Project acronym AstroFunc
Project Molecular Studies of Astrocyte Function in Health and Disease
Researcher (PI) Matthew Guy Holt
Host Institution (HI) VIB
Call Details Starting Grant (StG), LS5, ERC-2011-StG_20101109
Summary Brain consists of two basic cell types – neurons and glia. However, the study of glia in brain function has traditionally been neglected in favor of their more “illustrious” counter-parts – neurons that are classed as the computational units of the brain. Glia have usually been classed as “brain glue” - a supportive matrix on which neurons grow and function. However, recent evidence suggests that glia are more than passive “glue” and actually modulate neuronal function. This has lead to the proposal of a “tripartite synapse”, which recognizes pre- and postsynaptic neuronal elements and glia as a unit.
However, what is still lacking is rudimentary information on how these cells actually function in situ. Here we propose taking a “bottom-up” approach, by identifying the molecules (and interactions) that control glial function in situ. This is complicated by the fact that glia show profound changes when placed into culture. To circumvent this, we will use recently developed cell sorting techniques, to rapidly isolate genetically marked glial cells from brain – which can then be analyzed using advanced biochemical and physiological techniques. The long-term aim is to identify proteins that can be “tagged” using transgenic technologies to allow protein function to be studied in real-time in vivo, using sophisticated imaging techniques. Given the number of proteins that may be identified we envisage developing new methods of generating transgenic animals that provide an attractive alternative to current “state-of-the art” technology.
The importance of studying glial function is given by the fact that every major brain pathology shows reactive gliosis. In the time it takes to read this abstract, 5 people in the EU will have suffered a stroke – not to mention those who suffer other forms of neurotrauma. Thus, understanding glial function is not only critical to understanding normal brain function, but also for relieving the burden of severe neurological injury and disease
Summary
Brain consists of two basic cell types – neurons and glia. However, the study of glia in brain function has traditionally been neglected in favor of their more “illustrious” counter-parts – neurons that are classed as the computational units of the brain. Glia have usually been classed as “brain glue” - a supportive matrix on which neurons grow and function. However, recent evidence suggests that glia are more than passive “glue” and actually modulate neuronal function. This has lead to the proposal of a “tripartite synapse”, which recognizes pre- and postsynaptic neuronal elements and glia as a unit.
However, what is still lacking is rudimentary information on how these cells actually function in situ. Here we propose taking a “bottom-up” approach, by identifying the molecules (and interactions) that control glial function in situ. This is complicated by the fact that glia show profound changes when placed into culture. To circumvent this, we will use recently developed cell sorting techniques, to rapidly isolate genetically marked glial cells from brain – which can then be analyzed using advanced biochemical and physiological techniques. The long-term aim is to identify proteins that can be “tagged” using transgenic technologies to allow protein function to be studied in real-time in vivo, using sophisticated imaging techniques. Given the number of proteins that may be identified we envisage developing new methods of generating transgenic animals that provide an attractive alternative to current “state-of-the art” technology.
The importance of studying glial function is given by the fact that every major brain pathology shows reactive gliosis. In the time it takes to read this abstract, 5 people in the EU will have suffered a stroke – not to mention those who suffer other forms of neurotrauma. Thus, understanding glial function is not only critical to understanding normal brain function, but also for relieving the burden of severe neurological injury and disease
Max ERC Funding
1 490 168 €
Duration
Start date: 2012-01-01, End date: 2016-12-31
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 BRAINCANNABINOIDS
Project Understanding the molecular blueprint and functional complexity of the endocannabinoid metabolome in the brain
Researcher (PI) István Katona
Host Institution (HI) INSTITUTE OF EXPERIMENTAL MEDICINE - HUNGARIAN ACADEMY OF SCIENCES
Call Details Starting Grant (StG), LS5, ERC-2009-StG
Summary We and others have recently delineated the molecular architecture of a new feedback pathway in brain synapses, which operates as a synaptic circuit breaker. This pathway is supposed to use a group of lipid messengers as retrograde synaptic signals, the so-called endocannabinoids. Although heterogeneous in their chemical structures, these molecules along with the psychoactive compound in cannabis are thought to target the same effector in the brain, the CB1 receptor. However, the molecular catalog of these bioactive lipids and their metabolic enzymes has been expanding rapidly by recent advances in lipidomics and proteomics raising the possibility that these lipids may also serve novel, yet unidentified physiological functions. Thus, the overall aim of our research program is to define the molecular and anatomical organization of these endocannabinoid-mediated pathways and to determine their functional significance. In the present proposal, we will focus on understanding how these novel pathways regulate synaptic and extrasynaptic signaling in hippocampal neurons. Using combination of lipidomic, genetic and high-resolution anatomical approaches, we will identify distinct chemical species of endocannabinoids and will show how their metabolic enzymes are segregated into different subcellular compartments in cell type- and synapse-specific manner. Subsequently, we will use genetically encoded gain-of-function, loss-of-function and reporter constructs in imaging experiments and electrophysiological recordings to gain insights into the diverse tasks that these new pathways serve in synaptic transmission and extrasynaptic signal processing. Our proposed experiments will reveal fundamental principles of intercellular and intracellular endocannabinoid signaling in the brain.
Summary
We and others have recently delineated the molecular architecture of a new feedback pathway in brain synapses, which operates as a synaptic circuit breaker. This pathway is supposed to use a group of lipid messengers as retrograde synaptic signals, the so-called endocannabinoids. Although heterogeneous in their chemical structures, these molecules along with the psychoactive compound in cannabis are thought to target the same effector in the brain, the CB1 receptor. However, the molecular catalog of these bioactive lipids and their metabolic enzymes has been expanding rapidly by recent advances in lipidomics and proteomics raising the possibility that these lipids may also serve novel, yet unidentified physiological functions. Thus, the overall aim of our research program is to define the molecular and anatomical organization of these endocannabinoid-mediated pathways and to determine their functional significance. In the present proposal, we will focus on understanding how these novel pathways regulate synaptic and extrasynaptic signaling in hippocampal neurons. Using combination of lipidomic, genetic and high-resolution anatomical approaches, we will identify distinct chemical species of endocannabinoids and will show how their metabolic enzymes are segregated into different subcellular compartments in cell type- and synapse-specific manner. Subsequently, we will use genetically encoded gain-of-function, loss-of-function and reporter constructs in imaging experiments and electrophysiological recordings to gain insights into the diverse tasks that these new pathways serve in synaptic transmission and extrasynaptic signal processing. Our proposed experiments will reveal fundamental principles of intercellular and intracellular endocannabinoid signaling in the brain.
Max ERC Funding
1 638 000 €
Duration
Start date: 2009-11-01, End date: 2014-10-31
Project acronym BRAINSHAPE
Project Objects in sight: the neural basis of visuomotor transformations for actions towards objects
Researcher (PI) Peter Anna J Janssen
Host Institution (HI) KATHOLIEKE UNIVERSITEIT LEUVEN
Call Details Starting Grant (StG), LS5, ERC-2010-StG_20091118
Summary Humans and other primates possess an exquisite capacity to grasp and manipulate objects. The seemingly effortless interaction with objects in everyday life is subserved by a number of cortical areas of the visual and the motor system. Recent research has highlighted that dorsal stream areas in the posterior parietal cortex are involved in object processing. Because parietal lesions do not impair object recognition, the encoding of object shape in posterior parietal cortex is considered to be important for the planning of actions towards objects. In order to succesfully grasp an object, the complex pattern of visual information impinging on the retina has to be transformed into a motor plan that can control the muscle contractions. The neural basis of visuomotor transformations necessary for directing actions towards objects, however, has remained largely unknown. This proposal aims to unravel the pathways and mechanisms involved in programming actions towards objects - an essential capacity for our very survival. We envision an integrated approach to study the transformation of visual information into motor commands in the macaque brain, combining functional imaging, single-cell recording, microstimulation and reversible inactivation. Our research efforts will be focussed on parietal area AIP and premotor area F5, two key brain areas for visually-guided grasping. Above all, this proposal will move beyond purely descriptive measurements of neural activity by implementing manipulations of brain activity to reveal behavioral effects and interdependencies of cortical areas. Finally the data obtained in this project will pave the way to use the neural activity recorded in visuomotor areas to act upon the environment by grasping objects by means of a robot hand.
Summary
Humans and other primates possess an exquisite capacity to grasp and manipulate objects. The seemingly effortless interaction with objects in everyday life is subserved by a number of cortical areas of the visual and the motor system. Recent research has highlighted that dorsal stream areas in the posterior parietal cortex are involved in object processing. Because parietal lesions do not impair object recognition, the encoding of object shape in posterior parietal cortex is considered to be important for the planning of actions towards objects. In order to succesfully grasp an object, the complex pattern of visual information impinging on the retina has to be transformed into a motor plan that can control the muscle contractions. The neural basis of visuomotor transformations necessary for directing actions towards objects, however, has remained largely unknown. This proposal aims to unravel the pathways and mechanisms involved in programming actions towards objects - an essential capacity for our very survival. We envision an integrated approach to study the transformation of visual information into motor commands in the macaque brain, combining functional imaging, single-cell recording, microstimulation and reversible inactivation. Our research efforts will be focussed on parietal area AIP and premotor area F5, two key brain areas for visually-guided grasping. Above all, this proposal will move beyond purely descriptive measurements of neural activity by implementing manipulations of brain activity to reveal behavioral effects and interdependencies of cortical areas. Finally the data obtained in this project will pave the way to use the neural activity recorded in visuomotor areas to act upon the environment by grasping objects by means of a robot hand.
Max ERC Funding
1 499 200 €
Duration
Start date: 2010-11-01, End date: 2015-10-31
Project acronym CORTEXFOLDING
Project Understanding the development and function of cerebral cortex folding
Researcher (PI) Victor Borrell Franco
Host Institution (HI) AGENCIA ESTATAL CONSEJO SUPERIOR DEINVESTIGACIONES CIENTIFICAS
Call Details Starting Grant (StG), LS5, ERC-2012-StG_20111109
Summary The mammalian cerebral cortex was subject to a dramatic expansion in surface area during evolution. This process is recapitulated during development and is accompanied by folding of the cortical sheet, which allows fitting a large cortical surface within a limited cranial volume. A loss of cortical folds is linked to severe intellectual impairment in humans, so cortical folding is believed to be crucial for brain function. However, developmental mechanisms responsible for cortical folding, and the influence of this on cortical function, remain largely unknown. The goal of this proposal is to understand the genetic and cellular mechanisms that control the developmental expansion and folding of the cerebral cortex, and what is the impact of these processes on its functional organization. Human studies have identified genes essential for the proper folding of the human cerebral cortex. Genetic manipulations in mice have unraveled specific functions for some of those genes in the development of the cerebral cortex. But because the mouse cerebral cortex does not fold naturally, the mechanisms of cortical expansion and folding in larger brains remain unknown. We will study these mechanisms on ferret, an ideal model with a naturally folded cerebral cortex. We will combine the advantages of ferrets with cell biology, genetics and next-generation transcriptomics, together with state-of-the-art in vivo, in vitro and in silico approaches, including in vivo imaging of functional columnar maps. The successful execution of this project will provide insights into developmental and genetic risk factors for anomalies in human cortical topology, and into mechanisms responsible for the early formation of cortical functional maps.
Summary
The mammalian cerebral cortex was subject to a dramatic expansion in surface area during evolution. This process is recapitulated during development and is accompanied by folding of the cortical sheet, which allows fitting a large cortical surface within a limited cranial volume. A loss of cortical folds is linked to severe intellectual impairment in humans, so cortical folding is believed to be crucial for brain function. However, developmental mechanisms responsible for cortical folding, and the influence of this on cortical function, remain largely unknown. The goal of this proposal is to understand the genetic and cellular mechanisms that control the developmental expansion and folding of the cerebral cortex, and what is the impact of these processes on its functional organization. Human studies have identified genes essential for the proper folding of the human cerebral cortex. Genetic manipulations in mice have unraveled specific functions for some of those genes in the development of the cerebral cortex. But because the mouse cerebral cortex does not fold naturally, the mechanisms of cortical expansion and folding in larger brains remain unknown. We will study these mechanisms on ferret, an ideal model with a naturally folded cerebral cortex. We will combine the advantages of ferrets with cell biology, genetics and next-generation transcriptomics, together with state-of-the-art in vivo, in vitro and in silico approaches, including in vivo imaging of functional columnar maps. The successful execution of this project will provide insights into developmental and genetic risk factors for anomalies in human cortical topology, and into mechanisms responsible for the early formation of cortical functional maps.
Max ERC Funding
1 701 116 €
Duration
Start date: 2013-01-01, End date: 2018-06-30
Project acronym DeCode
Project Dendrites and memory: role of dendritic spikes in information coding by hippocampal CA3 pyramidal neurons
Researcher (PI) Judit MAKARA
Host Institution (HI) INSTITUTE OF EXPERIMENTAL MEDICINE - HUNGARIAN ACADEMY OF SCIENCES
Call Details Consolidator Grant (CoG), LS5, ERC-2017-COG
Summary The hippocampus is essential for building episodic memories. Coding of locations, contexts or events in the hippocampus is based on the correlated activity of neuronal ensembles; however, the mechanisms promoting the recruitment of individual neurons into information-coding ensembles are poorly understood.
In particular, the recurrent synaptic network of pyramidal cells (PCs) in the hippocampal CA3 area, receiving external inputs from the entorhinal cortex and the dentate gyrus, is thought to be essential for associative memory. Current models of the associative functions of CA3 are mainly based on plasticity of these synaptic connections. Recent work by us and others however suggests that active, voltage-dependent properties of CA3PC dendrites may also promote ensemble functions. Dendritic voltage-dependent ion channels allow nonlinear amplification of spatiotemporally correlated synaptic inputs (such as those produced by ensemble activity) and can even generate local dendritic spikes, which may elicit specific action potential patterns and induce synaptic plasticity. Furthermore, dendritic processing may be modulated by activity-dependent regulation of dendritic ion channels. However, still little is known about the active properties of CA3PC dendrites and their functions during spatial coding or memory tasks.
The general aim of my research program is to understand the cellular mechanisms that underlie the formation of hippocampal memory-coding neuronal ensembles. Specifically, we will test the hypothesis that active input integration by dendrites of individual CA3PCs plays an important role in their recruitment into specific context-coding ensembles. By combining in vitro (patch-clamp electrophysiology and two-photon (2P) microscopy in slices) and in vivo (2P imaging and activity-dependent labelling in behaving rodents) approaches, we will provide an in-depth understanding of the dendritic components contributing to the generation of the CA3 ensemble code.
Summary
The hippocampus is essential for building episodic memories. Coding of locations, contexts or events in the hippocampus is based on the correlated activity of neuronal ensembles; however, the mechanisms promoting the recruitment of individual neurons into information-coding ensembles are poorly understood.
In particular, the recurrent synaptic network of pyramidal cells (PCs) in the hippocampal CA3 area, receiving external inputs from the entorhinal cortex and the dentate gyrus, is thought to be essential for associative memory. Current models of the associative functions of CA3 are mainly based on plasticity of these synaptic connections. Recent work by us and others however suggests that active, voltage-dependent properties of CA3PC dendrites may also promote ensemble functions. Dendritic voltage-dependent ion channels allow nonlinear amplification of spatiotemporally correlated synaptic inputs (such as those produced by ensemble activity) and can even generate local dendritic spikes, which may elicit specific action potential patterns and induce synaptic plasticity. Furthermore, dendritic processing may be modulated by activity-dependent regulation of dendritic ion channels. However, still little is known about the active properties of CA3PC dendrites and their functions during spatial coding or memory tasks.
The general aim of my research program is to understand the cellular mechanisms that underlie the formation of hippocampal memory-coding neuronal ensembles. Specifically, we will test the hypothesis that active input integration by dendrites of individual CA3PCs plays an important role in their recruitment into specific context-coding ensembles. By combining in vitro (patch-clamp electrophysiology and two-photon (2P) microscopy in slices) and in vivo (2P imaging and activity-dependent labelling in behaving rodents) approaches, we will provide an in-depth understanding of the dendritic components contributing to the generation of the CA3 ensemble code.
Max ERC Funding
1 990 314 €
Duration
Start date: 2018-06-01, End date: 2023-05-31
Project acronym FunctionalProteomics
Project Proteomic fingerprinting of functionally characterized single synapses
Researcher (PI) Zoltan NUSSER
Host Institution (HI) INSTITUTE OF EXPERIMENTAL MEDICINE - HUNGARIAN ACADEMY OF SCIENCES
Call Details Advanced Grant (AdG), LS5, ERC-2017-ADG
Summary Our astonishing cognitive abilities are the consequence of complex connectivity within our neuronal networks and the large functional diversity of excitable nerve cells and their synapses. Investigations over the past half a century revealed dramatic diversity in shape, size and functional properties among synapses established by distinct cell types in different brain regions and demonstrated that the functional differences are partly due to different molecular mechanisms. However, synaptic diversity is also observed among synapses established by molecularly and morphologically uniform presynaptic cells on molecularly and morphologically uniform postsynaptic cells. Our hypothesis is that quantitative molecular differences underlie the functional diversity of such synapses. We will focus on hippocampal CA1 pyramidal cell (PC) to mGluR1α+ O-LM cell synapses, which show remarkable functional and molecular heterogeneity. In vitro multiple cell patch-clamp recordings followed by quantal analysis will be performed to quantify well-defined biophysical properties of these synapses. The molecular composition of the functionally characterized single synapses will be determined following the development of a novel postembedding immunolocalization method. Correlations between the molecular content and functional properties will be established and genetic up- and downregulation of individual synaptic proteins will be conducted to reveal causal relationships. Finally, correlations of the activity history and the functional properties of the synapses will be established by performing in vivo two-photon Ca2+ imaging in head-fixed behaving animals followed by in vitro functional characterization of their synapses. Our results will reveal quantitative molecular fingerprints of functional properties, allowing us to render dynamic behaviour to billions of synapses when the connectome of the hippocampal circuit is created using array tomography.
Summary
Our astonishing cognitive abilities are the consequence of complex connectivity within our neuronal networks and the large functional diversity of excitable nerve cells and their synapses. Investigations over the past half a century revealed dramatic diversity in shape, size and functional properties among synapses established by distinct cell types in different brain regions and demonstrated that the functional differences are partly due to different molecular mechanisms. However, synaptic diversity is also observed among synapses established by molecularly and morphologically uniform presynaptic cells on molecularly and morphologically uniform postsynaptic cells. Our hypothesis is that quantitative molecular differences underlie the functional diversity of such synapses. We will focus on hippocampal CA1 pyramidal cell (PC) to mGluR1α+ O-LM cell synapses, which show remarkable functional and molecular heterogeneity. In vitro multiple cell patch-clamp recordings followed by quantal analysis will be performed to quantify well-defined biophysical properties of these synapses. The molecular composition of the functionally characterized single synapses will be determined following the development of a novel postembedding immunolocalization method. Correlations between the molecular content and functional properties will be established and genetic up- and downregulation of individual synaptic proteins will be conducted to reveal causal relationships. Finally, correlations of the activity history and the functional properties of the synapses will be established by performing in vivo two-photon Ca2+ imaging in head-fixed behaving animals followed by in vitro functional characterization of their synapses. Our results will reveal quantitative molecular fingerprints of functional properties, allowing us to render dynamic behaviour to billions of synapses when the connectome of the hippocampal circuit is created using array tomography.
Max ERC Funding
2 498 750 €
Duration
Start date: 2018-10-01, End date: 2023-09-30
Project acronym GENDEVOCORTEX
Project Genetic links between development and evolution of the human cerebral cortex
Researcher (PI) Pierre Vanderhaeghen
Host Institution (HI) UNIVERSITE LIBRE DE BRUXELLES
Call Details Advanced Grant (AdG), LS5, ERC-2013-ADG
Summary "The mechanisms underlying the evolution of the human brain constitute one of the most fascinating unresolved questions of biology. The cerebral cortex has evolved rapidly in size and complexity in the hominid lineage, which is likely linked to quantitative and qualitative divergence in patterns of cortical development.
On the other hand, comparative genomics has revealed recently the existence of a number of ""hominid-specific"" genes, which constitute attractive candidates to underlie critical aspects of human brain evolution, but their function remains essentially unexplored, mostly because of the lack of appropriate experimental systems.
Here we propose to test a simple and radical hypothesis: that key species-specific features of the development of the human cerebral cortex, in particular the generation and differentiation of pyramidal neurons, are linked functionally to the emergence of hominid-specific (HS) genes controlling corticogenesis.
To achieve this high risk / high gain goal, we will first determine which HS genes are expressed in the human developing cortex in vivo, using a combination of genome-wide and in situ gene detection analyses, in order to select those most likely to impact corticogenesis.
The function of candidate HS genes will be determined using innovative models of human corticogenesis based on pluripotent stem cells, developed recently in our laboratory, as well as ex vivo cultures of human fetal cortex. In addition, the developmental and evolutionary impact of HS genes will be examined in a non-hominid context, the mouse embryonic cortex.
By identifying the function of hominid-specific genes in cortical developpment, we will uncover specific genetic mechanisms linking functionally the development and evolution of the human brain, with broad implications in neurobiology, developmental and evolutionary biology."
Summary
"The mechanisms underlying the evolution of the human brain constitute one of the most fascinating unresolved questions of biology. The cerebral cortex has evolved rapidly in size and complexity in the hominid lineage, which is likely linked to quantitative and qualitative divergence in patterns of cortical development.
On the other hand, comparative genomics has revealed recently the existence of a number of ""hominid-specific"" genes, which constitute attractive candidates to underlie critical aspects of human brain evolution, but their function remains essentially unexplored, mostly because of the lack of appropriate experimental systems.
Here we propose to test a simple and radical hypothesis: that key species-specific features of the development of the human cerebral cortex, in particular the generation and differentiation of pyramidal neurons, are linked functionally to the emergence of hominid-specific (HS) genes controlling corticogenesis.
To achieve this high risk / high gain goal, we will first determine which HS genes are expressed in the human developing cortex in vivo, using a combination of genome-wide and in situ gene detection analyses, in order to select those most likely to impact corticogenesis.
The function of candidate HS genes will be determined using innovative models of human corticogenesis based on pluripotent stem cells, developed recently in our laboratory, as well as ex vivo cultures of human fetal cortex. In addition, the developmental and evolutionary impact of HS genes will be examined in a non-hominid context, the mouse embryonic cortex.
By identifying the function of hominid-specific genes in cortical developpment, we will uncover specific genetic mechanisms linking functionally the development and evolution of the human brain, with broad implications in neurobiology, developmental and evolutionary biology."
Max ERC Funding
2 473 937 €
Duration
Start date: 2014-08-01, End date: 2019-07-31
Project acronym INTERIMPACT
Project Impact of identified interneurons on cellular network mechanisms in the human and rodent neocortex
Researcher (PI) Gábor Tamás
Host Institution (HI) Szegedi Tudomanyegyetem - Hungarian-Netherlands School of Educational Management
Call Details Advanced Grant (AdG), LS5, ERC-2010-AdG_20100317
Summary This application addresses mechanisms linking the activity of single neurons with network events by defining the function of identified cell types in the cerebral cortex. The key hypotheses emerged from our experiments and propose that neurogliaform cells and axo-axonic cells achieve their function in the cortex through extreme forms of unspecificity and specificity, respectively. The project capitalizes on our discovery that neurogliaform cells reach GABAA and GABAB receptors on target cells through unitary volume transmission going beyond the classical theory which states that single cortical neurons act in or around synaptic junctions. We propose that the spatial unspecificity of neurotransmitter action leads to unprecedented functional capabilities for a single neuron simultaneously acting on neuronal, glial and vascular components of the surrounding area allowing neurogliaform cells to synchronize metabolic demand and supply in microcircuits. In contrast, axo-axonic cells represent extreme spatial specificity in the brain: terminals of axo-axonic cells exclusively target the axon initial segment of pyramidal neurons. Axo-axonic cells were considered as the most potent inhibitory neurons of the cortex. However, our experiments suggested that axo-axonic cells can be the most powerful excitatory neurons known to date by triggering complex network events. Our unprecedented recordings in the human cortex show that axo-axonic cells are crucial in activating functional assemblies which were implicated in higher order cognitive representations. We aim to define interactions between active cortical networks and axo-axonic cell triggered assemblies with an emphasis on mechanisms modulated by neurogliaform cells and commonly prescribed drugs.
Summary
This application addresses mechanisms linking the activity of single neurons with network events by defining the function of identified cell types in the cerebral cortex. The key hypotheses emerged from our experiments and propose that neurogliaform cells and axo-axonic cells achieve their function in the cortex through extreme forms of unspecificity and specificity, respectively. The project capitalizes on our discovery that neurogliaform cells reach GABAA and GABAB receptors on target cells through unitary volume transmission going beyond the classical theory which states that single cortical neurons act in or around synaptic junctions. We propose that the spatial unspecificity of neurotransmitter action leads to unprecedented functional capabilities for a single neuron simultaneously acting on neuronal, glial and vascular components of the surrounding area allowing neurogliaform cells to synchronize metabolic demand and supply in microcircuits. In contrast, axo-axonic cells represent extreme spatial specificity in the brain: terminals of axo-axonic cells exclusively target the axon initial segment of pyramidal neurons. Axo-axonic cells were considered as the most potent inhibitory neurons of the cortex. However, our experiments suggested that axo-axonic cells can be the most powerful excitatory neurons known to date by triggering complex network events. Our unprecedented recordings in the human cortex show that axo-axonic cells are crucial in activating functional assemblies which were implicated in higher order cognitive representations. We aim to define interactions between active cortical networks and axo-axonic cell triggered assemblies with an emphasis on mechanisms modulated by neurogliaform cells and commonly prescribed drugs.
Max ERC Funding
2 391 695 €
Duration
Start date: 2011-06-01, End date: 2017-05-31
Project acronym IPLASTICITY
Project Induction of juvenile-like plasticity in the adult brain
Researcher (PI) Eero Castrén
Host Institution (HI) HELSINGIN YLIOPISTO
Call Details Advanced Grant (AdG), LS5, ERC-2012-ADG_20120314
Summary Neuronal networks are tuned to optimally represent external and internal milieu through neuronal plasticity during critical periods of juvenile life. After the closure of the critical periods, plasticity is considered to be much more limited. In a series of landmark studies, we have shown that critical period-like plasticity can be reactivated in the adult mammalian brain by pharmacological treatment with the antidepressant fluoxetine. These ground-breaking studies establish a new principle, induced juvenile-like plasticity (iPlasticity) and define a new class of drugs, iPlastic drugs. For optimal results, iPlastic drug must be combined with physical or psychological rehabilitation, which guide the plastic networks and together allow better adaptation towards changing environment. iPlasticity may facilitate functional recovery after brain injury and underlie the enhanced efficacy of combined antidepressant treatment and psychotherapy.
We have uncovered iPlasticity as an exciting new concept and established experimental models to study the molecular, cellular and network level mechanisms underlying it. We will here focus on the role of neurotrophin BDNF, because our previous and unpublished work clearly shows that BDNF and its receptors TrkB and p75 are essential and sufficient for iPlasticity. We have found that a major developmental reorganization in TrkB signalling takes place coinciding with the end of critical periods, and its reversal may underlie iPlasticity. We will utilize our resources as a leading lab in BDNF effects in adult brain and through novel controlled transgenic models, genomics and proteomics, we will reveal the role of BDNF signalling through TrkB and p75 in brain maturation, iPlasticity and brain disorders. Understanding the neurobiological background of iPlasticity will be vital for iPlastic drug development and the numerous translational applications of iPlasticity clearly in sight.
Summary
Neuronal networks are tuned to optimally represent external and internal milieu through neuronal plasticity during critical periods of juvenile life. After the closure of the critical periods, plasticity is considered to be much more limited. In a series of landmark studies, we have shown that critical period-like plasticity can be reactivated in the adult mammalian brain by pharmacological treatment with the antidepressant fluoxetine. These ground-breaking studies establish a new principle, induced juvenile-like plasticity (iPlasticity) and define a new class of drugs, iPlastic drugs. For optimal results, iPlastic drug must be combined with physical or psychological rehabilitation, which guide the plastic networks and together allow better adaptation towards changing environment. iPlasticity may facilitate functional recovery after brain injury and underlie the enhanced efficacy of combined antidepressant treatment and psychotherapy.
We have uncovered iPlasticity as an exciting new concept and established experimental models to study the molecular, cellular and network level mechanisms underlying it. We will here focus on the role of neurotrophin BDNF, because our previous and unpublished work clearly shows that BDNF and its receptors TrkB and p75 are essential and sufficient for iPlasticity. We have found that a major developmental reorganization in TrkB signalling takes place coinciding with the end of critical periods, and its reversal may underlie iPlasticity. We will utilize our resources as a leading lab in BDNF effects in adult brain and through novel controlled transgenic models, genomics and proteomics, we will reveal the role of BDNF signalling through TrkB and p75 in brain maturation, iPlasticity and brain disorders. Understanding the neurobiological background of iPlasticity will be vital for iPlastic drug development and the numerous translational applications of iPlasticity clearly in sight.
Max ERC Funding
2 500 000 €
Duration
Start date: 2013-04-01, End date: 2018-03-31
