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Dougal Tervo

Howard Hughes Medical Institute, Neuroscience, Faculty Member

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Neuroscientist
Address: Howard Hughes Medical Institute
Janelia Farm Research Campus
19700 Helix Drive
Ashburn, VA 20147 USA

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Papers by Dougal Tervo

Inactivation of Synaptic Transmission in Genetically Targeted Neurons

Inducible and reversible silencing of selected neurons in vivo is critical to understanding the s... more Inducible and reversible silencing of selected neurons in vivo is critical to understanding the structure and dynamics of brain circuits. We have developed Molecules for Inactivation of Synaptic Transmission (MISTs) that can be genetically targeted to allow the reversible inactivation of neurotransmitter release. MISTs consist of modified presynaptic proteins that interfere with the synaptic vesicle cycle when crosslinked by small molecule ‘‘dimerizers.’ ’ MISTs based on the vesicle proteins VAMP2/Synaptobrevin and Synaptophysin induced rapid (w10 min) and reversible block of synaptic transmission in cultured neurons and brain slices. In transgenic mice expressing MISTs selectively in Purkinje neurons, administration of dimerizer reduced learning and performance of the rotarod behavior. MISTs allow for specific, inducible, and reversible lesions in neuronal circuits and may provide treatment of disorders associated with neuronal hyperactivity.

Anterior Cingulate Cortex Directs Exploration of Alternative Strategies

SummaryThe ability to adjust one’s behavioral strategy in complex environments is at the core of ... more SummaryThe ability to adjust one’s behavioral strategy in complex environments is at the core of cognition. Doing so efficiently requires monitoring the reliability of the ongoing strategy and switching away from it to evaluate alternatives when appropriate. Studies in humans and non-human primates have uncovered signals in the anterior cingulate cortex (ACC) that track the pressure to switch away from the ongoing strategy, and others that relate to the pursuit of alternatives. However, whether these signals underlie computations that actually underpin strategy switching, or merely reflect tracking of related variables remains unclear. Here we provide causal evidence that rodent ACC actively arbitrates between persisting with ongoing behavioral choice and switching away temporarily to re-evaluate alternatives. Furthermore, by individually perturbing distinct output pathways, we establish that the two associated computations – whether to switch away from the current choice, and the p...

Expanding the Optogenetics Toolkit by Topological Inversion of Rhodopsins

Cell, Jan 16, 2018

Targeted manipulation of activity in specific populations of neurons is important for investigati... more Targeted manipulation of activity in specific populations of neurons is important for investigating the neural circuit basis of behavior. Optogenetic approaches using light-sensitive microbial rhodopsins have permitted manipulations to reach a level of temporal precision that is enabling functional circuit dissection. As demand for more precise perturbations to serve specific experimental goals increases, a palette of opsins with diverse selectivity, kinetics, and spectral properties will be needed. Here, we introduce a novel approach of "topological engineering"-inversion of opsins in the plasma membrane-and demonstrate that it can produce variants with unique functional properties of interest for circuit neuroscience. In one striking example, inversion of a Channelrhodopsin variant converted it from a potent activator into a fast-acting inhibitor that operates as a cation pump. Our findings argue that membrane topology provides a useful orthogonal dimension of protein en...

A Designer AAV Variant Permits Efficient Retrograde Access to Projection Neurons

Neuron, Jan 19, 2016

Efficient retrograde access to projection neurons for the delivery of sensors and effectors const... more Efficient retrograde access to projection neurons for the delivery of sensors and effectors constitutes an important and enabling capability for neural circuit dissection. Such an approach would also be useful for gene therapy, including the treatment of neurodegenerative disorders characterized by pathological spread through functionally connected and highly distributed networks. Viral vectors, in particular, are powerful gene delivery vehicles for the nervous system, but all available tools suffer from inefficient retrograde transport or limited clinical potential. To address this need, we applied in vivo directed evolution to engineer potent retrograde functionality into the capsid of adeno-associated virus (AAV), a vector that has shown promise in neuroscience research and the clinic. A newly evolved variant, rAAV2-retro, permits robust retrograde access to projection neurons with efficiency comparable to classical synthetic retrograde tracers and enables sufficient sensor/effec...

Neurotechnique Rapid and Reversible Chemical InactivationofSynapticTransmission in Genetically Targeted Neurons

ABSTRACT Summary

Behavioral variability through stochastic choice and its gating by anterior cingulate cortex

Cell, Jan 25, 2014

Behavioral choices that ignore prior experience promote exploration and unpredictability but are ... more Behavioral choices that ignore prior experience promote exploration and unpredictability but are seemingly at odds with the brain's tendency to use experience to optimize behavioral choice. Indeed, when faced with virtual competitors, primates resort to strategic counter prediction rather than to stochastic choice. Here, we show that rats also use history- and model-based strategies when faced with similar competitors but can switch to a "stochastic" mode when challenged with a competitor that they cannot defeat by counter prediction. In this mode, outcomes associated with an animal's actions are ignored, and normal engagement of anterior cingulate cortex (ACC) is suppressed. Using circuit perturbations in transgenic rats, we demonstrate that switching between strategic and stochastic behavioral modes is controlled by locus coeruleus input into ACC. Our findings suggest that, under conditions of uncertainty about environmental rules, changes in noradrenergic input ...

Toward the neural implementation of structure learning

Despite significant advances in neuroscience, the neural bases of intelligence remain poorly unde... more Despite significant advances in neuroscience, the neural bases of intelligence remain poorly understood. Arguably the most elusive aspect of intelligence is the ability to make robust inferences that go far beyond one's experience. Animals categorize objects, learn to vocalize and may even estimate causal relationships — all in the face of data that is often ambiguous and sparse. Such inductive leaps are thought to result from the brain's ability to infer latent structure that governs the environment. However, we know little about the neural computations that underlie this ability. Recent advances in developing computational frameworks that can support efficient structure learning and inductive inference may provide insight into the underlying component processes and help pave the path for uncovering their neural implementation.

A Designer AAV Variant Permits Efficient Retrograde Access to Projection Neurons

Efficient retrograde access to projection neurons for the delivery of sensors and effectors const... more Efficient retrograde access to projection neurons for the delivery of sensors and effectors constitutes an important and enabling capability for neural circuit dissection. Such an approach would also be useful for gene therapy, including the treatment of neurodegenerative disorders characterized by pathological spread through functionally connected and highly distributed networks. Viral vectors, in particular, are powerful gene delivery vehicles for the nervous system, but all available tools suffer from inefficient retrograde transport or limited clinical potential. To address this need, we applied in vivo directed evolution to engineer potent retrograde functionality into the capsid of adeno-associated virus (AAV), a vector that has shown promise in neuroscience research and the clinic. A newly evolved variant, rAAV2-retro, permits robust retrograde access to projection neurons with efficiency comparable to classical synthetic retrograde tracers and enables sufficient sensor/effector expression for functional circuit interrogation and in vivo genome editing in targeted neuronal populations.

Behavioral variability through stochastic choice and its gating by anterior cingulate cortex.

by Dougal Tervo and Alison Vollmer

Behavioral choices that ignore prior experience promote exploration and unpredictability but are ... more Behavioral choices that ignore prior experience promote exploration and unpredictability but are seemingly at odds with the brain's tendency to use experience to optimize behavioral choice. Indeed, when faced with virtual competitors, primates resort to strategic counter prediction rather than to stochastic choice. Here, we show that rats also use history- and model-based strategies when faced with similar competitors but can switch to a "stochastic" mode when challenged with a competitor that they cannot defeat by counter prediction. In this mode, outcomes associated with an animal's actions are ignored, and normal engagement of anterior cingulate cortex (ACC) is suppressed. Using circuit perturbations in transgenic rats, we demonstrate that switching between strategic and stochastic behavioral modes is controlled by locus coeruleus input into ACC. Our findings suggest that, under conditions of uncertainty about environmental rules, changes in noradrenergic input alter ACC output and prevent erroneous beliefs from guiding decisions, thus enabling behavioral variation.

Network resets in medial prefrontal cortex mark the onset of behavioral uncertainty

Science (New York, N.Y.), Jan 1, 2012

Regions within the prefrontal cortex are thought to process beliefs about the world, but little i... more Regions within the prefrontal cortex are thought to process beliefs about the world, but little is known about the circuit dynamics underlying the formation and modification of these beliefs. Using a task that permits dissociation between the activity encoding an animal’s internal state and that encoding aspects of behavior, we found that transient increases in the volatility of activity in the rat medial prefrontal cortex accompany periods when an animal’s belief is modified after an environmental change. Activity across the majority of sampled neurons underwent marked, abrupt, and coordinated changes when prior belief was abandoned in favor of exploration of alternative strategies. These dynamics reflect network switches to a state of instability, which diminishes over the period of exploration as new stable representations are formed.

Monitoring synaptic transmission in primary neuronal cultures using local extracellular stimulation

by Dougal Tervo and A. Maximov

Journal of neuroscience methods, Jan 1, 2007

Various techniques have been applied for the functional analysis of synaptic transmission in cult... more Various techniques have been applied for the functional analysis of synaptic transmission in cultured neurons. Here, we describe a method of studying synaptic transmission in neurons cultured at high-density from different brain regions such as the cortex, striatum and spinal cord. We use postsynaptic whole-cell recordings to monitor synaptic currents triggered by presynaptic action potentials that are induced by brief stimulations with a nearby extracellular bipolar electrode. Pharmacologically isolated excitatory or inhibitory postsynaptic currents can be reliably induced, with amplitudes, synaptic charge transfers, and short-term plasticity properties that are reproducible from culture to culture. We show that the size and kinetics of pharmacologically isolated inhibitory postsynaptic currents triggered by single action potentials or stimulus trains depend on the Ca2+ concentration, temperature and stimulation frequency. This method can be applied to study synaptic transmission in wildtype neurons infected with lentiviruses encoding various components of presynaptic release machinery, or in neurons from genetically modified mice, for example neurons carrying floxed genes in which gene expression can be acutely ablated by expression of Cre recombinase. The preparation described in this paper should be useful for analysis of synaptic transmission in inter-neuronal synapses formed by different types of neurons.

Rapidly inducible, genetically targeted inactivation of neural and synaptic activity in vivo

Current opinion in neurobiology, Jan 1, 2007

Inactivation of Synaptic Transmission in Genetically Targeted Neurons

Inducible and reversible silencing of selected neurons in vivo is critical to understanding the s... more Inducible and reversible silencing of selected neurons in vivo is critical to understanding the structure and dynamics of brain circuits. We have developed Molecules for Inactivation of Synaptic Transmission (MISTs) that can be genetically targeted to allow the reversible inactivation of neurotransmitter release. MISTs consist of modified presynaptic proteins that interfere with the synaptic vesicle cycle when crosslinked by small molecule ‘‘dimerizers.’ ’ MISTs based on the vesicle proteins VAMP2/Synaptobrevin and Synaptophysin induced rapid (w10 min) and reversible block of synaptic transmission in cultured neurons and brain slices. In transgenic mice expressing MISTs selectively in Purkinje neurons, administration of dimerizer reduced learning and performance of the rotarod behavior. MISTs allow for specific, inducible, and reversible lesions in neuronal circuits and may provide treatment of disorders associated with neuronal hyperactivity.

Anterior Cingulate Cortex Directs Exploration of Alternative Strategies

SummaryThe ability to adjust one’s behavioral strategy in complex environments is at the core of ... more SummaryThe ability to adjust one’s behavioral strategy in complex environments is at the core of cognition. Doing so efficiently requires monitoring the reliability of the ongoing strategy and switching away from it to evaluate alternatives when appropriate. Studies in humans and non-human primates have uncovered signals in the anterior cingulate cortex (ACC) that track the pressure to switch away from the ongoing strategy, and others that relate to the pursuit of alternatives. However, whether these signals underlie computations that actually underpin strategy switching, or merely reflect tracking of related variables remains unclear. Here we provide causal evidence that rodent ACC actively arbitrates between persisting with ongoing behavioral choice and switching away temporarily to re-evaluate alternatives. Furthermore, by individually perturbing distinct output pathways, we establish that the two associated computations – whether to switch away from the current choice, and the p...

Expanding the Optogenetics Toolkit by Topological Inversion of Rhodopsins

Cell, Jan 16, 2018

Targeted manipulation of activity in specific populations of neurons is important for investigati... more Targeted manipulation of activity in specific populations of neurons is important for investigating the neural circuit basis of behavior. Optogenetic approaches using light-sensitive microbial rhodopsins have permitted manipulations to reach a level of temporal precision that is enabling functional circuit dissection. As demand for more precise perturbations to serve specific experimental goals increases, a palette of opsins with diverse selectivity, kinetics, and spectral properties will be needed. Here, we introduce a novel approach of "topological engineering"-inversion of opsins in the plasma membrane-and demonstrate that it can produce variants with unique functional properties of interest for circuit neuroscience. In one striking example, inversion of a Channelrhodopsin variant converted it from a potent activator into a fast-acting inhibitor that operates as a cation pump. Our findings argue that membrane topology provides a useful orthogonal dimension of protein en...

A Designer AAV Variant Permits Efficient Retrograde Access to Projection Neurons

Neuron, Jan 19, 2016

Efficient retrograde access to projection neurons for the delivery of sensors and effectors const... more Efficient retrograde access to projection neurons for the delivery of sensors and effectors constitutes an important and enabling capability for neural circuit dissection. Such an approach would also be useful for gene therapy, including the treatment of neurodegenerative disorders characterized by pathological spread through functionally connected and highly distributed networks. Viral vectors, in particular, are powerful gene delivery vehicles for the nervous system, but all available tools suffer from inefficient retrograde transport or limited clinical potential. To address this need, we applied in vivo directed evolution to engineer potent retrograde functionality into the capsid of adeno-associated virus (AAV), a vector that has shown promise in neuroscience research and the clinic. A newly evolved variant, rAAV2-retro, permits robust retrograde access to projection neurons with efficiency comparable to classical synthetic retrograde tracers and enables sufficient sensor/effec...

Neurotechnique Rapid and Reversible Chemical InactivationofSynapticTransmission in Genetically Targeted Neurons

ABSTRACT Summary

Behavioral variability through stochastic choice and its gating by anterior cingulate cortex

Cell, Jan 25, 2014

Behavioral choices that ignore prior experience promote exploration and unpredictability but are ... more Behavioral choices that ignore prior experience promote exploration and unpredictability but are seemingly at odds with the brain's tendency to use experience to optimize behavioral choice. Indeed, when faced with virtual competitors, primates resort to strategic counter prediction rather than to stochastic choice. Here, we show that rats also use history- and model-based strategies when faced with similar competitors but can switch to a "stochastic" mode when challenged with a competitor that they cannot defeat by counter prediction. In this mode, outcomes associated with an animal's actions are ignored, and normal engagement of anterior cingulate cortex (ACC) is suppressed. Using circuit perturbations in transgenic rats, we demonstrate that switching between strategic and stochastic behavioral modes is controlled by locus coeruleus input into ACC. Our findings suggest that, under conditions of uncertainty about environmental rules, changes in noradrenergic input ...

Toward the neural implementation of structure learning

Despite significant advances in neuroscience, the neural bases of intelligence remain poorly unde... more Despite significant advances in neuroscience, the neural bases of intelligence remain poorly understood. Arguably the most elusive aspect of intelligence is the ability to make robust inferences that go far beyond one's experience. Animals categorize objects, learn to vocalize and may even estimate causal relationships — all in the face of data that is often ambiguous and sparse. Such inductive leaps are thought to result from the brain's ability to infer latent structure that governs the environment. However, we know little about the neural computations that underlie this ability. Recent advances in developing computational frameworks that can support efficient structure learning and inductive inference may provide insight into the underlying component processes and help pave the path for uncovering their neural implementation.

A Designer AAV Variant Permits Efficient Retrograde Access to Projection Neurons

Efficient retrograde access to projection neurons for the delivery of sensors and effectors const... more Efficient retrograde access to projection neurons for the delivery of sensors and effectors constitutes an important and enabling capability for neural circuit dissection. Such an approach would also be useful for gene therapy, including the treatment of neurodegenerative disorders characterized by pathological spread through functionally connected and highly distributed networks. Viral vectors, in particular, are powerful gene delivery vehicles for the nervous system, but all available tools suffer from inefficient retrograde transport or limited clinical potential. To address this need, we applied in vivo directed evolution to engineer potent retrograde functionality into the capsid of adeno-associated virus (AAV), a vector that has shown promise in neuroscience research and the clinic. A newly evolved variant, rAAV2-retro, permits robust retrograde access to projection neurons with efficiency comparable to classical synthetic retrograde tracers and enables sufficient sensor/effector expression for functional circuit interrogation and in vivo genome editing in targeted neuronal populations.

Behavioral variability through stochastic choice and its gating by anterior cingulate cortex.

by Dougal Tervo and Alison Vollmer

Behavioral choices that ignore prior experience promote exploration and unpredictability but are ... more Behavioral choices that ignore prior experience promote exploration and unpredictability but are seemingly at odds with the brain's tendency to use experience to optimize behavioral choice. Indeed, when faced with virtual competitors, primates resort to strategic counter prediction rather than to stochastic choice. Here, we show that rats also use history- and model-based strategies when faced with similar competitors but can switch to a "stochastic" mode when challenged with a competitor that they cannot defeat by counter prediction. In this mode, outcomes associated with an animal's actions are ignored, and normal engagement of anterior cingulate cortex (ACC) is suppressed. Using circuit perturbations in transgenic rats, we demonstrate that switching between strategic and stochastic behavioral modes is controlled by locus coeruleus input into ACC. Our findings suggest that, under conditions of uncertainty about environmental rules, changes in noradrenergic input alter ACC output and prevent erroneous beliefs from guiding decisions, thus enabling behavioral variation.

Network resets in medial prefrontal cortex mark the onset of behavioral uncertainty

Science (New York, N.Y.), Jan 1, 2012

Regions within the prefrontal cortex are thought to process beliefs about the world, but little i... more Regions within the prefrontal cortex are thought to process beliefs about the world, but little is known about the circuit dynamics underlying the formation and modification of these beliefs. Using a task that permits dissociation between the activity encoding an animal’s internal state and that encoding aspects of behavior, we found that transient increases in the volatility of activity in the rat medial prefrontal cortex accompany periods when an animal’s belief is modified after an environmental change. Activity across the majority of sampled neurons underwent marked, abrupt, and coordinated changes when prior belief was abandoned in favor of exploration of alternative strategies. These dynamics reflect network switches to a state of instability, which diminishes over the period of exploration as new stable representations are formed.

Monitoring synaptic transmission in primary neuronal cultures using local extracellular stimulation

by Dougal Tervo and A. Maximov

Journal of neuroscience methods, Jan 1, 2007

Various techniques have been applied for the functional analysis of synaptic transmission in cult... more Various techniques have been applied for the functional analysis of synaptic transmission in cultured neurons. Here, we describe a method of studying synaptic transmission in neurons cultured at high-density from different brain regions such as the cortex, striatum and spinal cord. We use postsynaptic whole-cell recordings to monitor synaptic currents triggered by presynaptic action potentials that are induced by brief stimulations with a nearby extracellular bipolar electrode. Pharmacologically isolated excitatory or inhibitory postsynaptic currents can be reliably induced, with amplitudes, synaptic charge transfers, and short-term plasticity properties that are reproducible from culture to culture. We show that the size and kinetics of pharmacologically isolated inhibitory postsynaptic currents triggered by single action potentials or stimulus trains depend on the Ca2+ concentration, temperature and stimulation frequency. This method can be applied to study synaptic transmission in wildtype neurons infected with lentiviruses encoding various components of presynaptic release machinery, or in neurons from genetically modified mice, for example neurons carrying floxed genes in which gene expression can be acutely ablated by expression of Cre recombinase. The preparation described in this paper should be useful for analysis of synaptic transmission in inter-neuronal synapses formed by different types of neurons.

Rapidly inducible, genetically targeted inactivation of neural and synaptic activity in vivo

Current opinion in neurobiology, Jan 1, 2007