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Otchy TM, Michas C, Lee B, Gopalan K, Nerurkar V, Gleick J, Semu D, Darkwa L, Holinski BJ, Chew DJ, White AE, Gardner TJ. Printable microscale interfaces for long-term peripheral nerve mapping and precision control. Nat Commun 2020; 11:4191. [PMID: 32826892 PMCID: PMC7442820 DOI: 10.1038/s41467-020-18032-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 07/29/2020] [Indexed: 12/28/2022] Open
Abstract
The nascent field of bioelectronic medicine seeks to decode and modulate peripheral nervous system signals to obtain therapeutic control of targeted end organs and effectors. Current approaches rely heavily on electrode-based devices, but size scalability, material and microfabrication challenges, limited surgical accessibility, and the biomechanically dynamic implantation environment are significant impediments to developing and deploying peripheral interfacing technologies. Here, we present a microscale implantable device - the nanoclip - for chronic interfacing with fine peripheral nerves in small animal models that begins to meet these constraints. We demonstrate the capability to make stable, high signal-to-noise ratio recordings of behaviorally-linked nerve activity over multi-week timescales. In addition, we show that multi-channel, current-steering-based stimulation within the confines of the small device can achieve multi-dimensional control of a small nerve. These results highlight the potential of new microscale design and fabrication techniques for realizing viable devices for long-term peripheral interfacing.
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Affiliation(s)
- Timothy M Otchy
- Department of Biology, Boston University, Boston, MA, 02215, USA.
- Neurophotonics Center, Boston University, Boston, MA, 02215, USA.
- Center for Systems Neuroscience, Boston University, Boston, MA, 02215, USA.
| | - Christos Michas
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - Blaire Lee
- Department of Biology, Boston University, Boston, MA, 02215, USA
| | - Krithi Gopalan
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - Vidisha Nerurkar
- Department of Biology, Boston University, Boston, MA, 02215, USA
| | - Jeremy Gleick
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - Dawit Semu
- Department of Biology, Boston University, Boston, MA, 02215, USA
| | - Louis Darkwa
- Department of Biology, Boston University, Boston, MA, 02215, USA
| | - Bradley J Holinski
- Bioelectronics Division, GlaxoSmithKline, Stevenage, Hertfordshire, SG1 2NY, UK
| | - Daniel J Chew
- Bioelectronics Division, GlaxoSmithKline, Stevenage, Hertfordshire, SG1 2NY, UK
| | - Alice E White
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
- Department of Mechanical Engineering, Boston University, Boston, MA, 02215, USA
| | - Timothy J Gardner
- Department of Biology, Boston University, Boston, MA, 02215, USA.
- Neurophotonics Center, Boston University, Boston, MA, 02215, USA.
- Center for Systems Neuroscience, Boston University, Boston, MA, 02215, USA.
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA.
- Knight Campus, University of Oregon, Eugene, OR, 97405, USA.
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Su CK, Chen YY, Ho CM. Nitric Oxide Orchestrates a Power-Law Modulation of Sympathetic Firing Behaviors in Neonatal Rat Spinal Cords. Front Physiol 2018; 9:163. [PMID: 29559921 PMCID: PMC5845561 DOI: 10.3389/fphys.2018.00163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 02/19/2018] [Indexed: 11/13/2022] Open
Abstract
Nitric oxide (NO) is a diffusible gas and has multifarious effects on both pre- and postsynaptic events. As a consequence of complex excitatory and inhibitory integrations, NO effects on neuronal activities are heterogeneous. Using in vitro preparations of neonatal rats that retain the splanchnic sympathetic nerves and the thoracic spinal cord as an experimental model, we report here that either enhancement or attenuation of NO production in the neonatal rat spinal cords could increase, decrease, or not change the spontaneous firing behaviors recorded from splanchnic sympathetic single fibers. To elucidate the mathematical features of NO-mediated heterogeneous responses, the ratios of changes in firing were plotted against their original firing rates. In log-log plots, a linear data distribution demonstrated that NO-mediated heterogeneity in sympathetic firing responses was well described by a power function. Selective antagonists were applied to test if glycinergic, GABAergic, glutamatergic, and cholinergic neurotransmission in the spinal cord are involved in NO-mediated power-law firing modulations (plFM). NO-mediated plFM diminished in the presence of mecamylamine (an open-channel blocker of nicotinic cholinergic receptors), indicating that endogenous nicotinic receptor activities were essential for plFM. Applications of strychnine (a glycine receptor blocker), gabazine (a GABAA receptor blocker), or kynurenate (a broad-spectrum ionotropic glutamate receptor blocker) also caused plFM. However, strychnine- or kynurenate-induced plFM was diminished by L-NAME (an NO synthase inhibitor) pretreatments, indicating that the involvements of glycine or ionotropic glutamate receptor activities in plFM were secondary to NO signaling. To recapitulate the arithmetic natures of the plFM, the plFM were simulated by firing changes in two components: a step increment and a fractional reduction of their basal firing activities. Ionotropic glutamate receptor activities were found to participate in plFM by both components. In contrast, GABAA receptor activities are involved in the component of fractional reduction only. These findings suggest that NO orchestrates a repertoire of excitatory and inhibitory neurotransmissions, incurs a shunting effect on postsynaptic membrane properties, and thus, alters sympathetic firing in a manner of plFM. We propose that the plFM mediated by NO forms a basic scheme of differential controls for heterogeneous sympathetic regulation of visceral functions.
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Affiliation(s)
- Chun-Kuei Su
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yi-Yin Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chiu-Ming Ho
- Department of Anesthesiology, Taipei Veterans General Hospital and National Yang-Ming University, Taipei, Taiwan
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Su CK. Modulation of synchronous sympathetic firing behaviors by endogenous GABA(A) and glycine receptor-mediated activities in the neonatal rat spinal cord in vitro. Neuroscience 2016; 312:227-46. [PMID: 26598070 DOI: 10.1016/j.neuroscience.2015.11.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 10/05/2015] [Accepted: 11/12/2015] [Indexed: 11/28/2022]
Abstract
Delivering effective commands in the nervous systems require a temporal integration of neural activities such as synchronous firing. Although sympathetic nerve discharges are characterized by synchronous firing, its temporal structures and how it is modulated are largely unknown. This study used a collagenase-dissociated splanchnic sympathetic nerve-thoracic spinal cord preparation of neonatal rats in vitro as an experimental model. Several single-fiber activities were recorded simultaneously and verified by rigorous computational algorithms. Among 3763 fiber pairs that had spontaneous fiber activities, 382 fiber pairs had firing positively correlated. Their temporal relationship was quantitatively evaluated by cross-correlogram. On average, correlated firing in a fiber pair occurred in scales of ∼40ms lasting for ∼11ms. The relative frequency distribution curves of correlogram parametrical values pertinent to the temporal features were best described by trimodal Gaussians, suggesting a correlated firing originated from three or less sources. Applications of bicuculline or gabazine (noncompetitive or competitive GABA(A) receptor antagonist) and/or strychnine (noncompetitive glycine receptor antagonist) increased, decreased, or did not change individual fiber activities. Antagonist-induced enhancement and attenuation of correlated firing were demonstrated by a respective increase and decrease of the peak probability of the cross-correlograms. Heterogeneity in antagonistic responses suggests that the inhibitory neurotransmission mediated by GABA(A) and glycine receptors is not essential for but can serve as a neural substrate to modulate synchronous firing behaviors. Plausible neural mechanisms were proposed to explain the temporal structures of correlated firing between sympathetic fibers.
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Affiliation(s)
- C-K Su
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
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Su CK, Chiang CH, Lee CM, Fan YP, Ho CM, Shyu LY. Computational solution of spike overlapping using data-based subtraction algorithms to resolve synchronous sympathetic nerve discharge. Front Comput Neurosci 2013; 7:149. [PMID: 24198782 PMCID: PMC3813947 DOI: 10.3389/fncom.2013.00149] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 10/09/2013] [Indexed: 01/09/2023] Open
Abstract
Sympathetic nerves conveying central commands to regulate visceral functions often display activities in synchronous bursts. To understand how individual fibers fire synchronously, we establish "oligofiber recording techniques" to record "several" nerve fiber activities simultaneously, using in vitro splanchnic sympathetic nerve-thoracic spinal cord preparations of neonatal rats as experimental models. While distinct spike potentials were easily recorded from collagenase-dissociated sympathetic fibers, a problem arising from synchronous nerve discharges is a higher incidence of complex waveforms resulted from spike overlapping. Because commercial softwares do not provide an explicit solution for spike overlapping, a series of custom-made LabVIEW programs incorporated with MATLAB scripts was therefore written for spike sorting. Spikes were represented as data points after waveform feature extraction and automatically grouped by k-means clustering followed by principal component analysis (PCA) to verify their waveform homogeneity. For dissimilar waveforms with exceeding Hotelling's T(2) distances from the cluster centroids, a unique data-based subtraction algorithm (SA) was used to determine if they were the complex waveforms resulted from superimposing a spike pattern close to the cluster centroid with the other signals that could be observed in original recordings. In comparisons with commercial software, higher accuracy was achieved by analyses using our algorithms for the synthetic data that contained synchronous spiking and complex waveforms. Moreover, both T(2)-selected and SA-retrieved spikes were combined as unit activities. Quantitative analyses were performed to evaluate if unit activities truly originated from single fibers. We conclude that applications of our programs can help to resolve synchronous sympathetic nerve discharges (SND).
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Affiliation(s)
- Chun-Kuei Su
- Institute of Biomedical Sciences, Academia Sinica Taipei, Taiwan
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Su CK, Ho CM, Kuo HH, Wen YC, Chai CY. Sympathetic-correlated c-Fos expression in the neonatal rat spinal cord in vitro. J Biomed Sci 2009; 16:44. [PMID: 19409080 PMCID: PMC2687431 DOI: 10.1186/1423-0127-16-44] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Accepted: 05/01/2009] [Indexed: 02/07/2023] Open
Abstract
An isolated thoracic spinal cord of the neonatal rat in vitro spontaneously generates sympathetic nerve discharge (SND) at ~25 degrees C, but it fails in SND genesis at < or = 10 degrees C. Basal levels of the c-Fos expression in the spinal cords incubated at < or = 10 degrees C and ~25 degrees C were compared to determine the anatomical substrates that might participate in SND genesis. Cells that exhibited c-Fos immunoreactivity were virtually absent in the spinal cords incubated at < or = 10 degrees C. However, in the spinal cords incubated at ~25 degrees C, c-Fos-positive cells were found in the dorsal laminae, the white matter, lamina X, and the intermediolateral cell column (IML). Cell identities were verified by double labeling of c-Fos with neuron-specific nuclear protein (NeuN), glial fibrillary acidic protein (GFAP), or choline acetyltransferase (ChAT). The c-Fos-positive cells distributed in the white matter and lamina X were NeuN-negative or GFAP-positive and were glial cells. Endogenously active neurons showing c-Fos and NeuN double labeling were scattered in the dorsal laminae and concentrated in the IML. Double labeling of c-Fos and ChAT confirmed the presence of active sympathetic preganglionic neurons (SPNs) in the IML. Suppression of SND genesis by tetrodotoxin (TTX) or mecamylamine (MECA, nicotinic receptor blocker) almost abolished c-Fos expression in dorsal laminae, but only mildly affected c-Fos expression in the SPNs. Therefore, c-Fos expression in some SPNs does not require synaptic activation. Our results suggest that spinal SND genesis is initiated from some spontaneously active SPNs, which are capable of TTX- or MECA-resistant c-Fos expression.
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Affiliation(s)
- Chun-Kuei Su
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan, Republic of China
| | - Chiu-Ming Ho
- Department of Anesthesiology, Taipei Veterans General Hospital and National Yang-Ming University, Taipei 112, Taiwan, Republic of China
| | - Hsiao-Hui Kuo
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan, Republic of China
- Department of Anesthesiology, Taipei Veterans General Hospital and National Yang-Ming University, Taipei 112, Taiwan, Republic of China
| | - Yu-Chuan Wen
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan, Republic of China
| | - Chok-Yung Chai
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan, Republic of China
- Department of Physiology and Biophysics, National Defense Medical Center, Taipei 114, Taiwan, Republic of China
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