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Germann M, Maffitt NJ, Poll A, Raditya M, Ting JSK, Baker SN. Pairing Transcranial Magnetic Stimulation and Loud Sounds Produces Plastic Changes in Motor Output. J Neurosci 2023; 43:2469-2481. [PMID: 36859307 PMCID: PMC10082460 DOI: 10.1523/jneurosci.0228-21.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 11/29/2022] [Accepted: 12/09/2022] [Indexed: 03/03/2023] Open
Abstract
Most current methods for neuromodulation target the cortex. Approaches for inducing plasticity in subcortical motor pathways, such as the reticulospinal tract, could help to boost recovery after damage (e.g., stroke). In this study, we paired loud acoustic stimulation (LAS) with transcranial magnetic stimulation (TMS) over the motor cortex in male and female healthy humans. LAS activates the reticular formation; TMS activates descending systems, including corticoreticular fibers. Two hundred paired stimuli were used, with 50 ms interstimulus interval at which LAS suppresses TMS responses. Before and after stimulus pairing, responses in the contralateral biceps muscle to TMS alone were measured. Ten, 20, and 30 min after stimulus pairing ended, TMS responses were enhanced, indicating the induction of LTP. No long-term changes were seen in control experiments which used 200 unpaired TMS or LAS, indicating the importance of associative stimulation. Following paired stimulation, no changes were seen in responses to direct corticospinal stimulation at the level of the medulla, or in the extent of reaction time shortening by a loud sound (StartReact effect), suggesting that plasticity did not occur in corticospinal or reticulospinal synapses. Direct measurements in female monkeys undergoing a similar paired protocol revealed no enhancement of corticospinal volleys after paired stimulation, suggesting no changes occurred in intracortical connections. The most likely substrate for the plastic changes, consistent with all our measurements, is an increase in the efficacy of corticoreticular connections. This new protocol may find utility, as it seems to target different motor circuits compared with other available paradigms.SIGNIFICANCE STATEMENT Induction of plasticity by neurostimulation protocols may be promising to enhance functional recovery after damage such as following stroke, but current protocols mainly target cortical circuits. In this study, we developed a novel paradigm which may generate long-term changes in connections between cortex and brainstem. This could provide an additional tool to modulate and improve recovery.
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Affiliation(s)
- Maria Germann
- Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Natalie J Maffitt
- Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Annie Poll
- Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Marco Raditya
- Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Jason S K Ting
- Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Stuart N Baker
- Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom
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Yi D, Hartner JP, Ung BS, Zhu HL, Watson BO, Chen L. 3D Printed Skull Cap and Benchtop Fabricated Microwire-Based Microelectrode Array for Custom Rat Brain Recordings. Bioengineering (Basel) 2022; 9:bioengineering9100550. [PMID: 36290518 PMCID: PMC9598465 DOI: 10.3390/bioengineering9100550] [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: 09/20/2022] [Revised: 10/05/2022] [Accepted: 10/08/2022] [Indexed: 11/16/2022] Open
Abstract
Microwire microelectrode arrays (MEAs) have been a popular low-cost tool for chronic electrophysiological recordings and are an inexpensive means to record the electrical dynamics crucial to brain function. However, both the fabrication and implantation procedures for multi-MEAs on a single rodent are time-consuming and the accuracy and quality are highly manual skill-dependent. To address the fabrication and implantation challenges for microwire MEAs, (1) a computer-aided designed and 3D printed skull cap for the pre-determined implantation locations of each MEA and (2) a benchtop fabrication approach for low-cost custom microwire MEAs were developed. A proof-of-concept design of a 32-channel 4-MEA (8-wire each) recording system was prototyped and tested through Sprague Dawley rat recordings. The skull cap design, based on the CT-scan of a single rat conforms well with multiple Sprague Dawley rats of various sizes, ages, and weight with a minimal bregma alignment error (A/P axis standard error of the mean = 0.25 mm, M/L axis standard error of the mean = 0.07 mm, n = 6). The prototyped 32-channel system was able to record the spiking activities over five months. The developed benchtop fabrication method and the 3D printed skull cap implantation platform would enable neuroscience groups to conduct in-house design, fabrication, and implantation of customizable microwire MEAs at a lower cost than the current commercial options and experience a shorter lead time for the design modifications and iterations.
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Affiliation(s)
- Dongyang Yi
- Department of Mechanical Engineering, University of Massachusetts Lowell, Lowell, MA 01854, USA
| | | | - Brian S. Ung
- Department of Mechanical Engineering, University of Massachusetts Lowell, Lowell, MA 01854, USA
| | - Harrison L. Zhu
- Department of Mechanical Engineering, University of Massachusetts Lowell, Lowell, MA 01854, USA
| | - Brendon O. Watson
- Department of Psychiatry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Lei Chen
- Department of Mechanical Engineering, University of Massachusetts Lowell, Lowell, MA 01854, USA
- Department of Psychiatry, University of Michigan, Ann Arbor, MI 48109, USA
- Correspondence:
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Extensive Cortical Convergence to Primate Reticulospinal Pathways. J Neurosci 2021; 41:1005-1018. [PMID: 33268548 PMCID: PMC7880280 DOI: 10.1523/jneurosci.1379-20.2020] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 10/19/2020] [Accepted: 10/21/2020] [Indexed: 11/30/2022] Open
Abstract
Early evolution of the motor cortex included development of connections to brainstem reticulospinal neurons; these projections persist in primates. In this study, we examined the organization of corticoreticular connections in five macaque monkeys (one male) using both intracellular and extracellular recordings from reticular formation neurons, including identified reticulospinal cells. Synaptic responses to stimulation of different parts of primary motor cortex (M1) and supplementary motor area (SMA) bilaterally were assessed. Widespread short latency excitation, compatible with monosynaptic transmission over fast-conducting pathways, was observed, as well as longer latency responses likely reflecting a mixture of slower monosynaptic and oligosynaptic pathways. There was a high degree of convergence: 56% of reticulospinal cells with input from M1 received projections from M1 in both hemispheres; for SMA, the equivalent figure was even higher (70%). Of reticulospinal neurons with input from the cortex, 78% received projections from both M1 and SMA (regardless of hemisphere); 83% of reticulospinal cells with input from M1 received projections from more than one of the tested M1 sites. This convergence at the single cell level allows reticulospinal neurons to integrate information from across the motor areas of the cortex, taking account of the bilateral motor context. Reticulospinal connections are known to strengthen following damage to the corticospinal tract, such as after stroke, partially contributing to functional recovery. Extensive corticoreticular convergence provides redundancy of control, which may allow the cortex to continue to exploit this descending pathway even after damage to one area.SIGNIFICANCE STATEMENT The reticulospinal tract (RST) provides a parallel pathway for motor control in primates, alongside the more sophisticated corticospinal system. We found extensive convergent inputs to primate reticulospinal cells from primary and supplementary motor cortex bilaterally. These redundant connections could maintain transmission of voluntary commands to the spinal cord after damage (e.g., after stroke or spinal cord injury), possibly assisting recovery of function.
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Atkinson D, D'Souza T, Rajput JS, Tasnim N, Muthuswamy J, Marvi H, Pancrazio JJ. Advances in Implantable Microelectrode Array Insertion and Positioning. Neuromodulation 2021; 25:789-795. [PMID: 33438369 DOI: 10.1111/ner.13355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 12/14/2020] [Accepted: 12/21/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Microelectrode arrays offer a means to probe the functional circuitry of the brain and the promise of cortical neuroprosthesis for individuals suffering from paralysis or limb loss. These devices are typically comprised of one or more shanks incorporating microelectrode sites, where the shanks are positioned by inserting the devices along a straight path that is normal to the brain surface. The lack of consistent long-term chronic recording technology has driven interest in novel probe design and approaches that go beyond the standard insertion approach that is limited to a single velocity or axis. This review offers a description of typical approaches and associated limitations and surveys emergent methods for implantation of microelectrode arrays, in particular those new approaches that leverage embedded microactuators and extend the insertion direction beyond a single axis. MATERIALS AND METHODS This review paper surveys the current technologies that enable probe implantation, repositioning, and the capability to record/stimulate from a tissue volume. A comprehensive literature search was performed using PubMed, Web of Science, and Google Scholar. RESULTS There has been substantial innovation in the development of microscale and embedded technology that enables probe repositioning to maintain quality recordings in the brain. Innovations in material science have resulted in novel strategies for deployable structures that can record from or stimulate a tissue volume. Moreover, new developments involving magnetically steerable catheters and needles offer an alternative approach to "pull" rather than "push" a probe into the tissue. CONCLUSION We envision the emergence of a new generation of probes and insertion methodologies for neuromodulation applications that enable reliable chronic performance from devices that can be positioned virtually anywhere in the brain.
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Affiliation(s)
- David Atkinson
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, TX, USA
| | - Tania D'Souza
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, TX, USA
| | - Jai Singh Rajput
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, TX, USA
| | - Nishat Tasnim
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, TX, USA
| | - Jit Muthuswamy
- Department of Biomedical Engineering, School of Biological and Health Systems, Engineering, Arizona State University, Tempe, AZ, USA
| | - Hamid Marvi
- School for Engineering of Matter Transport and Energy, Ira A. Fulton Schools of Engineering, Arizona State University, Tempe, AZ, USA
| | - Joseph J Pancrazio
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, TX, USA
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Habekost B, Germann M, Baker SN. Plastic changes in primate motor cortex following paired peripheral nerve stimulation. J Neurophysiol 2020; 125:458-475. [PMID: 33427573 PMCID: PMC8476207 DOI: 10.1152/jn.00288.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Repeated paired stimulation of two peripheral nerves can produce lasting changes in motor cortical excitability, but little is known of the underlying neuronal basis. Here, we trained two macaque monkeys to perform selective thumb and index finger abduction movements. Neural activity was recorded from the contralateral primary motor cortex during task performance, and following stimulation of the ulnar and median nerves, and the nerve supplying the extensor digitorum communis (EDC) muscle. Responses were compared before and after 1 h of synchronous or asynchronous paired ulnar/median nerve stimulation. Task performance was significantly enhanced after asynchronous and impaired after synchronous stimulation. The amplitude of short latency neural responses to median and ulnar nerve stimulation was increased after asynchronous stimulation; later components were reduced after synchronous stimulation. Synchronous stimulation increased neural activity during thumb movement and decreased it during index finger movement; asynchronous stimulation decreased activity during both movements. To assess how well neural activity could separate behavioral or sensory conditions, linear discriminant analysis was used to decode which nerve was stimulated, or which digit moved. Decoding accuracy for nerve stimulation was decreased after synchronous and increased after asynchronous paired stimulation. Decoding accuracy for task performance was decreased after synchronous but was unchanged after asynchronous paired stimulation. Paired stimulation produces changes in motor cortical circuits that outlast the stimulation. Some of these changes depend on precise stimulus timing. NEW & NOTEWORTHY Paired stimulation of peripheral nerves for 1 h induced lasting changes in neural responses within the motor cortex to nerve stimulation and to performance of a behavioral task. These changes were sufficient to alter the efficiency with which activity could encode stimulus type. Stimuli that can be easily applied noninvasively in human subjects can alter central motor circuits.
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Affiliation(s)
- Bonne Habekost
- Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Maria Germann
- Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Stuart N Baker
- Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
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Jerjian SJ, Sahani M, Kraskov A. Movement initiation and grasp representation in premotor and primary motor cortex mirror neurons. eLife 2020; 9:e54139. [PMID: 32628107 PMCID: PMC7384858 DOI: 10.7554/elife.54139] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 07/06/2020] [Indexed: 11/13/2022] Open
Abstract
Pyramidal tract neurons (PTNs) within macaque rostral ventral premotor cortex (F5) and (M1) provide direct input to spinal circuitry and are critical for skilled movement control. Contrary to initial hypotheses, they can also be active during action observation, in the absence of any movement. A population-level understanding of this phenomenon is currently lacking. We recorded from single neurons, including identified PTNs, in (M1) (n = 187), and F5 (n = 115) as two adult male macaques executed, observed, or withheld (NoGo) reach-to-grasp actions. F5 maintained a similar representation of grasping actions during both execution and observation. In contrast, although many individual M1 neurons were active during observation, M1 population activity was distinct from execution, and more closely aligned to NoGo activity, suggesting this activity contributes to withholding of self-movement. M1 and its outputs may dissociate initiation of movement from representation of grasp in order to flexibly guide behaviour.
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Affiliation(s)
- Steven Jack Jerjian
- Department of Clinical and Movement Neurosciences, UCL Institute of NeurologyLondonUnited Kingdom
| | - Maneesh Sahani
- Gatsby Computational Neuroscience Unit, University College LondonLondonUnited Kingdom
| | - Alexander Kraskov
- Department of Clinical and Movement Neurosciences, UCL Institute of NeurologyLondonUnited Kingdom
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Gupta P, Balasubramaniam N, Chang HY, Tseng FG, Santra TS. A Single-Neuron: Current Trends and Future Prospects. Cells 2020; 9:E1528. [PMID: 32585883 PMCID: PMC7349798 DOI: 10.3390/cells9061528] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/15/2020] [Accepted: 06/19/2020] [Indexed: 12/11/2022] Open
Abstract
The brain is an intricate network with complex organizational principles facilitating a concerted communication between single-neurons, distinct neuron populations, and remote brain areas. The communication, technically referred to as connectivity, between single-neurons, is the center of many investigations aimed at elucidating pathophysiology, anatomical differences, and structural and functional features. In comparison with bulk analysis, single-neuron analysis can provide precise information about neurons or even sub-neuron level electrophysiology, anatomical differences, pathophysiology, structural and functional features, in addition to their communications with other neurons, and can promote essential information to understand the brain and its activity. This review highlights various single-neuron models and their behaviors, followed by different analysis methods. Again, to elucidate cellular dynamics in terms of electrophysiology at the single-neuron level, we emphasize in detail the role of single-neuron mapping and electrophysiological recording. We also elaborate on the recent development of single-neuron isolation, manipulation, and therapeutic progress using advanced micro/nanofluidic devices, as well as microinjection, electroporation, microelectrode array, optical transfection, optogenetic techniques. Further, the development in the field of artificial intelligence in relation to single-neurons is highlighted. The review concludes with between limitations and future prospects of single-neuron analyses.
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Affiliation(s)
- Pallavi Gupta
- Department of Engineering Design, Indian Institute of Technology Madras, Tamil Nadu 600036, India; (P.G.); (N.B.)
| | - Nandhini Balasubramaniam
- Department of Engineering Design, Indian Institute of Technology Madras, Tamil Nadu 600036, India; (P.G.); (N.B.)
| | - Hwan-You Chang
- Department of Medical Science, National Tsing Hua University, Hsinchu 30013, Taiwan;
| | - Fan-Gang Tseng
- Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan;
| | - Tuhin Subhra Santra
- Department of Engineering Design, Indian Institute of Technology Madras, Tamil Nadu 600036, India; (P.G.); (N.B.)
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Xu W, Baker SN. In vitro characterization of intrinsic properties and local synaptic inputs to pyramidal neurons in macaque primary motor cortex. Eur J Neurosci 2018; 48:2071-2083. [PMID: 30019413 PMCID: PMC6175011 DOI: 10.1111/ejn.14076] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 06/29/2018] [Accepted: 07/12/2018] [Indexed: 01/23/2023]
Abstract
Primates (including humans) have a highly developed corticospinal tract, and specialized motor cortical areas which differ in key ways from rodents. Much work on motor cortex has therefore used macaque monkeys as a good animal model for human motor control. However, there is a paucity of data describing the fundamental functional architecture of primate primary motor cortex, which is best addressed with in vitro approaches. In this study we examined the cellular properties and the micro-circuitry of the adult macaque primary motor cortex by carrying out in-vitro intracellular recordings. We aimed to characterize the basic properties of the cortical circuitry by studying the intrinsic properties of its pyramidal neurons and their physiological interconnectivity. We studied the passive and active electrophysiological properties of pyramidal neurons in both superficial and deep cortical layers. Both superficial and deep pyramidal neurons exhibited bursting behaviour that could act as powerful excitation for downstream targets. Synaptic connections were lamina specific. Neurons in the deep layers had convergent excitatory inputs from all cortical layers whereas superficial neurons had only significant inputs from superficial layers. This sheds light on the functional architecture of the primate primary motor cortex and how its output is shaped. We also took the unique opportunity in our recording technique to characterize the relationship between intracellular and extracellular spike waveforms, with implications for cell-type identification in studies in awake behaving monkey. Our results will aid the interpretation of primate studies into motor control involving extracellular spike recordings and electrical stimulation in primary motor cortex.
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Affiliation(s)
- Wei Xu
- Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Stuart N. Baker
- Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
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9
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Classification of Neurons in the Primate Reticular Formation and Changes after Recovery from Pyramidal Tract Lesion. J Neurosci 2018; 38:6190-6206. [PMID: 29793974 PMCID: PMC6031583 DOI: 10.1523/jneurosci.3371-17.2018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 04/06/2018] [Accepted: 04/12/2018] [Indexed: 12/27/2022] Open
Abstract
The reticular formation is important in primate motor control, both in health and during recovery after brain damage. Little is known about the different neurons present in the reticular nuclei. Here we recorded extracellular spikes from the reticular formation in five healthy female awake behaving monkeys (193 cells), and in two female monkeys 1 year after recovery from a unilateral pyramidal tract lesion (125 cells). Analysis of spike shape and four measures derived from the interspike interval distribution identified four clusters of neurons in control animals. Cluster 1 cells had a slow firing rate. Cluster 2 cells had narrow spikes and irregular firing, which often included high-frequency bursts. Cluster 3 cells were highly rhythmic and fast firing. Cluster 4 cells showed negative spikes. A separate population of 42 cells was antidromically identified as reticulospinal neurons in five anesthetized female monkeys. The distribution of spike width in these cells closely overlaid the distribution for cluster 2, leading us tentatively to suggest that cluster 2 included neurons with reticulospinal projections. In animals after corticospinal lesion, cells could be identified in all four clusters. The firing rate of cells in clusters 1 and 2 was increased in lesioned animals relative to control animals (by 52% and 60%, respectively); cells in cluster 2 were also more regular and more bursting in the lesioned animals. We suggest that changes in both membrane properties and local circuits within the reticular formation occur following lesioning, potentially increasing reticulospinal output to help compensate for lost corticospinal descending drive. SIGNIFICANCE STATEMENT This work is the first to subclassify neurons in the reticular formation, providing insights into the local circuitry of this important but little understood structure. The approach developed can be applied to any extracellular recording from this region, allowing future studies to place their data within our current framework of four neural types. Changes in reticular neurons may be important to subserve functional recovery after damage in human patients, such as after stroke or spinal cord injury.
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A simple, inexpensive method for subcortical stereotactic targeting in nonhuman primates. J Neurosci Methods 2018; 305:89-97. [PMID: 29768185 DOI: 10.1016/j.jneumeth.2018.05.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 05/10/2018] [Accepted: 05/12/2018] [Indexed: 01/06/2023]
Abstract
BACKGROUND Many current neuroscience studies in large animal models have focused on recordings from cortical structures. While sufficient for analyzing sensorimotor systems, many processes are modulated by subcortical nuclei. Large animal models, such as nonhuman primates (NHP), provide an optimal model for studying these circuits, but the ability to target subcortical structures has been hampered by lack of a straightforward approach to targeting. NEW METHOD Here we present a method of subcortical targeting in NHP that uses MRI-compatible titanium screws as fiducials. The in vivo study used a cellular marker for histologic confirmation of accuracy. RESULTS Histologic results are presented showing a cellular stem cell marker within targeted structures, with mean errors ± standard deviations (SD) of 1.40 ± 1.19 mm in the X-axis and 0.9 ± 0.97 mm in the Z-axis. The Y-axis errors ± SD ranged from 1.5 ± 0.43 to 4.2 ± 1.72 mm. COMPARISON WITH EXISTING METHODS This method is easy and inexpensive, and requires no fabrication of equipment, keeping in mind the goal of optimizing a technique for implantation or injection into multiple interconnected areas. CONCLUSION This procedure will enable primate researchers to target deep, subcortical structures more precisely in animals of varying ages and weights.
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Zaaimi B, Dean LR, Baker SN. Different contributions of primary motor cortex, reticular formation, and spinal cord to fractionated muscle activation. J Neurophysiol 2018; 119:235-250. [PMID: 29046427 PMCID: PMC5866475 DOI: 10.1152/jn.00672.2017] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 10/12/2017] [Accepted: 10/12/2017] [Indexed: 12/12/2022] Open
Abstract
Coordinated movement requires patterned activation of muscles. In this study, we examined differences in selective activation of primate upper limb muscles by cortical and subcortical regions. Five macaque monkeys were trained to perform a reach and grasp task, and electromyogram (EMG) was recorded from 10 to 24 muscles while weak single-pulse stimuli were delivered through microelectrodes inserted in the motor cortex (M1), reticular formation (RF), or cervical spinal cord (SC). Stimulus intensity was adjusted to a level just above threshold. Stimulus-evoked effects were assessed from averages of rectified EMG. M1, RF, and SC activated 1.5 ± 0.9, 1.9 ± 0.8, and 2.5 ± 1.6 muscles per site (means ± SD); only M1 and SC differed significantly. In between recording sessions, natural muscle activity in the home cage was recorded using a miniature data logger. A novel analysis assessed how well natural activity could be reconstructed by stimulus-evoked responses. This provided two measures: normalized vector length L, reflecting how closely aligned natural and stimulus-evoked activity were, and normalized residual R, measuring the fraction of natural activity not reachable using stimulus-evoked patterns. Average values for M1, RF, and SC were L = 119.1 ± 9.6, 105.9 ± 6.2, and 109.3 ± 8.4% and R = 50.3 ± 4.9, 56.4 ± 3.5, and 51.5 ± 4.8%, respectively. RF was significantly different from M1 and SC on both measurements. RF is thus able to generate an approximation to the motor output with less activation than required by M1 and SC, but M1 and SC are more precise in reaching the exact activation pattern required. Cortical, brainstem, and spinal centers likely play distinct roles, as they cooperate to generate voluntary movements. NEW & NOTEWORTHY Brainstem reticular formation, primary motor cortex, and cervical spinal cord intermediate zone can all activate primate upper limb muscles. However, brainstem output is more efficient but less precise in producing natural patterns of motor output than motor cortex or spinal cord. We suggest that gross muscle synergies from the reticular formation are sculpted and refined by motor cortex and spinal circuits to reach the finely fractionated output characteristic of dexterous primate upper limb movements.
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Affiliation(s)
- Boubker Zaaimi
- Institute of Neuroscience, Newcastle University , Newcastle upon Tyne , United Kingdom
| | - Lauren R Dean
- Institute of Neuroscience, Newcastle University , Newcastle upon Tyne , United Kingdom
| | - Stuart N Baker
- Institute of Neuroscience, Newcastle University , Newcastle upon Tyne , United Kingdom
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12
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Corticospinal Inputs to Primate Motoneurons Innervating the Forelimb from Two Divisions of Primary Motor Cortex and Area 3a. J Neurosci 2016; 36:2605-16. [PMID: 26937002 DOI: 10.1523/jneurosci.4055-15.2016] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Previous anatomical work in primates has suggested that only corticospinal axons originating in caudal primary motor cortex ("new M1") and area 3a make monosynaptic cortico-motoneuronal connections with limb motoneurons. By contrast, the more rostral "old M1" is proposed to control motoneurons disynaptically via spinal interneurons. In six macaque monkeys, we examined the effects from focal stimulation within old and new M1 and area 3a on 135 antidromically identified motoneurons projecting to the upper limb. EPSPs with segmental latency shorter than 1.2 ms were classified as definitively monosynaptic; these were seen only after stimulation within new M1 or at the new M1/3a border (incidence 6.6% and 1.3%, respectively; total n = 27). However, most responses had longer latencies. Using measures of the response facilitation after a second stimulus compared with the first, and the reduction in response latency after a third stimulus compared with the first, we classified these late responses as likely mediated by either long-latency monosynaptic (n = 108) or non-monosynaptic linkages (n = 108). Both old and new M1 generated putative long-latency monosynaptic and non-monosynaptic effects; the majority of responses from area 3a were non-monosynaptic. Both types of responses from new M1 had significantly greater amplitude than those from old M1. We suggest that slowly conducting corticospinal fibers from old M1 generate weak late monosynaptic effects in motoneurons. These may represent a stage in control of primate motoneurons by the cortex intermediate between disynaptic output via an interposed interneuron seen in nonprimates and the fast direct monosynaptic connections present in new M1. SIGNIFICANCE STATEMENT The corticospinal tract in Old World primates makes monosynaptic connections to motoneurons; previous anatomical work suggests that these connections come only from corticospinal tract (CST) neurons in the subdivision of primary motor cortex within the central sulcus ("new M1") and area 3a. Here, we show using electrophysiology that cortico-motoneuronal connections from fast conducting CST fibers are indeed made exclusively from new M1 and its border with 3a. However, we also show that all parts of M1 and 3a have cortico-motoneuronal connections over more slowly conducting CST axons, as well as exert disynaptic effects on motoneurons via interposed interneurons. Differences between old and new M1 are thus more subtle than previously thought.
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Cooperrider J, Gale JT, Gopalakrishnan R, Chan HH, Wathen C, Park HJ, Baker KB, Shaikh AG, Machado AG. Differential frequency modulation of neural activity in the lateral cerebellar nucleus in failed and successful grasps. Exp Neurol 2015; 277:27-34. [PMID: 26698925 DOI: 10.1016/j.expneurol.2015.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 12/05/2015] [Accepted: 12/12/2015] [Indexed: 10/22/2022]
Abstract
The olivo-cerebellar system has an essential role in the detection and adaptive correction of movement errors. While there is evidence of an error signal in the cerebellar cortex and inferior olivary nucleus, the deep cerebellar nuclei have been less thoroughly investigated. Here, we recorded local field potential activity in the rodent lateral cerebellar nucleus during a skilled reaching task and compared event-related changes in neural activity between unsuccessful and successful attempts. Increased low gamma (40-50 Hz) band power was present throughout the reach and grasp behavior, with no difference between successful and unsuccessful trials. Beta band (12-30 Hz) power, however, was significantly increased in unsuccessful reaches, compared to successful, throughout the trial, including during the epoch preceding knowledge of the trial's outcome. This beta band activity was greater in unsuccessful trials of high-performing days, compared to unsuccessful trials of low-performing days, indicating that this activity may reflect an error prediction signal, developed over the course of motor learning. These findings suggest an error-related discriminatory oscillatory hallmark of movement in the deep cerebellar nuclei.
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Affiliation(s)
- Jessica Cooperrider
- Center for Neurological Restoration, Department of Neurosurgery, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195, United States; Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, United States
| | - John T Gale
- Center for Neurological Restoration, Department of Neurosurgery, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195, United States; Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, United States
| | - Raghavan Gopalakrishnan
- Center for Neurological Restoration, Department of Neurosurgery, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195, United States
| | - Hugh H Chan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, United States
| | - Connor Wathen
- Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio 44195, United States
| | - Hyun-Joo Park
- Center for Neurological Restoration, Department of Neurosurgery, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195, United States
| | - Kenneth B Baker
- Department of Neurology, University of Minnesota, Minneapolis, MN 55455, United States
| | - Aasef G Shaikh
- Center for Neurological Restoration, Department of Neurosurgery, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195, United States
| | - Andre G Machado
- Center for Neurological Restoration, Department of Neurosurgery, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195, United States; Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, United States.
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14
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Witham CL, Baker SN. Information theoretic analysis of proprioceptive encoding during finger flexion in the monkey sensorimotor system. J Neurophysiol 2014; 113:295-306. [PMID: 25298385 PMCID: PMC4294561 DOI: 10.1152/jn.00178.2014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
There is considerable debate over whether the brain codes information using neural firing rate or the fine-grained structure of spike timing. We investigated this issue in spike discharge recorded from single units in the sensorimotor cortex, deep cerebellar nuclei, and dorsal root ganglia in macaque monkeys trained to perform a finger flexion task. The task required flexion to four different displacements against two opposing torques; the eight possible conditions were randomly interleaved. We used information theory to assess coding of task condition in spike rate, discharge irregularity, and spectral power in the 15- to 25-Hz band during the period of steady holding. All three measures coded task information in all areas tested. Information coding was most often independent between irregularity and 15-25 Hz power (60% of units), moderately redundant between spike rate and irregularity (56% of units redundant), and highly redundant between spike rate and power (93%). Most simultaneously recorded unit pairs coded using the same measure independently (86%). Knowledge of two measures often provided extra information about task, compared with knowledge of only one alone. We conclude that sensorimotor systems use both rate and temporal codes to represent information about a finger movement task. As well as offering insights into neural coding, this work suggests that incorporating spike irregularity into algorithms used for brain-machine interfaces could improve decoding accuracy.
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Affiliation(s)
- Claire L Witham
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Stuart N Baker
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
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15
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Firmin L, Field P, Maier MA, Kraskov A, Kirkwood PA, Nakajima K, Lemon RN, Glickstein M. Axon diameters and conduction velocities in the macaque pyramidal tract. J Neurophysiol 2014; 112:1229-40. [PMID: 24872533 PMCID: PMC4137254 DOI: 10.1152/jn.00720.2013] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Small axons far outnumber larger fibers in the corticospinal tract, but the function of these small axons remains poorly understood. This is because they are difficult to identify, and therefore their physiology remains obscure. To assess the extent of the mismatch between anatomic and physiological measures, we compared conduction time and velocity in a large number of macaque corticospinal neurons with the distribution of axon diameters at the level of the medullary pyramid, using both light and electron microscopy. At the electron microscopic level, a total of 4,172 axons were sampled from 2 adult male macaque monkeys. We confirmed that there were virtually no unmyelinated fibers in the pyramidal tract. About 14% of pyramidal tract axons had a diameter smaller than 0.50 μm (including myelin sheath), most of these remaining undetected using light microscopy, and 52% were smaller than 1 μm. In the electrophysiological study, we determined the distribution of antidromic latencies of pyramidal tract neurons, recorded in primary motor cortex, ventral premotor cortex, and supplementary motor area and identified by pyramidal tract stimulation (799 pyramidal tract neurons, 7 adult awake macaques) or orthodromically from corticospinal axons recorded at the mid-cervical spinal level (192 axons, 5 adult anesthetized macaques). The distribution of antidromic and orthodromic latencies of corticospinal neurons was strongly biased toward those with large, fast-conducting axons. Axons smaller than 3 μm and with a conduction velocity below 18 m/s were grossly underrepresented in our electrophysiological recordings, and those below 1 μm (6 m/s) were probably not represented at all. The identity, location, and function of the majority of corticospinal neurons with small, slowly conducting axons remains unknown.
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Affiliation(s)
- L Firmin
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, United Kingdom; Research Department of Cell and Developmental Biology, University College London, United Kingdom; FR3636 Centre National de la Recherche Scientifique/Université Paris Descartes and Université Paris Diderot, Sorbonne Paris Cité, France; and
| | - P Field
- Research Department of Cell and Developmental Biology, University College London, United Kingdom
| | - M A Maier
- FR3636 Centre National de la Recherche Scientifique/Université Paris Descartes and Université Paris Diderot, Sorbonne Paris Cité, France; and
| | - A Kraskov
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, United Kingdom
| | - P A Kirkwood
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, United Kingdom
| | - K Nakajima
- Department of Physiology, Faculty of Medicine, Kinki University, Osaka, Japan
| | - R N Lemon
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, United Kingdom
| | - M Glickstein
- Research Department of Cell and Developmental Biology, University College London, United Kingdom;
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16
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Koželj S, Baker SN. Different phase delays of peripheral input to primate motor cortex and spinal cord promote cancellation at physiological tremor frequencies. J Neurophysiol 2014; 111:2001-16. [PMID: 24572094 PMCID: PMC4044345 DOI: 10.1152/jn.00935.2012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Neurons in the spinal cord and motor cortex (M1) are partially phase-locked to cycles of physiological tremor, but with opposite phases. Convergence of spinal and cortical activity onto motoneurons may thus produce phase cancellation and a reduction in tremor amplitude. The mechanisms underlying this phase difference are unknown. We investigated coherence between spinal and M1 activity with sensory input. In two anesthetized monkeys, we electrically stimulated the medial, ulnar, deep radial, and superficial radial nerves; stimuli were timed as independent Poisson processes (rate 10 Hz). Single units were recorded from M1 (147 cells) or cervical spinal cord (61 cells). Ninety M1 cells were antidromically identified as pyramidal tract neurons (PTNs); M1 neurons were additionally classified according to M1 subdivision (rostral/caudal, M1r/c). Spike-stimulus coherence analysis revealed significant coupling over a broad range of frequencies, with the strongest coherence at <50 Hz. Delays implied by the slope of the coherence phase-frequency relationship were greater than the response onset latency, reflecting the importance of late response components for the transmission of oscillatory inputs. The spike-stimulus coherence phase over the 6–13 Hz physiological tremor band differed significantly between M1 and spinal cells (phase differences relative to the cord of 2.72 ± 0.29 and 1.72 ± 0.37 radians for PTNs from M1c and M1r, respectively). We conclude that different phases of the response to peripheral input could partially underlie antiphase M1 and spinal cord activity during motor behavior. The coordinated action of spinal and cortical feedback will act to reduce tremulous oscillations, possibly improving the overall stability and precision of motor control.
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Affiliation(s)
- Saša Koželj
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Stuart N Baker
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
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17
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Cheron G, Prigogine C, Cheron J, Márquez-Ruiz J, Traub RD, Dan B. Emergence of a 600-Hz buzz UP state Purkinje cell firing in alert mice. Neuroscience 2014; 263:15-26. [PMID: 24440752 DOI: 10.1016/j.neuroscience.2014.01.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 12/19/2013] [Accepted: 01/03/2014] [Indexed: 12/25/2022]
Abstract
Purkinje cell (PC) firing represents the sole output from the cerebellar cortex onto the deep cerebellar and vestibular nuclei. Here, we explored the different modes of PC firing in alert mice by extracellular recording. We confirm the existence of a tonic and/or bursting and quiescent modes corresponding to UP and DOWN state, respectively. We demonstrate the existence of a novel 600-Hz buzz UP state of firing characterized by simple spikes (SS) of very small amplitude. Climbing fiber (CF) input is able to switch the 600-Hz buzz to the DOWN state, as for the classical UP-to-DOWN state transition. Conversely, the CF input can initiate a typical SS pattern terminating into 600-Hz buzz. The 600-Hz buzz was transiently suppressed by whisker pad stimulation demonstrating that it remained responsive to peripheral input. It must not be mistaken for a DOWN state or the sign of PC inhibition. Complex spike (CS) frequency was increased during the 600-Hz buzz, indicating that this PC output actively contributes to the cerebello-olivary loop by triggering a disinhibition of the inferior olive. During the 600-Hz buzz, the first depolarizing component of the CS was reduced and the second depolarizing component was suppressed. Consistent with our experimental observations, using a 559-compartment single-PC model - in which PC UP state (of about -43mV) was obtained by the combined action of large tonic AMPA conductances and counterbalancing GABAergic inhibition - removal of this inhibition produced the 600-Hz buzz; the simulated buzz frequency decreased following an artificial CS.
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Affiliation(s)
- G Cheron
- Laboratory of Electrophysiology, Université de Mons, 7000 Mons, Belgium; Laboratory of Neurophysiology and Movement Biomechanics, CP601, ULB Neurosciences Institut, Université Libre de Bruxelles, 1070 Brussels, Belgium.
| | - C Prigogine
- Laboratory of Electrophysiology, Université de Mons, 7000 Mons, Belgium; Laboratory of Neurophysiology and Movement Biomechanics, CP601, ULB Neurosciences Institut, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - J Cheron
- Laboratory of Electrophysiology, Université de Mons, 7000 Mons, Belgium; Laboratory of Neurophysiology and Movement Biomechanics, CP601, ULB Neurosciences Institut, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - J Márquez-Ruiz
- División de Neurociencias, Universidad Pablo de Olavide, 41013 Sevilla, Spain
| | - R D Traub
- Department of Physical Sciences, IBM T.J. Watson Research Center, Yorktown Heights, NY 10598, USA; Department of Neurology, Columbia University, New York, NY 10032, USA
| | - B Dan
- Laboratory of Neurophysiology and Movement Biomechanics, CP601, ULB Neurosciences Institut, Université Libre de Bruxelles, 1070 Brussels, Belgium
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Anderson NR, Blakely T, Schalk G, Leuthardt EC, Moran DW. Electrocorticographic (ECoG) correlates of human arm movements. Exp Brain Res 2012; 223:1-10. [PMID: 23001369 DOI: 10.1007/s00221-012-3226-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 08/08/2012] [Indexed: 10/27/2022]
Abstract
Invasive and non-invasive brain-computer interface (BCI) studies have long focused on the motor cortex for kinematic control of artificial devices. Most of these studies have used single-neuron recordings or electroencephalography (EEG). Electrocorticography (ECoG) is a relatively new recording modality in BCI research that has primarily been built on successes in EEG recordings. We built on prior experiments related to single-neuron recording and quantitatively compare the extent to which different brain regions reflect kinematic tuning parameters of hand speed, direction, and velocity in both a reaching and tracing task in humans. Hand and arm movement experiments using ECoG have shown positive results before, but the tasks were not designed to tease out which kinematics are encoded. In non-human primates, the relationships among these kinematics have been more carefully documented, and we sought to begin elucidating that relationship in humans using ECoG. The largest modulation in ECoG activity for direction, speed, and velocity representation was found in the primary motor cortex. We also found consistent cosine tuning across both tasks, to hand direction and velocity in the high gamma band (70-160 Hz). Thus, the results of this study clarify the neural substrates involved in encoding aspects of motor preparation and execution and confirm the important role of the motor cortex in BCI applications.
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Affiliation(s)
- Nicholas R Anderson
- Department of Biomedical Engineering, Cortech Solutions and Washington University in Saint Louis, 1409 Audubon Blvd, Wilmington, NC 28403, USA.
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Soteropoulos DS, Williams ER, Baker SN. Cells in the monkey ponto-medullary reticular formation modulate their activity with slow finger movements. J Physiol 2012; 590:4011-27. [PMID: 22641776 PMCID: PMC3476645 DOI: 10.1113/jphysiol.2011.225169] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 05/25/2012] [Indexed: 01/24/2023] Open
Abstract
Recent work has shown that the primate reticulospinal tract can influence spinal interneurons and motoneurons involved in control of the hand. However, demonstrating connectivity does not reveal whether reticular outputs are modulated during the control of different types of hand movement. Here, we investigated how single unit discharge in the pontomedullary reticular formation (PMRF) modulated during performance of a slow finger movement task in macaque monkeys. Two animals performed an index finger flexion–extension task to track a target presented on a computer screen; single units were recorded both from ipsilateral PMRF (115 cells) and contralateral primary motor cortex (M1, 210 cells). Cells in both areas modulated their activity with the task (M1: 87%, PMRF: 86%). Some cells (18/115 in PMRF; 96/210 in M1) received sensory input from the hand, showing a short-latency modulation in their discharge following a rapid passive extension movement of the index finger. Effects in ipsilateral electromyogram to trains of stimuli were recorded at 45 sites in the PMRF. These responses involved muscles controlling the digits in 13/45 sites (including intrinsic hand muscles, 5/45 sites). We conclude that PMRF may contribute to the control of fine finger movements, in addition to its established role in control of more proximal limb and trunk movements. This finding may be especially important in understanding functional recovery after brain lesions such as stroke.
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Affiliation(s)
- Demetris S Soteropoulos
- S. Baker: Institute of Neuroscience, Henry Wellcome Building, Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
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20
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Seidl K, Torfs T, De Mazière PA, Van Dijck G, Csercsa R, Dombovari B, Nurcahyo Y, Ramirez H, Van Hulle MM, Orban GA, Paul O, Ulbert I, Neves H, Ruther P. Control and data acquisition software for high-density CMOS-based microprobe arrays implementing electronic depth control. ACTA ACUST UNITED AC 2012; 55:183-91. [PMID: 20441537 DOI: 10.1515/bmt.2010.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This paper presents the NeuroSelect software for managing the electronic depth control of cerebral CMOS-based microprobes for extracellular in vivo recordings. These microprobes contain up to 500 electronically switchable electrodes which can be appropriately selected with regard to specific neuron locations in the course of a recording experiment. NeuroSelect makes it possible to scan the electrodes electronically and to (re)select those electrodes of best signal quality resulting in a closed-loop design of a neural acquisition system. The signal quality is calculated by the relative power of the spikes compared with the background noise. The spikes are detected by an adaptive threshold using a robust estimator of the standard deviation. Electrodes can be selected in a manual or semi-automatic mode based on the signal quality. This electronic depth control constitutes a significant improvement for multielectrode probes, given that so far the only alternative has been the fine positioning by mechanical probe translation. In addition to managing communication with the hardware controller of the probe array, the software also controls acquisition, processing, display and storage of the neural signals for further analysis.
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Affiliation(s)
- Karsten Seidl
- Department of Microsystems Engineering (IMTEK), Microsystem Materials Laboratory, University of Freiburg, Georges-Koehler-Allee 103, Freiburg, Germany.
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21
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Expert-like performance of an autonomous spike tracking algorithm in isolating and maintaining single units in the macaque cortex. J Neurosci Methods 2012; 205:72-85. [DOI: 10.1016/j.jneumeth.2011.12.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 12/20/2011] [Accepted: 12/21/2011] [Indexed: 11/22/2022]
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22
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Feingold J, Desrochers TM, Fujii N, Harlan R, Tierney PL, Shimazu H, Amemori KI, Graybiel AM. A system for recording neural activity chronically and simultaneously from multiple cortical and subcortical regions in nonhuman primates. J Neurophysiol 2011; 107:1979-95. [PMID: 22170970 DOI: 10.1152/jn.00625.2011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A major goal of neuroscience is to understand the functions of networks of neurons in cognition and behavior. Recent work has focused on implanting arrays of ∼100 immovable electrodes or smaller numbers of individually adjustable electrodes, designed to target a few cortical areas. We have developed a recording system that allows the independent movement of hundreds of electrodes chronically implanted in several cortical and subcortical structures. We have tested this system in macaque monkeys, recording simultaneously from up to 127 electrodes in 14 brain regions for up to one year at a time. A key advantage of the system is that it can be used to sample different combinations of sites over prolonged periods, generating multiple snapshots of network activity from a single implant. Used in conjunction with microstimulation and injection methods, this versatile system represents a powerful tool for studying neural network activity in the primate brain.
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Affiliation(s)
- Joseph Feingold
- Massachusetts Institute of Technology, 43 Vassar St., Bldg. 46-6133, Cambridge, MA 02139, USA
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23
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Large identified pyramidal cells in macaque motor and premotor cortex exhibit "thin spikes": implications for cell type classification. J Neurosci 2011; 31:14235-42. [PMID: 21976508 DOI: 10.1523/jneurosci.3142-11.2011] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Recent studies have suggested that extracellular recordings of putative cortical interneurons have briefer spikes than those of pyramidal neurons, providing a means of identifying cortical cell types in recordings from awake monkeys. To test this, we investigated the spike duration of antidromically identified pyramidal tract neurons (PTNs) recorded from primary motor (M1) or ventral premotor cortex (area F5) in 4 awake macaque monkeys. M1 antidromic latencies (ADLs) were skewed toward short ADLs (151 PTNs; 0.5-5.5 ms, median 1.1 ms) and significantly different from that of F5 ADLs (54 PTNs; 1.0-6.9 ms, median 2.6 ms). The duration of PTN spikes, recorded with a high-pass filter of 300 Hz and measured from the negative trough to the positive peak of the spike waveform, ranged from 0.15 to 0.71 ms. Importantly, we found a positive linear correlation between ADL and spike duration in both M1 (R(2) = 0.40, p < 0.001) and F5 (R(2) = 0.57, p < 0.001). Thus PTNs with the shortest ADL (fastest axons) had the briefest spikes, and since PTN soma size is correlated with axon size and conduction velocity, it is likely that the largest pyramidal neurons (Betz cells in M1) have spikes with short durations (0.15-0.45 ms), which overlap heavily with those reported for putative interneurons in previous studies in non-primates. In summary, one class of physiologically identified cortical pyramidal neuron exhibits a wide variety of spike durations and the results suggest that spike duration alone may not be a reliable indicator of cell type.
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Dubowitz DJ, Scadeng M. A frameless stereotaxic MRI technique for macaque neuroscience studies. Open Neuroimag J 2011; 5:198-205. [PMID: 22253662 PMCID: PMC3257065 DOI: 10.2174/1874440001105010198] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 01/06/2011] [Accepted: 01/14/2011] [Indexed: 12/03/2022] Open
Abstract
MRI has achieved widespread use for preplanning neuroscience procedures for non-human primate studies. However, orienting imaging studies in stereotaxic space has relied primarily on using a stereotaxic frame or co-registering fiducial markers with the neuroimaging. In this study, we present a simple approach in which the MRI dataset is aligned to the bony landmarks that define the Frankfurt stereotaxic baseline plane, without the need for a stereotaxic frame or additional external fiducials. To facilitate localizing the bony landmarks (infraorbital margin, external bony auditory meatus) on the MRI scans additional imaging landmarks (mid ocular plane, temporomandibular joint) are discussed that provide supplementary and readily visible points of reference. The frameless MRI stereotaxic technique was evaluated in 8 rhesus macaque monkeys using 3D fast gradient echo MRI images with 0.7mm isotropic resolution. 1) Difference in stereotaxic coordinates of fiducial markers was compared between a traditional stereotaxic frame and the frameless MRI technique (n=2). 2) Differences in stereotaxic coordinates for cerebral regions were compared between the frameless MRI technique and MRI obtained with the animal positioned in a MRI-compatible stereotaxic frame (n=4). 3) The frameless MRI technique was further refined to prescribe electrode penetrations within a dural recording chamber in stereotaxic coordinates relative to the electrode microdrive. Differences in MRI coordinates were compared with the electrode microdrive (n=3). Mean localization of fiducial markers differed by 1.6 +/- 0.6 mm between the frameless MRI technique and a traditional stereotaxic frame. Between the frameless technique and an MRI-compatible stereotaxic frame, localization of cerebral anatomy differed by 2.8 +/- 2.2 mm with the primary source of error being a pitch-up rotation in the sagittal plane. This localization difference was reduced to 0.5 +/- 0.6 mm when this rotation was removed. Frameless MRI coordinates for electrode tracts within the dural recording chamber were within 0.5mm +/- 0.2 mm of the electrode microdrive readings. This simple technique provides the ability to accurately plan surgery and neurophysiological recordings in an individual animal, and to define the location of cerebral anatomy and electrode or injection tracts using publically available software, and without the need for dedicated MRI-compatible localization hardware. The reduced need for deep anesthesia (a necessity with traditional stereotaxic frames) makes the technique more amenable for functional MRI studies. Since each animal provides the bony landmarks to define their own stereotaxic space, this technique is readily applicable to other species.
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Affiliation(s)
- David J Dubowitz
- Center for Functional Magnetic Resonance Imaging, Department of Radiology, University of California San Diego, La Jolla, CA 92093-0677, USA
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25
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Lack of evidence for direct corticospinal contributions to control of the ipsilateral forelimb in monkey. J Neurosci 2011; 31:11208-19. [PMID: 21813682 DOI: 10.1523/jneurosci.0257-11.2011] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Strong experimental evidence implicates the corticospinal tract in voluntary control of the contralateral forelimb. Its potential role in controlling the ipsilateral forelimb is less well understood, although anatomical projections to ipsilateral spinal circuits are identified. We investigated inputs to motoneurons innervating hand and forearm muscles from the ipsilateral corticospinal tract using multiple methods. Intracellular recordings from 62 motoneurons in three anesthetized monkeys revealed no monosynaptic and only one weak oligosynaptic EPSP after stimulation of the ipsilateral corticospinal tract. Single stimulus intracortical microstimulation of the primary motor cortex (M1) in awake animals failed to produce any responses in ipsilateral muscles. Strong stimulation (>500 μA, single stimulus) of the majority of corticospinal axons at the medullary pyramids revealed only weak suppressions in ipsilateral muscles at longer latencies than the robust facilitations seen contralaterally. Spike-triggered averaging of ipsilateral muscle activity from M1 neural discharge (184 cells) did not reveal any postspike effects consistent with monosynaptic corticomotoneuronal connections. We also examined the activity of 191 M1 neurons during ipsilateral or contralateral "reach to precision grip" movements. Many cells (67%) modulated their activity during ipsilateral limb movement trials (compared with 90% with contralateral trials), but the timing of this activity was best correlated with weak muscle activity in the contralateral nonmoving arm. We conclude that, in normal adults, any inputs to forelimb motoneurons from the ipsilateral corticospinal tract are weak and indirect and that modulation of M1 cell firing seems to be related primarily to control of the contralateral limb.
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Ventral premotor-motor cortex interactions in the macaque monkey during grasp: response of single neurons to intracortical microstimulation. J Neurosci 2011; 31:8812-21. [PMID: 21677165 DOI: 10.1523/jneurosci.0525-11.2011] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Recent stimulation studies in monkeys and humans have shown strong interactions between ventral premotor cortex (area F5) and the hand area of primary motor cortex (M1). These short-latency interactions usually involve facilitation from F5 of M1 outputs to hand muscles, although suppression has also been reported. This study, performed in three awake macaque monkeys, sought evidence that these interactions could be mediated by short-latency excitatory and inhibitory responses of single M1 neurons active during grasping tasks. We recorded responses of these M1 neurons to single low-threshold (≤40 μA) intracortical microstimuli delivered to F5 sites at which grasp-related neurons were recorded. In 29 sessions, we tested 232 M1 neurons with stimuli delivered to between one and four sites in F5. Of the 415 responses recorded, 142 (34%) showed significant effects. The most common type of response was pure excitation (53% of responses), with short latency (1.8-3.0 ms) and brief duration (∼1 ms); purely inhibitory responses had slightly longer latencies (2-5 ms) and were of small amplitude and longer duration (5-7 ms). They accounted for 13% of responses, whereas mixed excitation then inhibition was seen in 34%. Remarkably, a rather similar set of findings applied to 280 responses of 138 F5 neurons to M1 stimulation; 109 (34%) responses showed significant effects. Thus, with low-intensity stimuli, the dominant interaction between these two cortical areas is one of short-latency, brief excitation, most likely mediated by reciprocal F5-M1 connections. Some neurons were tested with stimuli at both 20 and 40 μA; inhibition tended to dominate at the higher intensity.
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Galashan FO, Rempel HC, Meyer A, Gruber-Dujardin E, Kreiter AK, Wegener D. A new type of recording chamber with an easy-to-exchange microdrive array for chronic recordings in macaque monkeys. J Neurophysiol 2011; 105:3092-105. [PMID: 21451061 DOI: 10.1152/jn.00508.2010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In monkeys, long-term recordings with chronically implanted microelectrodes frequently suffer from a continuously decreasing probability to record single units or even small multiunit clusters. This problem is associated with two technical limitations of the available devices: first, restrictions for electrode movement, and second, absent possibility to exchange electrodes easily on a regular basis. Permitting to adjust the recording site and to use new recording tracks with proper electrodes may avoid these problems and make chronic more similar to acute recordings. Here, we describe a novel type of implant tackling this issue. It consists of a new type of recording chamber combined with an exchangeable multielectrode array that precisely fits into it. The multielectrode array is reversibly fixed to the chamber, and within a minute it can be exchanged against another array equipped with new electrodes at the awake animal. The array allows for bidirectional movement of six electrodes for a distance of up to 12 mm. The recording chamber enables hermetical isolation of the intracranial space, resulting in long-lasting aseptic conditions and reducing dural thickening to a minimum, as confirmed by microbiological and histopathological analysis. The device has a simple design and is both easy to produce and low in cost. Functionality has been tested in primary and secondary visual cortex of three macaque monkeys over a period of up to 15 mo. The results show that even after more than a year, single and multiunit responses can be obtained with high incidence.
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Affiliation(s)
- F Orlando Galashan
- Brain Research Institute, Center for Cognitive Science, University of Bremen, Bremen, Germany
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Wang Z, Roe AW. Trial-to-trial noise cancellation of cortical field potentials in awake macaques by autoregression model with exogenous input (ARX). J Neurosci Methods 2011; 194:266-73. [PMID: 21074560 PMCID: PMC3016288 DOI: 10.1016/j.jneumeth.2010.10.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 10/25/2010] [Accepted: 10/28/2010] [Indexed: 11/24/2022]
Abstract
Gamma band synchronization has drawn increasing interest with respect to its potential role in neuronal encoding strategy and behavior in awake, behaving animals. However, contamination of these recordings by power line noise can confound the analysis and interpretation of cortical local field potential (LFP). Existing denoising methods are plagued by inadequate noise reduction, inaccuracies, and even introduction of new noise components. To carefully and more completely remove such contamination, we propose an automatic method based on the concept of adaptive noise cancellation that utilizes the correlative features of common noise sources, and implement with AutoRegressive model with eXogenous Input (ARX). We apply this technique to both simulated data and LFPs recorded in the primary visual cortex of awake macaque monkeys. The analyses here demonstrate a greater degree of accurate noise removal than conventional notch filters. Our method leaves desired signal intact and does not introduce artificial noise components. Application of this method to awake monkey V1 recordings reveals a significant power increase in the gamma range evoked by visual stimulation. Our findings suggest that the ARX denoising procedure will be an important pre-processing step in the analysis of large volumes of cortical LFP data as well as high frequency (gamma-band related) electroencephalography/magnetoencephalography (EEG/MEG) applications, one which will help to convincingly dissociate this notorious artifact from gamma-band activity.
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Affiliation(s)
- Zheng Wang
- Department of Psychology, Vanderbilt University, Nashville, TN 37212, USA.
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29
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Toda T, Hayashi H. The Gross Temporal Correlation of Nearby Neuron Activity in the Macaque Postcentral Somatosensory Cortex Representing Orofacial Structures: With Special Reference to Numerical Methods for Analysis. J Oral Biosci 2011. [DOI: 10.1016/s1349-0079(11)80020-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
This article provides an overview of the ethical issues raised by the use of non-human primates (NHPs) in research involving scientific procedures which may cause pain, suffering, distress or lasting harm. It is not an exhaustive review of the literature and views on this subject, and it does not present any conclusions about the moral acceptability or otherwise of NHP research. Rather the aim has been to identify the ethical issues involved and to provide guidance on how these might be addressed, in particular by carefully examining the scientific rationale for NHP use, implementing fully the 3Rs principle of Russell and Burch (1959) and applying a robust "harm-benefit assessment" to research proposals involving NHPs.
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Affiliation(s)
- M J Prescott
- National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs), 20 Park Crescent, London, W1B 1AL, UK
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31
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Prasad A, Sahin M. Characterization of neural activity recorded from the descending tracts of the rat spinal cord. Front Neurosci 2010; 4:21. [PMID: 20589238 PMCID: PMC2904587 DOI: 10.3389/fnins.2010.00021] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2010] [Accepted: 04/06/2010] [Indexed: 11/13/2022] Open
Abstract
A multi-electrode array (MEA) was implanted in the dorsolateral funiculus of the cervical spinal cord to record descending information during behavior in freely moving rats. Neural signals were characterized in terms of frequency and information content. Frequency analysis revealed components both at the range of local field potentials and multi-unit activity. Coherence between channels decreased steadily with inter-contact distance and frequency suggesting greater spatial selectivity for multi-unit activity compared to local field potentials. Principal component analysis (PCA) extracted multiple channels of neural activity with patterns that correlated to the behavior, indicating multiple dimensionality of the signals. Two different behaviors involving the forelimbs, face cleaning and food reaching, generated neural signals through distinctly different combination of neural channels, which suggested that these two behaviors could readily be differentiated from recordings. This preliminary data demonstrated that descending spinal cord signals recorded with MEAs can be used to extract multiple channels of command control information and potentially be utilized as a means of communication in high level spinal cord injury subjects.
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Affiliation(s)
- Abhishek Prasad
- Department of Biomedical Engineering, New Jersey Institute of Technology Newark, NJ, USA
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32
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Kraskov A, Dancause N, Quallo MM, Shepherd S, Lemon RN. Corticospinal neurons in macaque ventral premotor cortex with mirror properties: a potential mechanism for action suppression? Neuron 2010; 64:922-30. [PMID: 20064397 PMCID: PMC2862290 DOI: 10.1016/j.neuron.2009.12.010] [Citation(s) in RCA: 222] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/07/2009] [Indexed: 11/15/2022]
Abstract
The discovery of "mirror neurons" in area F5 of the ventral premotor cortex has prompted many theories as to their possible function. However, the identity of mirror neurons remains unknown. Here, we investigated whether identified pyramidal tract neurons (PTNs) in area F5 of two adult macaques exhibited "mirror-like" activity. About half of the 64 PTNs tested showed significant modulation of their activity while monkeys observed precision grip of an object carried out by an experimenter, with somewhat fewer showing modulation during precision grip without an object or grasping concealed from the monkey. Therefore, mirror-like activity can be transmitted directly to the spinal cord via PTNs. A novel finding is that many PTNs (17/64) showed complete suppression of discharge during action observation, while firing actively when the monkey grasped food rewards. We speculate that this suppression of PTN discharge might be involved in the inhibition of self-movement during action observation.
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Affiliation(s)
- Alexander Kraskov
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London WC1N3BG, UK
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33
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Chhatbar PY, von Kraus LM, Semework M, Francis JT. A bio-friendly and economical technique for chronic implantation of multiple microelectrode arrays. J Neurosci Methods 2010; 188:187-94. [PMID: 20153370 DOI: 10.1016/j.jneumeth.2010.02.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 02/03/2010] [Accepted: 02/03/2010] [Indexed: 10/19/2022]
Abstract
Many neurophysiological experiments on rodents and non-human primates involve the implantation of more than one multi-electrode array to record from many regions of the brain. So called 'floating' microelectrode arrays are implanted in cortical regions of interest and are coupled via a flexible cable to their connectors which are fixed to the skull by a cement cap or a titanium pedestal, such as the Cereport system, which has been approved for human use. The use of bone cement has several disadvantages including the creation of infection prone areas at the interface with the skull and surrounding skin. Alternatively, the more biocompatible Cereport has a limited carrying capacity and is far more expensive. In this paper, we describe a new implantation technique, which combines the biocompatibility of titanium, a high carrying capacity with a minimal skull footprint, and a decreased chance of infection, all in a relatively inexpensive package. This technique utilizes an in-house fabricated 'Nesting Platform' (NP), mounted on a titanium headpost to hold multiple connectors above the skin, making the headpost the only transcutaneous object. The use of delrin, a durable, lightweight and easily machinable material, allows easy customization of the NP for a wide variety of floating electrodes and their connectors. The ultimate result is a longer survival time with superior neural recordings that can potentially last longer than with traditional implantation techniques.
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Affiliation(s)
- Pratik Y Chhatbar
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, Brooklyn, 450 Clarkson Av, Box# 31, Brooklyn, NY 11203, USA
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Abstract
Previous studies have shown that hand translation is well represented by neuronal activity in the proximal arm area of primary motor cortex (M1). However, little is known about cortical representation of hand rotation in M1. In this study, single-unit activity was recorded from monkeys while they performed a "center-out with rotation" task. When reaching for a target, subjects had to match four separate kinematic parameters: three-dimensional location and one-dimensional orientation of the target. Among the 512 neurons modulated by hand movement, 446 were tuned to hand translation, 326 were tuned to hand rotation, and 260 neurons were tuned to both hand translation and hand rotation. Approximately half of the neurons that encoded both translation and rotation did so in a nonlinear manner. This nonlinear interaction can be modeled as a gain-field type of encoding whereby hand rotational velocity modulated the hand translational cosine tuning curves in a multiplicative manner. Furthermore, this study demonstrated that both hand translation and hand rotation can be decoded simultaneously from a population of motor cortical neurons.
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Nicolelis MAL, Lebedev MA. Principles of neural ensemble physiology underlying the operation of brain-machine interfaces. Nat Rev Neurosci 2009; 10:530-40. [PMID: 19543222 DOI: 10.1038/nrn2653] [Citation(s) in RCA: 232] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Research on brain-machine interfaces has been ongoing for at least a decade. During this period, simultaneous recordings of the extracellular electrical activity of hundreds of individual neurons have been used for direct, real-time control of various artificial devices. Brain-machine interfaces have also added greatly to our knowledge of the fundamental physiological principles governing the operation of large neural ensembles. Further understanding of these principles is likely to have a key role in the future development of neuroprosthetics for restoring mobility in severely paralysed patients.
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Affiliation(s)
- Miguel A L Nicolelis
- Duke University Center for Neuroengineering and the Department of Neurobiology, Duke University, Durham, North Carolina 27710, USA.
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36
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Wolf MT, Cham JG, Branchaud EA, Mulliken GH, Burdick JW, Andersen RA. A Robotic Neural Interface for Autonomous Positioning of Extracellular Recording Electrodes. Int J Rob Res 2009. [DOI: 10.1177/0278364908103788] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this paper we describe a set of algorithms and a novel miniature device that together can autonomously position electrodes in neural tissue to obtain high-quality extracellular recordings. This robotic system moves each electrode to detect the signals of individual neurons, optimize the signal quality of a target neuron, and then maintain this signal over time. Such neuronal signals provide the key inputs for emerging neuroprosthetic medical devices and serve as the foundation of basic neuroscientific and medical research. Experimental results from extensive use of the robotic electrodes in macaque parietal cortex are presented to validate the method and to quantify its effectiveness.
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Affiliation(s)
- Michael T. Wolf
- Department of Mechanical Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91106, USA,
| | - Jorge G. Cham
- Department of Mechanical Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91106, USA
| | - Edward A. Branchaud
- Department of Mechanical Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91106, USA
| | - Grant H. Mulliken
- Department of Mechanical Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91106, USA
| | - Joel W. Burdick
- Department of Mechanical Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91106, USA
| | - Richard A. Andersen
- Division of Biology California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91106, USA
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37
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Synchronization of Midbrain Dopaminergic Neurons Is Enhanced by Rewarding Events. Neuron 2009; 62:695-704. [DOI: 10.1016/j.neuron.2009.04.026] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Revised: 02/02/2009] [Accepted: 04/28/2009] [Indexed: 11/22/2022]
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Williams ER, Soteropoulos DS, Baker SN. Coherence between motor cortical activity and peripheral discontinuities during slow finger movements. J Neurophysiol 2009; 102:1296-309. [PMID: 19474171 DOI: 10.1152/jn.90996.2008] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Slow finger movements in man are not smooth, but are characterized by 8- to 12-Hz discontinuities in finger acceleration thought to have a central source. We trained two macaque monkeys to track a moving target by performing index finger flexion/extension movements and recorded local field potentials (LFPs) and spike activity from the primary motor cortex (M1); some cells were identified as pyramidal tract neurons by antidromic activation or as corticomotoneuronal cells by spike-triggered averaging. There was significant coherence between finger acceleration in the approximately 10-Hz range and both LFPs and spikes. LFP-acceleration coherence was similar for flexion and extension movements (0.094 at 9.8 Hz and 0.11 at 6.8 Hz, respectively), but substantially smaller during steady holding (0.0067 at 9.35 Hz). The coherence phase showed a significant linear relationship with frequency over the 6- to 13-Hz range, as expected for a constant conduction delay, but the slope indicated that LFP lagged acceleration by 18 +/- 14 or 36 +/- 8 ms for flexion and extension movements, respectively. Directed coherence analysis supported the conclusion that the dominant interaction was in the acceleration to LFP (i.e., sensory) direction. The phase relationships between finger acceleration and both LFPs and spikes shifted by about pi radians in flexion compared with extension trials. However, for a given trial type the phase relationship with acceleration was similar for cells that increased their firing during flexion or during extension trials. We conclude that movement discontinuities during slow finger movements arise from a reciprocally coupled network, which includes M1 and the periphery.
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Affiliation(s)
- Elizabeth R Williams
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom
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39
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Prabhu G, Shimazu H, Cerri G, Brochier T, Spinks RL, Maier MA, Lemon RN. Modulation of primary motor cortex outputs from ventral premotor cortex during visually guided grasp in the macaque monkey. J Physiol 2009; 587:1057-69. [PMID: 19139043 DOI: 10.1113/jphysiol.2008.165571] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Area F5, in the ventral premotor cortex of the macaque monkey, plays a critical role in determining the hand shape appropriate for grasp of a visible object. F5 neurones show increased firing for particular types of grasp, and inactivation of F5 produces deficits in visually guided grasp. But how is F5 activity transformed into the appropriate pattern of hand muscle activity for efficient grasp? Here we investigate the pathways that may be involved by testing the effect of single stimuli delivered through microwires chronically implanted in area F5 and in primary motor cortex (M1) of two macaque monkeys. The EMG responses from M1 test (T) stimulation were recorded from 4-11 contralateral hand, digit and arm muscles during reach-to-grasp of visually presented objects. Conditioning (C) stimulation of F5, at intensities subthreshold for motor effects, caused strong modulation (over twofold) of M1 test (T) responses. The pattern of facilitation was specific. First, facilitation of the T response was particularly evident at short C-T intervals of -1 to 1 ms. Second, this facilitation was only present in some muscles and during reach-to-grasp of a subset of objects; it did not appear to be simply related to the level of EMG activity in the muscles at the moment of cortical stimulation or indeed to the upcoming contribution of that muscle during grasp. At later C-T intervals (1-6 ms), F5 stimulation caused significant suppression of the test M1 response. The results are in keeping with the concept that during visually guided grasp, F5 modulates corticospinal outputs from M1 in a muscle- and grasp-specific manner.
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Affiliation(s)
- Gita Prabhu
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG
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40
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Selectivity for grasp in local field potential and single neuron activity recorded simultaneously from M1 and F5 in the awake macaque monkey. J Neurosci 2008; 28:10961-71. [PMID: 18945904 DOI: 10.1523/jneurosci.1956-08.2008] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The selectivity for object-specific grasp in local field potentials (LFPs) was investigated in two awake macaque monkeys trained to observe, reach out, grasp and hold one of six objects presented in a pseudorandom order. Simultaneous, multiple electrode recordings were made from the hand representations of primary motor cortex (M1) and ventral premotor cortex (area F5). LFP activity was well developed during the observation and hold periods of the task, especially in the beta-frequency range (15-30 Hz). Selectivity of LFP activity for upcoming grasp was rare in the observation period, but common during stable grasp. The majority of M1 (90 of 92) and F5 (81 of 97) sites showed selectivity for at least one frequency, which was maximal in the beta range but also present at higher frequencies (30-50 Hz). When the LFP power associated with grasp of a specific object was large in the beta-frequency range, it was usually of low power in the higher 30-50 Hz range, and vice-versa. Simple hook grips involving flexion of one or more fingers were associated with large beta power, whereas more complex grips involving the thumb (e.g., precision grip) were associated with small beta power. At many M1 sites, there was a highly significant inverse relationship between the tuning of spikes (including those of identified pyramidal tract neurons) and beta-range LFP for different grasps, whereas a positive correlation was found at higher frequencies (30-50 Hz). High levels of beta LFP and low pyramidal cell spike rate may reflect a common mechanism used to control motor set during different types of grasp.
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41
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Procedure for recording the simultaneous activity of single neurons distributed across cortical areas during sensory discrimination. Proc Natl Acad Sci U S A 2008; 105:16785-90. [PMID: 18946031 DOI: 10.1073/pnas.0808702105] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We report a procedure for recording the simultaneous activity of single neurons distributed across five cortical areas in behaving monkeys. The procedure consists of a commercially available microdrive adapted to a commercially available neural data collection system. The critical advantage of this procedure is that, in each cortical area, a configuration of seven microelectrodes spaced 250-500 mum can be inserted transdurally and each can be moved independently in the z axis. For each microelectrode, the data collection system can record the activity of up to five neurons together with the local field potential (LFP). With this procedure, we normally monitor the simultaneous activity of 70-100 neurons while trained monkeys discriminate the difference in frequency between two vibrotactile stimuli. Approximately 20-60 of these neurons have response properties previously reported in this task. The neuronal recordings show good signal-to-noise ratio, are remarkably stable along a 1-day session, and allow testing several protocols. Microelectrodes are removed from the brain after a 1-day recording session, but are reinserted again the next day by using the same or different x-y microelectrode array configurations. The fact that microelectrodes can be moved in the z axis during the recording session and that the x-y configuration can be changed from day to day maximizes the probability of studying simultaneous interactions, both local and across distant cortical areas, between neurons associated with the different components of this task.
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42
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Vitale A, Manciocco A, Alleva E. The 3R principle and the use of non-human primates in the study of neurodegenerative diseases: the case of Parkinson's disease. Neurosci Biobehav Rev 2008; 33:33-47. [PMID: 18773919 DOI: 10.1016/j.neubiorev.2008.08.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Revised: 08/11/2008] [Accepted: 08/11/2008] [Indexed: 12/28/2022]
Abstract
The aim of this paper is to offer an ethical perspective on the use of non-human primates in neurobiological studies, using the Parkinson's disease (PD) as an important case study. We refer, as theoretical framework, to the 3R principle, originally proposed by Russell and Burch [Russell, W.M.S., Burch, R.L., 1959. The Principles of Humane Experimental Technique. Universities Federation for Animal Welfare Wheathampstead, England (reprinted in 1992)]. Then, the use of non-human primates in the study of PD will be discussed in relation to the concepts of Replacement, Reduction, and Refinement. Replacement and Reduction result to be the more problematic concept to be applied, whereas Refinement offers relatively more opportunities of improvement. However, although in some cases the 3R principle shows its applicative limits, its value, as conceptual and inspirational tool remains extremely valuable. It suggests to the researchers a series of questions, both theoretical and methodological, which can have the results of improving the quality of life on the experimental models, the quality of the scientific data, and the public perception from the non-scientist community.
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Affiliation(s)
- Augusto Vitale
- Section of Behavioural Neuroscience, Dipartimento di Biologia Cellulare e Neuroscienze, Istituto Superiore di Sanità, Viale Regina Elena, 299, Rome 00161, Italy.
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43
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Pronounced reduction of digit motor responses evoked from macaque ventral premotor cortex after reversible inactivation of the primary motor cortex hand area. J Neurosci 2008; 28:5772-83. [PMID: 18509039 DOI: 10.1523/jneurosci.0944-08.2008] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In common with other secondary motor areas, the macaque ventral premotor cortex (PMv) gives rise to corticospinal projections; it also makes numerous reciprocal corticocortical connections with the primary motor cortex (M1). Repetitive intracortical microstimulation (rICMS) of the PMv gives rise to movements of the hand and digits. To investigate whether these motor effects are dependent on the corticocortical interactions with M1, the effect of reversible inactivation of the M1 hand area was tested in three macaque monkeys with chronically implanted intracortical electrodes in the hand representations of M1 and PMv (rostral division, area F5). Monkeys were lightly sedated. Test EMG responses to rICMS were recorded from intrinsic hand muscles before and after microinjection of the GABA agonist muscimol in the M1 hand area. This not only greatly reduced EMG responses evoked from M1, but also reduced or abolished responses from F5, over a similar time course (20-50 min). Muscimol in M1 reduced the level of background EMG activity in the contralateral hand, which was paretic for several hours after injection. However, because EMG responses to direct activation of the corticospinal tract were significantly less affected than the responses to F5 stimulation, it is unlikely that reduced motoneuronal excitability explained the loss of the evoked responses from F5. Finally, muscimol injections in M1 greatly reduced the corticospinal volleys evoked by rICMS in F5. The results suggest that the motor effects evoked from F5 depend, at least in part, on corticocortical interactions with M1, leading to activation of M1 corticospinal outputs to hand muscles.
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44
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Churchland MM, Yu BM, Sahani M, Shenoy KV. Techniques for extracting single-trial activity patterns from large-scale neural recordings. Curr Opin Neurobiol 2008; 17:609-18. [PMID: 18093826 DOI: 10.1016/j.conb.2007.11.001] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2007] [Revised: 10/15/2007] [Accepted: 11/03/2007] [Indexed: 11/29/2022]
Abstract
Large, chronically implanted arrays of microelectrodes are an increasingly common tool for recording from primate cortex and can provide extracellular recordings from many (order of 100) neurons. While the desire for cortically based motor prostheses has helped drive their development, such arrays also offer great potential to advance basic neuroscience research. Here we discuss the utility of array recording for the study of neural dynamics. Neural activity often has dynamics beyond that driven directly by the stimulus. While governed by those dynamics, neural responses may nevertheless unfold differently for nominally identical trials, rendering many traditional analysis methods ineffective. We review recent studies - some employing simultaneous recording, some not - indicating that such variability is indeed present both during movement generation and during the preceding premotor computations. In such cases, large-scale simultaneous recordings have the potential to provide an unprecedented view of neural dynamics at the level of single trials. However, this enterprise will depend not only on techniques for simultaneous recording but also on the use and further development of analysis techniques that can appropriately reduce the dimensionality of the data, and allow visualization of single-trial neural behavior.
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Affiliation(s)
- Mark M Churchland
- Neurosciences Program and Department of Electrical Engineering, Stanford University, CISX, 330 Serra Mall, Stanford, CA 94305-4075, United States.
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45
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Jackson N, Muthuswamy J. Artificial dural sealant that allows multiple penetrations of implantable brain probes. J Neurosci Methods 2008; 171:147-52. [PMID: 18420281 DOI: 10.1016/j.jneumeth.2008.02.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Revised: 02/18/2008] [Accepted: 02/22/2008] [Indexed: 10/22/2022]
Abstract
This study reports extensive characterization of the silicone gel (3-4680, Dow Corning, Midland, MI), for potential use as an artificial dural sealant in long-term electrophysiological experiments in neurophysiology. Dural sealants are important to preserve the integrity of the intracranial space after a craniotomy and in prolonging the lifetime and functionality of implanted brain probes. In this study, we report results of our tests on a commercially available silicone gel with unique properties that make it an ideal dural substitute. The substitute is transparent, elastic, easy to apply, and has re-sealing capabilities, which makes it desirable for applications where multiple penetrations by the brain probe is desirable over an extended period of time. Cytotoxicity tests (for up to 10 days) with fibroblasts and in vivo tests (for 12 weeks) show that the gel is non-toxic and does not produce any significant neuronal degeneration when applied to the rodent cortex even after 12 weeks. In vivo humidity testing showed no sign of CSF leakage for up to 6 weeks. The gel also allows silicon microprobes to penetrate with forces less than 0.5 mN, and a 200-microm diameter stainless steel microprobe with a blunt tip to penetrate with a force less than 2.5 mN. The force dependency on the velocity of penetration and thickness of the gel was also quantified and empirically modeled. The above results demonstrate that the silicone gel (3-4680) can be a viable dural substitute in long-term electrophysiology of the brain.
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Affiliation(s)
- Nathan Jackson
- Harrington Department of Bioengineering, Arizona State University, Tempe, AZ 85287, United States
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46
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Jackson A, Fetz EE. Compact Movable Microwire Array for Long-Term Chronic Unit Recording in Cerebral Cortex of Primates. J Neurophysiol 2007; 98:3109-18. [PMID: 17855584 DOI: 10.1152/jn.00569.2007] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We describe a small, chronically implantable microwire array for obtaining long-term unit recordings from the cortex of unrestrained nonhuman primates. After implantation, the depth of microwires can be individually adjusted to maintain large-amplitude action potential recordings from single neurons over many months. We present data recorded from the primary motor cortex of two monkeys by autonomous on-board electronic circuitry. Waveforms of individual neurons remained stable for recording periods of several weeks during unrestrained behavior. Signal-to-noise ratios, waveform stability, and rates of cell loss indicate that this method may be particularly suited to experiments investigating the neural correlates of processes extending over multiple days, such as learning and plasticity.
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Affiliation(s)
- Andrew Jackson
- School of Neurology, Neurobiology and Psychiatry, University of Newcastle, Newcastle-upon-Tyne, United Kingdom.
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Witham CL, Wang M, Baker SN. Cells in somatosensory areas show synchrony with beta oscillations in monkey motor cortex. Eur J Neurosci 2007; 26:2677-86. [PMID: 17970720 PMCID: PMC2228402 DOI: 10.1111/j.1460-9568.2007.05890.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Oscillatory synchronization between somatosensory and motor cortex has previously been reported using field potential recordings, but interpretation of such results can be confounded by volume conduction. We examined coherence between single-unit discharge in somatosensory/parietal areas and local field potential from the same area as the unit, or from the motor cortex, in two macaque monkeys trained to perform a finger movement task. There were clear coherence peaks at approximately 17.5 Hz for cells in the primary somatosensory cortex (both proprioceptive and cutaneous areas) and posterior parietal cortex (area 5). The size of coherence in all areas was comparable to previous reports analysing motor cortical cells and M1 field potentials. Many coherence phases clustered around -pi/2 radians, indicating zero lag synchronization of parietal cells with M1 oscillatory activity. These results indicate that cells in somatosensory and parietal areas have information about the presence of oscillations in the motor system. Such oscillatory coupling across the central sulcus may play an important role in sensorimotor integration of both proprioceptive and cutaneous signals.
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Affiliation(s)
- Claire L Witham
- Institute of Neuroscience, Newcastle University, Sir James Spence Building, Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne NE1 4LP, UK
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Bossi S, Menciassi A, Koch KP, Hoffmann KP, Yoshida K, Dario P, Micera S. Shape memory alloy microactuation of tf-lIFes: preliminary results. IEEE Trans Biomed Eng 2007; 54:1115-20. [PMID: 17554830 DOI: 10.1109/tbme.2007.895186] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this paper, a new approach aimed at improving the performance of intraneural longitudinal interfaces (tf-LIFEs) with the peripheral nervous system (PNS) is presented. Our goal is to develop a movable interface by embedding microactuators into the flexible tf-LIFEs structure. In this way, the optimal position of the electrical contacts can be searched inside the PNS and lost connections with neural cells could be replaced. For this purpose a thin film of shape memory alloy (tf-SMA) was selected. A multisegmented SMA was realized and embedded between two polyimide thin films in order to simulate the tf-LIFE structure. Thermal evaluation, fabrication procedure, the first characterization and preliminary experimental results of the new movable interface are described in the manuscript. A total controllable stroke of about 10 microm was obtained for the presented prototype.
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Affiliation(s)
- Silvia Bossi
- Institute for Advanced Studies on Biorobotic Engineering, IMT, 55100 Lucca, Italy.
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Gray CM, Goodell B, Lear A. Multichannel Micromanipulator and Chamber System for Recording Multineuronal Activity in Alert, Non-Human Primates. J Neurophysiol 2007; 98:527-36. [PMID: 17493924 DOI: 10.1152/jn.00259.2007] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We describe the design and performance of an electromechanical system for conducting multineuron recording experiments in alert non-human primates. The system is based on a simple design, consisting of a microdrive, control electronics, software, and a unique type of recording chamber. The microdrive consists of an aluminum frame, a set of eight linear actuators driven by computer-controlled miniature stepping motors, and two printed circuit boards (PCBs) that provide connectivity to the electrodes and the control electronics. The control circuitry is structured around an Atmel RISC-based microcontroller, which sends commands to as many as eight motor control cards, each capable of controlling eight motors. The microcontroller is programmed in C and uses serial communication to interface with a host computer. The graphical user interface for sending commands is written in C and runs on a conventional personal computer. The recording chamber is low in profile, mounts within a circular craniotomy, and incorporates a removable internal sleeve. A replaceable Sylastic membrane can be stretched across the bottom opening of the sleeve to provide a watertight seal between the cranial cavity and the external environment. This greatly reduces the susceptibility to infection, nearly eliminates the need for routine cleaning, and permits repeated introduction of electrodes into the brain at the same sites while maintaining the watertight seal. The system is reliable, easy to use, and has several advantages over other commercially available systems with similar capabilities.
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Affiliation(s)
- Charles M Gray
- Center for Computational Biology, Montana State University, Bozeman, MT 59717, USA.
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Andersen RA, Burdick JW, Musallam S, Scherberger H, Pesaran B, Meeker D, Corneil BD, Fineman I, Nenadic Z, Branchaud E, Cham JG, Greger B, Tai YC, Mojarradi MM. Recording advances for neural prosthetics. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2004:5352-5. [PMID: 17271551 DOI: 10.1109/iembs.2004.1404494] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
An important challenge for neural prosthetics research is to record from populations of neurons over long periods of time, ideally for the lifetime of the patient. Two new advances toward this goal are described, the use of local field potentials (LFPs) and autonomously positioned recording electrodes. LFPs are the composite extracellular potential field from several hundreds of neurons around the electrode tip. LFP recordings can be maintained for longer periods of time than single cell recordings. We find that similar information can be decoded from LFP and spike recordings, with better performance for state decodes with LFPs and, depending on the area, equivalent or slightly less than equivalent performance for signaling the direction of planned movements. Movable electrodes in microdrives can be adjusted in the tissue to optimize recordings, but their movements must be automated to be a practical benefit to patients. We have developed automation algorithms and a meso-scale autonomous electrode testbed, and demonstrated that this system can autonomously isolate and maintain the recorded signal quality of single cells in the cortex of awake, behaving monkeys. These two advances show promise for developing very long term recording for neural prosthetic applications.
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Affiliation(s)
- R A Andersen
- Division of Biology, California Institute of Technology, Pasadena, CA, USA
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