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Jeffrey C Magee - One of the best experts on this subject based on the ideXlab platform.
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network mechanisms of Theta related neuronal Activity in hippocampal ca1 pyramidal neurons
Nature Neuroscience, 2010Co-Authors: Attila Losonczy, Boris V Zemelman, Alipasha Vaziri, Jeffrey C MageeAbstract:Although hippocampal Theta oscillations represent a prime example of temporal coding in the mammalian brain, little is known about the specific biophysical mechanisms. Intracellular recordings implicate a particular abstract oscillatory interference model of hippocampal Theta Activity; the soma-dendrite interference model. To gain insight into the cellular and circuit level mechanisms of Theta Activity we implemented a similar form of interference using the actual hippocampal network in mice in vitro. We found that pairing increasing levels of phasic dendritic excitation with phasic stimulation of perisomatic projecting inhibitory interneurons induced a somatic polarization and action potential timing profile that reproduced most common features. Alterations in the temporal profile of inhibition were required to fully capture all features. These data suggest that Theta-related place cell Activity is generated through an interaction between a phasic dendritic excitation and a phasic perisomatic shunting inhibition delivered by interneurons; a subset of which undergo Activity-dependent presynaptic modulation.
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network mechanisms of Theta related neuronal Activity in hippocampal ca1 pyramidal neurons
Nature Neuroscience, 2010Co-Authors: Attila Losonczy, Boris V Zemelman, Alipasha Vaziri, Jeffrey C MageeAbstract:Although hippocampal Theta oscillations represent a prime example of temporal coding in the mammalian brain, little is known about the specific biophysical mechanisms. Intracellular recordings support a particular abstract oscillatory interference model of hippocampal Theta Activity, the soma-dendrite interference model. To gain insight into the cellular and circuit level mechanisms of Theta Activity, we implemented a similar form of interference using the actual hippocampal network in mice in vitro. We found that pairing increasing levels of phasic dendritic excitation with phasic stimulation of perisomatic projecting inhibitory interneurons induced a somatic polarization and action potential timing profile that reproduced most common features. Alterations in the temporal profile of inhibition were required to fully capture all features. These data suggest that Theta-related place cell Activity is generated through an interaction between a phasic dendritic excitation and a phasic perisomatic shunting inhibition delivered by interneurons, a subset of which undergo Activity-dependent presynaptic modulation.
Paul Sauseng - One of the best experts on this subject based on the ideXlab platform.
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anodal transcranial direct current stimulation tdcs increases frontal midline Theta Activity in the human eeg a preliminary investigation of non invasive stimulation
Neuroscience Letters, 2015Co-Authors: Joe Miller, Barbara Berger, Paul SausengAbstract:Rhythmical brain Activity in the range between four and eight Hz acquired over frontal-midline EEG recording sites - so called frontal-midline Theta Activity - is regarded as one of the most prominent neural signatures of sustained attention. It is reported to parametrically increase with cognitive load and is thought to be generated in medial prefrontal cortex. Here we explored the possibility of using anodal transcranial direct current stimulation over frontal sites to enhance frontal-midline Theta Activity and to increase sustained attention performance. We used a small preliminary sample to test a novel direct current stimulation electrode configuration by which we were able to significantly increase frontal-midline Theta amplitude in a resting condition after the end of the stimulation period. Using standardised low resolution electromagnetic tomography analysis the effect in the surface EEG was localised to right prefrontal and left medial prefrontal brain areas. Transcranial direct current stimulation did, however, not have any impact on behavioural performance during a sustained attention task. This most likely was due to a very fast washout of the stimulation's after effect on Theta Activity. Although these are only preliminary results from a rather small sample, this study demonstrates that transcranial direct current stimulation can be used to rather selectively enhance frontal-midline Theta amplitude.
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control mechanisms in working memory a possible function of eeg Theta oscillations
Neuroscience & Biobehavioral Reviews, 2010Co-Authors: Paul Sauseng, Birgit Griesmayr, Roman Freunberger, Wolfgang KlimeschAbstract:Abstract Neural correlates of control mechanisms in human working memory are discussed at two levels in this review: (i) at ‘item level’, where in multi-item working memory information needs to be organized into sequential memory representations, and (ii) at a ‘process level’, indicating the integration and control of a variety of cognitive functions involved in working memory, independent of item representations per se . It will be discussed that at both levels electroencephalographic Theta Activity is responsible for control of working memory functions. On item level, exact phase coding, e.g., approached by coupling between Theta and gamma oscillations or phase resetting of Theta frequency, is suggested to integrate information into working memory representations. At process level interregional Theta synchronization is discussed to integrate brain structures necessary for working memory. When discussing the specificity of Theta Activity for control of working memory processes it will be suggested that Theta oscillations might play an important general integrative role in organization of brain Activity. And as working memory often involves a variety of cognitive processes which need to be coordinated there is particular need for an integrative brain mechanism like Theta Activity as suggested in this review.
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dissociation of sustained attention from central executive functions local Activity and interregional connectivity in the Theta range
European Journal of Neuroscience, 2007Co-Authors: Paul Sauseng, Julia Hoppe, Wolfgang Klimesch, Christian Gerloff, Friedhelm C HummelAbstract:Human brain oscillatory Activity was analysed in the electroencephalographic Theta frequency range (4-7 Hz) while subjects executed complex sequential finger movements with varying task difficulty and memory load. Local frontal-midline Theta Activity was associated with the general level of cognitive demand, with the highest amplitudes in the most demanding condition. Using low-resolution electromagnetic tomography analysis (LORETA), this Theta Activity was localized in the anterior cingulate gyrus including the cingulate motor area. These results suggest that local Theta Activity in the anterior cingulate gyrus represents correlates of an attentional system that allocate cognitive resources. In addition, interregional connectivity in the Theta frequency range was modulated by memory-related executive functions independently of task difficulty. Connectivity analyses revealed a more distributed long-range network including frontal and parietal cortices during execution of novel compared with well-trained finger movement sequences. Thus, these results are compatible with a model in which Theta long-range coupling indicates integration of sensory information into executive control components of complex motor behaviour.
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episodic retrieval is reflected by a process specific increase in human electroencephalographic Theta Activity
Neuroscience Letters, 2001Co-Authors: Wolfgang Klimesch, Paul Sauseng, Michael Doppelmayr, Waltraud Stadler, D Pollhuber, D RohmAbstract:Is an increase in Theta during retrieval due (primarily) to the access of a stored code or to more general processes? The electroencephalogram was recorded while subjects performed a recognition task with pictures. According to the event-related desynchronization/synchronization method, the percentage of band power changes was calculated during encoding and retrieval for a Theta and three alpha bands. Significant results were obtained (with minor exceptions) only in the Theta band. The increase in Theta was significantly larger during retrieval than during encoding but did not differ significantly between new and successfully retrieved old pictures. Because a memory trace is lacking for new pictures, the increase in Theta during retrieval reflects primarily general processing demands of a complex episodic memory system.
Jeffrey A. Gray - One of the best experts on this subject based on the ideXlab platform.
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anxiolytic action on the behavioural inhibition system implies multiple types of arousal contribute to anxiety
Journal of Affective Disorders, 2000Co-Authors: Neil Mcnaughton, Jeffrey A. GrayAbstract:According to ''The Neuropsychology of Anxiety'' (Gray, J.A., 1982, The Neuropsychology of Anxiety: An Enquiry into the Functions of the Septo-hippocampal System, Oxford University Press, Oxford; Gray, J.A., McNaughton, N., 2000, The Neuropsychology of Anxiety: An Enquiry into the Functions of the Septo-hippocampal System, 2nd ed., Oxford University Press, Oxford), anxiolytic drugs of all types act on a behavioural inhibition system, the most important neural component of which is the septo-hippocampal system. Anxiolytics affect septo-hippocampal function by impairing the subcortical control of hippocampal 'Theta' Activity — the principle response of the septo-hippocampal system to arousal. Our recent experiments show that there are multiple systems controlling Theta Activity and that anxiolytics act on several, but not all, of these systems. This pattern of results implies that there are many different types of arousal, only some of which appear to contribute to the generation of anxiety in normal subjects and to the etiology of pathological anxiety. © 2000 Elsevier Science B.V. All rights reserved.
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anxiolytic action on the behavioural inhibition system implies multiple types of arousal contribute to anxiety
Journal of Affective Disorders, 2000Co-Authors: Neil Mcnaughton, Jeffrey A. GrayAbstract:According to "The Neuropsychology of Anxiety" [Gray, J.A., 1982, The Neuropsychology of Anxiety: An Enquiry into the Functions of the Septo-hippocampal System, Oxford University Press, Oxford; Gray, J.A., McNaughton, N., 2000, The Neuropsychology of Anxiety: An Enquiry into the Functions of the Septo-hippocampal System, 2nd ed., Oxford University Press, Oxford], anxiolytic drugs of all types act on a behavioural inhibition system, the most important neural component of which is the septo-hippocampal system. Anxiolytics affect septo-hippocampal function by impairing the subcortical control of hippocampal "Theta" Activity - the principle response of the septo-hippocampal system to arousal. Our recent experiments show that there are multiple systems controlling Theta Activity and that anxiolytics act on several, but not all, of these systems. This pattern of results implies that there are many different types of arousal, only some of which appear to contribute to the generation of anxiety in normal subjects and to the etiology of pathological anxiety.
Attila Losonczy - One of the best experts on this subject based on the ideXlab platform.
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network mechanisms of Theta related neuronal Activity in hippocampal ca1 pyramidal neurons
Nature Neuroscience, 2010Co-Authors: Attila Losonczy, Boris V Zemelman, Alipasha Vaziri, Jeffrey C MageeAbstract:Although hippocampal Theta oscillations represent a prime example of temporal coding in the mammalian brain, little is known about the specific biophysical mechanisms. Intracellular recordings implicate a particular abstract oscillatory interference model of hippocampal Theta Activity; the soma-dendrite interference model. To gain insight into the cellular and circuit level mechanisms of Theta Activity we implemented a similar form of interference using the actual hippocampal network in mice in vitro. We found that pairing increasing levels of phasic dendritic excitation with phasic stimulation of perisomatic projecting inhibitory interneurons induced a somatic polarization and action potential timing profile that reproduced most common features. Alterations in the temporal profile of inhibition were required to fully capture all features. These data suggest that Theta-related place cell Activity is generated through an interaction between a phasic dendritic excitation and a phasic perisomatic shunting inhibition delivered by interneurons; a subset of which undergo Activity-dependent presynaptic modulation.
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network mechanisms of Theta related neuronal Activity in hippocampal ca1 pyramidal neurons
Nature Neuroscience, 2010Co-Authors: Attila Losonczy, Boris V Zemelman, Alipasha Vaziri, Jeffrey C MageeAbstract:Although hippocampal Theta oscillations represent a prime example of temporal coding in the mammalian brain, little is known about the specific biophysical mechanisms. Intracellular recordings support a particular abstract oscillatory interference model of hippocampal Theta Activity, the soma-dendrite interference model. To gain insight into the cellular and circuit level mechanisms of Theta Activity, we implemented a similar form of interference using the actual hippocampal network in mice in vitro. We found that pairing increasing levels of phasic dendritic excitation with phasic stimulation of perisomatic projecting inhibitory interneurons induced a somatic polarization and action potential timing profile that reproduced most common features. Alterations in the temporal profile of inhibition were required to fully capture all features. These data suggest that Theta-related place cell Activity is generated through an interaction between a phasic dendritic excitation and a phasic perisomatic shunting inhibition delivered by interneurons, a subset of which undergo Activity-dependent presynaptic modulation.
Neil Mcnaughton - One of the best experts on this subject based on the ideXlab platform.
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anxiolytic action on the behavioural inhibition system implies multiple types of arousal contribute to anxiety
Journal of Affective Disorders, 2000Co-Authors: Neil Mcnaughton, Jeffrey A. GrayAbstract:According to ''The Neuropsychology of Anxiety'' (Gray, J.A., 1982, The Neuropsychology of Anxiety: An Enquiry into the Functions of the Septo-hippocampal System, Oxford University Press, Oxford; Gray, J.A., McNaughton, N., 2000, The Neuropsychology of Anxiety: An Enquiry into the Functions of the Septo-hippocampal System, 2nd ed., Oxford University Press, Oxford), anxiolytic drugs of all types act on a behavioural inhibition system, the most important neural component of which is the septo-hippocampal system. Anxiolytics affect septo-hippocampal function by impairing the subcortical control of hippocampal 'Theta' Activity — the principle response of the septo-hippocampal system to arousal. Our recent experiments show that there are multiple systems controlling Theta Activity and that anxiolytics act on several, but not all, of these systems. This pattern of results implies that there are many different types of arousal, only some of which appear to contribute to the generation of anxiety in normal subjects and to the etiology of pathological anxiety. © 2000 Elsevier Science B.V. All rights reserved.
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anxiolytic action on the behavioural inhibition system implies multiple types of arousal contribute to anxiety
Journal of Affective Disorders, 2000Co-Authors: Neil Mcnaughton, Jeffrey A. GrayAbstract:According to "The Neuropsychology of Anxiety" [Gray, J.A., 1982, The Neuropsychology of Anxiety: An Enquiry into the Functions of the Septo-hippocampal System, Oxford University Press, Oxford; Gray, J.A., McNaughton, N., 2000, The Neuropsychology of Anxiety: An Enquiry into the Functions of the Septo-hippocampal System, 2nd ed., Oxford University Press, Oxford], anxiolytic drugs of all types act on a behavioural inhibition system, the most important neural component of which is the septo-hippocampal system. Anxiolytics affect septo-hippocampal function by impairing the subcortical control of hippocampal "Theta" Activity - the principle response of the septo-hippocampal system to arousal. Our recent experiments show that there are multiple systems controlling Theta Activity and that anxiolytics act on several, but not all, of these systems. This pattern of results implies that there are many different types of arousal, only some of which appear to contribute to the generation of anxiety in normal subjects and to the etiology of pathological anxiety.
