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Traub RD, Whittington MA. Processing of cell assemblies in the lateral entorhinal cortex. Rev Neurosci 2022; 33:829-847. [PMID: 35447022 DOI: 10.1515/revneuro-2022-0011] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 03/11/2022] [Indexed: 12/14/2022]
Abstract
There is evidence that olfactory cortex responds to its afferent input with the generation of cell assemblies: collections of principal neurons that fire together over a time scale of tens of ms. If such assemblies form an odor representation, then a fundamental question is how each assembly then induces neuronal activity in downstream structures. We have addressed this question in a detailed model of superficial layers of lateral entorhinal cortex, a recipient of input from olfactory cortex and olfactory bulb. Our results predict that the response of the fan cell subpopulation can be approximated by a relatively simple Boolean process, somewhat along the lines of the McCulloch/Pitts scheme; this is the case because of the sparsity of recurrent excitation amongst fan cells. However, because of recurrent excitatory connections between layer 2 and layer 3 pyramidal cells, synaptic and probably also gap junctional, the response of pyramidal cell subnetworks cannot be so approximated. Because of the highly structured anatomy of entorhinal output projections, our model suggests that downstream targets of entorhinal cortex (dentate gyrus, hippocampal CA3, CA1, piriform cortex, olfactory bulb) receive differentially processed information.
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Affiliation(s)
- Roger D Traub
- AI Foundations, IBM T.J. Watson Research Center, Yorktown Heights, NY 10598, USA.,Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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2
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Nejad MM, Rotter S, Schmidt R. Basal ganglia and cortical control of thalamic rebound spikes. Eur J Neurosci 2021; 54:4295-4313. [PMID: 33914390 DOI: 10.1111/ejn.15258] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 04/09/2021] [Accepted: 04/24/2021] [Indexed: 12/29/2022]
Abstract
Movement-related decreases in firing rate have been observed in basal ganglia output neurons. They may transmit motor signals to the thalamus, but the effect of these firing rate decreases on downstream neurons in the motor thalamus is not known. One possibility is that they lead to thalamic post-inhibitory rebound spikes. However, it has also been argued that the physiological conditions permitting rebound spiking are pathological, and primarily present in Parkinson's disease. As in Parkinson's disease neural activity becomes pathologically correlated, we investigated the impact of correlations in basal ganglia output on the transmission of motor signals using a Hodgkin-Huxley model of thalamocortical neurons. We found that such correlations disrupt the transmission of motor signals via rebound spikes by decreasing the signal-to-noise ratio and increasing the trial-to-trial variability. We further examined the role of sensory responses in basal ganglia output neurons and the effect of cortical excitation of motor thalamus in modulating rebound spiking. Interestingly, both could either promote or suppress the generation of rebound spikes depending on their timing relative to the motor signal. Finally, we determined parameter regimes, such as levels of excitation, under which rebound spiking is feasible in the model, and confirmed that the conditions for rebound spiking are primarily given in pathological regimes. However, we also identified specific conditions in the model that would allow rebound spiking to occur in healthy animals in a small subset of thalamic neurons. Overall, our model provides novel insights into differences between normal and pathological transmission of motor signals.
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Affiliation(s)
- Mohammadreza Mohagheghi Nejad
- Bernstein Center Freiburg and Faculty of Biology, University of Freiburg, Freiburg, Germany
- Department of Computational Science and Technology, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Stefan Rotter
- Bernstein Center Freiburg and Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Robert Schmidt
- Department of Psychology, University of Sheffield, Sheffield, UK
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3
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Baaske MK, Kormann E, Holt AB, Gulberti A, McNamara CG, Pötter-Nerger M, Westphal M, Engel AK, Hamel W, Brown P, Moll CKE, Sharott A. Parkinson's disease uncovers an underlying sensitivity of subthalamic nucleus neurons to beta-frequency cortical input in vivo. Neurobiol Dis 2020; 146:105119. [PMID: 32991998 PMCID: PMC7710979 DOI: 10.1016/j.nbd.2020.105119] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 09/13/2020] [Accepted: 09/24/2020] [Indexed: 11/26/2022] Open
Abstract
Abnormally sustained beta-frequency synchronisation between the motor cortex and subthalamic nucleus (STN) is associated with motor symptoms in Parkinson's disease (PD). It is currently unclear whether STN neurons have a preference for beta-frequency input (12-35 Hz), rather than cortical input at other frequencies, and how such a preference would arise following dopamine depletion. To address this question, we combined analysis of cortical and STN recordings from awake human PD patients undergoing deep brain stimulation surgery with recordings of identified STN neurons in anaesthetised rats. In these patients, we demonstrate that a subset of putative STN neurons is strongly and selectively sensitive to magnitude fluctuations of cortical beta oscillations over time, linearly increasing their phase-locking strength with respect to the full range of instantaneous amplitude in the beta-frequency range. In rats, we probed the frequency response of STN neurons in the cortico-basal-ganglia-network more precisely, by recording spikes evoked by short bursts of cortical stimulation with variable frequency (4-40 Hz) and constant amplitude. In both healthy and dopamine-depleted rats, only beta-frequency stimulation led to a progressive reduction in the variability of spike timing through the stimulation train. This suggests, that the interval of beta-frequency input provides an optimal window for eliciting the next spike with high fidelity. We hypothesize, that abnormal activation of the indirect pathway, via dopamine depletion and/or cortical stimulation, could trigger an underlying sensitivity of the STN microcircuit to beta-frequency input. STN-neurons are selectively entrained to cortical beta oscillations in PD patients. Phase-locking of STN-neurons is linearly dependent on oscillation magnitude. Beta bursts in LFP/EEG are accompanied by transient synchronisation of STN spiking. STN neurons are selectively entrained to cortical beta stimulation in rats. Beta-selectivity of STN neurons is present in control and dopamine-depleted rats.
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Affiliation(s)
- Magdalena K Baaske
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Mansfield Road, Oxford OX1 3TH, UK; Department of Neurology, University of Lübeck, 23538 Lübeck, Germany; Institute of Neurogenetics, University of Lübeck, 23538 Lübeck, Germany
| | - Eszter Kormann
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Mansfield Road, Oxford OX1 3TH, UK
| | - Abbey B Holt
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Mansfield Road, Oxford OX1 3TH, UK
| | - Alessandro Gulberti
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Colin G McNamara
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Mansfield Road, Oxford OX1 3TH, UK
| | - Monika Pötter-Nerger
- Department of Neurology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Manfred Westphal
- Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Andreas K Engel
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Wolfgang Hamel
- Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Peter Brown
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Mansfield Road, Oxford OX1 3TH, UK; Department of Neurology, University of Lübeck, 23538 Lübeck, Germany
| | - Christian K E Moll
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Andrew Sharott
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Mansfield Road, Oxford OX1 3TH, UK.
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4
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Feng J. Modeling the pathophysiology of Parkinson's disease in patient-specific neurons. Exp Biol Med (Maywood) 2020; 246:298-304. [PMID: 32972199 DOI: 10.1177/1535370220961788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The 30 trillion cells that self-assemble into a human being originate from the pluripotent stem cells in the inner cell mass of a human blastocyst. The discovery of induced pluripotent stem cells (iPSCs) makes it possible to approximate various aspects of this natural developmental process artificially by generating materials that can be used in invasive mechanistic studies of virtually all human conditions. In Parkinson's disease, instructions computed by the basal ganglia to control voluntary motor functions break down, leading to widespread rhythmic bursting activities in the basal ganglia and beyond. It is thought that these oscillatory neuronal activities, which disrupt aperiodic neurotransmission in a normal brain, may reduce information content in the instructions for motor control. Using midbrain neuronal cultures differentiated from iPSCs of Parkinson's disease patients with parkin mutations, we find that parkin mutations cause oscillatory neuronal activities when dopamine D1-class receptors are activated. This system makes it possible to study the molecular basis of rhythmic bursting activities in Parkinson's disease. Further development of stem cell models of Parkinson's disease will enable better approximation of the situation in the brain of Parkinson's disease patients. In this review, I will discuss what has been found in the past about the pathophysiology of motor dysfunction in Parkinson's disease, especially oscillatory neuronal activities and how stem cell technologies may transform our abilities to understand the pathophysiology of Parkinson's disease.
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Affiliation(s)
- Jian Feng
- Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, NY 14203, USA
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5
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Wongmassang W, Hasegawa T, Chiken S, Nambu A. Weakly correlated activity of pallidal neurons in behaving monkeys. Eur J Neurosci 2020; 53:2178-2191. [PMID: 32649021 PMCID: PMC8247335 DOI: 10.1111/ejn.14903] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 07/03/2020] [Accepted: 07/03/2020] [Indexed: 11/29/2022]
Abstract
The basal ganglia play a crucial role in the control of voluntary movements. Neurons in both the external and internal segments of the globus pallidus, the connecting and output nuclei of the basal ganglia, respectively, change their firing rates in relation to movements. Firing rate changes of movement-related neurons seem to convey signals for motor control. On the other hand, coincident spikes among neurons, that is, correlated activity, may also contribute to motor control. To address this issue, we first identified multiple pallidal neurons receiving inputs from the forelimb regions of the primary motor cortex and supplementary motor area, recorded neuronal activity of these neurons simultaneously, and analyzed their spike correlations while monkeys performed a hand-reaching task. Most (79%) pallidal neurons exhibited task-related firing rate changes, whereas only a small fraction (20%) showed significant but small and short correlated activity during the task performance. These results suggest that motor control signals are conveyed primarily by firing rate changes in the external and internal segments of the globus pallidus and that the contribution of correlated activity may play only a minor role in the healthy state.
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Affiliation(s)
- Woranan Wongmassang
- Division of System Neurophysiology, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Physiological Sciences, SOKENDAI (Graduate University for Advanced Studies), Okazaki, Japan
| | - Taku Hasegawa
- Division of System Neurophysiology, National Institute for Physiological Sciences, Okazaki, Japan
| | - Satomi Chiken
- Division of System Neurophysiology, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Physiological Sciences, SOKENDAI (Graduate University for Advanced Studies), Okazaki, Japan
| | - Atsushi Nambu
- Division of System Neurophysiology, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Physiological Sciences, SOKENDAI (Graduate University for Advanced Studies), Okazaki, Japan
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Morales JC, Higgs MH, Song SC, Wilson CJ. Broadband Entrainment of Striatal Low-Threshold Spike Interneurons. Front Neural Circuits 2020; 14:36. [PMID: 32655378 PMCID: PMC7326000 DOI: 10.3389/fncir.2020.00036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 05/19/2020] [Indexed: 11/13/2022] Open
Abstract
Striatal interneurons and spiny projection (SP) neurons are differentially tuned to spectral components of their input. Previous studies showed that spike responses of somatostatin/NPY-expressing low threshold spike (LTS) interneurons have broad frequency tuning, setting these cells apart from other striatal GABAergic interneurons and SP neurons. We investigated the mechanism of LTS interneuron spiking resonance and its relationship to non-spiking membrane impedance resonance, finding that abolition of impedance resonance did not alter spiking resonance. Because LTS interneurons are pacemakers whose rhythmic firing is perturbed by synaptic input, we tested the hypothesis that their spiking resonance arises from their phase resetting properties. Phase resetting curves (PRCs) were measured in LTS interneurons and SP neurons and used to make phase-oscillator models of both cell types. The models reproduced the broad tuning of LTS interneurons, and the differences from SP neurons. The spectral components of the PRC predicted each cell's sensitivity to corresponding input frequencies. LTS interneuron PRCs contain larger high-frequency components than SP neuron PRCs, providing enhanced responses to input frequencies above the cells' average firing rates. Thus, LTS cells can be entrained by input oscillations to which SP neurons are less responsive. These findings suggest that feedforward inhibition by LTS interneurons may regulate SP neurons' entrainment by oscillatory afferents.
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Affiliation(s)
- Juan C Morales
- Department of Biology, University of Texas at San Antonio, San Antonio, TX, United States
| | - Matthew H Higgs
- Department of Biology, University of Texas at San Antonio, San Antonio, TX, United States
| | - Soomin C Song
- Skirball Institute of Biomolecular Medicine and Neurosciences Institute, New York University School of Medicine, New York, NY, United States
| | - Charles J Wilson
- Department of Biology, University of Texas at San Antonio, San Antonio, TX, United States
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7
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Corticomuscular control of walking in older people and people with Parkinson's disease. Sci Rep 2020; 10:2980. [PMID: 32076045 PMCID: PMC7031238 DOI: 10.1038/s41598-020-59810-w] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 01/30/2020] [Indexed: 12/29/2022] Open
Abstract
Changes in human gait resulting from ageing or neurodegenerative diseases are multifactorial. Here we assess the effects of age and Parkinson’s disease (PD) on corticospinal activity recorded during treadmill and overground walking. Electroencephalography (EEG) from 10 electrodes and electromyography (EMG) from bilateral tibialis anterior muscles were acquired from 22 healthy young, 24 healthy older and 20 adults with PD. Event-related power, corticomuscular coherence (CMC) and inter-trial coherence were assessed for EEG from bilateral sensorimotor cortices and EMG during the double-support phase of the gait cycle. CMC and EMG power at low beta frequencies (13–21 Hz) was significantly decreased in older and PD participants compared to young people, but there was no difference between older and PD groups. Older and PD participants spent shorter time in the swing phase than young individuals. These findings indicate age-related changes in the temporal coordination of gait. The decrease in low-beta CMC suggests reduced cortical input to spinal motor neurons in older people during the double-support phase. We also observed multiple changes in electrophysiological measures at low-gamma frequencies during treadmill compared to overground walking, indicating task-dependent differences in corticospinal locomotor control. These findings may be affected by artefacts and should be interpreted with caution.
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Schönfeld LM, Wojtecki L. Beyond Emotions: Oscillations of the Amygdala and Their Implications for Electrical Neuromodulation. Front Neurosci 2019; 13:366. [PMID: 31057358 PMCID: PMC6482269 DOI: 10.3389/fnins.2019.00366] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 04/01/2019] [Indexed: 01/18/2023] Open
Abstract
The amygdala is a structure involved in emotions, fear, learning and memory and is highly interconnected with other brain regions, for example the motor cortex and the basal ganglia that are often targets of treatments involving electrical stimulation. Deep brain stimulation of the basal ganglia is successfully used to treat movement disorders, but can carry along non-motor side effects. The origin of these non-motor side effects is not fully understood yet, but might be altered oscillatory communication between specific motor areas and the amygdala. Oscillations in various frequency bands have been detected in the amygdala during cognitive and emotional tasks, which can couple with oscillations in cortical regions or the hippocampus. However, data on oscillatory coupling between the amygdala and motor areas are still lacking. This review provides a summary of oscillation frequencies measured in the amygdala and their possible functional relevance in different species, followed by evidence for connectivity between the amygdala and motor areas, such as the basal ganglia and the motor cortex. We hypothesize that the amygdala could communicate with motor areas through coherence of low frequency bands in the theta-alpha range. Furthermore, we discuss a potential role of the amygdala in therapeutic approaches based on electrical stimulation.
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Affiliation(s)
- Lisa-Maria Schönfeld
- Comparative Psychology, Institute of Experimental Psychology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Lars Wojtecki
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.,Department of Neurology, Center for Movement Disorders and Neuromodulation, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.,Department of Neurology and Neurorehabilitation, Hospital zum Heiligen Geist, Kempen, Germany
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9
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Chhatbar PY, Kautz SA, Takacs I, Rowland NC, Revuelta GJ, George MS, Bikson M, Feng W. Evidence of transcranial direct current stimulation-generated electric fields at subthalamic level in human brain in vivo. Brain Stimul 2018; 11:727-733. [PMID: 29576498 PMCID: PMC6019625 DOI: 10.1016/j.brs.2018.03.006] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 02/28/2018] [Accepted: 03/08/2018] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Transcranial direct current stimulation (tDCS) is a promising brain modulation technique for several disease conditions. With this technique, some portion of the current penetrates through the scalp to the cortex and modulates cortical excitability, but a recent human cadaver study questions the amount. This insufficient intracerebral penetration of currents may partially explain the inconsistent and mixed results in tDCS studies to date. Experimental validation of a transcranial alternating current stimulation-generated electric field (EF) in vivo has been performed on the cortical (using electrocorticography, ECoG, electrodes), subcortical (using stereo electroencephalography, SEEG, electrodes) and deeper thalamic/subthalamic levels (using DBS electrodes). However, tDCS-generated EF measurements have never been attempted. OBJECTIVE We aimed to demonstrate that tDCS generates biologically relevant EF as deep as the subthalamic level in vivo. METHODS Patients with movement disorders who have implanted deep brain stimulation (DBS) electrodes serve as a natural experimental model for thalamic/subthalamic recordings of tDCS-generated EF. We measured voltage changes from DBS electrodes and body resistance from tDCS electrodes in three subjects while applying direct current to the scalp at 2 mA and 4 mA over two tDCS montages. RESULTS Voltage changes at the level of deep nuclei changed proportionally with the level of applied current and varied with different tDCS montages. CONCLUSIONS Our findings suggest that scalp-applied tDCS generates biologically relevant EF. Incorporation of these experimental results may improve finite element analysis (FEA)-based models.
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Affiliation(s)
- Pratik Y Chhatbar
- Department of Neurology, College of Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - Steven A Kautz
- Department of Health Science & Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, USA; Ralph H. Johnson VA Medical Center, Charleston, SC, USA
| | - Istvan Takacs
- Department of Neurosurgery, College of Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - Nathan C Rowland
- Department of Neurosurgery, College of Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - Gonzalo J Revuelta
- Department of Neurology, College of Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - Mark S George
- Ralph H. Johnson VA Medical Center, Charleston, SC, USA; Brain Stimulation Laboratory, Department of Psychiatry and Behavioral Science, College of Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of The City University of New York, New York, NY, USA
| | - Wuwei Feng
- Department of Neurology, College of Medicine, Medical University of South Carolina, Charleston, SC, USA; Department of Health Science & Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, USA.
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10
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Singh A. Oscillatory activity in the cortico-basal ganglia-thalamic neural circuits in Parkinson's disease. Eur J Neurosci 2018; 48:2869-2878. [DOI: 10.1111/ejn.13853] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 01/19/2018] [Accepted: 01/21/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Arun Singh
- Department of Neurology; University of Minnesota; Minneapolis MN 55455 USA
- Department of Neurology; University of Iowa; Iowa City IA USA
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11
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Dodla R, Wilson CJ. Effect of Phase Response Curve Shape and Synaptic Driving Force on Synchronization of Coupled Neuronal Oscillators. Neural Comput 2017; 29:1769-1814. [PMID: 28562223 DOI: 10.1162/neco_a_00978] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The role of the phase response curve (PRC) shape on the synchrony of synaptically coupled oscillating neurons is examined. If the PRC is independent of the phase, because of the synaptic form of the coupling, synchrony is found to be stable for both excitatory and inhibitory coupling at all rates, whereas the antisynchrony becomes stable at low rates. A faster synaptic rise helps extend the stability of antisynchrony to higher rates. If the PRC is not constant but has a profile like that of a leaky integrate-and-fire model, then, in contrast to the earlier reports that did not include the voltage effects, mutual excitation could lead to stable synchrony provided the synaptic reversal potential is below the voltage level the neuron would have reached in the absence of the interaction and threshold reset. This level is controlled by the applied current and the leakage parameters. Such synchrony is contingent on significant phase response (that would result, for example, by a sharp PRC jump) occurring during the synaptic rising phase. The rising phase, however, does not contribute significantly if it occurs before the voltage spike reaches its peak. Then a stable near-synchronous state can still exist between type 1 PRC neurons if the PRC shows a left skewness in its shape. These results are examined comprehensively using perfect integrate-and-fire, leaky integrate-and-fire, and skewed PRC shapes under the assumption of the weakly coupled oscillator theory applied to synaptically coupled neuron models.
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Affiliation(s)
- Ramana Dodla
- Department of Biology, University of Texas at San Antonio, San Antonio, TX 78249, U.S.A.
| | - Charles J Wilson
- Department of Biology, University of Texas at San Antonio, San Antonio, TX 78249, U.S.A.
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12
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Canessa A, Pozzi NG, Arnulfo G, Brumberg J, Reich MM, Pezzoli G, Ghilardi MF, Matthies C, Steigerwald F, Volkmann J, Isaias IU. Striatal Dopaminergic Innervation Regulates Subthalamic Beta-Oscillations and Cortical-Subcortical Coupling during Movements: Preliminary Evidence in Subjects with Parkinson's Disease. Front Hum Neurosci 2016; 10:611. [PMID: 27999534 PMCID: PMC5138226 DOI: 10.3389/fnhum.2016.00611] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 11/15/2016] [Indexed: 11/24/2022] Open
Abstract
Activation of the basal ganglia has been shown during the preparation and execution of movement. However, the functional interaction of cortical and subcortical brain areas during movement and the relative contribution of dopaminergic striatal innervation remains unclear. We recorded local field potential (LFP) activity from the subthalamic nucleus (STN) and high-density electroencephalography (EEG) signals in four patients with Parkinson’s disease (PD) off dopaminergic medication during a multi-joint motor task performed with their dominant and non-dominant hand. Recordings were performed by means of a fully-implantable deep brain stimulation (DBS) device at 4 months after surgery. Three patients also performed a single-photon computed tomography (SPECT) with [123I]N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane (FP-CIT) to assess striatal dopaminergic innervation. Unilateral movement execution led to event-related desynchronization (ERD) followed by a rebound after movement termination event-related synchronization (ERS) of oscillatory beta activity in the STN and primary sensorimotor cortex of both hemispheres. Dopamine deficiency directly influenced movement-related beta-modulation, with greater beta-suppression in the most dopamine-depleted hemisphere for both ipsi- and contralateral hand movements. Cortical-subcortical, but not interhemispheric subcortical coherencies were modulated by movement and influenced by striatal dopaminergic innervation, being stronger in the most dopamine-depleted hemisphere. The data are consistent with a role of dopamine in shielding subcortical structures from an excessive cortical entrapment and cross-hemispheric coupling, thus allowing fine-tuning of movement.
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Affiliation(s)
- Andrea Canessa
- Department of Neurology, University Hospital and Julius-Maximilian-University Wuerzburg, Germany
| | - Nicolò G Pozzi
- Department of Neurology, University Hospital and Julius-Maximilian-University Wuerzburg, Germany
| | - Gabriele Arnulfo
- Department of Neurology, University Hospital and Julius-Maximilian-University Wuerzburg, Germany
| | - Joachim Brumberg
- Department of Nuclear Medicine, University Hospital and Julius-Maximilian-University Wuerzburg, Germany
| | - Martin M Reich
- Department of Neurology, University Hospital and Julius-Maximilian-University Wuerzburg, Germany
| | | | - Maria F Ghilardi
- Department of Physiology, Pharmacology and Neuroscience, CUNY Medical School New York, NY, USA
| | - Cordula Matthies
- Department of Neurosurgery, University Hospital and Julius-Maximilian-University Wuerzburg, Germany
| | - Frank Steigerwald
- Department of Neurology, University Hospital and Julius-Maximilian-University Wuerzburg, Germany
| | - Jens Volkmann
- Department of Neurology, University Hospital and Julius-Maximilian-University Wuerzburg, Germany
| | - Ioannis U Isaias
- Department of Neurology, University Hospital and Julius-Maximilian-University Wuerzburg, Germany
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13
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Norman SE, Butera RJ, Canavier CC. Stochastic slowly adapting ionic currents may provide a decorrelation mechanism for neural oscillators by causing wander in the intrinsic period. J Neurophysiol 2016; 116:1189-98. [PMID: 27281746 DOI: 10.1152/jn.00193.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 06/01/2016] [Indexed: 11/22/2022] Open
Abstract
Oscillatory neurons integrate their synaptic inputs in fundamentally different ways than normally quiescent neurons. We show that the oscillation period of invertebrate endogenous pacemaker neurons wanders, producing random fluctuations in the interspike intervals (ISI) on a time scale of seconds to minutes, which decorrelates pairs of neurons in hybrid circuits constructed using the dynamic clamp. The autocorrelation of the ISI sequence remained high for many ISIs, but the autocorrelation of the ΔISI series had on average a single nonzero value, which was negative at a lag of one interval. We reproduced these results using a simple integrate and fire (IF) model with a stochastic population of channels carrying an adaptation current with a stochastic component that was integrated with a slow time scale, suggesting that a similar population of channels underlies the observed wander in the period. Using autoregressive integrated moving average (ARIMA) models, we found that a single integrator and a single moving average with a negative coefficient could simulate both the experimental data and the IF model. Feeding white noise into an integrator with a slow time constant is sufficient to produce the autocorrelation structure of the ISI series. Moreover, the moving average clearly accounted for the autocorrelation structure of the ΔISI series and is biophysically implemented in the IF model using slow stochastic adaptation. The observed autocorrelation structure may be a neural signature of slow stochastic adaptation, and wander generated in this manner may be a general mechanism for limiting episodes of synchronized activity in the nervous system.
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Affiliation(s)
- Sharon E Norman
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia; Bioengineering Graduate Program, Georgia Institute of Technology, Atlanta, Georgia
| | - Robert J Butera
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia; Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, Atlanta, Georgia; and
| | - Carmen C Canavier
- Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana; and Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana
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Higgs MH, Wilson CJ. Unitary synaptic connections among substantia nigra pars reticulata neurons. J Neurophysiol 2016; 115:2814-29. [PMID: 26961101 DOI: 10.1152/jn.00094.2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 03/09/2016] [Indexed: 11/22/2022] Open
Abstract
Neurons in substantia nigra pars reticulata (SNr) are synaptically coupled by local axon collaterals, providing a potential mechanism for local signal processing. Because SNr neurons fire spontaneously, these synapses are constantly active. To investigate their properties, we recorded spontaneous inhibitory postsynaptic currents (sIPSCs) from SNr neurons in brain slices, in which afferents from upstream nuclei are severed, and the cells fire rhythmically. The sIPSC trains contained a mixture of periodic and aperiodic events. Autocorrelation analysis of sIPSC trains showed that a majority of cells had one to four active unitary inputs. The properties of the unitary IPSCs (uIPSCs) were analyzed for cells with one unitary input, using a model of periodic presynaptic firing and stochastic synaptic transmission. The inferred presynaptic firing rates and coefficient of variation of interspike intervals (ISIs) corresponded well with direct measurements of spiking in SNr neurons. Methods were developed to estimate the success probability, amplitude distributions, and kinetics of the uIPSCs, while removing the contribution from aperiodic sIPSCs. The sIPSC amplitudes were not increased upon release from halorhodopsin silencing, suggesting that most synapses were not depressed at the spontaneous firing rate. Gramicidin perforated-patch recordings indicated that the average reversal potential of spontaneous inhibitory postsynaptic potentials was -64 mV. Because of the change in driving force across the ISI, the unitary inputs are predicted to have a larger postsynaptic impact when they arrive late in the ISI. Simulations of network activity suggest that this very sparse inhibitory coupling may act to desynchronize the activity of SNr neurons while having only a small effect on firing rate.
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Affiliation(s)
- Matthew H Higgs
- Department of Biology, The University of Texas at San Antonio, San Antonio, Texas
| | - Charles J Wilson
- Department of Biology, The University of Texas at San Antonio, San Antonio, Texas
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