1
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Stanis N, Khateeb K, Zhou J, Wang RK, Yazdan-Shahmorad A. Protocol to study ischemic stroke by photothrombotic lesioning in the cortex of non-human primates. STAR Protoc 2023; 4:102496. [PMID: 37573501 PMCID: PMC10448414 DOI: 10.1016/j.xpro.2023.102496] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/16/2023] [Accepted: 07/18/2023] [Indexed: 08/15/2023] Open
Abstract
Neurorehabilitation strategies for ischemic stroke have shown promise for functional recovery, yet minimal tools are available to study rehabilitation techniques in non-human primates (NHPs). Here, we present a protocol to study rehabilitation techniques in NHPs using a photothrombotic technique, a form of optical focal lesioning. We also describe steps for simultaneous neurophysiological recording and in vivo validation through vascular flow imaging. This interface can examine emerging neurorehabilitation strategies in the post-stroke environment in NHPs that are evolutionarily close to humans. For complete details on the use and execution of this protocol, please refer to Khateeb et al. (2022).6.
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Affiliation(s)
- Noah Stanis
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA; Washington National Primate Research Center, Seattle, WA 98195, USA
| | - Karam Khateeb
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA; Washington National Primate Research Center, Seattle, WA 98195, USA
| | - Jasmine Zhou
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA; Washington National Primate Research Center, Seattle, WA 98195, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA; Department of Ophthalmology, University of Washington Medicine, Seattle, WA 98195, USA
| | - Azadeh Yazdan-Shahmorad
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA; Washington National Primate Research Center, Seattle, WA 98195, USA; Department of Electrical and Computer Engineering, University of Washington, Seattle, WA 98195, USA.
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2
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Sato Y, Schmitt O, Ip Z, Rabiller G, Omodaka S, Tominaga T, Yazdan-Shahmorad A, Liu J. Pathological changes of brain oscillations following ischemic stroke. J Cereb Blood Flow Metab 2022; 42:1753-1776. [PMID: 35754347 PMCID: PMC9536122 DOI: 10.1177/0271678x221105677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 04/01/2022] [Accepted: 05/17/2022] [Indexed: 11/16/2022]
Abstract
Brain oscillations recorded in the extracellular space are among the most important aspects of neurophysiology data reflecting the activity and function of neurons in a population or a network. The signal strength and patterns of brain oscillations can be powerful biomarkers used for disease detection and prediction of the recovery of function. Electrophysiological signals can also serve as an index for many cutting-edge technologies aiming to interface between the nervous system and neuroprosthetic devices and to monitor the efficacy of boosting neural activity. In this review, we provided an overview of the basic knowledge regarding local field potential, electro- or magneto- encephalography signals, and their biological relevance, followed by a summary of the findings reported in various clinical and experimental stroke studies. We reviewed evidence of stroke-induced changes in hippocampal oscillations and disruption of communication between brain networks as potential mechanisms underlying post-stroke cognitive dysfunction. We also discussed the promise of brain stimulation in promoting post stroke functional recovery via restoring neural activity and enhancing brain plasticity.
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Affiliation(s)
- Yoshimichi Sato
- Department of Neurological Surgery, UCSF, San Francisco, CA, USA
- Department of Neurological Surgery, SFVAMC, San Francisco, CA, USA
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Oliver Schmitt
- Department of Anatomy, Medical School Hamburg, University of Applied Sciences and Medical University, Hamburg, Germany
| | - Zachary Ip
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA, USA
| | - Gratianne Rabiller
- Department of Neurological Surgery, UCSF, San Francisco, CA, USA
- Department of Neurological Surgery, SFVAMC, San Francisco, CA, USA
| | - Shunsuke Omodaka
- Department of Neurological Surgery, UCSF, San Francisco, CA, USA
- Department of Neurological Surgery, SFVAMC, San Francisco, CA, USA
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Teiji Tominaga
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Azadeh Yazdan-Shahmorad
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA, USA
| | - Jialing Liu
- Department of Neurological Surgery, UCSF, San Francisco, CA, USA
- Department of Neurological Surgery, SFVAMC, San Francisco, CA, USA
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3
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Moorjani S, Walvekar S, Fetz EE, Perlmutter SI. Movement-dependent electrical stimulation for volitional strengthening of cortical connections in behaving monkeys. Proc Natl Acad Sci U S A 2022; 119:e2116321119. [PMID: 35759657 PMCID: PMC9271159 DOI: 10.1073/pnas.2116321119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 04/29/2022] [Indexed: 12/30/2022] Open
Abstract
Correlated activity of neurons can lead to long-term strengthening or weakening of the connections between them. In addition, the behavioral context, imparted by execution of physical movements or the presence of a reward, can modulate the plasticity induced by Hebbian mechanisms. In the present study, we have combined behavior and induced neuronal correlations to strengthen connections in the motor cortex of adult behaving monkeys. Correlated activity was induced using an electrical-conditioning protocol in which stimuli gated by voluntary movements were used to produce coactivation of neurons at motor-cortical sites involved in those movements. Delivery of movement-dependent stimulation resulted in small increases in the strength of associated cortical connections immediately after conditioning. Remarkably, when paired with further repetition of the movements that gated the conditioning stimuli, there were substantially larger gains in the strength of cortical connections, which occurred in a use-dependent manner, without delivery of additional conditioning stimulation. In the absence of such movements, little change was observed in the strength of motor-cortical connections. Performance of the motor behavior in the absence of conditioning also did not produce any changes in connectivity. Our results show that combining movement-gated stimulation with further natural use of the "conditioned" pathways after stimulation ends can produce use-dependent strengthening of connections in adult primates, highlighting an important role for behavior in cortical plasticity. Our data also provide strong support for combining movement-gated stimulation with use-dependent physical rehabilitation for strengthening connections weakened by a stroke or spinal cord injury.
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Affiliation(s)
- Samira Moorjani
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
- Washington National Primate Research Center, University of Washington, Seattle, WA 98195
- Center for Neurotechnology, University of Washington, Seattle, WA 98195
| | - Sarita Walvekar
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
- Washington National Primate Research Center, University of Washington, Seattle, WA 98195
| | - Eberhard E Fetz
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
- Washington National Primate Research Center, University of Washington, Seattle, WA 98195
- Center for Neurotechnology, University of Washington, Seattle, WA 98195
| | - Steve I Perlmutter
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
- Washington National Primate Research Center, University of Washington, Seattle, WA 98195
- Center for Neurotechnology, University of Washington, Seattle, WA 98195
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4
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Yun R, Bogaard AR, Richardson AG, Zanos S, Perlmutter SI, Fetz EE. Cortical Stimulation Paired With Volitional Unimanual Movement Affects Interhemispheric Communication. Front Neurosci 2021; 15:782188. [PMID: 35002605 PMCID: PMC8739774 DOI: 10.3389/fnins.2021.782188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 12/07/2021] [Indexed: 11/30/2022] Open
Abstract
Cortical stimulation (CS) of the motor cortex can cause excitability changes in both hemispheres, showing potential to be a technique for clinical rehabilitation of motor function. However, previous studies that have investigated the effects of delivering CS during movement typically focus on a single hemisphere. On the other hand, studies exploring interhemispheric interactions typically deliver CS at rest. We sought to bridge these two approaches by documenting the consequences of delivering CS to a single motor cortex during different phases of contralateral and ipsilateral limb movement, and simultaneously assessing changes in interactions within and between the hemispheres via local field potential (LFP) recordings. Three macaques were trained in a unimanual reaction time (RT) task and implanted with epidural or intracortical electrodes over bilateral motor cortices. During a given session CS was delivered to one hemisphere with respect to movements of either the contralateral or ipsilateral limb. Stimulation delivered before contralateral limb movement onset shortened the contralateral limb RT. In contrast, stimulation delivered after the end of contralateral movement increased contralateral RT but decreased ipsilateral RT. Stimulation delivered before ipsilateral limb movement decreased ipsilateral RT. All other stimulus conditions as well as random stimulation and periodic stimulation did not have consistently significant effects on either limb. Simultaneous LFP recordings from one animal revealed correlations between changes in interhemispheric alpha band coherence and changes in RT, suggesting that alpha activity may be indicative of interhemispheric communication. These results show that changes caused by CS to the functional coupling within and between precentral cortices is contingent on the timing of CS relative to movement.
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Affiliation(s)
- Richy Yun
- Department of Bioengineering, University of Washington, Seattle, WA, United States
- Washington National Primate Research Center, University of Washington, Seattle, WA, United States
| | - Andrew R. Bogaard
- Washington National Primate Research Center, University of Washington, Seattle, WA, United States
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, United States
| | - Andrew G. Richardson
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, United States
| | - Stavros Zanos
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, New York, NY, United States
| | - Steve I. Perlmutter
- Washington National Primate Research Center, University of Washington, Seattle, WA, United States
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, United States
| | - Eberhard E. Fetz
- Department of Bioengineering, University of Washington, Seattle, WA, United States
- Washington National Primate Research Center, University of Washington, Seattle, WA, United States
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, United States
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5
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Shupe LE, Miles FP, Jones G, Yun R, Mishler J, Rembado I, Murphy RL, Perlmutter SI, Fetz EE. Neurochip3: An Autonomous Multichannel Bidirectional Brain-Computer Interface for Closed-Loop Activity-Dependent Stimulation. Front Neurosci 2021; 15:718465. [PMID: 34489634 PMCID: PMC8417105 DOI: 10.3389/fnins.2021.718465] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022] Open
Abstract
Toward addressing many neuroprosthetic applications, the Neurochip3 (NC3) is a multichannel bidirectional brain-computer interface that operates autonomously and can support closed-loop activity-dependent stimulation. It consists of four circuit boards populated with off-the-shelf components and is sufficiently compact to be carried on the head of a non-human primate (NHP). NC3 has six main components: (1) an analog front-end with an Intan biophysical signal amplifier (16 differential or 32 single-ended channels) and a 3-axis accelerometer, (2) a digital control system comprised of a Cyclone V FPGA and Atmel SAM4 MCU, (3) a micro SD Card for 128 GB or more storage, (4) a 6-channel differential stimulator with ±60 V compliance, (5) a rechargeable battery pack supporting autonomous operation for up to 24 h and, (6) infrared transceiver and serial ports for communication. The NC3 and earlier versions have been successfully deployed in many closed-loop operations to induce synaptic plasticity and bridge lost biological connections, as well as deliver activity-dependent intracranial reinforcement. These paradigms to strengthen or replace impaired connections have many applications in neuroprosthetics and neurorehabilitation.
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Affiliation(s)
- Larry E Shupe
- Department of Physiology & Biophysics, University of Washington, Seattle, WA, United States.,Washington National Primate Research Center, University of Washington, Seattle, WA, United States
| | - Frank P Miles
- Washington National Primate Research Center, University of Washington, Seattle, WA, United States
| | - Geoff Jones
- Independent Researcher, Seattle, CA, United States
| | - Richy Yun
- Department of Bioengineering, University of Washington, Seattle, WA, United States
| | - Jonathan Mishler
- Department of Bioengineering, University of Washington, Seattle, WA, United States
| | - Irene Rembado
- Department of Physiology & Biophysics, University of Washington, Seattle, WA, United States
| | - R Logan Murphy
- Department of Physiology & Biophysics, University of Washington, Seattle, WA, United States
| | - Steve I Perlmutter
- Department of Physiology & Biophysics, University of Washington, Seattle, WA, United States.,Washington National Primate Research Center, University of Washington, Seattle, WA, United States
| | - Eberhard E Fetz
- Department of Physiology & Biophysics, University of Washington, Seattle, WA, United States.,Washington National Primate Research Center, University of Washington, Seattle, WA, United States.,Department of Bioengineering, University of Washington, Seattle, WA, United States
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6
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An Integrate-and-Fire Spiking Neural Network Model Simulating Artificially Induced Cortical Plasticity. eNeuro 2021; 8:ENEURO.0333-20.2021. [PMID: 33632810 PMCID: PMC7986529 DOI: 10.1523/eneuro.0333-20.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 02/10/2021] [Accepted: 02/16/2021] [Indexed: 11/21/2022] Open
Abstract
We describe an integrate-and-fire (IF) spiking neural network that incorporates spike-timing-dependent plasticity (STDP) and simulates the experimental outcomes of four different conditioning protocols that produce cortical plasticity. The original conditioning experiments were performed in freely moving non-human primates (NHPs) with an autonomous head-fixed bidirectional brain-computer interface (BCI). Three protocols involved closed-loop stimulation triggered from (1) spike activity of single cortical neurons, (2) electromyographic (EMG) activity from forearm muscles, and (3) cycles of spontaneous cortical beta activity. A fourth protocol involved open-loop delivery of pairs of stimuli at neighboring cortical sites. The IF network that replicates the experimental results consists of 360 units with simulated membrane potentials produced by synaptic inputs and triggering a spike when reaching threshold. The 240 cortical units produce either excitatory or inhibitory postsynaptic potentials (PSPs) in their target units. In addition to the experimentally observed conditioning effects, the model also allows computation of underlying network behavior not originally documented. Furthermore, the model makes predictions about outcomes from protocols not yet investigated, including spike-triggered inhibition, γ-triggered stimulation and disynaptic conditioning. The success of the simulations suggests that a simple voltage-based IF model incorporating STDP can capture the essential mechanisms mediating targeted plasticity with closed-loop stimulation.
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7
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Cheng N, Phua KS, Lai HS, Tam PK, Tang KY, Cheng KK, Yeow RCH, Ang KK, Guan C, Lim JH. Brain-Computer Interface-Based Soft Robotic Glove Rehabilitation for Stroke. IEEE Trans Biomed Eng 2020; 67:3339-3351. [DOI: 10.1109/tbme.2020.2984003] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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8
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Ojemann WKS, Griggs DJ, Ip Z, Caballero O, Jahanian H, Martinez-Conde S, Macknik S, Yazdan-Shahmorad A. A MRI-Based Toolbox for Neurosurgical Planning in Nonhuman Primates. J Vis Exp 2020:10.3791/61098. [PMID: 32744531 PMCID: PMC8384434 DOI: 10.3791/61098] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In this paper, we outline a method for surgical preparation that allows for the practical planning of a variety of neurosurgeries in NHPs solely using data extracted from magnetic resonance imaging (MRI). This protocol allows for the generation of 3D printed anatomically accurate physical models of the brain and skull, as well as an agarose gel model of the brain modeling some of the mechanical properties of the brain. These models can be extracted from MRI using brain extraction software for the model of the brain, and custom code for the model of the skull. The preparation protocol takes advantage of state-of-the-art 3D printing technology to make interfacing brains, skulls, and molds for gel brain models. The skull and brain models can be used to visualize brain tissue inside the skull with the addition of a craniotomy in the custom code, allowing for better preparation for surgeries directly involving the brain. The applications of these methods are designed for surgeries involved in neurological stimulation and recording as well as injection, but the versatility of the system allows for future expansion of the protocol, extraction techniques, and models to a wider scope of surgeries.
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Affiliation(s)
- William K S Ojemann
- Bioengineering Department, University of Washington; Washington National Primate Research Center, University of Washington
| | - Devon J Griggs
- Washington National Primate Research Center, University of Washington; Electrical and Computer Engineering Department, University of Washington
| | - Zachary Ip
- Bioengineering Department, University of Washington; Washington National Primate Research Center, University of Washington
| | - Olivya Caballero
- Department of Ophthalmology, SUNY Downstate Health Sciences University
| | | | | | - Stephen Macknik
- Department of Ophthalmology, SUNY Downstate Health Sciences University
| | - Azadeh Yazdan-Shahmorad
- Bioengineering Department, University of Washington; Washington National Primate Research Center, University of Washington; Electrical and Computer Engineering Department, University of Washington;
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9
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Foysal KMR, Baker SN. Induction of plasticity in the human motor system by motor imagery and transcranial magnetic stimulation. J Physiol 2020; 598:2385-2396. [PMID: 32266976 DOI: 10.1113/jp279794] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 04/02/2020] [Indexed: 12/28/2022] Open
Abstract
KEY POINTS Delivering transcranial magnetic brain stimulation over the motor cortex during motor imagination leads to enhanced motor output, which is selective for the muscles primarily involved in the imagined movement. This novel protocol may be useful to enhance function after damage to the motor system, such as after stroke. ABSTRACT Several paired stimulation paradigms are known to induce plasticity in the motor cortex, reflected by changes in the motor evoked potential (MEP) following the paired stimulation. Motor imagery (MI) is capable of activating the motor system and affecting cortical excitability. We hypothesized that it might be possible to use MI in conjunction with transcranial magnetic stimulation (TMS) to induce plasticity in the human motor system. TMS was delivered to the motor cortex of healthy human subjects, and baseline MEPs recorded from forearm flexor, forearm extensor and intrinsic hand muscles. Subjects were then asked to imagine either wrist flexion or extension movements during TMS delivery (n = 90 trials). Immediately after this intervention, MEP measurement was repeated. Control protocols tested the impact of imagination or TMS alone. Flexion imagination with TMS increased MEPs in flexors and an intrinsic hand muscle. Extensor imagination with TMS increased MEPs in extensor muscles only. The control paradigms did not produce significant changes. We conclude that delivering TMS during MI is capable of inducing plastic changes in the motor system. This new protocol may find utility to enhance functional rehabilitation after brain injury.
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Affiliation(s)
- K M Riashad Foysal
- Institute of Neurosciences, Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Stuart N Baker
- Institute of Neurosciences, Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
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10
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Bloch JA, Khateeb K, Silversmith DB, O'Doherty JE, Sabes PN, Yazdan-Shahmorad A. Cortical Stimulation Induces Network-Wide Coherence Change In Non-Human Primate Somatosensory Cortex .. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:6446-6449. [PMID: 31947318 DOI: 10.1109/embc.2019.8856633] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Stimulation of the cortex can modulate the connectivity between brain regions. Although targeted neuroplasticity has been demonstrated in-vitro, in-vivo models have been inconsistent in their response to stimulation. In this paper, we tested various stimulation protocols to characterize the effect of stimulation on coherence in the non-human primate cortex in-vivo. We found that the stimulation latency, the state of the cortex during stimulation, and the stimulation site all affected the modulation of cortical coherence. We further investigated features of a resting-state network that could predict how a connection is likely to change with stimulation.
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11
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Ohashi H, Gribble PL, Ostry DJ. Somatosensory cortical excitability changes precede those in motor cortex during human motor learning. J Neurophysiol 2019; 122:1397-1405. [PMID: 31390294 DOI: 10.1152/jn.00383.2019] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Motor learning is associated with plasticity in both motor and somatosensory cortex. It is known from animal studies that tetanic stimulation to each of these areas individually induces long-term potentiation in its counterpart. In this context it is possible that changes in motor cortex contribute to somatosensory change and that changes in somatosensory cortex are involved in changes in motor areas of the brain. It is also possible that learning-related plasticity occurs in these areas independently. To better understand the relative contribution to human motor learning of motor cortical and somatosensory plasticity, we assessed the time course of changes in primary somatosensory and motor cortex excitability during motor skill learning. Learning was assessed using a force production task in which a target force profile varied from one trial to the next. The excitability of primary somatosensory cortex was measured using somatosensory evoked potentials in response to median nerve stimulation. The excitability of primary motor cortex was measured using motor evoked potentials elicited by single-pulse transcranial magnetic stimulation. These two measures were interleaved with blocks of motor learning trials. We found that the earliest changes in cortical excitability during learning occurred in somatosensory cortical responses, and these changes preceded changes in motor cortical excitability. Changes in somatosensory evoked potentials were correlated with behavioral measures of learning. Changes in motor evoked potentials were not. These findings indicate that plasticity in somatosensory cortex occurs as a part of the earliest stages of motor learning, before changes in motor cortex are observed.NEW & NOTEWORTHY We tracked somatosensory and motor cortical excitability during motor skill acquisition. Changes in both motor cortical and somatosensory excitability were observed during learning; however, the earliest changes were in somatosensory cortex, not motor cortex. Moreover, the earliest changes in somatosensory cortical excitability predict the extent of subsequent learning; those in motor cortex do not. This is consistent with the idea that plasticity in somatosensory cortex coincides with the earliest stages of human motor learning.
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Affiliation(s)
- Hiroki Ohashi
- Haskins Laboratories, New Haven, Connecticut.,Department of Psychology, McGill University, Montreal, Quebec, Canada
| | - Paul L Gribble
- Haskins Laboratories, New Haven, Connecticut.,The Brain and Mind Institute, Western University, London, Ontario, Canada.,Department of Psychology, Western University, London, Ontario, Canada.,Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
| | - David J Ostry
- Haskins Laboratories, New Haven, Connecticut.,Department of Psychology, McGill University, Montreal, Quebec, Canada
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12
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López-Larraz E, Sarasola-Sanz A, Irastorza-Landa N, Birbaumer N, Ramos-Murguialday A. Brain-machine interfaces for rehabilitation in stroke: A review. NeuroRehabilitation 2018; 43:77-97. [PMID: 30056435 DOI: 10.3233/nre-172394] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Motor paralysis after stroke has devastating consequences for the patients, families and caregivers. Although therapies have improved in the recent years, traditional rehabilitation still fails in patients with severe paralysis. Brain-machine interfaces (BMI) have emerged as a promising tool to guide motor rehabilitation interventions as they can be applied to patients with no residual movement. OBJECTIVE This paper reviews the efficiency of BMI technologies to facilitate neuroplasticity and motor recovery after stroke. METHODS We provide an overview of the existing rehabilitation therapies for stroke, the rationale behind the use of BMIs for motor rehabilitation, the current state of the art and the results achieved so far with BMI-based interventions, as well as the future perspectives of neural-machine interfaces. RESULTS Since the first pilot study by Buch and colleagues in 2008, several controlled clinical studies have been conducted, demonstrating the efficacy of BMIs to facilitate functional recovery in completely paralyzed stroke patients with noninvasive technologies such as the electroencephalogram (EEG). CONCLUSIONS Despite encouraging results, motor rehabilitation based on BMIs is still in a preliminary stage, and further improvements are required to boost its efficacy. Invasive and hybrid approaches are promising and might set the stage for the next generation of stroke rehabilitation therapies.
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Affiliation(s)
- E López-Larraz
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - A Sarasola-Sanz
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.,International Max Planck Research School (IMPRS) for Cognitive and Systems Neuroscience, University of Tübingen, Tübingen, Germany.,Neurotechnology, Tecnalia Research & Innovation, San Sebastián, Spain
| | - N Irastorza-Landa
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.,International Max Planck Research School (IMPRS) for Cognitive and Systems Neuroscience, University of Tübingen, Tübingen, Germany.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - N Birbaumer
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.,Wyss Center for Bio and Neuro Engineering, Geneva, Switzerland
| | - A Ramos-Murguialday
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.,Neurotechnology, Tecnalia Research & Innovation, San Sebastián, Spain
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13
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Yazdan-Shahmorad A, Silversmith DB, Kharazia V, Sabes PN. Targeted cortical reorganization using optogenetics in non-human primates. eLife 2018; 7:31034. [PMID: 29809133 PMCID: PMC5986269 DOI: 10.7554/elife.31034] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Accepted: 05/05/2018] [Indexed: 12/20/2022] Open
Abstract
Brain stimulation modulates the excitability of neural circuits and drives neuroplasticity. While the local effects of stimulation have been an active area of investigation, the effects on large-scale networks remain largely unexplored. We studied stimulation-induced changes in network dynamics in two macaques. A large-scale optogenetic interface enabled simultaneous stimulation of excitatory neurons and electrocorticographic recording across primary somatosensory (S1) and motor (M1) cortex (Yazdan-Shahmorad et al., 2016). We tracked two measures of network connectivity, the network response to focal stimulation and the baseline coherence between pairs of electrodes; these were strongly correlated before stimulation. Within minutes, stimulation in S1 or M1 significantly strengthened the gross functional connectivity between these areas. At a finer scale, stimulation led to heterogeneous connectivity changes across the network. These changes reflected the correlations introduced by stimulation-evoked activity, consistent with Hebbian plasticity models. This work extends Hebbian plasticity models to large-scale circuits, with significant implications for stimulation-based neurorehabilitation. From riding a bike to reaching for a cup of coffee, all skilled actions rely on precise connections between the sensory and motor areas of the brain. While sensory areas receive and analyse input from the senses, motor areas plan and trigger muscle contractions. Precisely adjusting the connections between these and other areas enables us to learn new skills, and it also helps us to relearn skills lost as a result of brain injury or stroke. About 70 years ago, a psychologist named Donald Hebb came up with an idea for how this process might occur. He proposed that whenever two neurons are active at the same time, the connection between them becomes stronger. This idea, that ‘cells that fire together, wire together’, became known as Hebb’s rule. Many studies have since shown that Hebb’s rule can explain changes in the strength of connections between pairs of neurons. But can it also explain how connections between entire brain regions become stronger or weaker? New results show that it can. The data were obtained using a technique called optogenetics, in which viruses are used to introduce genes for light-sensitive proteins into neurons. Shining light onto the brain will then activate any cells within that area that contain the resulting proteins. Yazdan-Shahmorad, Silversmith et al. used this technique to activate small regions of either sensory or motor brain tissue in live macaque monkeys. Doing so strengthened the overall connectivity between the two areas. The effects were more variable at the level of smaller brain regions, with some connections becoming weaker rather than stronger. However, Yazdan-Shahmorad, Silversmith et al. show that Hebb’s rule explains most of the observed changes. Many neurological and psychiatric disorders stem from abnormal brain connectivity. Simple forms of brain stimulation are already used to treat certain neurological disorders, such as Parkinson’s disease. Stimulating the brain to induce specific changes in connectivity may ultimately enable us to leverage the brain’s natural learning mechanisms to cure, instead of just treat, these conditions.
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Affiliation(s)
- Azadeh Yazdan-Shahmorad
- Department of Physiology, University of California, San Francisco, San Francisco, United States.,Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, United States.,Departments of Bioengineering and Electrical Engineering, University of Washington, Seattle, United States
| | - Daniel B Silversmith
- Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, United States.,UC Berkeley - UCSF Graduate Program in Bioengineering, University of California, San Francisco, San Francisco, United States
| | - Viktor Kharazia
- Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Philip N Sabes
- Department of Physiology, University of California, San Francisco, San Francisco, United States.,Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, United States.,UC Berkeley - UCSF Graduate Program in Bioengineering, University of California, San Francisco, San Francisco, United States
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Developmental abnormality contributes to cortex-dependent motor impairments and higher intracortical current requirement in the reeler homozygous mutants. Brain Struct Funct 2018. [PMID: 29536172 DOI: 10.1007/s00429-018-1647-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The motor deficit of the reeler mutants has largely been considered cerebellum related, and the developmental consequences of the cortex on reeler motor behavior have not been examined. We herein showed that there is a behavioral consequence to reeler mutation in models examined at cortex-dependent bimanual tasks that require forepaw dexterity. Using intracortical microstimulation, we found the forelimb representation in the motor cortex was significantly reduced in the reeler. The reeler cortex required a significantly higher current to evoke skeletal muscle movements, suggesting the cortical trans-synaptic propagation is disrupted. When the higher current was applied, the reeler motor representation was found preserved. To elucidate the influence of cerebellum atrophy and ataxia on the obtained results, the behavioral and neurophysiological findings in reeler mice were reproduced using the Disabled-1 (Dab1) cKO mice, in which the Reelin-Dab1 signal deficiency is confined to the cerebral cortex. The Dab1 cKO mice were further assessed at the single-pellet reach and retrieval task, displaying a lower number of successfully retrieved pellets. It suggests the abnormality confined to the cortex still reduced the dexterous motor performance. Although possible muscular dysfunction was reported in REELIN-deficient humans, the function of the reeler forelimb muscle examined by electromyography, morphology of neuromuscular junction and the expression level of choline acetyltransferase were normal. Our results suggest that the mammalian laminar structure is necessary for the forepaw skill performance and for trans-synaptic efficacy in the cortical output.
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Recruitment of Additional Corticospinal Pathways in the Human Brain with State-Dependent Paired Associative Stimulation. J Neurosci 2018; 38:1396-1407. [PMID: 29335359 DOI: 10.1523/jneurosci.2893-17.2017] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 11/20/2017] [Accepted: 12/18/2017] [Indexed: 01/14/2023] Open
Abstract
Standard brain stimulation protocols modify human motor cortex excitability by modulating the gain of the activated corticospinal pathways. However, the restoration of motor function following lesions of the corticospinal tract requires also the recruitment of additional neurons to increase the net corticospinal output. For this purpose, we investigated a novel protocol based on brain state-dependent paired associative stimulation.Motor imagery (MI)-related electroencephalography was recorded in healthy males and females for brain state-dependent control of both cortical and peripheral stimulation in a brain-machine interface environment. State-dependency was investigated with concurrent, delayed, and independent stimulation relative to the MI task. Specifically, sensorimotor event-related desynchronization (ERD) in the β-band (16-22 Hz) triggered peripheral stimulation through passive hand opening by a robotic orthosis and transcranial magnetic stimulation to the respective cortical motor representation, either synchronously or subsequently. These MI-related paradigms were compared with paired cortical and peripheral input applied independent of the brain state. Cortical stimulation resulted in a significant increase in corticospinal excitability only when applied brain state-dependently and synchronously to peripheral input. These gains were resistant to a depotentiation task, revealed a nonlinear evolution of plasticity, and were mediated via the recruitment of additional corticospinal neurons rather than via synchronization of neuronal firing. Recruitment of additional corticospinal pathways may be achieved when cortical and peripheral inputs are applied concurrently, and during β-ERD. These findings resemble a gating mechanism and are potentially important for developing closed-loop brain stimulation for the treatment of hand paralysis following lesions of the corticospinal tract.SIGNIFICANCE STATEMENT The activity state of the motor system influences the excitability of corticospinal pathways to external input. State-dependent interventions harness this property to increase the connectivity between motor cortex and muscles. These stimulation protocols modulate the gain of the activated pathways, but not the overall corticospinal recruitment. In this study, a brain-machine interface paired peripheral stimulation through passive hand opening with transcranial magnetic stimulation to the respective cortical motor representation during volitional β-band desynchronization. Cortical stimulation resulted in the recruitment of additional corticospinal pathways, but only when applied brain state-dependently and synchronously to peripheral input. These effects resemble a gating mechanism and may be important for the restoration of motor function following lesions of the corticospinal tract.
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Lebedev MA, Nicolelis MAL. Brain-Machine Interfaces: From Basic Science to Neuroprostheses and Neurorehabilitation. Physiol Rev 2017; 97:767-837. [PMID: 28275048 DOI: 10.1152/physrev.00027.2016] [Citation(s) in RCA: 235] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Brain-machine interfaces (BMIs) combine methods, approaches, and concepts derived from neurophysiology, computer science, and engineering in an effort to establish real-time bidirectional links between living brains and artificial actuators. Although theoretical propositions and some proof of concept experiments on directly linking the brains with machines date back to the early 1960s, BMI research only took off in earnest at the end of the 1990s, when this approach became intimately linked to new neurophysiological methods for sampling large-scale brain activity. The classic goals of BMIs are 1) to unveil and utilize principles of operation and plastic properties of the distributed and dynamic circuits of the brain and 2) to create new therapies to restore mobility and sensations to severely disabled patients. Over the past decade, a wide range of BMI applications have emerged, which considerably expanded these original goals. BMI studies have shown neural control over the movements of robotic and virtual actuators that enact both upper and lower limb functions. Furthermore, BMIs have also incorporated ways to deliver sensory feedback, generated from external actuators, back to the brain. BMI research has been at the forefront of many neurophysiological discoveries, including the demonstration that, through continuous use, artificial tools can be assimilated by the primate brain's body schema. Work on BMIs has also led to the introduction of novel neurorehabilitation strategies. As a result of these efforts, long-term continuous BMI use has been recently implicated with the induction of partial neurological recovery in spinal cord injury patients.
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Lajoie G, Krouchev NI, Kalaska JF, Fairhall AL, Fetz EE. Correlation-based model of artificially induced plasticity in motor cortex by a bidirectional brain-computer interface. PLoS Comput Biol 2017; 13:e1005343. [PMID: 28151957 PMCID: PMC5313237 DOI: 10.1371/journal.pcbi.1005343] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 02/16/2017] [Accepted: 01/03/2017] [Indexed: 12/19/2022] Open
Abstract
Experiments show that spike-triggered stimulation performed with Bidirectional Brain-Computer-Interfaces (BBCI) can artificially strengthen connections between separate neural sites in motor cortex (MC). When spikes from a neuron recorded at one MC site trigger stimuli at a second target site after a fixed delay, the connections between sites eventually strengthen. It was also found that effective spike-stimulus delays are consistent with experimentally derived spike-timing-dependent plasticity (STDP) rules, suggesting that STDP is key to drive these changes. However, the impact of STDP at the level of circuits, and the mechanisms governing its modification with neural implants remain poorly understood. The present work describes a recurrent neural network model with probabilistic spiking mechanisms and plastic synapses capable of capturing both neural and synaptic activity statistics relevant to BBCI conditioning protocols. Our model successfully reproduces key experimental results, both established and new, and offers mechanistic insights into spike-triggered conditioning. Using analytical calculations and numerical simulations, we derive optimal operational regimes for BBCIs, and formulate predictions concerning the efficacy of spike-triggered conditioning in different regimes of cortical activity.
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Affiliation(s)
- Guillaume Lajoie
- University of Washington Institute for Neuroengineering, University of Washington, Seattle, WA, USA
| | | | - John F. Kalaska
- Groupe de recherche sur le système nerveux central, Département de neurosciences, Université de Montreal, Montreal, QC, Canada
| | - Adrienne L. Fairhall
- University of Washington Institute for Neuroengineering, University of Washington, Seattle, WA, USA
- Dept. of Physiology and Biophysics, University of Washington, Seattle, WA, USA
- Dept. of Physics, University of Washington, Seattle, WA, USA
| | - Eberhard E. Fetz
- University of Washington Institute for Neuroengineering, University of Washington, Seattle, WA, USA
- Dept. of Physiology and Biophysics, University of Washington, Seattle, WA, USA
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18
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Paired Stimulation for Spike-Timing-Dependent Plasticity in Primate Sensorimotor Cortex. J Neurosci 2017; 37:1935-1949. [PMID: 28093479 DOI: 10.1523/jneurosci.2046-16.2017] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 12/29/2016] [Accepted: 01/07/2017] [Indexed: 11/21/2022] Open
Abstract
Classic in vitro studies have described spike-timing-dependent plasticity (STDP) at a synapse: the connection from neuron A to neuron B is strengthened (or weakened) when A fires before (or after) B within an optimal time window. Accordingly, more recent in vivo works have demonstrated behavioral effects consistent with an STDP mechanism; however, many relied on single-unit recordings. The ability to modify cortical connections becomes useful in the context of injury, when connectivity and associated behavior are compromised. To avoid the need for long-term, stable isolation of single units, one could control timed activation of two cortical sites with paired electrical stimulation. We tested the hypothesis that STDP could be induced via prolonged paired stimulation as quantified by cortical evoked potentials (EPs) in the sensorimotor cortex of awake, behaving monkeys. Paired simulation between two interconnected sites produced robust effects in EPs consistent with STDP, but only at 2/15 tested pairs. The stimulation protocol often produced increases in global network excitability or depression of the conditioned pair. Together, these results suggest that paired stimulation in vivo is a viable method to induce STDP between cortical populations, but that factors beyond activation timing must be considered to produce conditioning effects.SIGNIFICANCE STATEMENT Plasticity of neural connections is important for development, learning, memory, and recovery from injury. Cellular mechanisms underlying spike-timing-dependent plasticity have been studied extensively in vitro Recent in vivo work has demonstrated results consistent with the previously defined cellular mechanisms; however, the output measure in these studies was typically an indirect assessment of plasticity at the neural level. Here, we show direct plasticity in recordings of neuronal populations in awake, behaving nonhuman primates induced by paired electrical stimulation. In contrast to in vitro studies, we found that plastic effects were only produced between specific cortical areas. These findings suggest that similar mechanisms drive plasticity in vitro and in vivo, but that cortical architecture may contribute significantly to site-dependent effects.
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Brown KI, Williams ER, de Carvalho F, Baker SN. Plastic Changes in Human Motor Cortical Output Induced by Random but not Closed-Loop Peripheral Stimulation: the Curse of Causality. Front Hum Neurosci 2016; 10:590. [PMID: 27895572 PMCID: PMC5108789 DOI: 10.3389/fnhum.2016.00590] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 11/04/2016] [Indexed: 11/13/2022] Open
Abstract
Previous work showed that repetitive peripheral nerve stimulation can induce plastic changes in motor cortical output. Triggering electrical stimulation of central structures from natural activity can also generate plasticity. In this study, we tested whether triggering peripheral nerve stimulation from muscle activity would likewise induce changes in motor output. We developed a wearable electronic device capable of recording electromyogram (EMG) and delivering electrical stimulation under closed-loop control. This allowed paired stimuli to be delivered over longer periods than standard laboratory-based protocols. We tested this device in healthy human volunteers. Motor cortical output in relaxed thenar muscles was first assessed via the recruitment curve of responses to contralateral transcranial magnetic stimulation. The wearable device was then configured to record thenar EMG and stimulate the median nerve at the wrist (intensity around motor threshold, rate ~0.66 Hz). Subjects carried out normal daily activities for 4-7 h, before returning to the laboratory for repeated recruitment curve assessment. Four stimulation protocols were tested (9-14 subjects each): No Stim, no stimuli delivered; Activity, stimuli triggered by EMG activity above threshold; Saved, stimuli timed according to a previous Activity session in the same subject; Rest, stimuli given when EMG was silent. As expected, No Stim did not modify the recruitment curve. Activity and Rest conditions produced no significant effects across subjects, although there were changes in some individuals. Saved produced a significant and substantial increase, with average responses 2.14 times larger at 30% stimulator intensity above threshold. We argue that unavoidable delays in the closed loop feedback, due mainly to central and peripheral conduction times, mean that stimuli in the Activity paradigm arrived too late after cortical activation to generate consistent plastic changes. By contrast, stimuli delivered essentially at random during the Saved paradigm may have caused a generalized increase in cortical excitability akin to stochastic resonance, leading to plastic changes in corticospinal output. Our study demonstrates that non-invasive closed loop stimulation may be critically limited by conduction delays and the unavoidable constraint of causality.
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Affiliation(s)
- Kenneth I Brown
- Institute of Neuroscience, Newcastle University Newcastle upon Tyne, UK
| | | | | | - Stuart N Baker
- Institute of Neuroscience, Newcastle University Newcastle upon Tyne, UK
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20
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Chaudhary U, Birbaumer N, Ramos-Murguialday A. Brain-computer interfaces for communication and rehabilitation. Nat Rev Neurol 2016; 12:513-25. [PMID: 27539560 DOI: 10.1038/nrneurol.2016.113] [Citation(s) in RCA: 334] [Impact Index Per Article: 41.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Brain-computer interfaces (BCIs) use brain activity to control external devices, thereby enabling severely disabled patients to interact with the environment. A variety of invasive and noninvasive techniques for controlling BCIs have been explored, most notably EEG, and more recently, near-infrared spectroscopy. Assistive BCIs are designed to enable paralyzed patients to communicate or control external robotic devices, such as prosthetics; rehabilitative BCIs are designed to facilitate recovery of neural function. In this Review, we provide an overview of the development of BCIs and the current technology available before discussing experimental and clinical studies of BCIs. We first consider the use of BCIs for communication in patients who are paralyzed, particularly those with locked-in syndrome or complete locked-in syndrome as a result of amyotrophic lateral sclerosis. We then discuss the use of BCIs for motor rehabilitation after severe stroke and spinal cord injury. We also describe the possible neurophysiological and learning mechanisms that underlie the clinical efficacy of BCIs.
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Affiliation(s)
- Ujwal Chaudhary
- Institute of Medical Psychology and Behavioural Neurobiology, University of Tübingen, Silcherstrasse 5, 72076 Tübingen, Germany
| | - Niels Birbaumer
- Institute of Medical Psychology and Behavioural Neurobiology, University of Tübingen, Silcherstrasse 5, 72076 Tübingen, Germany.,Wyss-Center for Bio- and Neuro-Engineering, Chenin de Mines 9, Ch 1202, Geneva, Switzerland
| | - Ander Ramos-Murguialday
- Institute of Medical Psychology and Behavioural Neurobiology, University of Tübingen, Silcherstrasse 5, 72076 Tübingen, Germany.,TECNALIA, Health Department, Neural Engineering Laboratory, San Sebastian, Paseo Mikeletegi 1, 20009 San Sebastian, Spain
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Chaudhary U, Birbaumer N, Ramos-Murguialday A. Brain-computer interfaces in the completely locked-in state and chronic stroke. PROGRESS IN BRAIN RESEARCH 2016; 228:131-61. [PMID: 27590968 DOI: 10.1016/bs.pbr.2016.04.019] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Brain-computer interfaces (BCIs) use brain activity to control external devices, facilitating paralyzed patients to interact with the environment. In this chapter, we discuss the historical perspective of development of BCIs and the current advances of noninvasive BCIs for communication in patients with amyotrophic lateral sclerosis and for restoration of motor impairment after severe stroke. Distinct techniques have been explored to control a BCI in patient population especially electroencephalography (EEG) and more recently near-infrared spectroscopy (NIRS) because of their noninvasive nature and low cost. Previous studies demonstrated successful communication of patients with locked-in state (LIS) using EEG- and invasive electrocorticography-BCI and intracortical recordings when patients still showed residual eye control, but not with patients with complete LIS (ie, complete paralysis). Recently, a NIRS-BCI and classical conditioning procedure was introduced, allowing communication in patients in the complete locked-in state (CLIS). In severe chronic stroke without residual hand function first results indicate a possible superior motor rehabilitation to available treatment using BCI training. Here we present an overview of the available studies and recent results, which open new doors for communication, in the completely paralyzed and rehabilitation in severely affected stroke patients. We also reflect on and describe possible neuronal and learning mechanisms responsible for BCI control and perspective for future BMI research for communication in CLIS and stroke motor recovery.
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Affiliation(s)
- U Chaudhary
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.
| | - N Birbaumer
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; Wyss-Center for Bio- and Neuro-Engineering, Geneva, Switzerland
| | - A Ramos-Murguialday
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; TECNALIA, San Sebastian, Spain.
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Manca A, Ginatempo F, Cabboi MP, Mercante B, Ortu E, Dragone D, De Natale ER, Dvir Z, Rothwell JC, Deriu F. No evidence of neural adaptations following chronic unilateral isometric training of the intrinsic muscles of the hand: a randomized controlled study. Eur J Appl Physiol 2016; 116:1993-2005. [DOI: 10.1007/s00421-016-3451-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 07/28/2016] [Indexed: 11/27/2022]
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Moritz CT, Ruther P, Goering S, Stett A, Ball T, Burgard W, Chudler EH, Rao RPN. New Perspectives on Neuroengineering and Neurotechnologies: NSF-DFG Workshop Report. IEEE Trans Biomed Eng 2016; 63:1354-67. [PMID: 27008657 DOI: 10.1109/tbme.2016.2543662] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
GOAL To identify and overcome barriers to creating new neurotechnologies capable of restoring both motor and sensory function in individuals with neurological conditions. METHODS This report builds upon the outcomes of a joint workshop between the US National Science Foundation and the German Research Foundation on New Perspectives in Neuroengineering and Neurotechnology convened in Arlington, VA, USA, November 13-14, 2014. RESULTS The participants identified key technological challenges for recording and manipulating neural activity, decoding, and interpreting brain data in the presence of plasticity, and early considerations of ethical and social issues pertinent to the adoption of neurotechnologies. CONCLUSIONS The envisaged progress in neuroengineering requires tightly integrated hardware and signal processing efforts, advances in understanding of physiological adaptations to closed-loop interactions with neural devices, and an open dialog with stakeholders and potential end-users of neurotechnology. SIGNIFICANCE The development of new neurotechnologies (e.g., bidirectional brain-computer interfaces) could significantly improve the quality of life of people living with the effects of brain or spinal cord injury, or other neurodegenerative diseases. Focused efforts aimed at overcoming the remaining barriers at the electrode tissue interface, developing implantable hardware with on-board computation, and refining stimulation methods to precisely activate neural tissue will advance both our understanding of brain function and our ability to treat currently intractable disorders of the nervous system.
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25
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Kato K, Sasada S, Nishimura Y. Flexible adaptation to an artificial recurrent connection from muscle to peripheral nerve in man. J Neurophysiol 2016; 115:978-91. [PMID: 26631144 DOI: 10.1152/jn.00143.2015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 12/01/2015] [Indexed: 11/22/2022] Open
Abstract
Controlling a neuroprosthesis requires learning a novel input-output transformation; however, how subjects incorporate this into limb control remains obscure. To elucidate the underling mechanisms, we investigated the motor adaptation process to a novel artificial recurrent connection (ARC) from a muscle to a peripheral nerve in healthy humans. In this paradigm, the ulnar nerve was electrically stimulated in proportion to the activation of the flexor carpi ulnaris (FCU), which is ulnar-innervated and monosynaptically innervated from Ia afferents of the FCU, defined as the "homonymous muscle," or the palmaris longus (PL), which is not innervated by the ulnar nerve and produces similar movement to the FCU, defined as the "synergist muscle." The ARC boosted the activity of the homonymous muscle and wrist joint movement during a visually guided reaching task. Participants could control muscle activity to utilize the ARC for the volitional control of wrist joint movement and then readapt to the absence of the ARC to either input muscle. Participants reduced homonymous muscle recruitment with practice, regardless of the input muscle. However, the adaptation process in the synergist muscle was dependent on the input muscle. The activity of the synergist muscle decreased when the input was the homonymous muscle, whereas it increased when it was the synergist muscle. This reorganization of the neuromotor map, which was maintained as an aftereffect of the ARC, was observed only when the input was the synergist muscle. These findings demonstrate that the ARC induced reorganization of neuromotor map in a targeted and sustainable manner.
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Affiliation(s)
- Kenji Kato
- Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Japan; Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced studies (SOKENDAI), Hayama, Japan; The Japan Society for the Promotion of Science, Tokyo, Japan; and
| | - Syusaku Sasada
- Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Japan
| | - Yukio Nishimura
- Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Japan; Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced studies (SOKENDAI), Hayama, Japan; Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Tokyo, Japan
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Greenwald E, Masters MR, Thakor NV. Erratum to: Implantable neurotechnologies: bidirectional neural interfaces--applications and VLSI circuit implementations. Med Biol Eng Comput 2016; 54:19-22. [PMID: 26924780 PMCID: PMC4955539 DOI: 10.1007/s11517-016-1452-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Elliot Greenwald
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
| | - Matthew R Masters
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Nitish V Thakor
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
- Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, Singapore, Singapore.
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Greenwald E, Masters MR, Thakor NV. Implantable neurotechnologies: bidirectional neural interfaces--applications and VLSI circuit implementations. Med Biol Eng Comput 2016; 54:1-17. [PMID: 26753776 PMCID: PMC4839984 DOI: 10.1007/s11517-015-1429-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 12/10/2015] [Indexed: 12/20/2022]
Abstract
A bidirectional neural interface is a device that transfers information into and out of the nervous system. This class of devices has potential to improve treatment and therapy in several patient populations. Progress in very large-scale integration has advanced the design of complex integrated circuits. System-on-chip devices are capable of recording neural electrical activity and altering natural activity with electrical stimulation. Often, these devices include wireless powering and telemetry functions. This review presents the state of the art of bidirectional circuits as applied to neuroprosthetic, neurorepair, and neurotherapeutic systems.
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Affiliation(s)
- Elliot Greenwald
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
| | - Matthew R Masters
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Nitish V Thakor
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
- Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, Singapore, Singapore.
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Targeted, activity-dependent spinal stimulation produces long-lasting motor recovery in chronic cervical spinal cord injury. Proc Natl Acad Sci U S A 2015; 112:12193-8. [PMID: 26371306 DOI: 10.1073/pnas.1505383112] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Use-dependent movement therapies can lead to partial recovery of motor function after neurological injury. We attempted to improve recovery by developing a neuroprosthetic intervention that enhances movement therapy by directing spike timing-dependent plasticity in spared motor pathways. Using a recurrent neural-computer interface in rats with a cervical contusion of the spinal cord, we synchronized intraspinal microstimulation below the injury with the arrival of functionally related volitional motor commands signaled by muscle activity in the impaired forelimb. Stimulation was delivered during physical retraining of a forelimb behavior and throughout the day for 3 mo. Rats receiving this targeted, activity-dependent spinal stimulation (TADSS) exhibited markedly enhanced recovery compared with animals receiving targeted but open-loop spinal stimulation and rats receiving physical retraining alone. On a forelimb reach and grasp task, TADSS animals recovered 63% of their preinjury ability, more than two times the performance level achieved by the other therapy groups. Therapeutic gains were maintained for 3 additional wk without stimulation. The results suggest that activity-dependent spinal stimulation can induce neural plasticity that improves behavioral recovery after spinal cord injury.
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Fetz EE. Restoring motor function with bidirectional neural interfaces. PROGRESS IN BRAIN RESEARCH 2015; 218:241-52. [PMID: 25890141 DOI: 10.1016/bs.pbr.2015.01.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Closed-loop brain-computer interfaces have bidirectional connections that allow activity-dependent stimulation of the brain, spinal cord, or muscles. Such bidirectional brain-computer interfaces (BBCI) have three major applications that can be used to restore lost motor function. First, the brain could learn to incorporate a long-term artificial recurrent connection into normal behavior, exploiting the brain's ability to adapt to consistent sensorimotor conditions. The obvious clinical application for restoring motor function is to use an artificial recurrent connection to bridge a lost biological connection. Second, activity-dependent stimulation can generate synaptic plasticity on the cellular level. The corresponding clinical application is to strengthen weakened neural connections, such as occur in stroke. A third application involves delivery of activity-dependent deep brain stimulation at subcortical reward sites, which can operantly reinforce the activity that generates the stimulation. The BBCI paradigm has numerous specific applications, depending on the source of the signals and the stimulated targets.
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Affiliation(s)
- Eberhard E Fetz
- Department of Physiology and Biophysics, Washington National Primate Research Center, University of Washington, Seattle, WA, USA.
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Edwardson MA, Avery DH, Fetz EE. Volitional muscle activity paired with transcranial magnetic stimulation increases corticospinal excitability. Front Neurosci 2015; 8:442. [PMID: 25628525 PMCID: PMC4290610 DOI: 10.3389/fnins.2014.00442] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 12/16/2014] [Indexed: 01/17/2023] Open
Abstract
Studies of activity-dependent stimulation in non-human primates suggest that pairing each instance of volitional muscle activity with immediate intracortical stimulation causes long-term-potentiation-like effects. This technique holds promise for clinical rehabilitation, yet few investigators have tested activity-dependent stimulation in human subjects. In addition, no one has studied activity-dependent stimulation on the cortical representation for two separate target muscles in human subjects. We hypothesized that 40 min of transcranial magnetic stimulation (TMS) triggered from ballistic muscle activity at a mean repetition rate of 1 Hz would cause greater increases in corticospinal excitability than TMS-cued muscle activity, and that these changes would be specific to the muscle of study. Ten healthy human subjects participated in 4 separate sessions in this crossover study: (1) visually cued volitional activation of the abductor pollicis brevis (APB) muscle triggering TMS (APB-Triggered TMS), (2) volitional activation of APB in response to TMS delivered from a recording of the prior APB-Triggered TMS session (TMS-Cued APB), (3) visually cued volitional activation of the extensor digitorum (ED) triggering TMS (ED-Triggered TMS), and (4) volitional activation of ED in response to TMS delivered from a recording of the prior ED-Triggered TMS session (TMS-Cued ED). Contrary to our hypothesis, we discovered evidence of increased corticospinal excitability for all conditions as measured by change in area of the motor evoked potential. We conclude that single TMS pulses paired either before or after muscle activity may increase corticospinal excitability and that further studies are needed to clarify the optimal time window for inducing neural plasticity with activity-dependent stimulation. These findings will inform the design of future activity-dependent stimulation protocols for clinical rehabilitation.
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Affiliation(s)
| | - David H Avery
- Department of Psychiatry and Behavioral Sciences, University of Washington Seattle, WA, USA
| | - Eberhard E Fetz
- Department of Physiology and Biophysics, University of Washington Seattle, WA, USA
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31
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Volitional walking via upper limb muscle-controlled stimulation of the lumbar locomotor center in man. J Neurosci 2014; 34:11131-42. [PMID: 25122909 DOI: 10.1523/jneurosci.4674-13.2014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Gait disturbance in individuals with spinal cord lesion is attributed to the interruption of descending pathways to the spinal locomotor center, whereas neural circuits below and above the lesion maintain their functional capability. An artificial neural connection (ANC), which bridges supraspinal centers and locomotor networks in the lumbar spinal cord beyond the lesion site, may restore the functional impairment. To achieve an ANC that sends descending voluntary commands to the lumbar locomotor center and bypasses the thoracic spinal cord, upper limb muscle activity was converted to magnetic stimuli delivered noninvasively over the lumbar vertebra. Healthy participants were able to initiate and terminate walking-like behavior and to control the step cycle through an ANC controlled by volitional upper limb muscle activity. The walking-like behavior stopped just after the ANC was disconnected from the participants even when the participant continued to swing arms. Furthermore, additional simultaneous peripheral electrical stimulation to the foot via the ANC enhanced this walking-like behavior. Kinematics of the induced behaviors were identical to those observed in voluntary walking. These results demonstrate that the ANC induces volitionally controlled, walking-like behavior of the legs. This paradigm may be able to compensate for the dysfunction of descending pathways by sending commands to the preserved locomotor center at the lumbar spinal cord and may enable individuals with paraplegia to regain volitionally controlled walking.
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Abstract
Brain–computer interface (BCI) has proven to be a useful tool for providing alternative communication and mobility to patients suffering from nervous system injury. BCI has been and will continue to be implemented into rehabilitation practices for more interactive and speedy neurological recovery. The most exciting BCI technology is evolving to provide therapeutic benefits by inducing cortical reorganization via neuronal plasticity. This article presents a state-of-the-art review of BCI technology used after nervous system injuries, specifically: amyotrophic lateral sclerosis, Parkinson’s disease, spinal cord injury, stroke, and disorders of consciousness. Also presented is transcending, innovative research involving new treatment of neurological disorders.
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Affiliation(s)
- Alexis Burns
- Biomedical Engineering Graduate Program, The Ohio State University, Columbus, OH, USA
| | - Hojjat Adeli
- Departments of Biomedical Engineering, Biomedical Informatics, Civil and Environmental Engineering and Geodetic Science, Electrical and Computer Engineering, and Neuroscience, and the Biophysics Graduate Program, The Ohio State University, Columbus, OH, USA
| | - John A. Buford
- Physical Therapy Division, School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, OH, USA
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Energy-optimal electrical-stimulation pulses shaped by the Least-Action Principle. PLoS One 2014; 9:e90480. [PMID: 24625822 PMCID: PMC3953645 DOI: 10.1371/journal.pone.0090480] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 01/30/2014] [Indexed: 12/03/2022] Open
Abstract
Electrical stimulation (ES) devices interact with excitable neural tissue toward eliciting action potentials (AP’s) by specific current patterns. Low-energy ES prevents tissue damage and loss of specificity. Hence to identify optimal stimulation-current waveforms is a relevant problem, whose solution may have significant impact on the related medical (e.g. minimized side-effects) and engineering (e.g. maximized battery-life) efficiency. This has typically been addressed by simulation (of a given excitable-tissue model) and iterative numerical optimization with hard discontinuous constraints - e.g. AP’s are all-or-none phenomena. Such approach is computationally expensive, while the solution is uncertain - e.g. may converge to local-only energy-minima and be model-specific. We exploit the Least-Action Principle (LAP). First, we derive in closed form the general template of the membrane-potential’s temporal trajectory, which minimizes the ES energy integral over time and over any space-clamp ionic current model. From the given model we then obtain the specific energy-efficient current waveform, which is demonstrated to be globally optimal. The solution is model-independent by construction. We illustrate the approach by a broad set of example situations with some of the most popular ionic current models from the literature. The proposed approach may result in the significant improvement of solution efficiency: cumbersome and uncertain iteration is replaced by a single quadrature of a system of ordinary differential equations. The approach is further validated by enabling a general comparison to the conventional simulation and optimization results from the literature, including one of our own, based on finite-horizon optimal control. Applying the LAP also resulted in a number of general ES optimality principles. One such succinct observation is that ES with long pulse durations is much more sensitive to the pulse’s shape whereas a rectangular pulse is most frequently optimal for short pulse durations.
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Chen HI, Attiah M, Baltuch G, Smith DH, Hamilton RH, Lucas TH. Harnessing plasticity for the treatment of neurosurgical disorders: an overview. World Neurosurg 2014; 82:648-59. [PMID: 24518888 DOI: 10.1016/j.wneu.2014.02.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Revised: 11/30/2013] [Accepted: 02/06/2014] [Indexed: 12/11/2022]
Abstract
Plasticity is fundamental to normal central nervous system function and its response to injury. Understanding this adaptive capacity is central to the development of novel surgical approaches to neurologic disease. These innovative interventions offer the promise of maximizing functional recovery for patients by harnessing targeted plasticity. Developing novel therapies will require the unprecedented integration of neuroscience, bioengineering, molecular biology, and physiology. Such synergistic approaches will create therapeutic options for patients previously outside of the scope of neurosurgery, such as those with permanent disability after traumatic brain injury or stroke. In this review, we synthesize the rapidly evolving field of plasticity and explore ways that neurosurgeons may enhance functional recovery in the future. We conclude that understanding plasticity is fundamental to modern neurosurgical education and practice.
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Affiliation(s)
- H Isaac Chen
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
| | - Mark Attiah
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Gordon Baltuch
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Douglas H Smith
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Roy H Hamilton
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Timothy H Lucas
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Mehić E, Xu JM, Caler CJ, Coulson NK, Moritz CT, Mourad PD. Increased anatomical specificity of neuromodulation via modulated focused ultrasound. PLoS One 2014; 9:e86939. [PMID: 24504255 PMCID: PMC3913583 DOI: 10.1371/journal.pone.0086939] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 12/16/2013] [Indexed: 11/19/2022] Open
Abstract
Transcranial ultrasound can alter brain function transiently and nondestructively, offering a new tool to study brain function now and inform future therapies. Previous research on neuromodulation implemented pulsed low-frequency (250–700 kHz) ultrasound with spatial peak temporal average intensities (ISPTA) of 0.1–10 W/cm2. That work used transducers that either insonified relatively large volumes of mouse brain (several mL) with relatively low-frequency ultrasound and produced bilateral motor responses, or relatively small volumes of brain (on the order of 0.06 mL) with relatively high-frequency ultrasound that produced unilateral motor responses. This study seeks to increase anatomical specificity to neuromodulation with modulated focused ultrasound (mFU). Here, ‘modulated’ means modifying a focused 2-MHz carrier signal dynamically with a 500-kHz signal as in vibro-acoustography, thereby creating a low-frequency but small volume (approximately 0.015 mL) source of neuromodulation. Application of transcranial mFU to lightly anesthetized mice produced various motor movements with high spatial selectivity (on the order of 1 mm) that scaled with the temporal average ultrasound intensity. Alone, mFU and focused ultrasound (FUS) each induced motor activity, including unilateral motions, though anatomical location and type of motion varied. Future work should include larger animal models to determine the relative efficacy of mFU versus FUS. Other studies should determine the biophysical processes through which they act. Also of interest is exploration of the potential research and clinical applications for targeted, transcranial neuromodulation created by modulated focused ultrasound, especially mFU’s ability to produce compact sources of ultrasound at the very low frequencies (10–100s of Hertz) that are commensurate with the natural frequencies of the brain.
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Affiliation(s)
- Edin Mehić
- Department of Bioengineering, University of Washington, Seattle, Washington, United States of America
| | - Julia M. Xu
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington, United States of America
| | - Connor J. Caler
- Department of Bioengineering, University of Washington, Seattle, Washington, United States of America
| | - Nathaniel K. Coulson
- Department of Bioengineering, University of Washington, Seattle, Washington, United States of America
| | - Chet T. Moritz
- Department of Rehabilitation Medicine, University of Washington, Seattle, Washington, United States of America
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington, United States of America
| | - Pierre D. Mourad
- Department of Bioengineering, University of Washington, Seattle, Washington, United States of America
- Applied Physics Laboratory, University of Washington, Seattle, Washington, United States of America
- Department of Neurological Surgery, University of Washington, Seattle, Washington, United States of America
- Department of Engineering and Mathematics, University of Washington, Bothell, Washington, United States of America
- * E-mail:
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36
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Nishimura Y, Perlmutter SI, Eaton RW, Fetz EE. Spike-timing-dependent plasticity in primate corticospinal connections induced during free behavior. Neuron 2013; 80:1301-9. [PMID: 24210907 PMCID: PMC4079851 DOI: 10.1016/j.neuron.2013.08.028] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/22/2013] [Indexed: 11/28/2022]
Abstract
Motor learning and functional recovery from brain damage involve changes in the strength of synaptic connections between neurons. Relevant in vivo evidence on the underlying cellular mechanisms remains limited and indirect. We found that the strength of neural connections between motor cortex and spinal cord in monkeys can be modified with an autonomous recurrent neural interface that delivers electrical stimuli in the spinal cord triggered by action potentials of corticospinal cells during free behavior. The activity-dependent stimulation modified the strength of the terminal connections of single corticomotoneuronal cells, consistent with a bidirectional spike-timing-dependent plasticity rule previously derived from in vitro experiments. For some cells, the changes lasted for days after the end of conditioning, but most effects eventually reverted to preconditioning levels. These results provide direct evidence of corticospinal synaptic plasticity in vivo at the level of single neurons induced by normal firing patterns during free behavior.
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Affiliation(s)
- Yukio Nishimura
- Department of Physiology & Biophysics and Washington National Primate Research Center, University of Washington, Seattle, Washington 98195-7290, USA
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, Chiyoda, Tokyo 102-0076, Japan
| | - Steve I. Perlmutter
- Department of Physiology & Biophysics and Washington National Primate Research Center, University of Washington, Seattle, Washington 98195-7290, USA
| | - Ryan W. Eaton
- Department of Physiology & Biophysics and Washington National Primate Research Center, University of Washington, Seattle, Washington 98195-7290, USA
| | - Eberhard E. Fetz
- Department of Physiology & Biophysics and Washington National Primate Research Center, University of Washington, Seattle, Washington 98195-7290, USA
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