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Jamali M, Grannan B, Cai J, Khanna AR, Muñoz W, Caprara I, Paulk AC, Cash SS, Fedorenko E, Williams ZM. Semantic encoding during language comprehension at single-cell resolution. Nature 2024; 631:610-616. [PMID: 38961302 PMCID: PMC11254762 DOI: 10.1038/s41586-024-07643-2] [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: 05/26/2020] [Accepted: 05/31/2024] [Indexed: 07/05/2024]
Abstract
From sequences of speech sounds1,2 or letters3, humans can extract rich and nuanced meaning through language. This capacity is essential for human communication. Yet, despite a growing understanding of the brain areas that support linguistic and semantic processing4-12, the derivation of linguistic meaning in neural tissue at the cellular level and over the timescale of action potentials remains largely unknown. Here we recorded from single cells in the left language-dominant prefrontal cortex as participants listened to semantically diverse sentences and naturalistic stories. By tracking their activities during natural speech processing, we discover a fine-scale cortical representation of semantic information by individual neurons. These neurons responded selectively to specific word meanings and reliably distinguished words from nonwords. Moreover, rather than responding to the words as fixed memory representations, their activities were highly dynamic, reflecting the words' meanings based on their specific sentence contexts and independent of their phonetic form. Collectively, we show how these cell ensembles accurately predicted the broad semantic categories of the words as they were heard in real time during speech and how they tracked the sentences in which they appeared. We also show how they encoded the hierarchical structure of these meaning representations and how these representations mapped onto the cell population. Together, these findings reveal a finely detailed cortical organization of semantic representations at the neuron scale in humans and begin to illuminate the cellular-level processing of meaning during language comprehension.
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Affiliation(s)
- Mohsen Jamali
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Benjamin Grannan
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Jing Cai
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Arjun R Khanna
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - William Muñoz
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Irene Caprara
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Angelique C Paulk
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Sydney S Cash
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Evelina Fedorenko
- Department of Brain and Cognitive Sciences and McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ziv M Williams
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
- Harvard-MIT Division of Health Sciences and Technology, Boston, MA, USA.
- Harvard Medical School, Program in Neuroscience, Boston, MA, USA.
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Alanazi FI, Kalia SK, Hodaie M, Lopez Rios AL, Lozano AM, Milosevic L, Hutchison WD. Top-down control of human motor thalamic neuronal activity during the auditory oddball task. NPJ Parkinsons Dis 2023; 9:46. [PMID: 36973276 PMCID: PMC10042852 DOI: 10.1038/s41531-023-00493-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 03/08/2023] [Indexed: 03/29/2023] Open
Abstract
The neurophysiology of selective attention in visual and auditory systems has been studied in animal models but not with single unit recordings in human. Here, we recorded neuronal activity in the ventral intermediate nucleus as well as the ventral oral anterior, and posterior nuclei of the motor thalamus in 25 patients with parkinsonian (n = 6) and non-parkinsonian tremors (n = 19) prior to insertion of deep brain stimulation electrodes while they performed an auditory oddball task. In this task, patients were requested to attend and count the randomly occurring odd or "deviant" tones, ignore the frequent standard tones and report the number of deviant tones at trial completion. The neuronal firing rate decreased compared to baseline during the oddball task. Inhibition was specific to auditory attention as incorrect counting or wrist flicking to the deviant tones did not produce such inhibition. Local field potential analysis showed beta (13-35 Hz) desynchronization in response to deviant tones. Parkinson's disease patients off medications had more beta power than the essential tremor group but less neuronal modulation of beta power to the attended tones, suggesting that dopamine modulates thalamic beta oscillations for selective attention. The current study demonstrated that ascending information to the motor thalamus can be suppressed during auditory attending tasks, providing indirect evidence for the searchlight hypothesis in humans. These results taken together implicate the ventral intermediate nucleus in non-motor cognitive functions, which has implications for the brain circuitry for attention and the pathophysiology of Parkinson's disease.
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Affiliation(s)
- Frhan I Alanazi
- Department of Physiology, University of Toronto, Toronto, ON, Canada.
- Krembil Brain Institute, Leonard St, Toronto, ON, Canada.
- Department of Basic Sciences, Prince Sultan bin Abdulaziz College for Emergency Medical Services, King Saud University, Riyadh, Kingdom of Saudi Arabia.
| | - Suneil K Kalia
- Krembil Brain Institute, Leonard St, Toronto, ON, Canada
- Division of Neurosurgery, Toronto Western Hospital, 399 Bathurst Street, Toronto, ON, Canada
- Department of Surgery, University of Toronto, Toronto, ON, Canada
| | - Mojgan Hodaie
- Krembil Brain Institute, Leonard St, Toronto, ON, Canada
- Division of Neurosurgery, Toronto Western Hospital, 399 Bathurst Street, Toronto, ON, Canada
- Department of Surgery, University of Toronto, Toronto, ON, Canada
| | | | - Andrés M Lozano
- Krembil Brain Institute, Leonard St, Toronto, ON, Canada
- Division of Neurosurgery, Toronto Western Hospital, 399 Bathurst Street, Toronto, ON, Canada
- Department of Surgery, University of Toronto, Toronto, ON, Canada
| | - Luka Milosevic
- Krembil Brain Institute, Leonard St, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - William D Hutchison
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Krembil Brain Institute, Leonard St, Toronto, ON, Canada
- Division of Neurosurgery, Toronto Western Hospital, 399 Bathurst Street, Toronto, ON, Canada
- Department of Surgery, University of Toronto, Toronto, ON, Canada
- Hospital Universitario San Vicente Fundación, Medellin (Rionegro), Colombia
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Lee SH, Thunemann M, Lee K, Cleary DR, Tonsfeldt KJ, Oh H, Azzazy F, Tchoe Y, Bourhis AM, Hossain L, Ro YG, Tanaka A, Kılıç K, Devor A, Dayeh SA. Scalable Thousand Channel Penetrating Microneedle Arrays on Flex for Multimodal and Large Area Coverage BrainMachine Interfaces. ADVANCED FUNCTIONAL MATERIALS 2022; 32:2112045. [PMID: 36381629 PMCID: PMC9648634 DOI: 10.1002/adfm.202112045] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Indexed: 05/29/2023]
Abstract
The Utah array powers cutting-edge projects for restoration of neurological function, such as BrainGate, but the underlying electrode technology has itself advanced little in the last three decades. Here, advanced dual-side lithographic microfabrication processes is exploited to demonstrate a 1024-channel penetrating silicon microneedle array (SiMNA) that is scalable in its recording capabilities and cortical coverage and is suitable for clinical translation. The SiMNA is the first penetrating microneedle array with a flexible backing that affords compliancy to brain movements. In addition, the SiMNA is optically transparent permitting simultaneous optical and electrophysiological interrogation of neuronal activity. The SiMNA is used to demonstrate reliable recordings of spontaneous and evoked field potentials and of single unit activity in chronically implanted mice for up to 196 days in response to optogenetic and to whisker air-puff stimuli. Significantly, the 1024-channel SiMNA establishes detailed spatiotemporal mapping of broadband brain activity in rats. This novel scalable and biocompatible SiMNA with its multimodal capability and sensitivity to broadband brain activity will accelerate the progress in fundamental neurophysiological investigations and establishes a new milestone for penetrating and large area coverage microelectrode arrays for brain-machine interfaces.
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Affiliation(s)
- Sang Heon Lee
- Integrated Electronics and Biointerfaces Laboratory, Department of Electrical and Computer Engineering, University of California San Diego, CA 92093, USA
| | - Martin Thunemann
- Biomedical Engineering Department, Boston University, Boston, MA 02215, USA
| | - Keundong Lee
- Integrated Electronics and Biointerfaces Laboratory, Department of Electrical and Computer Engineering, University of California San Diego, CA 92093, USA
| | - Daniel R Cleary
- Integrated Electronics and Biointerfaces Laboratory, Department of Electrical and Computer Engineering, University of California San Diego, CA 92093, USA
- Department of Neurological Surgery, University of California San Diego, La Jolla, CA 92093, USA
| | - Karen J Tonsfeldt
- Integrated Electronics and Biointerfaces Laboratory, Department of Electrical and Computer Engineering, University of California San Diego, CA 92093, USA
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Hongseok Oh
- Integrated Electronics and Biointerfaces Laboratory, Department of Electrical and Computer Engineering, University of California San Diego, CA 92093, USA
| | - Farid Azzazy
- Integrated Electronics and Biointerfaces Laboratory, Department of Electrical and Computer Engineering, University of California San Diego, CA 92093, USA
| | - Youngbin Tchoe
- Integrated Electronics and Biointerfaces Laboratory, Department of Electrical and Computer Engineering, University of California San Diego, CA 92093, USA
| | - Andrew M Bourhis
- Integrated Electronics and Biointerfaces Laboratory, Department of Electrical and Computer Engineering, University of California San Diego, CA 92093, USA
| | - Lorraine Hossain
- Integrated Electronics and Biointerfaces Laboratory, Department of Electrical and Computer Engineering, University of California San Diego, CA 92093, USA
- Graduate Program of Materials Science and Engineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Yun Goo Ro
- Integrated Electronics and Biointerfaces Laboratory, Department of Electrical and Computer Engineering, University of California San Diego, CA 92093, USA
| | - Atsunori Tanaka
- Integrated Electronics and Biointerfaces Laboratory, Department of Electrical and Computer Engineering, University of California San Diego, CA 92093, USA
- Graduate Program of Materials Science and Engineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Kıvılcım Kılıç
- Biomedical Engineering Department, Boston University, Boston, MA 02215, USA
| | - Anna Devor
- Biomedical Engineering Department, Boston University, Boston, MA 02215, USA
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Shadi A Dayeh
- Integrated Electronics and Biointerfaces Laboratory, Department of Electrical and Computer Engineering, University of California San Diego, CA 92093, USA
- Graduate Program of Materials Science and Engineering, University of California San Diego, La Jolla, CA 92093, USA
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Swan BD, Gasperson LB, Krucoff MO, Grill WM, Turner DA. Sensory percepts induced by microwire array and DBS microstimulation in human sensory thalamus. Brain Stimul 2017; 11:416-422. [PMID: 29126946 DOI: 10.1016/j.brs.2017.10.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 10/20/2017] [Accepted: 10/23/2017] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Microstimulation in human sensory thalamus (ventrocaudal, VC) results in focal sensory percepts in the hand and arm which may provide an alternative target site (to somatosensory cortex) for the input of prosthetic sensory information. Sensory feedback to facilitate motor function may require simultaneous or timed responses across separate digits to recreate perceptions of slip as well as encoding of intensity variations in pressure or touch. OBJECTIVES To determine the feasibility of evoking sensory percepts on separate digits with variable intensity through either a microwire array or deep brain stimulation (DBS) electrode, recreating "natural" and scalable percepts relating to the arm and hand. METHODS We compared microstimulation within ventrocaudal sensory thalamus through either a 16-channel microwire array (∼400 kΩ per channel) or a 4-channel DBS electrode (∼1.2 kΩ per contact) for percept location, size, intensity, and quality sensation, during thalamic DBS electrode placement in patients with essential tremor. RESULTS Percepts in small hand or finger regions were evoked by microstimulation through individual microwires and in 5/6 patients sensation on different digits could be perceived from stimulation through separate microwires. Microstimulation through DBS electrode contacts evoked sensations over larger areas in 5/5 patients, and the apparent intensity of the perceived response could be modulated with stimulation amplitude. The perceived naturalness of the sensation depended both on the pattern of stimulation as well as intensity of the stimulation. CONCLUSIONS Producing consistent evoked perceptions across separate digits within sensory thalamus is a feasible concept and a compact alternative to somatosensory cortex microstimulation for prosthetic sensory feedback. This approach will require a multi-element low impedance electrode with a sufficient stimulation range to evoke variable intensities of perception and a predictable spread of contacts to engage separate digits.
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Affiliation(s)
- Brandon D Swan
- Department of Biomedical Engineering, Duke University, Durham, NC 27710, United States
| | - Lynne B Gasperson
- Department of Neurosurgery, Duke University Medical Center, Durham, NC 27710, United States
| | - Max O Krucoff
- Department of Neurosurgery, Duke University Medical Center, Durham, NC 27710, United States
| | - Warren M Grill
- Department of Neurosurgery, Duke University Medical Center, Durham, NC 27710, United States; Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, United States; Department of Biomedical Engineering, Duke University, Durham, NC 27710, United States
| | - Dennis A Turner
- Department of Neurosurgery, Duke University Medical Center, Durham, NC 27710, United States; Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, United States; Department of Biomedical Engineering, Duke University, Durham, NC 27710, United States.
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5
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Abstract
Single neuron actions and interactions are the sine qua non of brain function, and nearly all diseases and injuries of the CNS trace their clinical sequelae to neuronal dysfunction or failure. Remarkably, discussion of neuronal activity is largely absent in clinical neuroscience. Advances in neurotechnology and computational capabilities, accompanied by shifts in theoretical frameworks, have led to renewed interest in the information represented by single neurons. Using direct interfaces with the nervous system, millisecond-scale information will soon be extracted from single neurons in clinical environments, supporting personalized treatment of neurologic and psychiatric disease. In this Perspective, we focus on single-neuronal activity in restoring communication and motor control in patients suffering from devastating neurological injuries. We also explore the single neuron's role in epilepsy and movement disorders, surgical anesthesia, and in cognitive processes disrupted in neurodegenerative and neuropsychiatric disease. Finally, we speculate on how technological advances will revolutionize neurotherapeutics.
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Affiliation(s)
- Sydney S Cash
- Neurotechnology Trials Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
| | - Leigh R Hochberg
- Neurotechnology Trials Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; School of Engineering and Institute for Brain Science, Brown University, Providence, RI 02912, USA; Center for Neurorestoration and Neurotechnology, Providence VA Medical Center, Providence, RI 02908, USA.
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6
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Tenan MS, Peng YL, Hackney AC, Griffin L. Menstrual cycle mediates vastus medialis and vastus medialis oblique muscle activity. Med Sci Sports Exerc 2014; 45:2151-7. [PMID: 23657168 DOI: 10.1249/mss.0b013e318299a69d] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE Sports medicine professionals commonly describe two functionally different units of the vastus medialis (VM), the VM, and the vastus medialis oblique (VMO), but the anatomical support is equivocal. The functional difference of the VMO is principle to rehabilitation programs designed to alleviate anterior knee pain, a pathology that is known to have a greater occurrence in women. The purpose of this study was to determine whether the motor units of the VM and VMO are differentially recruited and if this recruitment pattern has an effect of sex or menstrual cycle phase. METHODS Single motor unit recordings from the VM and VMO were obtained for men and women during an isometric ramp knee extension. Eleven men were tested once. Seven women were tested during five different phases of the menstrual cycle, determined by basal body temperature mapping. The recruitment threshold and the initial firing rate at recruitment were determined from 510 motor unit recordings. RESULTS The initial firing rate was lower in the VMO than that in the VM in women (P < 0.001) but not in men. There was no difference in recruitment thresholds for the VM and VMO in either sex or across the menstrual cycle. There was a main effect of menstrual phase on initial firing rate, showing increases from the early follicular to late luteal phase (P = 0.003). The initial firing rate in the VMO was lower than that in the VM during ovulatory (P = 0.009) and midluteal (P = 0.009) phases. CONCLUSION The relative control of the VM and VMO changes across the menstrual cycle. This could influence patellar pathologies that have a higher incidence in women.
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Affiliation(s)
- Matthew S Tenan
- 1Department of Kinesiology, University of Texas at Austin, Austin, TX; 2Human Research and Engineering Directorate, U.S. Army Research Laboratory, Aberdeen Proving Ground, MD; and 3Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC
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Lewis MM, Galley S, Johnson S, Stevenson J, Huang X, McKeown MJ. The role of the cerebellum in the pathophysiology of Parkinson's disease. Can J Neurol Sci 2013; 40:299-306. [PMID: 23603164 PMCID: PMC6939223 DOI: 10.1017/s0317167100014232] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Parkinson's disease (PD), the most common neurodegenerative movement disorder, has traditionally been considered a "classic" basal ganglia disease, as the most obvious pathology is seen in the dopaminergic cells in the substantia nigra pars compacta. Nevertheless recent discoveries in anatomical connections linking the basal ganglia and the cerebellum have led to a re-examination of the role of the cerebellum in the pathophysiology of PD. This review summarizes the role of the cerebellum in explaining many curious features of PD: the significant variation in disease progression between individuals; why severity of dopaminergic deficit correlates with many features of PD such as bradykinesia, but not tremor; and why PD subjects with a tremor-predominant presentation tend to have a more benign prognosis. It is clear that the cerebellum participates in compensatory mechanisms associated with the disease and must be considered an essential contributor to the overall pathophysiology of PD.
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Affiliation(s)
- Mechelle M Lewis
- Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA, USA Department of Pharmacology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA, USA
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Hutchison WD, Galati S. Introduction to Festschrift/special issue: normal and abnormal neuronal oscillations in sensorimotor pathways. Exp Neurol 2013; 245:1-4. [PMID: 23466930 DOI: 10.1016/j.expneurol.2013.02.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Barnikol UB, Popovych OV, Hauptmann C, Sturm V, Freund HJ, Tass PA. Tremor entrainment by patterned low-frequency stimulation. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2008; 366:3545-3573. [PMID: 18632457 DOI: 10.1098/rsta.2008.0104] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
High-frequency test stimulation for tremor suppression is a standard procedure for functional target localization during deep brain stimulation. This method does not work in cases where tremor vanishes intraoperatively, for example, due to general anaesthesia or due to an insertional effect. To overcome this difficulty, we developed a stimulation technique that effectively evokes tremor in a well-defined and quantifiable manner. For this, we used patterned low-frequency stimulation (PLFS), i.e. brief high-frequency pulse trains administered at pulse rates similar to neurons' preferred burst frequency. Unlike periodic single-pulse stimulation, PLFS enables one to convey effective and considerably greater integral charge densities without violation of safety requirements. In a computational investigation of an oscillatory neuronal network temporarily rendered inactive, we found that PLFS evokes synchronized activity, phase locked to the stimulus. While a stronger increase in the amount of synchrony in the neuronal population requires higher stimulus intensities, the portion of synchronously active neurons nevertheless becomes strongly phase locked to PLFS already at weak stimulus intensities. The phase entrainment effect of PLFS turned out to be robust against variations in the stimulation frequency, whereas enhancement of synchrony required precisely tuned stimulation frequencies. We applied PLFS to a patient with spinocerebellar ataxia type 2 (SCA2) with pronounced tremor that disappeared intraoperatively under general anaesthesia. In accordance with our computational results, PLFS evoked tremor, phase locked to the stimulus. In particular, weak PLFS caused low-amplitude, but strongly phase-locked tremor. PLFS test stimulations provided the only functional information about target localization. Optimal target point selection was confirmed by excellent post-operative tremor suppression.
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Affiliation(s)
- Utako B Barnikol
- Institute of Neurosciences and Biophysics 3-Medicine, Research Center Jülich, Leo-Brand-Street, 52425 Jülich, Germany
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Montgomery EB, Gale JT. Mechanisms of action of deep brain stimulation (DBS). Neurosci Biobehav Rev 2008; 32:388-407. [PMID: 17706780 DOI: 10.1016/j.neubiorev.2007.06.003] [Citation(s) in RCA: 223] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2005] [Revised: 03/29/2007] [Accepted: 06/01/2007] [Indexed: 10/23/2022]
Abstract
Deep brain stimulation (DBS) is remarkably effective for a range of neurological and psychiatric disorders that have failed pharmacological and cell transplant therapies. Clinical investigations are underway for a variety of other conditions. Yet, the therapeutic mechanisms of action are unknown. In addition, DBS research demonstrates the need to re-consider many hypotheses regarding basal ganglia physiology and pathophysiology such as the notion that increased activity in the globus pallidus internal segment is causal to Parkinson's disease symptoms. Studies reveal a variety of apparently discrepant results. At the least, it is unclear which DBS effects are therapeutically effective. This systematic review attempts to organize current DBS research into a series of unifying themes or issues such as whether the therapeutic effects are local or systems-wide or whether the effects are related to inhibition or excitation. A number of alternative hypotheses are offered for consideration including suppression of abnormal activity, striping basal ganglia output of misinformation, reduction of abnormal stochastic resonance effects due to increased noise in the disease state, and reinforcement of dynamic modulation of neuronal activity by resonance effects.
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Affiliation(s)
- Erwin B Montgomery
- Department of Neurology, National Primate Research Center, University of Wisconsin-Madison, Madison, WI 53792, USA.
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Gowen E, Miall RC. Differentiation between external and internal cuing: an fMRI study comparing tracing with drawing. Neuroimage 2007; 36:396-410. [PMID: 17448689 PMCID: PMC2570483 DOI: 10.1016/j.neuroimage.2007.03.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Revised: 03/05/2007] [Accepted: 03/08/2007] [Indexed: 11/28/2022] Open
Abstract
Externally cued movement is thought to preferentially involve cerebellar and premotor circuits whereas internally generated movement recruits basal ganglia, pre-supplementary motor cortex (pre-SMA) and dorsolateral prefrontal cortex (DLPFC). Tracing and drawing are exemplar externally and internally guided actions and Parkinson's patients and cerebellar patients show deficits in tracking and drawing, respectively. In this study we aimed to examine this external/internal distinction in healthy subjects using functional imaging. Ten healthy subjects performed tracing and drawing of simple geometric shapes using pencil and paper while in a 3-T fMRI scanner. Results indicated that compared to tracing, drawing generated greater activation in the right cerebellar crus I, bilateral pre-SMA, right dorsal premotor cortex and right frontal eye field. Tracing did not recruit any additional activation compared to drawing except in striate and extrastriate visual areas. Therefore, drawing recruited areas more frequently associated with cognitively challenging tasks, attention and memory, but basal ganglia and cerebellar activity did not differentiate tracing from drawing in the hypothesised manner. As our paradigm was of a simple, repetitive and static design, these results suggest that the task familiarity and the temporal nature of visual feedback in tracking tasks, compared to tracing, may be important contributing factors towards the degree of cerebellar involvement. Future studies comparing dynamic with static external cues and visual feedback may clarify the role of the cerebellum and basal ganglia in the visual guidance of drawing actions.
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Affiliation(s)
- E Gowen
- Faculty of Life Sciences, Moffat Building, The University of Manchester, Manchester, M60 1QD, UK.
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12
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Fawcett AP, Cunic D, Hamani C, Hodaie M, Lozano AM, Chen R, Hutchison WD. Saccade-related potentials recorded from human subthalamic nucleus. Clin Neurophysiol 2007; 118:155-63. [PMID: 17097341 DOI: 10.1016/j.clinph.2006.09.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Revised: 09/14/2006] [Accepted: 09/19/2006] [Indexed: 10/23/2022]
Abstract
OBJECTIVE To investigate an ocular motor role for the STN in Parkinson's disease (PD) patients. METHODS Potentials were recorded from deep brain stimulation (DBS) electrodes implanted in the vicinity of STN in five PD patients, while patients simultaneously performed visually cued saccades, self-paced saccades and in two patients self-paced wrist extensions. RESULTS Premovement potentials related to visually cued saccades were found in 4/5 patients and 56% (5/9) of potentials showed phase reversal indicating a local generator. Onsets of these potentials began closer to saccade initiation from STN contacts (0.88+/-0.30s) than thalamic ones (1.39+/-0.28 s). Self-paced saccade-related potentials were found in 4/4 patients. Self-paced saccade potential onsets (1.82+/-0.88 s) were not different from self-paced wrist extension onsets (1.27+/-0.98 s), suggesting a non-specific mechanism could be responsible for both potentials. 50% (3/6) of potentials to self-paced saccades and 66% (2/3) of potentials to self-paced wrist extensions showed phase reversal. Potentials could be found either ipsilaterally or contralaterally with respect to saccade direction. CONCLUSIONS These subcortical premovement potentials to saccades are similar to Bereitschaftspotentials and contingent negative variations to limb movements recorded in cortical and subcortical regions. SIGNIFICANCE These studies further support a role of STN in ocular motor control and suggest a common mechanism of motor preparation for both eye and limb movements in the basal ganglia.
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Affiliation(s)
- Adrian P Fawcett
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ont., Canada
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13
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Abstract
Abstract
THE MOTOR THALAMUS is an important target for the treatment of tremor. It receives afferents from the cerebellum, globus pallidus internus, and substantia nigra and projects mainly to the motor cortex, premotor cortex, and supplementary motor area. Various nomenclatures have been proposed to subdivide the motor thalamus, none of which are universally accepted. Both thalamic lesions and high-frequency stimulation ameliorate tremor in diverse pathological conditions. Modern neurophysiological techniques have allowed the recording of the activity of thalamic neurons in patients with different clinical conditions. This has provided a better understanding of the functions of the motor thalamus in humans. The aim of the present article is to briefly review the major anatomic and physiological aspects of the motor thalamus as well as the electrophysiological findings described in humans undergoing surgical procedures.
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Affiliation(s)
- Clement Hamani
- Division of Neurosurgery, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
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14
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Engel AK, Moll CKE, Fried I, Ojemann GA. Invasive recordings from the human brain: clinical insights and beyond. Nat Rev Neurosci 2005; 6:35-47. [PMID: 15611725 DOI: 10.1038/nrn1585] [Citation(s) in RCA: 219] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Although non-invasive methods such as functional magnetic resonance imaging, electroencephalograms and magnetoencephalograms provide most of the current data about the human brain, their resolution is insufficient to show physiological processes at the cellular level. Clinical approaches sometimes allow invasive recordings to be taken from the human brain, mainly in patients with epilepsy or with movement disorders, and such recordings can sample neural activity at spatial scales ranging from single cells to distributed cell assemblies. In addition to their clinical relevance, these recordings can provide unique insights into brain functions such as movement control, perception, memory, language and even consciousness.
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Affiliation(s)
- Andreas K Engel
- Institute of Neurophysiology and Pathophysiology, Center of Experimental Medicine, University Hospital Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
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Patil PG, Carmena JM, Nicolelis MA, Turner DA. Ensemble Recordings Of Human Subcortical Neurons as a Source Of Motor Control Signals For a Brain-Machine Interface. Neurosurgery 2004. [DOI: 10.1227/01.neu.0000126872.23715.e5] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Abstract
Two characteristics of the thalamus--its apparently simple relay function and its daunting multinuclear structure--have been customarily viewed as good reasons to study something else. Yet, now that many other brain regions have been explored and neurophysiologists are turning to questions of how larger circuits operate, these two characteristics are starting to seem more attractive. First, the relay nature of thalamic neurons means that recording from them, like tapping into a wire, can reveal the signals carried by specific circuits. Second, the concentration of like relay neurons into nuclei means that inactivating or stimulating them can efficiently test the functions of the circuits. Recent studies implementing these principles have revealed pathways through the thalamus that contribute to generating movements and to monitoring one's own actions (corollary discharge).
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Affiliation(s)
- Marc A Sommer
- Laboratory of Sensorimotor Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892-4435, USA.
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