of excised tissue segments, which inherit an aligned supra-cellular cytoskeletal organization from the parent Hydra, as well as cell aggregates, which lack any prior organization. We will employ advanced microscopy techniques and develop elaborate image analysis tools to track cytoskeletal organization and collective cell migration and correlate them with global tissue morphology, from the onset of regeneration all the way to the formation of complete animals. Furthermore, to directly probe the influence of mechanics on Hydra morphogenesis, we propose to apply various mechanical perturbations, and intervene with the axis formation process using external forces and mechanical constraints. Overall, the proposed work seeks to develop an effective phenomenological description of morphogenesis during Hydra regeneration, at the level of cells and tissues, and reveal the mechanical basis of this process. More generally, our research will shed light on the role of mechanics in animal morphogenesis, and inspire new approaches for using external forces to direct tissue engineering and advance regenerative medicine.
Summary
Morphogenesis is one of the most remarkable examples of biological pattern formation. Despite substantial progress in the field, we still do not understand the organizational principles responsible for the robust convergence of the morphogenesis process, across scales, to form viable organisms under variable conditions. We focus here on the less-studied mechanical aspects of this problem, and aim to uncover how mechanical forces and feedback contribute to the formation and stabilization of the body plan. Regenerating Hydra offer a powerful platform to explore this direction, thanks to their simple body plan, extraordinary regeneration capabilities, and the accessibility and flexibility of their tissues. We propose to follow the regeneration of excised tissue segments, which inherit an aligned supra-cellular cytoskeletal organization from the parent Hydra, as well as cell aggregates, which lack any prior organization. We will employ advanced microscopy techniques and develop elaborate image analysis tools to track cytoskeletal organization and collective cell migration and correlate them with global tissue morphology, from the onset of regeneration all the way to the formation of complete animals. Furthermore, to directly probe the influence of mechanics on Hydra morphogenesis, we propose to apply various mechanical perturbations, and intervene with the axis formation process using external forces and mechanical constraints. Overall, the proposed work seeks to develop an effective phenomenological description of morphogenesis during Hydra regeneration, at the level of cells and tissues, and reveal the mechanical basis of this process. More generally, our research will shed light on the role of mechanics in animal morphogenesis, and inspire new approaches for using external forces to direct tissue engineering and advance regenerative medicine.
Max ERC Funding
2 000 000 €
Duration
Start date: 2019-02-01, End date: 2024-01-31
Project acronym IMMUNE/MEMORY AGING
Project Can immune system rejuvenation restore age-related memory loss?
Researcher (PI) Michal Eisenbach-Schwartz
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Call Details Advanced Grant (AdG), LS5, ERC-2008-AdG
Summary With increased life expectancy, there has been a critical growth in the portion of the population that suffers from age-related cognitive decline and dementia. Attempts are therefore being made to find ways to slow brain-aging processes; successful therapies would have a significant impact on the quality of life of individuals, and decrease healthcare expenditures. Aging of the immune system has never been suggested as a factor in memory loss. My group formulated the concept of protective autoimmunity , suggesting a linkage between immunity and self-maintenance in the context of the brain in health and disease. Recently, we showed that T lymphocytes recognizing brain-self antigens have a pivotal role in maintaining hippocampal plasticity, as manifested by reduced neurogenesis and impaired cognitive abilities in T-cell deficient mice. Taken together, our novel observations that T cell immunity contributes to hippocampal plasticity, and the fact that T cell immunity decreases with progressive aging create the basis for the present proposal. We will focus on the following questions: (a) Which aspects of cognition are supported by the immune system- learning, memory or both; (b) whether aging of the immune system is sufficient to induce aging of the brain; (c) whether activation of the immune system is sufficient to reverse age-related cognitive decline; (d) the mechanism underlying the effect of peripheral immunity on brain cognition; and (e) potential therapeutic implications of our findings. Our preliminary results demonstrate that the immune system contributes to spatial memory, and that imposing an immune deficiency is sufficient to cause a reversible memory deficit. These findings give strong reason for optimism that memory loss in the elderly is preventable and perhaps reversible by immune-based therapies; we hope that, in the not too distant future, our studies will enable development of a vaccine to prevent CNS aging and cognitive loss in elderly.
Summary
With increased life expectancy, there has been a critical growth in the portion of the population that suffers from age-related cognitive decline and dementia. Attempts are therefore being made to find ways to slow brain-aging processes; successful therapies would have a significant impact on the quality of life of individuals, and decrease healthcare expenditures. Aging of the immune system has never been suggested as a factor in memory loss. My group formulated the concept of protective autoimmunity , suggesting a linkage between immunity and self-maintenance in the context of the brain in health and disease. Recently, we showed that T lymphocytes recognizing brain-self antigens have a pivotal role in maintaining hippocampal plasticity, as manifested by reduced neurogenesis and impaired cognitive abilities in T-cell deficient mice. Taken together, our novel observations that T cell immunity contributes to hippocampal plasticity, and the fact that T cell immunity decreases with progressive aging create the basis for the present proposal. We will focus on the following questions: (a) Which aspects of cognition are supported by the immune system- learning, memory or both; (b) whether aging of the immune system is sufficient to induce aging of the brain; (c) whether activation of the immune system is sufficient to reverse age-related cognitive decline; (d) the mechanism underlying the effect of peripheral immunity on brain cognition; and (e) potential therapeutic implications of our findings. Our preliminary results demonstrate that the immune system contributes to spatial memory, and that imposing an immune deficiency is sufficient to cause a reversible memory deficit. These findings give strong reason for optimism that memory loss in the elderly is preventable and perhaps reversible by immune-based therapies; we hope that, in the not too distant future, our studies will enable development of a vaccine to prevent CNS aging and cognitive loss in elderly.
Max ERC Funding
1 650 000 €
Duration
Start date: 2009-01-01, End date: 2012-12-31
Project acronym ImmuneCheckpointsAD
Project Immune checkpoint blockade for fighting Alzheimer’s disease
Researcher (PI) Michal EISENBACH-SCHWARTZ
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Call Details Advanced Grant (AdG), LS5, ERC-2016-ADG
Summary Understanding, and ultimately treating Alzheimer’s disease (AD) is a major need in Western countries. Currently, there is no available treatment to modify the disease. Several pioneering discoveries made by my team, attributing a key role to systemic immunity in brain maintenance and repair, and identifying unique interface between the brain’s borders through which the immune system assists the brain, led us to our recent discovery that transient reduction of systemic immune suppression could modify disease pathology, and reverse cognitive loss in mouse models of AD (Nature Communications, 2015; Nature Medicine, 2016; Science, 2014). This discovery emphasizes that AD is not restricted to the brain, but is associated with systemic immune dysfunction. Thus, the goal of addressing numerous risk factors that go awry in the AD brain, many of which are -as yet- unknown, could be accomplished by immunotherapy, using immune checkpoint blockade directed at the Programmed-death (PD)-1 pathway, to empower the immune system. In this proposal, we will adopt our new experimental paradigm to discover mechanisms through which the immune system supports the brain, and to identify key/novel molecular and cellular processes at various stages of the disease that are responsible for cognitive decline long before neurons are lost, and whose reversal or modification is needed to mitigate AD pathology, and prevent cognitive loss. Achieving our goals requires the multidisciplinary approaches and expertise at our disposal, including state-of-the art immunological, cellular, molecular, and genomic tools. The results will pave the way for developing a novel next-generation immunotherapy, by targeting additional selective immune checkpoint pathways, or identifying a specific immune-based therapeutic target, for prevention and treatment of AD. We expect that our results will help attain the ultimate goal of converting an escalating untreatable disease into a chronic treatable one.
Summary
Understanding, and ultimately treating Alzheimer’s disease (AD) is a major need in Western countries. Currently, there is no available treatment to modify the disease. Several pioneering discoveries made by my team, attributing a key role to systemic immunity in brain maintenance and repair, and identifying unique interface between the brain’s borders through which the immune system assists the brain, led us to our recent discovery that transient reduction of systemic immune suppression could modify disease pathology, and reverse cognitive loss in mouse models of AD (Nature Communications, 2015; Nature Medicine, 2016; Science, 2014). This discovery emphasizes that AD is not restricted to the brain, but is associated with systemic immune dysfunction. Thus, the goal of addressing numerous risk factors that go awry in the AD brain, many of which are -as yet- unknown, could be accomplished by immunotherapy, using immune checkpoint blockade directed at the Programmed-death (PD)-1 pathway, to empower the immune system. In this proposal, we will adopt our new experimental paradigm to discover mechanisms through which the immune system supports the brain, and to identify key/novel molecular and cellular processes at various stages of the disease that are responsible for cognitive decline long before neurons are lost, and whose reversal or modification is needed to mitigate AD pathology, and prevent cognitive loss. Achieving our goals requires the multidisciplinary approaches and expertise at our disposal, including state-of-the art immunological, cellular, molecular, and genomic tools. The results will pave the way for developing a novel next-generation immunotherapy, by targeting additional selective immune checkpoint pathways, or identifying a specific immune-based therapeutic target, for prevention and treatment of AD. We expect that our results will help attain the ultimate goal of converting an escalating untreatable disease into a chronic treatable one.
Max ERC Funding
2 287 500 €
Duration
Start date: 2017-06-01, End date: 2022-05-31
Project acronym InterActive
Project Interacting with Active Particles
Researcher (PI) Jaakko Vaino Isakki TIMONEN
Host Institution (HI) AALTO KORKEAKOULUSAATIO SR
Call Details Starting Grant (StG), PE3, ERC-2018-STG
Summary Active particles refer to out-of-equilibrium self-propulsive objects such as biological microswimmers and engineered colloidal particles that can form various fascinating collective states. Active particles are easy to observe experimentally but notoriously difficult to interact with due to their fast and stochastic dynamics at both single-particle and collective state levels. In this project, I aim at scientific breakthrough in both instrumentation that allows direct interaction with active particles and using the methodology to progress substantially our understanding of dynamics and phase transitions of active particles.
The first part focuses on rendering active particles, including E. coli, C. reinhardtii and Quincke rollers, permanently magnetized and designing suitable hardware for controlling them in real time. These particles are rendered “intelligent” by programming their behavior based on real-time image analysis (long-range vision) and steering with external magnetic field. I will program these particles to reveal the limits of using local dissipative hydrodynamic near-fields to guiding active particles, and demonstrate unambiguously the extent to which a single active particle within a collective state can control the collective behaviour.
The second part aims at realizing tuneable magnetic traps and other conservative potential energy landscapes for non-magnetic active particles by using magnetophoresis in superparamagnetic fluids. I will use the technique to establishing confinement-activity phase diagrams for both biological (C. reinhardtii) and synthetic (Quincke rollers) active particles in quadratic confinements. I will further reveal the role of dimensionality (1D vs 2D vs 3D) in the phase transitions of active particles and carry out the seminal investigation of active particles in periodic potentials.
The results and methodologies will have a major impact, both immediately and in long-term, on experimental physics of active particles.
Summary
Active particles refer to out-of-equilibrium self-propulsive objects such as biological microswimmers and engineered colloidal particles that can form various fascinating collective states. Active particles are easy to observe experimentally but notoriously difficult to interact with due to their fast and stochastic dynamics at both single-particle and collective state levels. In this project, I aim at scientific breakthrough in both instrumentation that allows direct interaction with active particles and using the methodology to progress substantially our understanding of dynamics and phase transitions of active particles.
The first part focuses on rendering active particles, including E. coli, C. reinhardtii and Quincke rollers, permanently magnetized and designing suitable hardware for controlling them in real time. These particles are rendered “intelligent” by programming their behavior based on real-time image analysis (long-range vision) and steering with external magnetic field. I will program these particles to reveal the limits of using local dissipative hydrodynamic near-fields to guiding active particles, and demonstrate unambiguously the extent to which a single active particle within a collective state can control the collective behaviour.
The second part aims at realizing tuneable magnetic traps and other conservative potential energy landscapes for non-magnetic active particles by using magnetophoresis in superparamagnetic fluids. I will use the technique to establishing confinement-activity phase diagrams for both biological (C. reinhardtii) and synthetic (Quincke rollers) active particles in quadratic confinements. I will further reveal the role of dimensionality (1D vs 2D vs 3D) in the phase transitions of active particles and carry out the seminal investigation of active particles in periodic potentials.
The results and methodologies will have a major impact, both immediately and in long-term, on experimental physics of active particles.
Max ERC Funding
1 499 938 €
Duration
Start date: 2019-01-01, End date: 2023-12-31
Project acronym LearnAnx_CircAmyg
Project Learning and Anxiety in Amygdala-based Neural Circuits
Researcher (PI) Rony PAZ
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Call Details Consolidator Grant (CoG), LS5, ERC-2016-COG
Summary Major advances were made in understanding circuits that underlie aversive emotional learning. The majority gained by using classical associative models, mainly tone/context-shock conditioning. Failure to extinguish the response or to discriminate from other safe stimuli (generalization), form two main animal models for human anxiety-disorders and post-traumatic-stress. These simple yet powerful approaches enabled cutting-edge techniques in rodents to unveil amygdala circuitry and its connectivity with the medial-prefrontal-cortex. Yet, we have less understanding of the mechanisms that underlie elaborated behavioural models of mal-adaptive behaviour, as well as less understanding of neural codes and computations in the evolutionary-expanded primate amygdala. Our lab recently embarked on exploring these venues by pioneering physiological studies of generalization and extinction protocols in primates. The goal of the current project is to develop behavioural models of complex learning and maladaptive behaviour, and then examine and shed light on the underlying computations in primate amygdala-PFC circuit. We design a novel rule-based learning task, and examine its acquisition, extinction, generalization and exploration-exploitation trade-off in dangerous environments. Specifically, the concepts of rule learning and exploration-exploitation tradeoff form novel insights and aspects of [mal-]adaptive behaviours, and will suggest new animal models of learned anxiety. We record dozens of neurons in the amygdala and prefrontal-cortex simultaneously using deep multi-contact arrays, supplemented by stimulation to address functional connectivity, and development of modelling approaches for the behaviour and neural codes. We posit that the development of more [complex] models is crucial and the next logical step in achieving translation of animal models of anxiety disorders, as well as in understanding basic mechanisms behind the rich repertoire of emotional behaviours.
Summary
Major advances were made in understanding circuits that underlie aversive emotional learning. The majority gained by using classical associative models, mainly tone/context-shock conditioning. Failure to extinguish the response or to discriminate from other safe stimuli (generalization), form two main animal models for human anxiety-disorders and post-traumatic-stress. These simple yet powerful approaches enabled cutting-edge techniques in rodents to unveil amygdala circuitry and its connectivity with the medial-prefrontal-cortex. Yet, we have less understanding of the mechanisms that underlie elaborated behavioural models of mal-adaptive behaviour, as well as less understanding of neural codes and computations in the evolutionary-expanded primate amygdala. Our lab recently embarked on exploring these venues by pioneering physiological studies of generalization and extinction protocols in primates. The goal of the current project is to develop behavioural models of complex learning and maladaptive behaviour, and then examine and shed light on the underlying computations in primate amygdala-PFC circuit. We design a novel rule-based learning task, and examine its acquisition, extinction, generalization and exploration-exploitation trade-off in dangerous environments. Specifically, the concepts of rule learning and exploration-exploitation tradeoff form novel insights and aspects of [mal-]adaptive behaviours, and will suggest new animal models of learned anxiety. We record dozens of neurons in the amygdala and prefrontal-cortex simultaneously using deep multi-contact arrays, supplemented by stimulation to address functional connectivity, and development of modelling approaches for the behaviour and neural codes. We posit that the development of more [complex] models is crucial and the next logical step in achieving translation of animal models of anxiety disorders, as well as in understanding basic mechanisms behind the rich repertoire of emotional behaviours.
Max ERC Funding
2 000 000 €
Duration
Start date: 2017-09-01, End date: 2022-08-31
Project acronym MacroStability
Project Stability and dynamics at different spatial scales: From physiology to Alzheimer's degeneration
Researcher (PI) Inna Slutsky
Host Institution (HI) TEL AVIV UNIVERSITY
Call Details Consolidator Grant (CoG), LS5, ERC-2016-COG
Summary How neuronal circuits maintain the balance between stability and plasticity in a constantly changing environment remains one of the most fundamental questions in neuroscience. Empirical and theoretical studies suggest that homeostatic negative feedback mechanisms operate to stabilize the function of a system at a set point level of activity. While extensive research uncovered diverse homeostatic mechanisms that maintain activity of neural circuits at extended timescales, several key questions remain open. First, what are the basic principles and the molecular machinery underlying invariant population dynamics of neural circuits, composed from intrinsically unstable activity patterns of individual neurons? Second, is homeostatic regulation compromised in Alzheimer's disease (AD) and do homeostatic failures lead to aberrant brain activity and memory decline, the overlapping phenotypes of AD and many other distinct neurodegenerative disorders? And finally, how do homeostatic systems operate in vivo under experience-dependent changes in firing rates and patterns?
To target these questions, we have developed an integrative approach to study the relationships between ongoing spiking activity of individual neurons and neuronal populations, signaling processes at the level of single synapses and neuronal meta-plasticity. We will focus on hippocampal circuitry and combine ex vivo electrophysiology, single- and two-photon excitation imaging, time-resolved fluorescence microscopy and molecular biology, together with longitudinal monitoring of activity from large populations of hippocampal neurons in freely behaving mice. Utilizing these state-of-the-art approaches, we will determine how firing stability is maintained at different spatial scales and what are the mechanisms leading to destabilization of firing patterns in AD-related context. The proposed research will elucidate fundamental principles of neuronal function and offer conceptual insights into AD pathophysiology.
Summary
How neuronal circuits maintain the balance between stability and plasticity in a constantly changing environment remains one of the most fundamental questions in neuroscience. Empirical and theoretical studies suggest that homeostatic negative feedback mechanisms operate to stabilize the function of a system at a set point level of activity. While extensive research uncovered diverse homeostatic mechanisms that maintain activity of neural circuits at extended timescales, several key questions remain open. First, what are the basic principles and the molecular machinery underlying invariant population dynamics of neural circuits, composed from intrinsically unstable activity patterns of individual neurons? Second, is homeostatic regulation compromised in Alzheimer's disease (AD) and do homeostatic failures lead to aberrant brain activity and memory decline, the overlapping phenotypes of AD and many other distinct neurodegenerative disorders? And finally, how do homeostatic systems operate in vivo under experience-dependent changes in firing rates and patterns?
To target these questions, we have developed an integrative approach to study the relationships between ongoing spiking activity of individual neurons and neuronal populations, signaling processes at the level of single synapses and neuronal meta-plasticity. We will focus on hippocampal circuitry and combine ex vivo electrophysiology, single- and two-photon excitation imaging, time-resolved fluorescence microscopy and molecular biology, together with longitudinal monitoring of activity from large populations of hippocampal neurons in freely behaving mice. Utilizing these state-of-the-art approaches, we will determine how firing stability is maintained at different spatial scales and what are the mechanisms leading to destabilization of firing patterns in AD-related context. The proposed research will elucidate fundamental principles of neuronal function and offer conceptual insights into AD pathophysiology.
Max ERC Funding
2 000 000 €
Duration
Start date: 2017-10-01, End date: 2022-09-30
