Project acronym 5HT-OPTOGENETICS
Project Optogenetic Analysis of Serotonin Function in the Mammalian Brain
Researcher (PI) Zachary Mainen
Host Institution (HI) FUNDACAO D. ANNA SOMMER CHAMPALIMAUD E DR. CARLOS MONTEZ CHAMPALIMAUD
Country Portugal
Call Details Advanced Grant (AdG), LS5, ERC-2009-AdG
Summary Serotonin (5-HT) is implicated in a wide spectrum of brain functions and disorders. However, its functions remain controversial and enigmatic. We suggest that past work on the 5-HT system have been significantly hampered by technical limitations in the selectivity and temporal resolution of the conventional pharmacological and electrophysiological methods that have been applied. We therefore propose to apply novel optogenetic methods that will allow us to overcome these limitations and thereby gain new insight into the biological functions of this important molecule. In preliminary studies, we have demonstrated that we can deliver exogenous proteins specifically to 5-HT neurons using viral vectors. Our objectives are to (1) record, (2) stimulate and (3) silence the activity of 5-HT neurons with high molecular selectivity and temporal precision by using genetically-encoded sensors, activators and inhibitors of neural function. These tools will allow us to monitor and control the 5-HT system in real-time in freely-behaving animals and thereby to establish causal links between information processing in 5-HT neurons and specific behaviors. In combination with quantitative behavioral assays, we will use this approach to define the role of 5-HT in sensory, motor and cognitive functions. The significance of the work is three-fold. First, we will establish a new arsenal of tools for probing the physiological and behavioral functions of 5-HT neurons. Second, we will make definitive tests of major hypotheses of 5-HT function. Third, we will have possible therapeutic applications. In this way, the proposed work has the potential for a major impact in research on the role of 5-HT in brain function and dysfunction.
Summary
Serotonin (5-HT) is implicated in a wide spectrum of brain functions and disorders. However, its functions remain controversial and enigmatic. We suggest that past work on the 5-HT system have been significantly hampered by technical limitations in the selectivity and temporal resolution of the conventional pharmacological and electrophysiological methods that have been applied. We therefore propose to apply novel optogenetic methods that will allow us to overcome these limitations and thereby gain new insight into the biological functions of this important molecule. In preliminary studies, we have demonstrated that we can deliver exogenous proteins specifically to 5-HT neurons using viral vectors. Our objectives are to (1) record, (2) stimulate and (3) silence the activity of 5-HT neurons with high molecular selectivity and temporal precision by using genetically-encoded sensors, activators and inhibitors of neural function. These tools will allow us to monitor and control the 5-HT system in real-time in freely-behaving animals and thereby to establish causal links between information processing in 5-HT neurons and specific behaviors. In combination with quantitative behavioral assays, we will use this approach to define the role of 5-HT in sensory, motor and cognitive functions. The significance of the work is three-fold. First, we will establish a new arsenal of tools for probing the physiological and behavioral functions of 5-HT neurons. Second, we will make definitive tests of major hypotheses of 5-HT function. Third, we will have possible therapeutic applications. In this way, the proposed work has the potential for a major impact in research on the role of 5-HT in brain function and dysfunction.
Max ERC Funding
2 318 636 €
Duration
Start date: 2010-07-01, End date: 2015-12-31
Project acronym 5HTCircuits
Project Modulation of cortical circuits and predictive neural coding by serotonin
Researcher (PI) Zachary Mainen
Host Institution (HI) FUNDACAO D. ANNA SOMMER CHAMPALIMAUD E DR. CARLOS MONTEZ CHAMPALIMAUD
Country Portugal
Call Details Advanced Grant (AdG), LS5, ERC-2014-ADG
Summary Serotonin (5-HT) is a central neuromodulator and a major target of therapeutic psychoactive drugs, but relatively little is known about how it modulates information processing in neural circuits. The theory of predictive coding postulates that the brain combines raw bottom-up sensory information with top-down information from internal models to make perceptual inferences about the world. We hypothesize, based on preliminary data and prior literature, that a role of 5-HT in this process is to report prediction errors and promote the suppression and weakening of erroneous internal models. We propose that it does this by inhibiting top-down relative to bottom-up cortical information flow. To test this hypothesis, we propose a set of experiments in mice performing olfactory perceptual tasks. Our specific aims are: (1) We will test whether 5-HT neurons encode sensory prediction errors. (2) We will test their causal role in using predictive cues to guide perceptual decisions. (3) We will characterize how 5-HT influences the encoding of sensory information by neuronal populations in the olfactory cortex and identify the underlying circuitry. (4) Finally, we will map the effects of 5-HT across the whole brain and use this information to target further causal manipulations to specific 5-HT projections. We accomplish these aims using state-of-the-art optogenetic, electrophysiological and imaging techniques (including 9.4T small-animal functional magnetic resonance imaging) as well as psychophysical tasks amenable to quantitative analysis and computational theory. Together, these experiments will tackle multiple facets of an important general computational question, bringing to bear an array of cutting-edge technologies to address with unprecedented mechanistic detail how 5-HT impacts neural coding and perceptual decision-making.
Summary
Serotonin (5-HT) is a central neuromodulator and a major target of therapeutic psychoactive drugs, but relatively little is known about how it modulates information processing in neural circuits. The theory of predictive coding postulates that the brain combines raw bottom-up sensory information with top-down information from internal models to make perceptual inferences about the world. We hypothesize, based on preliminary data and prior literature, that a role of 5-HT in this process is to report prediction errors and promote the suppression and weakening of erroneous internal models. We propose that it does this by inhibiting top-down relative to bottom-up cortical information flow. To test this hypothesis, we propose a set of experiments in mice performing olfactory perceptual tasks. Our specific aims are: (1) We will test whether 5-HT neurons encode sensory prediction errors. (2) We will test their causal role in using predictive cues to guide perceptual decisions. (3) We will characterize how 5-HT influences the encoding of sensory information by neuronal populations in the olfactory cortex and identify the underlying circuitry. (4) Finally, we will map the effects of 5-HT across the whole brain and use this information to target further causal manipulations to specific 5-HT projections. We accomplish these aims using state-of-the-art optogenetic, electrophysiological and imaging techniques (including 9.4T small-animal functional magnetic resonance imaging) as well as psychophysical tasks amenable to quantitative analysis and computational theory. Together, these experiments will tackle multiple facets of an important general computational question, bringing to bear an array of cutting-edge technologies to address with unprecedented mechanistic detail how 5-HT impacts neural coding and perceptual decision-making.
Max ERC Funding
2 486 074 €
Duration
Start date: 2016-01-01, End date: 2020-12-31
Project acronym DAMAGECONTROL
Project Tissue Damage Control Regulates The Pathogenesis of Immune Mediated Inflammatory Diseases
Researcher (PI) Miguel Parreira Soares
Host Institution (HI) FUNDACAO CALOUSTE GULBENKIAN
Country Portugal
Call Details Advanced Grant (AdG), LS6, ERC-2011-ADG_20110310
Summary "We propose to study evolutionarily conserved stress-responsive protective mechanisms that limit the extent of tissue damage caused by pathogens or by the innate as well as adaptive immune response elicited by those pathogens, which, without a countervailing response would lead to irreversible tissue damage and disease. We refer to these protective mechanisms as “tissue damage control”, and will argue they are an essential component of immunity that allows the effector mechanisms involved in pathogen clearance to operate without causing disease. This proposal aims at identifying and characterizing the mechanism of action of stress-induced genetic programs conferring tissue damage control and to relate those to the pathogenesis of different immune mediated inflammatory diseases. We hypothesize that these genetic programs share as a common denominator their regulation by a restricted number of evolutionary conserved transcription factors that act as “master regulators” of different protective responses to specific forms of stress. We will use “loss” and “gain” of function approaches targeting these master regulators in mice to characterize their function and identify stress-responsive genes conferring tissue metabolic adaptation, cytoprotection and/or tissue regeneration, all of which are components of tissue damage control. Expression of these master regulators likely impacts the pathogenesis of immune mediated inflammatory conditions, as tested under this proposal for infectious as well as autoimmune-like diseases. This proposal should unveil an essential component of immunity that uncouples pathogen clearance from tissue damage and disease, namely tissue damage control, providing new therapeutic targets to suppress the pathogenesis of a broad range of immune mediated inflammatory diseases."
Summary
"We propose to study evolutionarily conserved stress-responsive protective mechanisms that limit the extent of tissue damage caused by pathogens or by the innate as well as adaptive immune response elicited by those pathogens, which, without a countervailing response would lead to irreversible tissue damage and disease. We refer to these protective mechanisms as “tissue damage control”, and will argue they are an essential component of immunity that allows the effector mechanisms involved in pathogen clearance to operate without causing disease. This proposal aims at identifying and characterizing the mechanism of action of stress-induced genetic programs conferring tissue damage control and to relate those to the pathogenesis of different immune mediated inflammatory diseases. We hypothesize that these genetic programs share as a common denominator their regulation by a restricted number of evolutionary conserved transcription factors that act as “master regulators” of different protective responses to specific forms of stress. We will use “loss” and “gain” of function approaches targeting these master regulators in mice to characterize their function and identify stress-responsive genes conferring tissue metabolic adaptation, cytoprotection and/or tissue regeneration, all of which are components of tissue damage control. Expression of these master regulators likely impacts the pathogenesis of immune mediated inflammatory conditions, as tested under this proposal for infectious as well as autoimmune-like diseases. This proposal should unveil an essential component of immunity that uncouples pathogen clearance from tissue damage and disease, namely tissue damage control, providing new therapeutic targets to suppress the pathogenesis of a broad range of immune mediated inflammatory diseases."
Max ERC Funding
2 306 197 €
Duration
Start date: 2012-04-01, End date: 2017-03-31
