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Hikishima K, Tsurugizawa T, Kasahara K, Hayashi R, Takagi R, Yoshinaka K, Nitta N. Functional ultrasound reveals effects of MRI acoustic noise on brain function. Neuroimage 2023; 281:120382. [PMID: 37734475 DOI: 10.1016/j.neuroimage.2023.120382] [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: 07/27/2023] [Revised: 09/02/2023] [Accepted: 09/18/2023] [Indexed: 09/23/2023] Open
Abstract
Loud acoustic noise from the scanner during functional magnetic resonance imaging (fMRI) can affect functional connectivity (FC) observed in the resting state, but the exact effect of the MRI acoustic noise on resting state FC is not well understood. Functional ultrasound (fUS) is a neuroimaging method that visualizes brain activity based on relative cerebral blood volume (rCBV), a similar neurovascular coupling response to that measured by fMRI, but without the audible acoustic noise. In this study, we investigated the effects of different acoustic noise levels (silent, 80 dB, and 110 dB) on FC by measuring resting state fUS (rsfUS) in awake mice in an environment similar to fMRI measurement. Then, we compared the results to those of resting state fMRI (rsfMRI) conducted using an 11.7 Tesla scanner. RsfUS experiments revealed a significant reduction in FC between the retrosplenial dysgranular and auditory cortexes (0.56 ± 0.07 at silence vs 0.05 ± 0.05 at 110 dB, p=.01) and a significant increase in FC anticorrelation between the infralimbic and motor cortexes (-0.21 ± 0.08 at silence vs -0.47 ± 0.04 at 110 dB, p=.017) as acoustic noise increased from silence to 80 dB and 110 dB, with increased consistency of FC patterns between rsfUS and rsfMRI being found with the louder noise conditions. Event-related auditory stimulation experiments using fUS showed strong positive rCBV changes (16.5% ± 2.9% at 110 dB) in the auditory cortex, and negative rCBV changes (-6.7% ± 0.8% at 110 dB) in the motor cortex, both being constituents of the brain network that was altered by the presence of acoustic noise in the resting state experiments. Anticorrelation between constituent brain regions of the default mode network (such as the infralimbic cortex) and those of task-positive sensorimotor networks (such as the motor cortex) is known to be an important feature of brain network antagonism, and has been studied as a biological marker of brain disfunction and disease. This study suggests that attention should be paid to the acoustic noise level when using rsfMRI to evaluate the anticorrelation between the default mode network and task-positive sensorimotor network.
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Affiliation(s)
- Keigo Hikishima
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564, Japan; Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinwa 904-0495, Japan.
| | - Tomokazu Tsurugizawa
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8568, Japan
| | - Kazumi Kasahara
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8568, Japan
| | - Ryusuke Hayashi
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8568, Japan
| | - Ryo Takagi
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564, Japan
| | - Kiyoshi Yoshinaka
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564, Japan
| | - Naotaka Nitta
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564, Japan
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2
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Mooney RA, Bastian AJ, Celnik PA. Mapping subcortical motor pathways in humans with startle-conditioned TMS. Brain Stimul 2023; 16:1232-1239. [PMID: 37595834 DOI: 10.1016/j.brs.2023.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 08/11/2023] [Accepted: 08/14/2023] [Indexed: 08/20/2023] Open
Abstract
Subcortical motor pathways, such as the reticulospinal tract, are critical for producing and modulating voluntary movements and have been implicated in neurological conditions. Previous research has described the presence of ipsilateral motor evoked potentials (iMEPs) in the arm to transcranial magentic stimulation (TMS), and suggested they could be mediated by the uncrossed corticospinal tract or by ipsilateral cortico-reticulospinal connections. Here, we sought to elucidate the role of the reticulospinal tract in mediating iMEPs by assessing their modulation by a startling acoustic stimulus and mapping these responses across multiple upper limb effectors. In a first experiment, we delivered TMS at various intervals (1, 5, 10 and 15 ms) after a startling acoustic stimulus, known to excite the reticular formation, to elicit iMEPs in the arm. We observed robust facilitation of iMEP area when startle conditioning preceded TMS at the 10 ms interval. In a second experiment, we replicated our findings showing that both the area and number of iMEPs in the arm increases with startle conditioning. Using this technique, we observed that iMEPs are more prominent in the arm compared with the hand. In a third experiment, we also observed greater presence of iMEPs in flexor compared with extensor muscles. Together, these findings are consistent with properties of the reticulospinal tract observed in animals, suggesting that iMEPs primarily reflect reticulospinal activity. Our findings imply that we can use this approach to track modulation of cortico-reticulospinal excitability following interventions or neurological conditions where the reticulospinal tract may be involved in motor recovery.
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Affiliation(s)
- Ronan A Mooney
- Department of Physical Medicine and Rehabilitation, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Amy J Bastian
- Kennedy Krieger Institute, Baltimore, MD, USA; Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Pablo A Celnik
- Department of Physical Medicine and Rehabilitation, Johns Hopkins University, School of Medicine, Baltimore, MD, USA.
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3
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Teku F, Maslovat D, Carlsen AN. A TMS-induced cortical silent period delays the contralateral limb for bimanual symmetrical movements and the reaction time delay is reduced on startle trials. J Neurophysiol 2022; 127:1298-1308. [PMID: 35417257 DOI: 10.1152/jn.00476.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bimanual actions are typically initiated and executed in a temporally synchronous manner, likely due to planning bilateral commands as a single motor "program." Applying high intensity transcranial magnetic stimulation (TMS) to the motor cortex can result in a contralateral cortical silent period that delays reaction time (RT), if timed to coincide with the final motor output stage. The current study examined the impact of a unilateral TMS silent period on the RT and inter-limb timing of bilateral wrist extension. In addition, because a loud, startling acoustic stimulus (SAS) can result in the involuntary release of pre-programmed actions via increased reticulospinal activation, it was of interest whether startle-induced speeding of response initiation would moderate the impact of the TMS-induced RT delay. Participants performed blocks of unilateral and bilateral wrist extension in response to an acoustic (82dB) go-signal. On selected trials, either TMS was applied to the left motor cortex 70 ms prior to the expected EMG response onset, a SAS (120dB) replaced the go-signal, or both TMS and SAS were delivered. Results showed that TMS led to a significant RT delay in the right limb during both unimanual and bimanual extension but had no impact on the left limb initiation. In addition, the magnitude of the right limb RT delay was smaller when the response was triggered by a SAS. These results imply that preplanned bimanually synchronous movements are susceptible to lateralized dissociation late into the cortical motor output stage and movements triggered by startle involve increased reticulospinal output.
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Affiliation(s)
- Faven Teku
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Dana Maslovat
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
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4
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McInnes AN, Nguyen AT, Carroll TJ, Lipp OV, Marinovic W. Engagement of the contralateral limb can enhance the facilitation of motor output by loud acoustic stimuli. J Neurophysiol 2022; 127:840-855. [PMID: 35264005 DOI: 10.1152/jn.00235.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
When intense sound is presented during light muscle contraction, inhibition of the corticomotoneuronal pathway is observed. During action preparation, this effect is reversed, with sound resulting in excitation of the corticomotoneuronal pathway. We investigated how combined maintenance of a muscle contraction during preparation for a ballistic action impacts the magnitude of the facilitation of motor output by a loud acoustic stimulus (LAS) - a phenomenon known as the StartReact effect. Participants executed ballistic wrist flexion movements and a LAS was presented simultaneously with the imperative signal in a subset of trials. We examined whether the force level or muscle used to maintain a contraction during preparation for the ballistic response impacted reaction time and/or the force of movements triggered by the LAS. These contractions were sustained either ipsilaterally or contralaterally to the ballistic response. The magnitude of facilitation by the LAS was greatest when low force flexion contractions were maintained in the limb contralateral to the ballistic response during preparation. There was little change in facilitation when contractions recruited the contralateral extensor muscle, or when they were sustained in the same limb that executed the ballistic response. We conclude that a larger network of neurons which may be engaged by a contralateral sustained contraction prior to initiation may be recruited by the LAS, further contributing to the motor output of the response. These findings may be particularly applicable in stroke rehabilitation where engagement of the contralesional side may increase the benefits of a LAS to the functional recovery of movement.
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Affiliation(s)
- Aaron N McInnes
- School of Population Health, Discipline of Psychology, Curtin University, Perth, Australia.,Department of Psychiatry and Behavioral Sciences, University of Minnesota, Minneapolis, MN, United States
| | - An T Nguyen
- School of Population Health, Discipline of Psychology, Curtin University, Perth, Australia
| | - Timothy John Carroll
- School of Human Movement and Nutrition Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Ottmar V Lipp
- School of Psychology and Counselling, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Welber Marinovic
- School of Population Health, Discipline of Psychology, Curtin University, Perth, Australia
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5
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Startling Acoustic Stimulation Has Task-Specific Effects on Intracortical Facilitation and Inhibition at Rest and During Visually Guided Isometric Elbow Flexion in Healthy Individuals. Motor Control 2022; 27:96-111. [DOI: 10.1123/mc.2022-0014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 10/03/2022] [Accepted: 10/03/2022] [Indexed: 11/20/2022]
Abstract
Startling acoustic stimulation (SAS) causes a transient effect on the primary motor cortex (M1) nonreflexively. It reduces the cortical excitability at rest, but not during voluntary contraction. However, the effect of SAS on intracortical activity is not clear. The purpose of this study was to investigate the SAS effect on short-interval intracortical inhibition and intracortical facilitation using transcranial magnetic stimulation (TMS). Eleven healthy individuals performed isometric elbow flexion at 10% of maximum voluntary contraction on the dominant side with a real-time visual target (i.e., M1 preactivation) or at rest. TMS was delivered to the M1 ipsilateral to elbow flexion without or with SAS delivered 90 ms prior to TMS. There were three TMS delivery conditions: (a) single pulse, (b) short-interval intracortical inhibition, and (c) intracortical facilitation. TMS-induced motor-evoked potential (MEP) was compared between predetermined TMS and SAS conditions at rest and during ipsilateral voluntary contraction. We confirmed that SAS decreased the MEP amplitude at rest, but not during M1 preactivation. SAS caused task-specific effects on intracortical excitability. Specifically, SAS increased intracortical facilitation at rest and during voluntary contraction. However, SAS decreased short-interval intracortical inhibition only during M1 preactivation. Collectively, our results suggest that SAS transiently influences the motor cortex excitability, possibly via its activation of higher centers, to achieve a visually guided goal-directed task.
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Leow LA, Tresilian JR, Uchida A, Koester D, Spingler T, Riek S, Marinovic W. Acoustic stimulation increases implicit adaptation in sensorimotor adaptation. Eur J Neurosci 2021; 54:5047-5062. [PMID: 34021941 DOI: 10.1111/ejn.15317] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 05/07/2021] [Accepted: 05/14/2021] [Indexed: 11/29/2022]
Abstract
Sensorimotor adaptation is an important part of our ability to perform novel motor tasks (i.e., learning of motor skills). Efforts to improve adaptation in healthy and clinical patients using non-invasive brain stimulation methods have been hindered by inter-individual and intra-individual variability in brain susceptibility to stimulation. Here, we explore unpredictable loud acoustic stimulation as an alternative method of modulating brain excitability to improve sensorimotor adaptation. In two experiments, participants moved a cursor towards targets, and adapted to a 30º rotation of cursor feedback, either with or without unpredictable acoustic stimulation. Acoustic stimulation improved initial adaptation to sensory prediction errors in Study 1, and improved overnight retention of adaptation in Study 2. Unpredictable loud acoustic stimulation might thus be a potent method of modulating sensorimotor adaptation in healthy adults.
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Affiliation(s)
- Li-Ann Leow
- School of Psychology, The University of Queensland, Brisbane, QLD, Australia.,School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, QLD, Australia
| | | | - Aya Uchida
- School of Psychology, The University of Queensland, Brisbane, QLD, Australia
| | - Dirk Koester
- BSP Business School Berlin, Berlin, Germany.,Department of Sport Science, Bielefeld University, Bielefeld, Germany
| | - Tamara Spingler
- Spinal Cord Injury Center, Heidelberg University Hospital, Heidelberg, Germany
| | - Stephan Riek
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, QLD, Australia.,Graduate Research School, University of Sunshine Coast, Sippy Downs, Australia
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7
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Fossataro C, Burin D, Ronga I, Galigani M, Rossi Sebastiano A, Pia L, Garbarini F. Agent-dependent modulation of corticospinal excitability during painful transcutaneous electrical stimulation. Neuroimage 2020; 217:116897. [DOI: 10.1016/j.neuroimage.2020.116897] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 03/11/2020] [Accepted: 04/29/2020] [Indexed: 12/28/2022] Open
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Possible Contributions of Ipsilateral Pathways From the Contralesional Motor Cortex to the Voluntary Contraction of the Spastic Elbow Flexors in Stroke Survivors: A TMS Study. Am J Phys Med Rehabil 2020; 98:558-565. [PMID: 30672773 DOI: 10.1097/phm.0000000000001147] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECTIVE The contribution of the contralesional motor cortex to the impaired limbs is still controversial. The aim of this study was to investigate the role of descending projections from the contralesional hemisphere during voluntary elbow flexion on the paretic side. DESIGN Eleven healthy and 10 stroke subjects performed unilateral isometric elbow flexion tasks at various submaximal levels. Transcranial magnetic stimulation was delivered to the hotspot of biceps muscles ipsilateral to the target side (paretic side in stroke subjects or right side in controls) at rest and during elbow flexion tasks. Motor-evoked potential amplitudes of the contralateral resting biceps muscles, transcranial magnetic stimulation-induced ipsilateral force increment, and reflex torque and weakness of spastic elbow flexors were quantified. RESULTS The normalized motor-evoked potential amplitude increased with force level in both healthy and stroke subjects. However, stroke subjects exhibited significantly higher force increment compared with healthy subjects only at low level of elbow flexion but similar at moderate to high levels. The greater force increment significantly correlated with reflex torque of the spastic elbow flexors, but not weakness. CONCLUSIONS These results provide novel evidence that ipsilateral projections are not likely to contribute to strength but are correlated to spasticity of spastic-paretic elbow flexors after stroke.
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9
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The effects of conditioning startling acoustic stimulation (SAS) on the corticospinal motor system: a SAS-TMS study. Exp Brain Res 2019; 237:1973-1980. [PMID: 31143970 DOI: 10.1007/s00221-019-05569-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 05/27/2019] [Indexed: 12/25/2022]
Abstract
A startling acoustic stimulus (SAS) could cause transient effects on the primary motor cortex and its descending tracts after habituation of reflex responses. In the literature, there is evidence that the effects of SAS depend on the status of M1 excitability and delivery time of SAS. In this study, we aimed to comprehensively investigate the effects of SAS on the excitability of primary motor cortex. Eleven healthy subjects participated in this study. Transcranial magnetic stimulation (TMS) was delivered to the hot spot for left biceps at rest and during isometric right elbow flexion (10, 30, and 60% of their maximum voluntary contraction, MVC). There were three SAS conditions: (1) No SAS; (2) SAS was delivered 50 ms prior to TMS (SAS50); (3) SAS 90 ms prior to TMS (SAS90). For each subject, the induced MEP amplitude was normalized to the largest response at rest with No SAS. Two-way ANOVAs (4 force levels × 3 SAS conditions) with repeated measures were used to determine the differences under different conditions. For the MEP amplitude, there were significant force level effect and FORCE LEVEL × SAS interactions. Specifically, the MEP amplitude increased with force level. Furthermore, post hoc analysis showed that the MEP amplitude reduced during SAS50 and SAS90 compared to No SAS only at rest. Our results provide evidence that a conditioning SAS causes a transient suppression of the corticospinal excitability at rest when it is delivered 50 ms and 90 ms prior to TMS. However, a conditioning SAS has no effect when the corticospinal excitability is already elevated with an external visual target.
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10
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Li S, Chen YT, Francisco GE, Zhou P, Rymer WZ. A Unifying Pathophysiological Account for Post-stroke Spasticity and Disordered Motor Control. Front Neurol 2019; 10:468. [PMID: 31133971 PMCID: PMC6524557 DOI: 10.3389/fneur.2019.00468] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 04/17/2019] [Indexed: 11/18/2022] Open
Abstract
Cortical and subcortical plastic reorganization occurs in the course of motor recovery after stroke. It is largely accepted that plasticity of ipsilesional motor cortex primarily contributes to recovery of motor function, while the contributions of contralesional motor cortex are not completely understood. As a result of damages to motor cortex and its descending pathways and subsequent unmasking of inhibition, there is evidence of upregulation of reticulospinal tract (RST) excitability in the contralesional side. Both animal studies and human studies with stroke survivors suggest and support the role of RST hyperexcitability in post-stroke spasticity. Findings from animal studies demonstrate the compensatory role of RST hyperexcitability in recovery of motor function. In contrast, RST hyperexcitability appears to be related more to abnormal motor synergy and disordered motor control in stroke survivors. It does not contribute to recovery of normal motor function. Recent animal studies highlight laterality dominance of corticoreticular projections. In particular, there exists upregulation of ipsilateral corticoreticular projections from contralesional premotor cortex (PM) and supplementary motor area (SMA) to medial reticular nuclei. We revisit and revise the previous theoretical framework and propose a unifying account. This account highlights the importance of ipsilateral PM/SMA-cortico-reticulospinal tract hyperexcitability from the contralesional motor cortex as a result of disinhibition after stroke. This account provides a pathophysiological basis for post-stroke spasticity and related movement impairments, such as abnormal motor synergy and disordered motor control. However, further research is needed to examine this pathway in stroke survivors to better understand its potential roles, especially in muscle strength and motor recovery. This account could provide a pathophysiological target for developing neuromodulatory interventions to manage spasticity and thus possibly to facilitate motor recovery.
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Affiliation(s)
- Sheng Li
- Department of Physical Medicine and Rehabilitation, McGovern Medical School, University of Texas Health Science Center – Houston and TIRR Memorial Hermann Hospital, Houston, TX, United States
| | - Yen-Ting Chen
- Department of Physical Medicine and Rehabilitation, McGovern Medical School, University of Texas Health Science Center – Houston and TIRR Memorial Hermann Hospital, Houston, TX, United States
| | - Gerard E. Francisco
- Department of Physical Medicine and Rehabilitation, McGovern Medical School, University of Texas Health Science Center – Houston and TIRR Memorial Hermann Hospital, Houston, TX, United States
| | - Ping Zhou
- Department of Physical Medicine and Rehabilitation, McGovern Medical School, University of Texas Health Science Center – Houston and TIRR Memorial Hermann Hospital, Houston, TX, United States
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11
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Zhang C, Chen YT, Liu Y, Zhou P, Li S, Zhang Y. Three dimensional innervation zone imaging in spastic muscles of stroke survivors. J Neural Eng 2019; 16:034001. [PMID: 30870833 DOI: 10.1088/1741-2552/ab0fe1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
OBJECTIVE The outcome of botulinum toxin (BTX) therapy of post-stroke spasticity relies largely on accuracy of BTX injection to the proximity of innervation zones (IZs). Recently developed three-dimensional IZ imaging (3DIZI) is the only technique currently available to provide 3D distributions of IZs in vivo, yet its performance has not been validated under pathological conditions. APPROACH The performance of 3DIZI was evaluated in the spastic biceps brachii muscles of four chronic stroke subjects. High-density surface electromyography (sEMG) and intramuscular electromyography (iEMG) were simultaneously recorded. The IZ location in the 3D space of the spastic biceps calculated using the 3DIZI technique from sEMG recordings were compared against the IZ location detected using intramuscular wires. MAIN RESULTS 3DIZI successfully reconstructed the IZs in the 3D space of the spastic biceps of all four stroke subjects, with a localization error of 4.7 ± 2.7 mm, and specifically a depth error of 1.8 ± 0.4 mm. SIGNIFICANCE Results have demonstrated the robust performance of 3DIZI under pathological conditions, laying a solid foundation for clinical application of 3D source imaging in leading precise BTX injections for spasticity management.
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Affiliation(s)
- Chuan Zhang
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, United States of America. The authors contribute equally to this work
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12
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Chen YT, Li S, Zhou P, Li S. A startling acoustic stimulation (SAS)-TMS approach to assess the reticulospinal system in healthy and stroke subjects. J Neurol Sci 2019; 399:82-88. [PMID: 30782527 DOI: 10.1016/j.jns.2019.02.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 02/08/2019] [Accepted: 02/10/2019] [Indexed: 12/21/2022]
Abstract
Reticulospinal (RS) hyperexcitability is observed in stroke survivors with spastic hemiparesis. Habituated startle acoustic stimuli (SAS) can be used to stimulate the RS pathways non-reflexively. However, the role of RS pathways in motor function and its interactions with the corticospinal system after stroke still remain unclear. Therefore, the purpose of this study was to investigate the effects of conditioning SAS on the corticospinal system in healthy subjects and in stroke subjects with spastic hemiparesis. An established conditioning SAS- transcranial magnetic stimulation (TMS) paradigm was used to test the interactions between the RS pathways and the corticospinal system. TMS was delivered to the right hemisphere of eleven healthy subjects and the contralesional hemisphere of eleven stroke subjects during isometric elbow flexor contraction on the non-impaired (or left) side. Conditioning SAS had similar effects on the corticospinal motor system in both healthy and stroke subjects, including similar SAS-induced motor evoked potential (MEP) reduction at rest, but not during voluntary contraction tasks; similar magnitudes of TMS-induced MEP and force increment and shortening of the silent period during voluntary elbow flexor contraction. This study provides evidence that RS excitability on the contralesional side in stroke subjects with spastic hemiparesis is not abnormal, and suggests that RS projections are likely to be primarily unilateral in humans.
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Affiliation(s)
- Yen-Ting Chen
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center, Houston, United States; TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, United States
| | - Shengai Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center, Houston, United States; TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, United States.
| | - Ping Zhou
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center, Houston, United States; TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, United States
| | - Sheng Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center, Houston, United States; TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, United States
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13
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Kirkpatrick NJ, Ravichandran VJ, Perreault EJ, Schaefer SY, Honeycutt CF. Evidence for startle as a measurable behavioral indicator of motor learning. PLoS One 2018; 13:e0195689. [PMID: 29742130 PMCID: PMC5942773 DOI: 10.1371/journal.pone.0195689] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 03/27/2018] [Indexed: 02/06/2023] Open
Abstract
The ability of the classic startle reflex to evoke voluntarily prepared movement involuntarily has captured the attention of neuroscientists for its wide-ranging functional utility and potential uses in patient populations. To date, there is only one documented task resistant to the startReact phenomenon-index finger abduction. Previous reports have suggested the lack of startReact is due to different neural mechanisms driving individuated finger movement and more proximal joint control (e.g. elbow, wrist movement). However, an alternative hypothesis exists. Though not particularly difficult to execute, isolated index finger abduction is rarely performed during activities of daily living and is not a natural correlate to common individuated finger tasks. We propose that startReact can be evoked during individuated finger movements but only during tasks that are highly trained or familiar. The objective of this study was to determine the impact of a 2-week training regimen on the ability to elicit startReact. We found evidence in support of our hypothesis that following training, individuated movements of the hands (specifically index finger abduction) become susceptible to startReact. This is significant not only because it indicates that individuated finger movements are in fact amenable to startReact, but also that startle has differential response characteristics in novel tasks compared to highly trained tasks suggesting that startle is a measurable behavioral indicator of motor learning.
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Affiliation(s)
- Nathan J. Kirkpatrick
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, United States of America
| | | | - Eric J. Perreault
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, United States of America
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States of America
- Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, IL, United States of America
| | - Sydney Y. Schaefer
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, United States of America
| | - Claire F. Honeycutt
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, United States of America
- * E-mail:
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14
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Li S, Bhadane M, Gao F, Zhou P. The Reticulospinal Pathway Does Not Increase Its Contribution to the Strength of Contralesional Muscles in Stroke Survivors as Compared to Ipsilesional Side or Healthy Controls. Front Neurol 2017; 8:627. [PMID: 29230191 PMCID: PMC5712067 DOI: 10.3389/fneur.2017.00627] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 11/09/2017] [Indexed: 11/13/2022] Open
Abstract
Objective Startling acoustic stimulation (SAS), via activation of reticulospinal (RS) pathways, has shown to increase muscle strength in healthy subjects. We hypothesized that, given RS hyperexcitability in stroke survivors, SAS could increase muscle strength in stroke survivors. The objective was to quantify the effect of SAS on maximal and sub-maximal voluntary elbow flexion on the contralesional (impaired) side in stroke survivors as compared to ipsilesional (non-impaired) side and healthy controls. Design Thirteen hemiparetic stroke survivors and 12 healthy subjects volunteered for this investigation. Acoustic stimulation was given at rest, during ballistic maximal and sustained sub-maximal isometric elbow contractions using low (80 dB) and high intensity sound (105 dB). The effect of acoustic stimuli was evaluated from EMG and force recordings. Results Prevalence of acoustic startle reflex with shorter latency in the impaired biceps was greater as compared to the response in the non-impaired side of stroke subjects and in healthy subjects. Delivery of SAS resulted in earlier initiation of elbow flexion and greater peak torque in healthy subjects and in stroke subjects with spastic hemiplegia during maximal voluntary elbow flexion tasks. During sub-maximal elbow flexion tasks, SAS-induced force responses were slightly greater on the impaired side than the non-impaired side. However, no statistically significant difference was found in SAS-induced responses between impaired and non-impaired sides at maximal and sub-maximal elbow flexion tasks. Conclusion The findings suggest RS hyperexcitability in stroke survivors with spastic hemiplegia. The results of similar SAS-induced responses between healthy and stroke subjects indicate that RS projections via acoustic stimulation are not likely to contribute to muscle strength for stroke survivors to a significant extent.
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Affiliation(s)
- Sheng Li
- Department of Physical Medicine and Rehabilitation, McGoven Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States.,TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, Houston, TX, United States
| | - Minal Bhadane
- Department of Physical Medicine and Rehabilitation, McGoven Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States.,TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, Houston, TX, United States
| | - Fan Gao
- The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Ping Zhou
- Department of Physical Medicine and Rehabilitation, McGoven Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States.,TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, Houston, TX, United States
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15
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Marinovic W. Focus of attention changes intracortical excitability in the primary motor cortex. Acta Physiol (Oxf) 2017; 220:179-180. [PMID: 27804214 DOI: 10.1111/apha.12822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- W. Marinovic
- Curtin University - School of Psychology and Speech Pathology; Perth WA Australia
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