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Sánchez-León CA, Sánchez-Garrido Campos G, Fernández M, Sánchez-López A, Medina JF, Márquez-Ruiz J. Somatodendritic orientation determines tDCS-induced neuromodulation of Purkinje cell activity in awake mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.02.18.529047. [PMID: 36824866 PMCID: PMC9949160 DOI: 10.1101/2023.02.18.529047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Transcranial direct-current stimulation (tDCS) of the cerebellum is a promising non-invasive neuromodulatory technique being proposed for the treatment of neurological and neuropsychiatric disorders. However, there is a lack of knowledge about how externally applied currents affect neuronal spiking activity in cerebellar circuits in vivo. We investigated how Cb-tDCS affects the firing rate of Purkinje cells (PC) and non-PC in the mouse cerebellar cortex to understand the underlying mechanisms behind the polarity-dependent modulation of neuronal activity induced by tDCS. Mice (n = 9) were prepared for the chronic recording of LFPs to assess the actual electric field gradient imposed by Cb-tDCS in our experimental design. Single-neuron extracellular recording of PCs in awake (n = 24) and anesthetized (n = 27) mice was combined with juxtacellular recordings and subsequent staining of PC with neurobiotin under anesthesia (n = 8) to correlate their neuronal orientation with their response to Cb-tDCS. Finally, a high-density Neuropixels recording system was used to demonstrate the relevance of neuronal orientation during the application of Cb-tDCS in awake mice (n = 6) In this study, we observe that Cb-tDCS induces a heterogeneous polarity-dependent modulation of the firing rate of Purkinje cells (PC) and non-PC in the mouse cerebellar cortex. We demonstrate that the apparently heterogeneous effects of tDCS on PC activity can be explained by taking into account the somatodendritic orientation relative to the electric field. Our findings highlight the need to consider neuronal orientation and morphology to improve tDCS computational models, enhance stimulation protocol reliability, and optimize effects in both basic and clinical applications.
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Latorre A, Rocchi L, Paparella G, Manzo N, Bhatia KP, Rothwell JC. Changes in cerebellar output abnormally modulate cortical myoclonus sensorimotor hyperexcitability. Brain 2024; 147:1412-1422. [PMID: 37956080 PMCID: PMC10994547 DOI: 10.1093/brain/awad384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 10/07/2023] [Accepted: 11/02/2023] [Indexed: 11/15/2023] Open
Abstract
Cortical myoclonus is produced by abnormal neuronal discharges within the sensorimotor cortex, as demonstrated by electrophysiology. Our hypothesis is that the loss of cerebellar inhibitory control over the motor cortex, via cerebello-thalamo-cortical connections, could induce the increased sensorimotor cortical excitability that eventually causes cortical myoclonus. To explore this hypothesis, in the present study we applied anodal transcranial direct current stimulation over the cerebellum of patients affected by cortical myoclonus and healthy controls and assessed its effect on sensorimotor cortex excitability. We expected that anodal cerebellar transcranial direct current stimulation would increase the inhibitory cerebellar drive to the motor cortex and therefore reduce the sensorimotor cortex hyperexcitability observed in cortical myoclonus. Ten patients affected by cortical myoclonus of various aetiology and 10 aged-matched healthy control subjects were included in the study. All participants underwent somatosensory evoked potentials, long-latency reflexes and short-interval intracortical inhibition recording at baseline and immediately after 20 min session of cerebellar anodal transcranial direct current stimulation. In patients, myoclonus was recorded by the means of surface EMG before and after the cerebellar stimulation. Anodal cerebellar transcranial direct current stimulation did not change the above variables in healthy controls, while it significantly increased the amplitude of somatosensory evoked potential cortical components, long-latency reflexes and decreased short-interval intracortical inhibition in patients; alongside, a trend towards worsening of the myoclonus after the cerebellar stimulation was observed. Interestingly, when dividing patients in those with and without giant somatosensory evoked potentials, the increment of the somatosensory evoked potential cortical components was observed mainly in those with giant potentials. Our data showed that anodal cerebellar transcranial direct current stimulation facilitates-and does not inhibit-sensorimotor cortex excitability in cortical myoclonus syndromes. This paradoxical response might be due to an abnormal homeostatic plasticity within the sensorimotor cortex, driven by dysfunctional cerebello-thalamo-cortical input to the motor cortex. We suggest that the cerebellum is implicated in the pathophysiology of cortical myoclonus and that these results could open the way to new forms of treatment or treatment targets.
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Affiliation(s)
- Anna Latorre
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Lorenzo Rocchi
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
- Department of Medical Sciences and Public Health, University of Cagliari, Cagliari 09042, Italy
| | - Giulia Paparella
- Department of Neurology, IRCCS Neuromed, Pozzilli, IS 86077, Italy
- Department of Human Neurosciences, Sapienza University of Rome, Rome 00185, Italy
| | - Nicoletta Manzo
- Department of Neurology, IRCCS San Camillo Hospital, Venice 30126, Italy
| | - Kailash P Bhatia
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - John C Rothwell
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
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Guerra A, Paparella G, Passaretti M, Costa D, Birreci D, De Biase A, Colella D, Angelini L, Cannavacciuolo A, Berardelli A, Bologna M. Theta-tACS modulates cerebellar-related motor functions and cerebellar-cortical connectivity. Clin Neurophysiol 2024; 158:159-169. [PMID: 38219405 DOI: 10.1016/j.clinph.2023.12.129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 11/21/2023] [Accepted: 12/11/2023] [Indexed: 01/16/2024]
Abstract
OBJECTIVE To evaluate the effects of cerebellar transcranial alternating current stimulation (tACS) delivered at cerebellar-resonant frequencies, i.e., theta (θ) and gamma (γ), on upper limb motor performance and cerebellum-primary motor cortex (M1) connectivity, as assessed by cerebellar-brain inhibition (CBI), in healthy subjects. METHODS Participants underwent cerebellar-tACS while performing three cerebellar-dependent motor tasks: (i) rhythmic finger-tapping, (ii) arm reaching-to-grasp ('grasping') and (iii) arm reaching-to-point ('pointing') an object. Also, we evaluated possible changes in CBI during cerebellar-tACS. RESULTS θ-tACS decreased movement regularity during the tapping task and increased the duration of the pointing task compared to sham- and γ-tACS. Additionally, θ-tACS increased the CBI effectiveness (greater inhibition). The effect of θ-tACS on movement rhythm correlated with CBI changes and less tapping regularity corresponded to greater CBI. CONCLUSIONS Cerebellar-tACS delivered at the θ frequency modulates cerebellar-related motor behavior and this effect is, at least in part, mediated by changes in the cerebellar inhibitory output onto M1. The effects of θ-tACS may be due to the modulation of cerebellar neurons that resonate to the θ rhythm. SIGNIFICANCE These findings contribute to a better understanding of the physiological mechanisms of motor control and provide new evidence on cerebellar non-invasive brain stimulation.
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Affiliation(s)
- Andrea Guerra
- Parkinson and Movement Disorders Unit, Study Center on Neurodegeneration (CESNE), Department of Neuroscience, University of Padua, Padua, Italy; Padova Neuroscience Center (PNC), University of Padua, Padua, Italy
| | - Giulia Paparella
- IRCCS Neuromed, Pozzilli (IS) 86077, Italy; Department of Human Neurosciences, Sapienza University of Rome, Rome 00185, Italy
| | | | - Davide Costa
- Department of Human Neurosciences, Sapienza University of Rome, Rome 00185, Italy
| | - Daniele Birreci
- Department of Human Neurosciences, Sapienza University of Rome, Rome 00185, Italy
| | - Alessandro De Biase
- Department of Human Neurosciences, Sapienza University of Rome, Rome 00185, Italy
| | - Donato Colella
- Department of Human Neurosciences, Sapienza University of Rome, Rome 00185, Italy
| | | | | | - Alfredo Berardelli
- IRCCS Neuromed, Pozzilli (IS) 86077, Italy; Department of Human Neurosciences, Sapienza University of Rome, Rome 00185, Italy
| | - Matteo Bologna
- IRCCS Neuromed, Pozzilli (IS) 86077, Italy; Department of Human Neurosciences, Sapienza University of Rome, Rome 00185, Italy.
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Kang Q, Lang EJ, Sahin M. Transsynaptic entrainment of cerebellar nuclear cells by alternating currents in a frequency dependent manner. Front Neurosci 2023; 17:1282322. [PMID: 38027520 PMCID: PMC10667418 DOI: 10.3389/fnins.2023.1282322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 10/30/2023] [Indexed: 12/01/2023] Open
Abstract
Transcranial alternating current stimulation (tACS) is a non-invasive neuromodulation technique that is being tested clinically for treatment of a variety of neural disorders. Animal studies investigating the underlying mechanisms of tACS are scarce, and nearly absent in the cerebellum. In the present study, we applied 10-400 Hz alternating currents (AC) to the cerebellar cortex in ketamine/xylazine anesthetized rats. The spiking activity of cerebellar nuclear (CN) cells was transsynaptically entrained to the frequency of AC stimulation in an intensity and frequency-dependent manner. Interestingly, there was a tuning curve for modulation where the frequencies in the midrange (100 and 150 Hz) were more effective, although the stimulation frequency for maximum modulation differed for each CN cell with slight dependence on the stimulation amplitude. CN spikes were entrained with latencies of a few milliseconds with respect to the AC stimulation cycle. These short latencies and that the transsynaptic modulation of the CN cells can occur at such high frequencies strongly suggests that PC simple spike synchrony at millisecond time scales is the underlying mechanism for CN cell entrainment. These results show that subthreshold AC stimulation can induce such PC spike synchrony without resorting to supra-threshold pulse stimulation for precise timing. Transsynaptic entrainment of deep CN cells via cortical stimulation could help keep stimulation currents within safety limits in tACS applications, allowing development of tACS as an alternative treatment to deep cerebellar stimulation. Our results also provide a possible explanation for human trials of cerebellar stimulation where the functional impacts of tACS were frequency dependent.
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Affiliation(s)
- Qi Kang
- Biomedical Engineering Department, New Jersey Institute of Technology, Newark, NJ, United States
| | - Eric J. Lang
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Grossman School of Medicine, New York City, NY, United States
| | - Mesut Sahin
- Biomedical Engineering Department, New Jersey Institute of Technology, Newark, NJ, United States
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Spampinato DA, Casula EP, Koch G. The Cerebellum and the Motor Cortex: Multiple Networks Controlling Multiple Aspects of Behavior. Neuroscientist 2023:10738584231189435. [PMID: 37649430 DOI: 10.1177/10738584231189435] [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: 09/01/2023]
Abstract
The cerebellum and its thalamic projections to the primary motor cortex (M1) are well known to play an essential role in executing daily actions. Anatomic investigations in animals and postmortem humans have established the reciprocal connections between these regions; however, how these pathways can shape cortical activity in behavioral contexts and help promote recovery in neuropathological conditions remains not well understood. The present review aims to provide a comprehensive description of these pathways in animals and humans and discuss how novel noninvasive brain stimulation (NIBS) methods can be used to gain a deeper understanding of the cerebellar-M1 connections. In the first section, we focus on recent animal literature that details how information sent from the cerebellum and thalamus is integrated into an broad network of cortical motor neurons. We then discuss how NIBS approaches in humans can be used to reliably assess the connectivity between the cerebellum and M1. Moreover, we provide the latest perspectives on using advanced NIBS approaches to investigate and modulate multiple cerebellar-cortical networks involved in movement behavior and plasticity. Finally, we discuss how these emerging methods have been used in translation research to produce long-lasting modifications of cerebellar-thalamic-M1 to restore cortical activity and motor function in neurologic patients.
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Herzog R, Bolte C, Radecke JO, von Möller K, Lencer R, Tzvi E, Münchau A, Bäumer T, Weissbach A. Neuronavigated Cerebellar 50 Hz tACS: Attenuation of Stimulation Effects by Motor Sequence Learning. Biomedicines 2023; 11:2218. [PMID: 37626715 PMCID: PMC10452137 DOI: 10.3390/biomedicines11082218] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/02/2023] [Accepted: 08/04/2023] [Indexed: 08/27/2023] Open
Abstract
Cerebellar transcranial alternating current stimulation (tACS) is an emerging non-invasive technique that induces electric fields to modulate cerebellar function. Although the effect of cortical tACS seems to be state-dependent, the impact of concurrent motor activation and the duration of stimulation on the effects of cerebellar tACS has not yet been examined. In our study, 20 healthy subjects received neuronavigated 50 Hz cerebellar tACS for 40 s or 20 min, each during performance using a motor sequence learning task (MSL) and at rest. We measured the motor evoked potential (MEP) before and at two time points after tACS application to assess corticospinal excitability. Additionally, we investigated the online effect of tACS on MSL. Individual electric field simulations were computed to evaluate the distribution of electric fields, showing a focal electric field in the right cerebellar hemisphere with the highest intensities in lobe VIIb, VIII and IX. Corticospinal excitability was only increased after tACS was applied for 40 s or 20 min at rest, and motor activation during tACS (MSL) cancelled this effect. In addition, performance was better (shorter reaction times) for the learned sequences after 20 min of tACS, indicating more pronounced learning under 20 min of tACS compared to tACS applied only in the first 40 s.
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Affiliation(s)
- Rebecca Herzog
- Institute of Systems Motor Science, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany; (R.H.); (C.B.)
- Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
- Department of Neurology, University Hospital Schleswig Holstein, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Christina Bolte
- Institute of Systems Motor Science, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany; (R.H.); (C.B.)
- Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Jan-Ole Radecke
- Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
- Department of Psychiatry and Psychotherapy, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Kathinka von Möller
- Institute of Systems Motor Science, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany; (R.H.); (C.B.)
- Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Rebekka Lencer
- Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
- Department of Psychiatry and Psychotherapy, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Elinor Tzvi
- Department of Neurology, Leipzig University, Liebigstraße 20, 04103 Leipzig, Germany
- Syte Institute, Hohe Bleichen 8, 20354 Hamburg, Germany
| | - Alexander Münchau
- Institute of Systems Motor Science, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany; (R.H.); (C.B.)
- Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Tobias Bäumer
- Institute of Systems Motor Science, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany; (R.H.); (C.B.)
- Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Anne Weissbach
- Institute of Systems Motor Science, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany; (R.H.); (C.B.)
- Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
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Avlar B, Rahman R, Vendidandi S, Cetinkaya E, Asan AS, Sahin M, Lang EJ. Modulation of cerebellar cortical, cerebellar nuclear and vestibular nuclear activity using alternating electric currents. Front Syst Neurosci 2023; 17:1173738. [PMID: 37274077 PMCID: PMC10232809 DOI: 10.3389/fnsys.2023.1173738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Accepted: 04/17/2023] [Indexed: 06/06/2023] Open
Abstract
Introduction Cerebellar transcranial alternating current stimulation (ctACS) has shown promise as a therapeutic modality for treating a variety of neurological disorders, and for affecting normal learning processes. Yet, little is known about how electric fields induced by applied currents affect cerebellar activity in the mammalian cerebellum under in vivo conditions. Methods Alternating current (AC) stimulation with frequencies from 0.5 to 20 Hz was applied to the surface of the cerebellum in anesthetized rats. Extracellular recordings were obtained from Purkinje cells (PC), cerebellar and vestibular nuclear neurons, and other cerebellar cortical neurons. Results and discussion AC stimulation modulated the activity of all classes of neurons. Cerebellar and vestibular nuclear neurons most often showed increased spike activity during the negative phase of the AC stimulation. Purkinje cell simple spike activity was also increased during the negative phase at most locations, except for the cortex directly below the stimulus electrode, where activity was most often increased during the positive phase of the AC cycle. Other cortical neurons showed a more mixed, generally weaker pattern of modulation. The patterns of Purkinje cell responses suggest that AC stimulation induces a complex electrical field with changes in amplitude and orientation between local regions that may reflect the folding of the cerebellar cortex. Direct measurements of the induced electric field show that it deviates significantly from the theoretically predicted radial field for an isotropic, homogeneous medium, in both its orientation and magnitude. These results have relevance for models of the electric field induced in the cerebellum by AC stimulation.
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Affiliation(s)
- Billur Avlar
- Department of Neuroscience and Physiology, NYU Neuroscience Institute, New York University Grossman School of Medicine,, New York, NY, United States
| | - Ramia Rahman
- Department of Neuroscience and Physiology, NYU Neuroscience Institute, New York University Grossman School of Medicine,, New York, NY, United States
| | - Sai Vendidandi
- Department of Neuroscience and Physiology, NYU Neuroscience Institute, New York University Grossman School of Medicine,, New York, NY, United States
| | - Esma Cetinkaya
- Department of Neuroscience and Physiology, NYU Neuroscience Institute, New York University Grossman School of Medicine,, New York, NY, United States
| | - Ahmet S. Asan
- Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ, United States
| | - Mesut Sahin
- Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ, United States
| | - Eric J. Lang
- Department of Neuroscience and Physiology, NYU Neuroscience Institute, New York University Grossman School of Medicine,, New York, NY, United States
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Wessel MJ, Draaisma LR, Hummel FC. Mini-review: Transcranial Alternating Current Stimulation and the Cerebellum. CEREBELLUM (LONDON, ENGLAND) 2023; 22:120-128. [PMID: 35060078 DOI: 10.1007/s12311-021-01362-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/22/2021] [Indexed: 02/01/2023]
Abstract
Oscillatory activity in the cerebellum and linked networks is an important aspect of neuronal processing and functional implementation of behavior. So far, it was challenging to quantify and study cerebellar oscillatory signatures in human neuroscience due to the constraints of non-invasive cerebellar electrophysiological recording and interventional techniques. The emerging cerebellar transcranial alternating current stimulation technique (CB-tACS) is a promising tool, which may partially overcome this challenge and provides an exciting non-invasive opportunity to better understand cerebellar physiology.Several studies have successfully demonstrated that CB-tACS can modulate the cerebellar outflow and cerebellum-linked behavior. In the present narrative review, we summarize current studies employing the CB-tACS approach and discuss open research questions. Hereby, we aim to provide an overview on this emerging electrophysiological technique and strive to promote future research in the field. CB-tACS will contribute in the further deciphering of cerebellar oscillatory signatures and its role for motor, cognitive, or affective functions. In long term, CB-tACS could develop into a therapeutic tool for retuning disturbed oscillatory activity in cerebellar networks underlying brain disorders.
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Affiliation(s)
- Maximilian J Wessel
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), École polytechnique fédérale de Lausanne (EPFL), Campus Biotech, Chemin des Mines 9, 1202, Geneva, Switzerland. .,Defitech Chair of Clinical Neuroengineering, Clinique Romande de Réadaptation, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), École polytechnique fédérale de Lausanne (EPFL Valais), Sion, Switzerland. .,Department of Neurology, Julius-Maximilians-University Würzburg, Würzburg, Germany.
| | - Laurijn R Draaisma
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), École polytechnique fédérale de Lausanne (EPFL), Campus Biotech, Chemin des Mines 9, 1202, Geneva, Switzerland.,Defitech Chair of Clinical Neuroengineering, Clinique Romande de Réadaptation, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), École polytechnique fédérale de Lausanne (EPFL Valais), Sion, Switzerland
| | - Friedhelm C Hummel
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), École polytechnique fédérale de Lausanne (EPFL), Campus Biotech, Chemin des Mines 9, 1202, Geneva, Switzerland.,Defitech Chair of Clinical Neuroengineering, Clinique Romande de Réadaptation, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), École polytechnique fédérale de Lausanne (EPFL Valais), Sion, Switzerland.,Clinical Neuroscience, University of Geneva Medical School, Geneva, Switzerland
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Weightman M, Lalji N, Lin CHS, Galea JM, Jenkinson N, Miall RC. Short duration event related cerebellar TDCS enhances visuomotor adaptation. Brain Stimul 2023; 16:431-441. [PMID: 36720304 DOI: 10.1016/j.brs.2023.01.1673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/24/2023] [Accepted: 01/24/2023] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Transcranial direct current stimulation (TDCS) is typically applied before or during a task, for periods ranging from 5 to 30 min. HYPOTHESIS We hypothesise that briefer stimulation epochs synchronous with individual task actions may be more effective. METHODS In two separate experiments, we applied brief bursts of event-related anodal stimulation (erTDCS) to the cerebellum during a visuomotor adaptation task. RESULTS The first study demonstrated that 1 s duration erTDCS time-locked to the participants' reaching actions enhanced adaptation significantly better than sham. A close replication in the second study demonstrated 0.5 s erTDCS synchronous with the reaching actions again resulted in better adaptation than standard TDCS, significantly better than sham. Stimulation either during the inter-trial intervals between movements or after movement, during assessment of visual feedback, had no significant effect. Because short duration stimulation with rapid onset and offset is more readily perceived by the participants, we additionally show that a non-electrical vibrotactile stimulation of the scalp, presented with the same timing as the erTDCS, had no significant effect. CONCLUSIONS We conclude that short duration, event related, anodal TDCS targeting the cerebellum enhances motor adaptation compared to the standard model. We discuss possible mechanisms of action and speculate on neural learning processes that may be involved.
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Affiliation(s)
- Matthew Weightman
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, UK; School of Psychology, University of Birmingham, UK
| | - Neeraj Lalji
- School of Psychology, University of Birmingham, UK
| | - Chin-Hsuan Sophie Lin
- Cognitive Neuroscience and Computational Psychiatry Lab, University of Melbourne, Australia
| | | | - Ned Jenkinson
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, UK
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Nakazono H, Taniguchi T, Mitsutake T, Takeda A, Yamada E, Ogata K. Phase-dependent modulation of the vestibular-cerebellar network via combined alternating current stimulation influences human locomotion and posture. Front Neurosci 2022; 16:1057021. [PMID: 36590300 PMCID: PMC9795064 DOI: 10.3389/fnins.2022.1057021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 11/28/2022] [Indexed: 12/15/2022] Open
Abstract
Background Human locomotion induces rhythmic movements of the trunk and head. Vestibular signaling is relayed to multiple regions in the brainstem and cerebellum, and plays an essential role in maintaining head stability. However, how the vestibular-cerebellar network contributes to the rhythmic locomotor pattern in humans is unclear. Transcranial alternating current stimulation (tACS) has been used to investigate the effects of the task-related network between stimulation regions in a phase-dependent manner. Here, we investigated the relationship between the vestibular system and the cerebellum during walking imagery using combined tACS over the left cerebellum and alternating current galvanic vestibular stimulation (AC-GVS). Methods In Experiment 1, we tested the effects of AC-GVS alone at around individual gait stride frequencies. In Experiment 2, we then determined the phase-specificity of combined stimulation at the gait frequency. Combined stimulation was applied at in-phase (0° phase lag) or anti-phase (180° phase lag) between the left vestibular and left cerebellar stimulation, and the sham stimulation. We evaluated the AC-GVS-induced periodic postural response during walking imagery or no-imagery using the peak oscillatory power on the angular velocity signals of the head in both experiments. In Experiment 2, we also examined the phase-locking value (PLV) between the periodic postural responses and the left AC-GVS signals to estimate entrainment of the postural response by AC-GVS. Results AC-GVS alone induced the periodic postural response in the yaw and roll axes, but no interactions with imagery walking were observed in Experiment 1 (p > 0.05). By contrast, combined in-phase stimulation increased yaw motion (0.345 ± 0.23) compared with sham (-0.044 ± 0.19) and anti-phase stimulation (-0.066 ± 0.18) during imaginary walking (in-phase vs. other conditions, imagery: p < 0.05; no-imagery: p ≥ 0.125). Furthermore, there was a positive correlation between the yaw peak power of actual locomotion and in-phase stimulation in the imagery session (imagery: p = 0.041; no-imagery: p = 0.177). Meanwhile, we found no imagery-dependent effects in roll peak power or PLV, although in-phase stimulation enhanced roll motion and PLV in Experiment 2. Conclusion These findings suggest that combined stimulation can influence vestibular-cerebellar network activity, and modulate postural control and locomotion systems in a temporally sensitive manner. This novel combined tACS/AC-GVS stimulation approach may advance development of therapeutic applications.
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Affiliation(s)
- Hisato Nakazono
- Department of Occupational Therapy, Faculty of Medical Science, Fukuoka International University of Health and Welfare, Fukuoka, Japan,Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan,*Correspondence: Hisato Nakazono,
| | - Takanori Taniguchi
- Department of Physical Therapy, Faculty of Medical Science, Fukuoka International University of Health and Welfare, Fukuoka, Japan
| | - Tsubasa Mitsutake
- Department of Physical Therapy, Faculty of Medical Science, Fukuoka International University of Health and Welfare, Fukuoka, Japan
| | - Akinori Takeda
- Research Center for Brain Communication, Research Institute, Kochi University of Technology, Kochi, Japan
| | - Emi Yamada
- Department of Linguistics, Faculty of Humanities, Kyushu University, Fukuoka, Japan
| | - Katsuya Ogata
- Department of Pharmaceutical Sciences, School of Pharmacy at Fukuoka, International University of Health and Welfare, Fukuoka, Japan
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Herzog R, Berger TM, Pauly MG, Xue H, Rueckert E, Münchau A, Bäumer T, Weissbach A. Cerebellar transcranial current stimulation – An intraindividual comparison of different techniques. Front Neurosci 2022; 16:987472. [PMID: 36188449 PMCID: PMC9521312 DOI: 10.3389/fnins.2022.987472] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
Transcranial current stimulation (tCS) techniques have been shown to induce cortical plasticity. As an important relay in the motor system, the cerebellum is an interesting target for plasticity induction using tCS, aiming to modulate its excitability and connectivity. However, until now it remains unclear, which is the most effective tCS method for inducing plasticity in the cerebellum. Thus, in this study, the effects of anodal transcranial direct current stimulation (tDCS), 50 Hz transcranial alternating current stimulation (50 Hz tACS), and high frequency transcranial random noise stimulation (tRNS) were compared with sham stimulation in 20 healthy subjects in a within-subject design. tCS was applied targeting the cerebellar lobe VIIIA using neuronavigation. We measured corticospinal excitability, short-interval intracortical inhibition (SICI), short-latency afferent inhibition (SAI), and cerebellar brain inhibition (CBI) and performed a sensor-based movement analysis at baseline and three times after the intervention (post1 = 15 min; post2 = 55 min; post3 = 95 min). Corticospinal excitability increased following cerebellar tACS and tRNS compared to sham stimulation. This effect was most pronounced directly after stimulation but lasted for at least 55 min after tACS. Cortico-cortical and cerebello-cortical conditioning protocols, as well as sensor-based movement analyses, did not change. Our findings suggest that cerebellar 50 Hz tACS is the most effective protocol to change corticospinal excitability.
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Affiliation(s)
- Rebecca Herzog
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
- Department of Neurology, University Hospital Schleswig Holstein, Lübeck, Germany
| | - Till M. Berger
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
| | - Martje G. Pauly
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
- Department of Neurology, University Hospital Schleswig Holstein, Lübeck, Germany
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Honghu Xue
- Institute for Robotics and Cognitive Systems, University of Lübeck, Lübeck, Germany
| | | | - Alexander Münchau
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
| | - Tobias Bäumer
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
| | - Anne Weissbach
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
- *Correspondence: Anne Weissbach,
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12
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Timing is everything: Event-related transcranial direct current stimulation improves motor adaptation. Brain Stimul 2022; 15:750-757. [PMID: 35533836 DOI: 10.1016/j.brs.2022.05.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/28/2022] [Accepted: 05/02/2022] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND There is a current discord between the foundational theories underpinning motor learning and how we currently apply transcranial direct current stimulation (TDCS): the former is dependent on tight coupling of events while the latter is conducted with very low temporal resolution. OBJECTIVE Here we aimed to investigate the temporal specificity of stimulation by applying TDCS in short epochs, and coincidentally with movement, during a motor adaptation task. METHODS Participants simultaneously adapted a reaching movement to two opposing velocity-dependent force-fields (clockwise and counter-clockwise), distinguished by a contextual leftward or rightward shift in the task display and cursor location respectively. Brief bouts (<3 s) of event-related TDCS (er-TDCS) were applied over M1 or the cerebellum during movements for only one of these learning contexts. RESULTS We show that when short duration stimulation is applied to the cerebellum and yoked to movement, only those reaching movements performed simultaneously with stimulation are selectively enhanced, whilst similar and interleaved movements are left unaffected. We found no evidence of improved adaptation following M1 er-TDCS, as participants displayed equivalent levels of error during both stimulated and unstimulated movements. Similarly, participants in the sham stimulation group adapted comparably during left and right-shift trials. CONCLUSIONS It is proposed that the coupling of cerebellar stimulation and movement influences timing-dependent (i.e. Hebbian-like) mechanisms of plasticity to facilitate enhanced learning in the stimulated context.
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13
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Transcranial direct current stimulation of cerebellum alters spiking precision in cerebellar cortex: A modeling study of cellular responses. PLoS Comput Biol 2021; 17:e1009609. [PMID: 34882680 PMCID: PMC8691604 DOI: 10.1371/journal.pcbi.1009609] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 12/21/2021] [Accepted: 11/02/2021] [Indexed: 01/13/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) of the cerebellum has rapidly raised interest but the effects of tDCS on cerebellar neurons remain unclear. Assessing the cellular response to tDCS is challenging because of the uneven, highly stratified cytoarchitecture of the cerebellum, within which cellular morphologies, physiological properties, and function vary largely across several types of neurons. In this study, we combine MRI-based segmentation of the cerebellum and a finite element model of the tDCS-induced electric field (EF) inside the cerebellum to determine the field imposed on the cerebellar neurons throughout the region. We then pair the EF with multicompartment models of the Purkinje cell (PC), deep cerebellar neuron (DCN), and granule cell (GrC) and quantify the acute response of these neurons under various orientations, physiological conditions, and sequences of presynaptic stimuli. We show that cerebellar tDCS significantly modulates the postsynaptic spiking precision of the PC, which is expressed as a change in the spike count and timing in response to presynaptic stimuli. tDCS has modest effects, instead, on the PC tonic firing at rest and on the postsynaptic activity of DCN and GrC. In Purkinje cells, anodal tDCS shortens the repolarization phase following complex spikes (-14.7 ± 6.5% of baseline value, mean ± S.D.; max: -22.7%) and promotes burstiness with longer bursts compared to resting conditions. Cathodal tDCS, instead, promotes irregular spiking by enhancing somatic excitability and significantly prolongs the repolarization after complex spikes compared to baseline (+37.0 ± 28.9%, mean ± S.D.; max: +84.3%). tDCS-induced changes to the repolarization phase and firing pattern exceed 10% of the baseline values in Purkinje cells covering up to 20% of the cerebellar cortex, with the effects being distributed along the EF direction and concentrated in the area under the electrode over the cerebellum. Altogether, the acute effects of tDCS on cerebellum mainly focus on Purkinje cells and modulate the precision of the response to synaptic stimuli, thus having the largest impact when the cerebellar cortex is active. Since the spatiotemporal precision of the PC spiking is critical to learning and coordination, our results suggest cerebellar tDCS as a viable therapeutic option for disorders involving cerebellar hyperactivity such as ataxia. Transcranial direct current stimulation (tDCS) of the cerebellum is gaining momentum as a neuromodulation tool for the treatment of neurological diseases like movement disorders. Nonetheless, the response of cells in the cerebellum to tDCS is unclear and hardly generalizes from our understanding of tDCS of the cerebral cortex. We use computational models to investigate the response of several types of cerebellar neurons to the electric field induced by tDCS and show that, differently from the cerebral cortex, tDCS has significant acute effects on the cerebellar cortex. These effects (i) primarily alter the way Purkinje cells encode synaptic stimuli from the molecular layer and (ii) can help hyperactive cells regain postsynaptic spiking precision. Since the spatiotemporal precision of the Purkinje cell spiking is critical to learning and coordination, the study shows how tDCS can operate at the cellular level to treat movement disorders like tremor and ataxia.
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14
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Manto M, Argyropoulos GPD, Bocci T, Celnik PA, Corben LA, Guidetti M, Koch G, Priori A, Rothwell JC, Sadnicka A, Spampinato D, Ugawa Y, Wessel MJ, Ferrucci R. Consensus Paper: Novel Directions and Next Steps of Non-invasive Brain Stimulation of the Cerebellum in Health and Disease. CEREBELLUM (LONDON, ENGLAND) 2021; 21:1092-1122. [PMID: 34813040 DOI: 10.1007/s12311-021-01344-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/08/2021] [Indexed: 12/11/2022]
Abstract
The cerebellum is involved in multiple closed-loops circuitry which connect the cerebellar modules with the motor cortex, prefrontal, temporal, and parietal cortical areas, and contribute to motor control, cognitive processes, emotional processing, and behavior. Among them, the cerebello-thalamo-cortical pathway represents the anatomical substratum of cerebellum-motor cortex inhibition (CBI). However, the cerebellum is also connected with basal ganglia by disynaptic pathways, and cerebellar involvement in disorders commonly associated with basal ganglia dysfunction (e.g., Parkinson's disease and dystonia) has been suggested. Lately, cerebellar activity has been targeted by non-invasive brain stimulation (NIBS) techniques including transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) to indirectly affect and tune dysfunctional circuitry in the brain. Although the results are promising, several questions remain still unsolved. Here, a panel of experts from different specialties (neurophysiology, neurology, neurosurgery, neuropsychology) reviews the current results on cerebellar NIBS with the aim to derive the future steps and directions needed. We discuss the effects of TMS in the field of cerebellar neurophysiology, the potentials of cerebellar tDCS, the role of animal models in cerebellar NIBS applications, and the possible application of cerebellar NIBS in motor learning, stroke recovery, speech and language functions, neuropsychiatric and movement disorders.
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Affiliation(s)
- Mario Manto
- Service de Neurologie, CHU-Charleroi, 6000, Charleroi, Belgium.,Service Des Neurosciences, UMons, 7000, Mons, Belgium
| | - Georgios P D Argyropoulos
- Division of Psychology, Faculty of Natural Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Tommaso Bocci
- Aldo Ravelli Research Center for Neurotechnology and Experimental Neurotherapeutics, Department of Health Sciences, University of Milan, 20142, Milan, Italy.,ASST Santi Paolo E Carlo, Via di Rudinì, 8, 20142, Milan, Italy
| | - Pablo A Celnik
- Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Louise A Corben
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Department of Paediatrics, University of Melbourne, Parkville. Victoria, Australia
| | - Matteo Guidetti
- Aldo Ravelli Research Center for Neurotechnology and Experimental Neurotherapeutics, Department of Health Sciences, University of Milan, 20142, Milan, Italy.,Department of Electronics, Information and Bioengineering, Politecnico Di Milano, 20133, Milan, Italy
| | - Giacomo Koch
- Fondazione Santa Lucia IRCCS, via Ardeatina 306, 00179, Rome, Italy
| | - Alberto Priori
- Aldo Ravelli Research Center for Neurotechnology and Experimental Neurotherapeutics, Department of Health Sciences, University of Milan, 20142, Milan, Italy.,ASST Santi Paolo E Carlo, Via di Rudinì, 8, 20142, Milan, Italy
| | - John C Rothwell
- Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, London, UK
| | - Anna Sadnicka
- Motor Control and Movement Disorders Group, St George's University of London, London, UK.,Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - Danny Spampinato
- Fondazione Santa Lucia IRCCS, via Ardeatina 306, 00179, Rome, Italy
| | - Yoshikazu Ugawa
- Department of Human Neurophysiology, Fukushima Medical University, Fukushima, Japan
| | - Maximilian J Wessel
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Swiss Federal Institute of Technology (EPFL), Geneva, Switzerland.,Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Swiss Federal Institute of Technology (EPFL Valais), Clinique Romande de Réadaptation, Sion, Switzerland
| | - Roberta Ferrucci
- Aldo Ravelli Research Center for Neurotechnology and Experimental Neurotherapeutics, Department of Health Sciences, University of Milan, 20142, Milan, Italy. .,ASST Santi Paolo E Carlo, Via di Rudinì, 8, 20142, Milan, Italy.
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15
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Dong XL, Sun X, Sun WM, Yuan Q, Yu GH, Shuai L, Yuan YF. A randomized controlled trial to explore the efficacy and safety of transcranial direct current stimulation on patients with post-stroke fatigue. Medicine (Baltimore) 2021; 100:e27504. [PMID: 34731132 PMCID: PMC8519229 DOI: 10.1097/md.0000000000027504] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/25/2021] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Post-stroke fatigue seriously affects the quality of life for stroke patients. There is no effective treatment at present. transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation which may have therapeutic effect on post-stroke fatigue. This study will explore about this. METHOD A total of 60 patients with post-stroke fatigue were randomly divided into the control group and the treatment group with 30 patients each by minimization randomization. Both groups received basic treatment and conventional rehabilitation. In the treatment group, patients were treated with active tDCS, while in the control group, sham tDCS. Both active and sham tDCS were administered 6 times a week for 4 weeks. Before and after the trial, the Fatigue Severity Scale (FSS), Fugl-Meyer Assessment (FMA) and Modified Barthel Index (MBI) were evaluated and analyzed. And comparisons were made among groups. And there were an 8-week follow-up after the intervention. RESULT Before the intervention, there were no significant differences in baseline data and assessment scores between the groups (P > 0.05). After 4 weeks of intervention, FSS scores in the treatment group were significantly lower than those in the control group (P = 0.012), and FMA and BMI scores were significantly higher than those in the control group (P < 0.05). There was no significant change in FSS scores after 8 months of follow-up (P > 0.05). DISCUSSION TDCS is a safe treatment that can effectively reduce the degree of fatigue after stroke, improve the motor function and daily activity ability of patients after stroke, and the efficacy is better than only routine rehabilitation training. TRIAL REGISTRATION NUMBER Chinese Clinical Trial Registry, ChiCTR2000031120. Registered on March 22, 2020.
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Affiliation(s)
- Xiang-Li Dong
- Department of Psychosomatic Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Xing Sun
- First Clinical Medical School, Nanchang University, Nanchang, China
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Wei-Ming Sun
- First Clinical Medical School, Nanchang University, Nanchang, China
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Qin Yuan
- Department of Psychology, Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi Province, China
| | - Guo-Hua Yu
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Lang Shuai
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Ye-Feng Yuan
- First Clinical Medical School, Nanchang University, Nanchang, China
- Department of Psychosomatic Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China
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16
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Schubert C, Dabbagh A, Classen J, Krämer UM, Tzvi E. Alpha oscillations modulate premotor-cerebellar connectivity in motor learning: Insights from transcranial alternating current stimulation. Neuroimage 2021; 241:118410. [PMID: 34303797 DOI: 10.1016/j.neuroimage.2021.118410] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 06/15/2021] [Accepted: 07/19/2021] [Indexed: 11/25/2022] Open
Abstract
Alpha oscillations (8-13 Hz) have been suggested to play an important role in dynamic neural processes underlying learning and memory. The goal of this study was to scrutinize the role of alpha oscillations in communication within a cortico-cerebellar network implicated in motor sequence learning. To this end, we conducted two EEG experiments using a serial reaction time task. In the first experiment, we explored changes in alpha power and cross-channel alpha coherence as subjects learned a motor sequence. We found a gradual decrease in spectral alpha power over left premotor cortex (PMC) and sensorimotor cortex (SM1) during learning blocks. In addition, alpha coherence between left PMC/SM1 and left cerebellar crus I was specifically decreased during sequence learning, possibly reflecting a functional decoupling in the broader motor learning network. In the second experiment in a different cohort, we applied 10Hz transcranial alternating current stimulation (tACS), a method shown to entrain local oscillatory activity, to left M1 (lM1) and right cerebellum (rCB) during sequence learning. We observed a tendency for diminished learning following rCB tACS compared to sham, but not following lM1 tACS. Learning-related alpha power following rCB tACS was increased in left PMC, possibly reflecting increase in local inhibitory neural activity. Importantly, learning-specific alpha coherence between left PMC and right cerebellar lobule VIIb was enhanced following rCB tACS. These findings provide strong evidence for a causal role of alpha oscillations in controlling information transfer in a premotor-cerebellar loop during motor sequence learning. Our findings are consistent with a model in which sequence learning may be impaired by enhancing premotor cortical alpha oscillation via external modulation of cerebellar oscillations.
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Affiliation(s)
- Christine Schubert
- Department of Neurology, University of Leipzig, Liebigstraße 20, Leipzig 04103, Germany
| | - Alhuda Dabbagh
- Department of Neurology, University of Leipzig, Liebigstraße 20, Leipzig 04103, Germany
| | - Joseph Classen
- Department of Neurology, University of Leipzig, Liebigstraße 20, Leipzig 04103, Germany
| | - Ulrike M Krämer
- Department of Neurology, University of Lübeck, Ratzeburger Allee 160, Lübeck 23562, Germany; Department of Psychology, University of Lübeck, Ratzeburger Allee 160, Lübeck 23562, Germany; Center for Brain, Behavior and Metabolism, University of Lübeck, Ratzeburger Allee 160, Lübeck 23562, Germany
| | - Elinor Tzvi
- Department of Neurology, University of Leipzig, Liebigstraße 20, Leipzig 04103, Germany.
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17
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Abbasi A, Danielsen NP, Leung J, Muhammad AKMG, Patel S, Gulati T. Epidural cerebellar stimulation drives widespread neural synchrony in the intact and stroke perilesional cortex. J Neuroeng Rehabil 2021; 18:89. [PMID: 34039346 PMCID: PMC8157634 DOI: 10.1186/s12984-021-00881-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 05/19/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cerebellar electrical stimulation has shown promise in improving motor recovery post-stroke in both rodent and human studies. Past studies have used motor evoked potentials (MEPs) to evaluate how cerebellar stimulation modulates ongoing activity in the cortex, but the underlying mechanisms are incompletely understood. Here we used invasive electrophysiological recordings from the intact and stroke-injured rodent primary motor cortex (M1) to assess how epidural cerebellar stimulation modulates neural dynamics at the level of single neurons as well as at the level of mesoscale dynamics. METHODS We recorded single unit spiking and local field potentials (LFPs) in both the intact and acutely stroke-injured M1 contralateral to the stimulated cerebellum in adult Long-Evans rats under anesthesia. We analyzed changes in the firing rates of single units, the extent of synchronous spiking and power spectral density (PSD) changes in LFPs during and post-stimulation. RESULTS Our results show that post-stimulation, the firing rates of a majority of M1 neurons changed significantly with respect to their baseline rates. These firing rate changes were diverse in character, as the firing rate of some neurons increased while others decreased. Additionally, these changes started to set in during stimulation. Furthermore, cross-correlation analysis showed a significant increase in coincident firing amongst neuronal pairs. Interestingly, this increase in synchrony was unrelated to the direction of firing rate change. We also found that neuronal ensembles derived through principal component analysis were more active post-stimulation. Lastly, these changes occurred without a significant change in the overall spectral power of LFPs post-stimulation. CONCLUSIONS Our results show that cerebellar stimulation caused significant, long-lasting changes in the activity patterns of M1 neurons by altering firing rates, boosting neural synchrony and increasing neuronal assemblies' activation strength. Our study provides evidence that cerebellar stimulation can directly modulate cortical dynamics. Since these results are present in the perilesional cortex, our data might also help explain the facilitatory effects of cerebellar stimulation post-stroke.
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Affiliation(s)
- Aamir Abbasi
- Center for Neural Science and Medicine, Departments of Biomedical Sciences and Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Nathan P Danielsen
- Center for Neural Science and Medicine, Departments of Biomedical Sciences and Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Jennifer Leung
- PhD Program in Biomedical Sciences, Graduate School of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - A K M G Muhammad
- Center for Neural Science and Medicine, Departments of Biomedical Sciences and Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Saahil Patel
- Center for Neural Science and Medicine, Departments of Biomedical Sciences and Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Tanuj Gulati
- Center for Neural Science and Medicine, Departments of Biomedical Sciences and Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA. .,Department of Medicine, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA. .,Department of Bioengineering, Henri Samueli School of Engineering, University of California-Los Angeles, Los Angeles, CA, USA.
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18
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Asan AS, Kang Q, Oralkan Ö, Sahin M. Entrainment of cerebellar Purkinje cell spiking activity using pulsed ultrasound stimulation. Brain Stimul 2021; 14:598-606. [PMID: 33774207 PMCID: PMC8164992 DOI: 10.1016/j.brs.2021.03.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 03/09/2021] [Accepted: 03/09/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Focused ultrasound (FUS) has excellent characteristics over other non-invasive stimulation methods in terms of spatial resolution and steering capability of the target. FUS has not been tested in the cerebellar cortex and cellular effects of FUS are not fully understood. OBJECTIVE/HYPOTHESIS To investigate how the activity of cerebellar Purkinje cells (PCs) is modulated by FUS with varying pulse durations and pulse repetition frequencies. METHODS A glass microelectrode was inserted into the cerebellar vermis lobule 6 from the dorsal side to extracellularly record single unit activity of the PCs in anesthetized rats. Ultrasonic stimulation (500 kHz) was applied through a coupling cone, filled with degassed water, from the posterior side to target the recording area with varying pulse durations and frequencies. RESULTS Simple spike (SS) activity of PCs was entrained by the FUS pattern where the probability of spike occurrences peaked at around 1 ms following the onset of the stimulus regardless of its duration (0.5, 1, or 2 ms). The level of entrainment was stronger with shorter pulse durations at 50-Hz pulse repetition frequency (PRF), however, peri-event histograms spread wider and the peaks delayed slightly at 100-Hz PRF, suggesting involvement of a long-lasting inhibitory mechanism. There was no significant difference between the average firing rates in the baseline and stimulation periods. CONCLUSION FUS can entrain spiking activity of single cells on a spike-by-spike basis as demonstrated here in the rat cerebellar cortex. The observed modulation potentially results from the aggregate of excitatory and inhibitory effects of FUS on the entire cortical network rather than on the PCs alone.
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Affiliation(s)
- Ahmet S Asan
- Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ, USA
| | - Qi Kang
- Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ, USA
| | - Ömer Oralkan
- Department of Electrical and Computer Engineering, NC State University, Raleigh, NC, USA
| | - Mesut Sahin
- Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ, USA.
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