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Galer EL, Huang R, Madhavan M, Wang E, Zhou Y, Leiter JC, Lu DC. Cervical Epidural Electrical Stimulation Increases Respiratory Activity through Somatostatin-Expressing Neurons in the Dorsal Cervical Spinal Cord in Rats. J Neurosci 2023; 43:419-432. [PMID: 36639888 PMCID: PMC9864577 DOI: 10.1523/jneurosci.1958-21.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 09/21/2022] [Accepted: 09/29/2022] [Indexed: 12/12/2022] Open
Abstract
We tested the hypothesis that dorsal cervical epidural electrical stimulation (CEES) increases respiratory activity in male and female anesthetized rats. Respiratory frequency and minute ventilation were significantly increased when CEES was applied dorsally to the C2-C6 region of the cervical spinal cord. By injecting pseudorabies virus into the diaphragm and using c-Fos activity to identify neurons activated during CEES, we found neurons in the dorsal horn of the cervical spinal cord in which c-Fos and pseudorabies were co-localized, and these neurons expressed somatostatin (SST). Using dual viral infection to express the inhibitory Designer Receptors Exclusively Activated by Designer Drugs (DREADD), hM4D(Gi), selectively in SST-positive cells, we inhibited SST-expressing neurons by administering Clozapine N-oxide (CNO). During CNO-mediated inhibition of SST-expressing cervical spinal neurons, the respiratory excitation elicited by CEES was diminished. Thus, dorsal cervical epidural stimulation activated SST-expressing neurons in the cervical spinal cord, likely interneurons, that communicated with the respiratory pattern generating network to effect changes in ventilation.SIGNIFICANCE STATEMENT A network of pontomedullary neurons within the brainstem generates respiratory behaviors that are susceptible to modulation by a variety of inputs; spinal sensory and motor circuits modulate and adapt this output to meet the demands placed on the respiratory system. We explored dorsal cervical epidural electrical stimulation (CEES) excitation of spinal circuits to increase ventilation in rats. We identified dorsal somatostatin (SST)-expressing neurons in the cervical spinal cord that were activated (c-Fos-positive) by CEES. CEES no longer stimulated ventilation during inhibition of SST-expressing spinal neuronal activity, thereby demonstrating that spinal SST neurons participate in the activation of respiratory circuits affected by CEES. This work establishes a mechanistic foundation to repurpose a clinically accessible neuromodulatory therapy to activate respiratory circuits and stimulate ventilation.
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Affiliation(s)
- Erika L Galer
- Department of Neurosurgery, University of California Los Angeles, Los Angeles 90095, California
- Department of Molecular Cellular and Integrative Physiology, University of California Los Angeles, Los Angeles 90095, California
| | - Ruyi Huang
- Department of Neurosurgery, University of California Los Angeles, Los Angeles 90095, California
| | - Meghna Madhavan
- Department of Neurosurgery, University of California Los Angeles, Los Angeles 90095, California
| | - Emily Wang
- Department of Neurosurgery, University of California Los Angeles, Los Angeles 90095, California
| | - Yan Zhou
- Department of Neurosurgery, University of California Los Angeles, Los Angeles 90095, California
| | - James C Leiter
- Department of Neurosurgery, University of California Los Angeles, Los Angeles 90095, California
- Research Service, White River Junction VA Medical Center, White River Junction 05009, Vermont
| | - Daniel C Lu
- Department of Neurosurgery, University of California Los Angeles, Los Angeles 90095, California
- Department of Molecular Cellular and Integrative Physiology, University of California Los Angeles, Los Angeles 90095, California
- Brain Research Institute, University of California Los Angeles, Los Angeles 90095, California
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2
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Jantz MK, Gopinath C, Kumar R, Chin C, Wong L, Ogren JI, Fisher LE, McLaughlin BL, Gaunt RA. High-density spinal cord stimulation selectively activates lower urinary tract nerves. J Neural Eng 2022; 19:066014. [PMID: 36343359 PMCID: PMC9855651 DOI: 10.1088/1741-2552/aca0c2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 11/07/2022] [Indexed: 11/09/2022]
Abstract
Objective.Epidural spinal cord stimulation (SCS) is a potential intervention to improve limb and autonomic functions, with lumbar stimulation improving locomotion and thoracic stimulation regulating blood pressure. Here, we asked whether sacral SCS could be used to target the lower urinary tract (LUT) and used a high-density epidural electrode array to test whether individual electrodes could selectively recruit LUT nerves.Approach. We placed a high-density epidural SCS array on the dorsal surface of the sacral spinal cord and cauda equina of anesthetized cats and recorded the stimulation-evoked activity from nerve cuffs on the pelvic, pudendal and sciatic nerves.Main results. Here we show that sacral SCS evokes responses in nerves innervating the bladder and urethra and that these nerves can be activated selectively. Sacral SCS always recruited the pelvic and pudendal nerves and selectively recruited both of these nerves in all but one animal. Individual branches of the pudendal nerve were always recruited as well. Electrodes that selectively recruited specific peripheral nerves were spatially clustered on the arrays, suggesting anatomically organized sensory pathways.Significance.This selective recruitment demonstrates a mechanism to directly modulate bladder and urethral function through known reflex pathways, which could be used to restore bladder and urethral function after injury or disease.
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Affiliation(s)
- Maria K Jantz
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, Pittsburgh, PA, United States of America
| | - Chaitanya Gopinath
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Ritesh Kumar
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, Pittsburgh, PA, United States of America
| | - Celine Chin
- Micro-Leads Inc., Somerville, MA, United States of America
| | - Liane Wong
- Micro-Leads Inc., Somerville, MA, United States of America
| | - John I Ogren
- Micro-Leads Inc., Somerville, MA, United States of America
| | - Lee E Fisher
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, Pittsburgh, PA, United States of America
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States of America
- Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States of America
| | | | - Robert A Gaunt
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, Pittsburgh, PA, United States of America
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States of America
- Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States of America
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Huang R, Worrell J, Garner E, Wang S, Homsey T, Xu B, Galer EL, Zhou Y, Tavakol S, Daneshvar M, Le T, Vinters HV, Salamon N, McArthur DL, Nuwer MR, Wu I, Leiter JC, Lu DC. Epidural electrical stimulation of the cervical spinal cord opposes opioid-induced respiratory depression. J Physiol 2022; 600:2973-2999. [PMID: 35639046 DOI: 10.1113/jp282664] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 03/25/2022] [Indexed: 02/02/2023] Open
Abstract
Opioid overdose suppresses brainstem respiratory circuits, causes apnoea and may result in death. Epidural electrical stimulation (EES) at the cervical spinal cord facilitated motor activity in rodents and humans, and we hypothesized that EES of the cervical spinal cord could antagonize opioid-induced respiratory depression in humans. Eighteen patients requiring surgical access to the dorsal surface of the spinal cord between C2 and C7 received EES or sham stimulation for up to 90 s at 5 or 30 Hz during complete (OFF-State) or partial suppression (ON-State) of respiration induced by remifentanil. During the ON-State, 30 Hz EES at C4 and 5 Hz EES at C3/4 increased tidal volume and decreased the end-tidal carbon dioxide level compared to pre-stimulation control levels. EES of 5 Hz at C5 and C7 increased respiratory frequency compared to pre-stimulation control levels. In the OFF-State, 30 Hz cervical EES at C3/4 terminated apnoea and induced rhythmic breathing. In cadaveric tissue obtained from a brain bank, more neurons expressed both the neurokinin 1 receptor (NK1R) and somatostatin (SST) in the cervical spinal levels responsive to EES (C3/4, C6 and C7) compared to a region non-responsive to EES (C2). Thus, the capacity of cervical EES to oppose opioid depression of respiration may be mediated by NK1R+/SST+ neurons in the dorsal cervical spinal cord. This study provides proof of principle that cervical EES may provide a novel therapeutic approach to augment respiratory activity when the neural function of the central respiratory circuits is compromised by opioids or other pathological conditions. KEY POINTS: Epidural electrical stimulation (EES) using an implanted spinal cord stimulator (SCS) is an FDA-approved method to manage chronic pain. We tested the hypothesis that cervical EES facilitates respiration during administration of opioids in 18 human subjects who were treated with low-dose remifentanil that suppressed respiration (ON-State) or high-dose remifentanil that completely inhibited breathing (OFF-State) during the course of cervical surgery. Dorsal cervical EES of the spinal cord augmented the respiratory tidal volume or increased the respiratory frequency, and the response to EES varied as a function of the stimulation frequency (5 or 30 Hz) and the cervical level stimulated (C2-C7). Short, continuous cervical EES restored a cyclic breathing pattern (eupnoea) in the OFF-State, suggesting that cervical EES reversed the opioid-induced respiratory depression. These findings add to our understanding of respiratory pattern modulation and suggest a novel mechanism to oppose the respiratory depression caused by opioids.
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Affiliation(s)
- Ruyi Huang
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Interdepartmental Program in Neuroscience, University of California, Los Angeles, CA, USA
| | - Jason Worrell
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Eric Garner
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Stephanie Wang
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Tali Homsey
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Bo Xu
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Erika L Galer
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Molecular, Cellular, Integrated Physiology Program, University of California, Los Angeles, CA, USA
| | - Yan Zhou
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Sherwin Tavakol
- Department of Neurosurgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Meelod Daneshvar
- University of California Fresno, Department of Surgery, Fresno, CA, USA
| | - Timothy Le
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Harry V Vinters
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Brain Research Institute, University of California, Los Angeles, CA, USA
| | - Noriko Salamon
- Department of Radiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - David L McArthur
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Marc R Nuwer
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Irene Wu
- Department of Anesthesiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - James C Leiter
- Department of Molecular and Systems Biology, Geisel School of Medicine, Lebanon, NH, USA
| | - Daniel C Lu
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Interdepartmental Program in Neuroscience, University of California, Los Angeles, CA, USA.,Brain Research Institute, University of California, Los Angeles, CA, USA
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Sunshine MD, Ganji CN, Fuller DD, Moritz CT. Respiratory resetting elicited by single pulse spinal stimulation. Respir Physiol Neurobiol 2019; 274:103339. [PMID: 31734416 DOI: 10.1016/j.resp.2019.103339] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/04/2019] [Accepted: 11/12/2019] [Indexed: 01/21/2023]
Abstract
Intraspinal microstimulation (ISMS) can effectively activate spinal motor circuits, but the impact on the endogenous respiratory pattern has not been systematically evaluated. Here we delivered ISMS in spontaneously breathing adult rats while simultaneously recording diaphragm and external intercostal electromyography activity. ISMS pulses were delivered from C2-T1 along two rostrocaudal tracts located 0.5 or 1 mm lateral to midline. A tungsten electrode was incrementally advanced from the dorsal spinal surface and 300μs biphasic pulses (10-90 μA) were delivered at depth increments of 600 μm. Dorsal ISMS often produced fractionated inspiratory bursting or caused early termination of the inspiratory effort. Conversely, ventral stimulation had no discernable impact on respiratory resetting. We conclude that ISMS targeting the ventral spinal cord is unlikely to directly alter the respiratory rhythm. Dorsal ISMS, however, may terminate the inspiratory burst through activation of spinobulbar pathways. We suggest that respiratory patterns should be included as an outcome variable in preclinical studies of ISMS.
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Affiliation(s)
- Michael D Sunshine
- Department of Rehabilitation Medicine, University of Washington, United States; Center for Neurotechnology, an NSF ERC, United States; Department of Physical Therapy, University of Florida, United States; McKnight Brain Institute, University of Florida, United States; Rehabilitation Science PhD Program, University of Florida, United States; Center for Respiratory Research and Rehabilitation, University of Florida, United States.
| | - Comron N Ganji
- Department of Rehabilitation Medicine, University of Washington, United States
| | - David D Fuller
- Department of Physical Therapy, University of Florida, United States; McKnight Brain Institute, University of Florida, United States; Center for Respiratory Research and Rehabilitation, University of Florida, United States
| | - Chet T Moritz
- Department of Rehabilitation Medicine, University of Washington, United States; Center for Neurotechnology, an NSF ERC, United States; Center for Respiratory Research and Rehabilitation, University of Florida, United States; Department of Electrical and Computer Engineering, United States; University of Washington, Institute for Neuroengineering (UWIN), University of Washington, United States; Department of Physiology and Biophysics, University of Washington, United States
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Satkunendrarajah K, Karadimas SK, Laliberte AM, Montandon G, Fehlings MG. Cervical excitatory neurons sustain breathing after spinal cord injury. Nature 2018; 562:419-422. [DOI: 10.1038/s41586-018-0595-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 08/14/2018] [Indexed: 11/09/2022]
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Cregg JM, Chu KA, Hager LE, Maggard RSJ, Stoltz DR, Edmond M, Alilain WJ, Philippidou P, Landmesser LT, Silver J. A Latent Propriospinal Network Can Restore Diaphragm Function after High Cervical Spinal Cord Injury. Cell Rep 2017; 21:654-665. [PMID: 29045834 PMCID: PMC5687843 DOI: 10.1016/j.celrep.2017.09.076] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 08/08/2017] [Accepted: 09/24/2017] [Indexed: 10/18/2022] Open
Abstract
Spinal cord injury (SCI) above cervical level 4 disrupts descending axons from the medulla that innervate phrenic motor neurons, causing permanent paralysis of the diaphragm. Using an ex vivo preparation in neonatal mice, we have identified an excitatory spinal network that can direct phrenic motor bursting in the absence of medullary input. After complete cervical SCI, blockade of fast inhibitory synaptic transmission caused spontaneous, bilaterally coordinated phrenic bursting. Here, spinal cord glutamatergic neurons were both sufficient and necessary for the induction of phrenic bursts. Direct stimulation of phrenic motor neurons was insufficient to evoke burst activity. Transection and pharmacological manipulations showed that this spinal network acts independently of medullary circuits that normally generate inspiration, suggesting a distinct non-respiratory function. We further show that this "latent" network can be harnessed to restore diaphragm function after high cervical SCI in adult mice and rats.
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Affiliation(s)
- Jared M Cregg
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Kevin A Chu
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Lydia E Hager
- Spinal Cord and Brain Injury Research Center, Department of Neuroscience, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Rachel S J Maggard
- Spinal Cord and Brain Injury Research Center, Department of Neuroscience, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Daimen R Stoltz
- Spinal Cord and Brain Injury Research Center, Department of Neuroscience, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Michaela Edmond
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Warren J Alilain
- Spinal Cord and Brain Injury Research Center, Department of Neuroscience, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Polyxeni Philippidou
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Lynn T Landmesser
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Jerry Silver
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH 44106, USA.
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7
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Gonzalez-Rothi EJ, Streeter KA, Hanna MH, Stamas AC, Reier PJ, Baekey DM, Fuller DD. High-frequency epidural stimulation across the respiratory cycle evokes phrenic short-term potentiation after incomplete cervical spinal cord injury. J Neurophysiol 2017; 118:2344-2357. [PMID: 28615341 DOI: 10.1152/jn.00913.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 06/13/2017] [Accepted: 06/14/2017] [Indexed: 01/15/2023] Open
Abstract
C2 spinal hemilesion (C2Hx) paralyzes the ipsilateral diaphragm, but recovery is possible through activation of "crossed spinal" synaptic inputs to ipsilateral phrenic motoneurons. We tested the hypothesis that high-frequency epidural stimulation (HF-ES) would potentiate ipsilateral phrenic output after subacute and chronic C2Hx. HF-ES (300 Hz) was applied to the ventrolateral C4 or T2 spinal cord ipsilateral to C2Hx in anesthetized and mechanically ventilated adult rats. Stimulus duration was 60 s, and currents ranged from 100 to 1,000 µA. Bilateral phrenic nerve activity and ipsilateral hypoglossal (XII) nerve activity were recorded before and after HF-ES. Higher T2 stimulus currents potentiated ipsilateral phasic inspiratory activity at both 2 and 12 wk post-C2Hx, whereas higher stimulus currents delivered at C4 potentiated ipsilateral phasic phrenic activity only at 12 wk (P = 0.028). Meanwhile, tonic output in the ipsilateral phrenic nerve reached 500% of baseline values at the high currents with no difference between 2 and 12 wk. HF-ES did not trigger inspiratory burst-frequency changes. Similar responses occurred following T2 HF-ES. Increases in contralateral phrenic and XII nerve output were induced by C4 and T2 HF-ES at higher currents, but the relative magnitude of these changes was small compared with the ipsilateral phrenic response. We conclude that following incomplete cervical spinal cord injury, HF-ES of the ventrolateral midcervical or thoracic spinal cord can potentiate efferent phrenic motor output with little impact on inspiratory burst frequency. However, the substantial increases in tonic output indicate that the uninterrupted 60-s stimulation paradigm used is unlikely to be useful for respiratory muscle activation after spinal injury.NEW & NOTEWORTHY Previous studies reported that high-frequency epidural stimulation (HF-ES) activates the diaphragm following acute spinal transection. This study examined HF-ES and phrenic motor output following subacute and chronic incomplete cervical spinal cord injury. Short-term potentiation of phrenic bursting following HF-ES illustrates the potential for spinal stimulation to induce respiratory neuroplasticity. Increased tonic phrenic output indicates that alternatives to the continuous stimulation paradigm used in this study will be required for respiratory muscle activation after spinal cord injury.
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Affiliation(s)
- Elisa J Gonzalez-Rothi
- McKnight Brain Institute, Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, Florida;
| | - Kristi A Streeter
- McKnight Brain Institute, Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, Florida
| | - Marie H Hanna
- McKnight Brain Institute, Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, Florida
| | - Anna C Stamas
- McKnight Brain Institute, Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, Florida
| | - Paul J Reier
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida; and
| | - David M Baekey
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - David D Fuller
- McKnight Brain Institute, Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, Florida
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