51
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Xu AG, Qian M, Tian F, Xu B, Friedman RM, Wang J, Song X, Sun Y, Chernov MM, Cayce JM, Jansen ED, Mahadevan-Jansen A, Zhang X, Chen G, Roe AW. Focal infrared neural stimulation with high-field functional MRI: A rapid way to map mesoscale brain connectomes. SCIENCE ADVANCES 2019; 5:eaau7046. [PMID: 31032400 PMCID: PMC6482007 DOI: 10.1126/sciadv.aau7046] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Accepted: 03/14/2019] [Indexed: 05/13/2023]
Abstract
We have developed a way to map brain-wide networks using focal pulsed infrared neural stimulation in ultrahigh-field magnetic resonance imaging (MRI). The patterns of connections revealed are similar to those of connections previously mapped with anatomical tract tracing methods. These include connections between cortex and subcortical locations and long-range cortico-cortical connections. Studies of local cortical connections reveal columnar-sized laminar activation, consistent with feed-forward and feedback projection signatures. This method is broadly applicable and can be applied to multiple areas of the brain in different species and across different MRI platforms. Systematic point-by-point application of this method may lead to fundamental advances in our understanding of brain connectomes.
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Affiliation(s)
- Augix Guohua Xu
- Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310029, China
- Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou 310029, China
| | - Meizhen Qian
- Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310029, China
- Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou 310029, China
| | - Feiyan Tian
- Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310029, China
- Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou 310029, China
| | - Bin Xu
- Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310029, China
- Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou 310029, China
| | - Robert M. Friedman
- Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR 97239-3098, USA
| | - Jianbao Wang
- Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310029, China
- Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou 310029, China
| | - Xuemei Song
- Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310029, China
- Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou 310029, China
| | - Yi Sun
- MR Collaboration Northeast Asia, Siemens Healthcare, Shanghai 200001, China
| | - Mykyta M. Chernov
- Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR 97239-3098, USA
| | - Jonathan M. Cayce
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37203, USA
- Biophotonics Center, Vanderbilt University, Nashville, TN 37232, USA
| | - E. Duco Jansen
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37203, USA
- Biophotonics Center, Vanderbilt University, Nashville, TN 37232, USA
| | - Anita Mahadevan-Jansen
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37203, USA
- Biophotonics Center, Vanderbilt University, Nashville, TN 37232, USA
- Medical Center, Vanderbilt University, Nashville, TN 37232, USA
| | - Xiaotong Zhang
- Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310029, China
- Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou 310029, China
- Corresponding author. (A.W.R.); (G.C.); (X.Z.)
| | - Gang Chen
- Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310029, China
- Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou 310029, China
- Corresponding author. (A.W.R.); (G.C.); (X.Z.)
| | - Anna Wang Roe
- Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310029, China
- Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou 310029, China
- Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR 97239-3098, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37203, USA
- Corresponding author. (A.W.R.); (G.C.); (X.Z.)
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52
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Cohen D, Goddard E, Mullen KT. Reevaluating hMT+ and hV4 functional specialization for motion and static contrast using fMRI-guided repetitive transcranial magnetic stimulation. J Vis 2019; 19:11. [PMID: 30916726 DOI: 10.1167/19.3.11] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Although visual areas hMT+ and hV4 are considered to have segregated functions for the processing of motion and form within dorsal and ventral streams, respectively, more recent evidence favors some functional overlap. Here we use fMRI-guided online repetitive transcranial magnetic stimulation (rTMS) to test two associated hypotheses: that area hV4 is causally involved in the perception of motion and hMT+ in the perception of static form. We use variations of a common global stimulus to test two dynamic motion-based tasks and two static form-based tasks in ipsilateral and contralateral visual fields. We find that rTMS to both hMT+ and hV4 significantly impairs direction discrimination and causes a perceptual slowing of motion, implicating hV4 in motion perception. Stimulation of hMT+ impairs motion in both visual fields, implying that disruption to one hMT+ disrupts the other with both needed for optimal performance. For the second hypothesis, we find the novel result that hV4 stimulation markedly reduces perceived contrast of a static stimulus. hMT+ stimulation also produces an effect, implicating it in static contrast perception. Our findings are the first to show that rTMS of hV4 can produce a large perceptual effect and, taken together, suggest a less rigid functional segregation between hMT+ and hV4 than previously thought.
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Affiliation(s)
- Daniel Cohen
- McGill Vision Research, Department of Ophthalmology, McGill University, Montreal, Quebec, Canada
| | - Erin Goddard
- McGill Vision Research, Department of Ophthalmology, McGill University, Montreal, Quebec, Canada
| | - Kathy T Mullen
- McGill Vision Research, Department of Ophthalmology, McGill University, Montreal, Quebec, Canada
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53
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Tanaka Y, Nomoto T, Shiki T, Sakata Y, Shimada Y, Hayashida Y, Yagi T. Focal activation of neuronal circuits induced by microstimulation in the visual cortex. J Neural Eng 2019; 16:036007. [PMID: 30818288 DOI: 10.1088/1741-2552/ab0b80] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Microstimulation to the cortical tissue applied with penetrating electrodes delivers current that spreads concentrically around the electrode tip and is known to evoke focal visual sensations, i.e. phosphenes. However, to date, there is no direct evidence depicting the spatiotemporal properties of neuronal activity induced immediately after microstimulation and how such activity drives the subsequent local cortical circuits. APPROACH In the present study, we imaged the spatiotemporal distribution of action potentials (APs) directly induced by microstimulation and the subsequent trans-synaptic signal propagation using a voltage-sensitive dye (VSD) and a calcium-sensitive dye (CaSD) in slice preparations of the mouse primary visual cortex. MAIN RESULTS The directly induced APs were confined to the close vicinity of the electrode tip, and the effective distance of excitation was proportional to the square root of the current intensity. The excitation around the electrode tip in layer IV mainly propagated to layer II/III to further induce the subsequent focal activation in downstream local cortical circuits. The extent of activation in the downstream circuits was restrained by competitive interactions between excitatory and inhibitory signals. Namely, the spread of the excitation to lateral neighbor neurons along the layer II/III was confined by the delayed inhibition that also spread laterally at a faster rate. SIGNIFICANCE These observations indicate that dynamic interactions between excitatory and inhibitory signals play a critical role in the focal activation of a cortical circuit in response to intracortical microstimulation and, therefore, in evoking a localized phosphene.
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Affiliation(s)
- Yuta Tanaka
- Division of Electrical, Electronic, and Information Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
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54
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Michelson NJ, Eles JR, Vazquez AL, Ludwig KA, Kozai TDY. Calcium activation of cortical neurons by continuous electrical stimulation: Frequency dependence, temporal fidelity, and activation density. J Neurosci Res 2018; 97:620-638. [PMID: 30585651 DOI: 10.1002/jnr.24370] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/20/2018] [Accepted: 11/28/2018] [Indexed: 01/18/2023]
Abstract
Electrical stimulation of the brain has become a mainstay of fundamental neuroscience research and an increasingly prevalent clinical therapy. Despite decades of use in basic neuroscience research and the growing prevalence of neuromodulation therapies, gaps in knowledge regarding activation or inactivation of neural elements over time have limited its ability to adequately interpret evoked downstream responses or fine-tune stimulation parameters to focus on desired responses. In this work, in vivo two-photon microscopy was used to image neuronal calcium activity in layer 2/3 neurons of somatosensory cortex (S1) in male C57BL/6J-Tg(Thy1-GCaMP6s)GP4.3Dkim/J mice during 30 s of continuous electrical stimulation at varying frequencies. We show frequency-dependent differences in spatial and temporal somatic responses during continuous stimulation. Our results elucidate conflicting results from prior studies reporting either dense spherical activation of somas biased toward those near the electrode, or sparse activation of somas at a distance via axons near the electrode. These findings indicate that the neural element specific temporal response local to the stimulating electrode changes as a function of applied charge density and frequency. These temporal responses need to be considered to properly interpret downstream circuit responses or determining mechanisms of action in basic science experiments or clinical therapeutic applications.
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Affiliation(s)
- Nicholas J Michelson
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada
| | - James R Eles
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania.,Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Alberto L Vazquez
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania.,Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania.,Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Kip A Ludwig
- Department of Biomedical Engineering, University of Wisconsin Madison, Madison, Wisconsin.,Department of Neurological Surgery, University of Wisconsin Madison, Madison, Wisconsin
| | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania.,Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, Pennsylvania.,Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.,NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, Pennsylvania
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55
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Asymmetric effective connectivity between primate anterior cingulate and lateral prefrontal cortex revealed by electrical microstimulation. Brain Struct Funct 2018; 224:779-793. [DOI: 10.1007/s00429-018-1806-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 11/27/2018] [Indexed: 10/27/2022]
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56
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Mapping Structure-Function Relationships in the Brain. BIOLOGICAL PSYCHIATRY: COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2018; 4:510-521. [PMID: 30528965 DOI: 10.1016/j.bpsc.2018.10.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 10/17/2018] [Accepted: 10/17/2018] [Indexed: 01/06/2023]
Abstract
Mapping the structural and functional connectivity of the brain is a major focus of systems neuroscience research and will help to identify causally important changes in neural circuitry responsible for behavioral dysfunction. Several methods for examining brain activity in humans have been extended to rodent and monkey models in which molecular and genetic manipulations exist for linking to human disease. In this review, which is part of a special issue focused on bridging brain connectivity information across species and spatiotemporal scales, we address mapping brain activity and neural connectivity in rodents using optogenetics in conjunction with either functional magnetic resonance imaging or optical intrinsic signal imaging. We chose to focus on these techniques because they are capable of reporting spontaneous or evoked hemodynamic activity most closely linked to human neuroimaging studies. We discuss the capabilities and limitations of blood-based imaging methods, usage of optogenetic techniques to map neural systems in rodent models, and other powerful mapping techniques for examining neural connectivity over different spatial and temporal scales. We also discuss implementing strategies for mapping brain connectivity in humans with both basic and clinical applications, and conclude with how cross-species mapping studies can be utilized to influence preclinical imaging studies and clinical practices alike.
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57
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Solomon EA, Kragel JE, Gross R, Lega B, Sperling MR, Worrell G, Sheth SA, Zaghloul KA, Jobst BC, Stein JM, Das S, Gorniak R, Inman CS, Seger S, Rizzuto DS, Kahana MJ. Medial temporal lobe functional connectivity predicts stimulation-induced theta power. Nat Commun 2018; 9:4437. [PMID: 30361627 PMCID: PMC6202342 DOI: 10.1038/s41467-018-06876-w] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 10/01/2018] [Indexed: 02/04/2023] Open
Abstract
Focal electrical stimulation of the brain incites a cascade of neural activity that propagates from the stimulated region to both nearby and remote areas, offering the potential to control the activity of brain networks. Understanding how exogenous electrical signals perturb such networks in humans is key to its clinical translation. To investigate this, we applied electrical stimulation to subregions of the medial temporal lobe in 26 neurosurgical patients fitted with indwelling electrodes. Networks of low-frequency (5–13 Hz) spectral coherence predicted stimulation-evoked increases in theta (5–8 Hz) power, particularly when stimulation was applied in or adjacent to white matter. Stimulation tended to decrease power in the high-frequency broadband (HFB; 50–200 Hz) range, and these modulations were correlated with HFB-based networks in a subset of subjects. Our results demonstrate that functional connectivity is predictive of causal changes in the brain, capturing evoked activity across brain regions and frequency bands. Direct electrical brain stimulation can induce widespread changes in neural activity, offering a means to modulate network-wide activity and treat disease. Here, the authors show that the low-frequency functional connectivity profile of a stimulation target predicts where induced theta activity occurs.
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Affiliation(s)
- E A Solomon
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, 19146, USA.
| | - J E Kragel
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, 19146, USA
| | - R Gross
- Department of Neurosurgery, Emory School of Medicine, Atlanta, GA, 30322, USA
| | - B Lega
- Department of Neurosurgery, University of Texas Southwestern, Dallas, TX, 75390, USA
| | - M R Sperling
- Department of Neurology, Thomas Jefferson University Hospital, Philadelphia, PA, 19107, USA
| | - G Worrell
- Department of Neurology, Department of Physiology and Bioengineering, Mayo Clinic, Rochester, MN, 55905, USA
| | - S A Sheth
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX, 77030, USA
| | - K A Zaghloul
- Surgical Neurology Branch, National Institutes of Health, Bethesda, MD, 20814, USA
| | - B C Jobst
- Department of Neurology, Dartmouth Medical Center, Lebanon, NH, 03756, USA
| | - J M Stein
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - S Das
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - R Gorniak
- Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, PA, 19107, USA
| | - C S Inman
- Department of Neurosurgery, Emory School of Medicine, Atlanta, GA, 30322, USA
| | - S Seger
- Department of Neurosurgery, University of Texas Southwestern, Dallas, TX, 75390, USA
| | - D S Rizzuto
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, 19146, USA
| | - M J Kahana
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, 19146, USA.
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58
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Spatio-temporal characteristics of population responses evoked by microstimulation in the barrel cortex. Sci Rep 2018; 8:13913. [PMID: 30224723 PMCID: PMC6141467 DOI: 10.1038/s41598-018-32148-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 09/03/2018] [Indexed: 11/09/2022] Open
Abstract
Intra-cortical microstimulation (ICMS) is a widely used technique to artificially stimulate cortical tissue. This method revealed functional maps and provided causal links between neuronal activity and cognitive, sensory or motor functions. The effects of ICMS on neural activity depend on stimulation parameters. Past studies investigated the effects of stimulation frequency mainly at the behavioral or motor level. Therefore the direct effect of frequency stimulation on the evoked spatio-temporal patterns of cortical activity is largely unknown. To study this question we used voltage-sensitive dye imaging to measure the population response in the barrel cortex of anesthetized rats evoked by high frequency stimulation (HFS), a lower frequency stimulation (LFS) of the same duration or a single pulse stimulation. We found that single pulse and short trains of ICMS induced cortical activity extending over few mm. HFS evoked a lower population response during the sustained response and showed a smaller activation across time and space compared with LFS. Finally the evoked population response started near the electrode site and spread horizontally at a propagation velocity in accordance with horizontal connections. In summary, HFS was less effective in cortical activation compared to LFS although HFS had 5 fold more energy than LFS.
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59
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Kirsch V, Boegle R, Keeser D, Kierig E, Ertl-Wagner B, Brandt T, Dieterich M. Handedness-dependent functional organizational patterns within the bilateral vestibular cortical network revealed by fMRI connectivity based parcellation. Neuroimage 2018; 178:224-237. [DOI: 10.1016/j.neuroimage.2018.05.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/02/2018] [Accepted: 05/05/2018] [Indexed: 12/19/2022] Open
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d-Lysergic acid diethylamide, psilocybin, and other classic hallucinogens: Mechanism of action and potential therapeutic applications in mood disorders. PROGRESS IN BRAIN RESEARCH 2018; 242:69-96. [PMID: 30471683 DOI: 10.1016/bs.pbr.2018.07.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Depression and anxiety are psychiatric diagnoses commonly associated with low quality of life and low percentage of responsiveness by patients treated with currently available drugs. Thus, research into alternative compounds to treat these disorders is essential to guarantee a patient's remission. The last decade has witnessed a revamped interest for the application of psychedelic medicine for the treatment of mental disorders due to anecdotal reports and clinical studies which show that low doses of d-lysergic acid diethylamide (LSD) and psilocybin may have antidepressant effects. LSD and psilocybin have demonstrated mood-modulating properties likely due to their capacity to modulate serotonergic (5-HT), dopaminergic (DA) and glutamatergic systems. LSD, belonging to the category of "classic halluginogens," interacts with the 5-HT system through 5HT1A, and 5HT2A receptors, with the DA system through D2 receptors, and indirectly also the glutamatergic neurotransmission thought the recruitment of N-methyl-d-aspartate (NMDA) receptors. Randomized clinical studies have confirmed its antidepressant and anxiolytic effects in humans. Thus, in this chapter, we will review the pharmacology of psychedelic drugs, report the most striking clinical evidence which substantiate the therapeutic potentials of these fascinating compounds in mood disorders, and look into the horizon of where psychedelic medicine is heading.
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61
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Electrical Stimulation Mapping of the Brain: Basic Principles and Emerging Alternatives. J Clin Neurophysiol 2018; 35:86-97. [PMID: 29499015 DOI: 10.1097/wnp.0000000000000440] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The application of electrical stimulation mapping (ESM) of the brain for clinical use is approximating a century. Despite this long-standing history, the value of ESM for guiding surgical resections and sparing eloquent cortex is documented largely by small retrospective studies, and ESM protocols are largely inherited and lack standardization. Although models are imperfect and mechanisms are complex, the probabilistic causality of ESM has guaranteed its perpetuation into the 21st century. At present, electrical stimulation of cortical tissue is being revisited for network connectivity. In addition, noninvasive and passive mapping techniques are rapidly evolving to complement and potentially replace ESM in specific clinical situations. Lesional and epilepsy neurosurgery cases now offer different opportunities for multimodal functional assessments.
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62
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Bauer AQ, Kraft AW, Baxter GA, Wright PW, Reisman MD, Bice AR, Park JJ, Bruchas MR, Snyder AZ, Lee JM, Culver JP. Effective Connectivity Measured Using Optogenetically Evoked Hemodynamic Signals Exhibits Topography Distinct from Resting State Functional Connectivity in the Mouse. Cereb Cortex 2018; 28:370-386. [PMID: 29136125 PMCID: PMC6057523 DOI: 10.1093/cercor/bhx298] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Indexed: 02/07/2023] Open
Abstract
Brain connectomics has expanded from histological assessment of axonal projection connectivity (APC) to encompass resting state functional connectivity (RS-FC). RS-FC analyses are efficient for whole-brain mapping, but attempts to explain aspects of RS-FC (e.g., interhemispheric RS-FC) based on APC have been only partially successful. Neuroimaging with hemoglobin alone lacks specificity for determining how activity in a population of cells contributes to RS-FC. Wide-field mapping of optogenetically defined connectivity could provide insights into the brain's structure-function relationship. We combined optogenetics with optical intrinsic signal imaging to create an efficient, optogenetic effective connectivity (Opto-EC) mapping assay. We examined EC patterns of excitatory neurons in awake, Thy1-ChR2 transgenic mice. These Thy1-based EC (Thy1-EC) patterns were evaluated against RS-FC over the cortex. Compared to RS-FC, Thy1-EC exhibited increased spatial specificity, reduced interhemispheric connectivity in regions with strong RS-FC, and appreciable connection strength asymmetry. Comparing the topography of Thy1-EC and RS-FC patterns to maps of APC revealed that Thy1-EC more closely resembled APC than did RS-FC. The more general method of Opto-EC mapping with hemoglobin can be determined for 100 sites in single animals in under an hour, and is amenable to other neuroimaging modalities. Opto-EC mapping represents a powerful strategy for examining evolving connectivity-related circuit plasticity.
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Affiliation(s)
- Adam Q Bauer
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Andrew W Kraft
- Department of Neurology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Grant A Baxter
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Patrick W Wright
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO 63110, USA.,Department of Biomedical Engineering, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Matthew D Reisman
- Department of Physics, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Annie R Bice
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Jasmine J Park
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Michael R Bruchas
- Department of Biomedical Engineering, Washington University School of Medicine, Saint Louis, MO 63110, USA.,Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO 63110, USA.,Department of Neuroscience, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Abraham Z Snyder
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Jin-Moo Lee
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO 63110, USA.,Department of Neurology, Washington University School of Medicine, Saint Louis, MO 63110, USA.,Department of Biomedical Engineering, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Joseph P Culver
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO 63110, USA.,Department of Biomedical Engineering, Washington University School of Medicine, Saint Louis, MO 63110, USA.,Department of Physics, Washington University School of Medicine, Saint Louis, MO 63110, USA
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63
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Bimbard C, Demene C, Girard C, Radtke-Schuller S, Shamma S, Tanter M, Boubenec Y. Multi-scale mapping along the auditory hierarchy using high-resolution functional UltraSound in the awake ferret. eLife 2018; 7:35028. [PMID: 29952750 PMCID: PMC6039176 DOI: 10.7554/elife.35028] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Accepted: 06/16/2018] [Indexed: 12/22/2022] Open
Abstract
A major challenge in neuroscience is to longitudinally monitor whole brain activity across multiple spatial scales in the same animal. Functional UltraSound (fUS) is an emerging technology that offers images of cerebral blood volume over large brain portions. Here we show for the first time its capability to resolve the functional organization of sensory systems at multiple scales in awake animals, both within small structures by precisely mapping and differentiating sensory responses, and between structures by elucidating the connectivity scheme of top-down projections. We demonstrate that fUS provides stable (over days), yet rapid, highly-resolved 3D tonotopic maps in the auditory pathway of awake ferrets, thus revealing its unprecedented functional resolution (100/300µm). This was performed in four different brain regions, including very small (1–2 mm3 size), deeply situated subcortical (8 mm deep) and previously undescribed structures in the ferret. Furthermore, we used fUS to map long-distance projections from frontal cortex, a key source of sensory response modulation, to auditory cortex.
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Affiliation(s)
- Célian Bimbard
- Audition Team, Laboratoire des Systèmes Perceptifs CNRS UMR 8248, École Normale Supérieure, PSL Research University, Paris, France
| | - Charlie Demene
- Institut Langevin, ESPCI ParisTech, INSERM U979, CNRS UMR 7587, PSL Research University, Paris, France
| | - Constantin Girard
- Audition Team, Laboratoire des Systèmes Perceptifs CNRS UMR 8248, École Normale Supérieure, PSL Research University, Paris, France
| | - Susanne Radtke-Schuller
- Audition Team, Laboratoire des Systèmes Perceptifs CNRS UMR 8248, École Normale Supérieure, PSL Research University, Paris, France
| | - Shihab Shamma
- Audition Team, Laboratoire des Systèmes Perceptifs CNRS UMR 8248, École Normale Supérieure, PSL Research University, Paris, France.,Institute for Systems Research, Department of Electrical and Computer Engineering, University of Maryland College Park, Maryland, United States
| | - Mickael Tanter
- Institut Langevin, ESPCI ParisTech, INSERM U979, CNRS UMR 7587, PSL Research University, Paris, France
| | - Yves Boubenec
- Audition Team, Laboratoire des Systèmes Perceptifs CNRS UMR 8248, École Normale Supérieure, PSL Research University, Paris, France
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64
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Najarpour Foroushani A, Pack CC, Sawan M. Cortical visual prostheses: from microstimulation to functional percept. J Neural Eng 2018; 15:021005. [DOI: 10.1088/1741-2552/aaa904] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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65
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Bosking WH, Beauchamp MS, Yoshor D. Electrical Stimulation of Visual Cortex: Relevance for the Development of Visual Cortical Prosthetics. Annu Rev Vis Sci 2017; 3:141-166. [PMID: 28753382 PMCID: PMC6916716 DOI: 10.1146/annurev-vision-111815-114525] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Electrical stimulation of the cerebral cortex is a powerful tool for exploring cortical function. Stimulation of early visual cortical areas is easily detected by subjects and produces simple visual percepts known as phosphenes. A device implanted in visual cortex that generates patterns of phosphenes could be used as a substitute for natural vision in blind patients. We review the possibilities and limitations of such a device, termed a visual cortical prosthetic. Currently, we can predict the location and size of phosphenes produced by stimulation of single electrodes. A functional prosthetic, however, must produce spatial temporal patterns of activity that will result in the perception of complex visual objects. Although stimulation of later visual cortical areas alone usually does not lead to a visual percept, it can alter visual perception and the performance of visual behaviors, and training subjects to use signals injected into these areas may be possible.
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Affiliation(s)
- William H Bosking
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas 77030; , ,
| | - Michael S Beauchamp
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas 77030; , ,
| | - Daniel Yoshor
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas 77030; , ,
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66
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Circuit changes in motor cortex during motor skill learning. Neuroscience 2017; 368:283-297. [PMID: 28918262 DOI: 10.1016/j.neuroscience.2017.09.010] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 09/05/2017] [Accepted: 09/05/2017] [Indexed: 01/08/2023]
Abstract
Motor cortex is important for motor skill learning, particularly the dexterous skills necessary for our favorite sports and careers. We are especially interested in understanding how plasticity in motor cortex contributes to skill learning. Although human studies have been helpful in understanding the importance of motor cortex in learning skilled tasks, animal models are necessary for achieving a detailed understanding of the circuitry underlying these behaviors and the changes that occur during training. We review data from these models to try to identify sites of plasticity in motor cortex, focusing on rodents asa model system. Rodent neocortex contains well-differentiated motor and sensory regions, as well as neurons expressing similar genetic markers to many of the same circuit components in human cortex. Furthermore, rodents have circuit mapping tools for labeling, targeting, and manipulating these cell types as circuit nodes. Crucially, the projection from rodent primary somatosensory cortex to primary motor cortex is a well-studied corticocortical projection and a model of sensorimotor integration. We first summarize some of the descending pathways involved in making dexterous movements, including reaching. We then describe local and long-range circuitry in mouse motor cortex, summarizing structural and functional changes associated with motor skill acquisition. We then address which specific connections might be responsible for plasticity. For insight into the range of plasticity mechanisms employed by cortex, we review plasticity in sensory systems. The similarities and differences between motor cortex plasticity and critical periods of plasticity in sensory systems are discussed.
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67
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Saturation in Phosphene Size with Increasing Current Levels Delivered to Human Visual Cortex. J Neurosci 2017; 37:7188-7197. [PMID: 28652411 DOI: 10.1523/jneurosci.2896-16.2017] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 05/19/2017] [Accepted: 05/25/2017] [Indexed: 11/21/2022] Open
Abstract
Electrically stimulating early visual cortex results in a visual percept known as a phosphene. Although phosphenes can be evoked by a wide range of electrode sizes and current amplitudes, they are invariably described as small. To better understand this observation, we electrically stimulated 93 electrodes implanted in the visual cortex of 13 human subjects who reported phosphene size while stimulation current was varied. Phosphene size increased as the stimulation current was initially raised above threshold, but then rapidly reached saturation. Phosphene size also depended on the location of the stimulated site, with size increasing with distance from the foveal representation. We developed a model relating phosphene size to the amount of activated cortex and its location within the retinotopic map. First, a sigmoidal curve was used to predict the amount of activated cortex at a given current. Second, the amount of active cortex was converted to degrees of visual angle by multiplying by the inverse cortical magnification factor for that retinotopic location. This simple model accurately predicted phosphene size for a broad range of stimulation currents and cortical locations. The unexpected saturation in phosphene sizes suggests that the functional architecture of cerebral cortex may impose fundamental restrictions on the spread of artificially evoked activity and this may be an important consideration in the design of cortical prosthetic devices.SIGNIFICANCE STATEMENT Understanding the neural basis for phosphenes, the visual percepts created by electrical stimulation of visual cortex, is fundamental to the development of a visual cortical prosthetic. Our experiments in human subjects implanted with electrodes over visual cortex show that it is the activity of a large population of cells spread out across several millimeters of tissue that supports the perception of a phosphene. In addition, we describe an important feature of the production of phosphenes by electrical stimulation: phosphene size saturates at a relatively low current level. This finding implies that, with current methods, visual prosthetics will have a limited dynamic range available to control the production of spatial forms and that more advanced stimulation methods may be required.
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68
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Klink PC, Dagnino B, Gariel-Mathis MA, Roelfsema PR. Distinct Feedforward and Feedback Effects of Microstimulation in Visual Cortex Reveal Neural Mechanisms of Texture Segregation. Neuron 2017. [PMID: 28625487 DOI: 10.1016/j.neuron.2017.05.033] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The visual cortex is hierarchically organized, with low-level areas coding for simple features and higher areas for complex ones. Feedforward and feedback connections propagate information between areas in opposite directions, but their functional roles are only partially understood. We used electrical microstimulation to perturb the propagation of neuronal activity between areas V1 and V4 in monkeys performing a texture-segregation task. In both areas, microstimulation locally caused a brief phase of excitation, followed by inhibition. Both these effects propagated faithfully in the feedforward direction from V1 to V4. Stimulation of V4, however, caused little V1 excitation, but it did yield a delayed suppression during the late phase of visually driven activity. This suppression was pronounced for the V1 figure representation and weaker for background representations. Our results reveal functional differences between feedforward and feedback processing in texture segregation and suggest a specific modulating role for feedback connections in perceptual organization.
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Affiliation(s)
- P Christiaan Klink
- Department of Vision and Cognition, Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA, Amsterdam, the Netherlands; Department of Neuromodulation and Behaviour, Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA, Amsterdam, the Netherlands; Department of Psychiatry, Academic Medical Center, University of Amsterdam, 1100 DD Amsterdam, the Netherlands; Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University, 1081 HV Amsterdam, the Netherlands
| | - Bruno Dagnino
- Department of Vision and Cognition, Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA, Amsterdam, the Netherlands
| | - Marie-Alice Gariel-Mathis
- Department of Vision and Cognition, Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA, Amsterdam, the Netherlands
| | - Pieter R Roelfsema
- Department of Vision and Cognition, Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA, Amsterdam, the Netherlands; Department of Psychiatry, Academic Medical Center, University of Amsterdam, 1100 DD Amsterdam, the Netherlands; Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University, 1081 HV Amsterdam, the Netherlands.
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69
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Birba A, Hesse E, Sedeño L, Mikulan EP, García MDC, Ávalos J, Adolfi F, Legaz A, Bekinschtein TA, Zimerman M, Parra M, García AM, Ibáñez A. Enhanced Working Memory Binding by Direct Electrical Stimulation of the Parietal Cortex. Front Aging Neurosci 2017. [PMID: 28642698 PMCID: PMC5462969 DOI: 10.3389/fnagi.2017.00178] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recent works evince the critical role of visual short-term memory (STM) binding deficits as a clinical and preclinical marker of Alzheimer’s disease (AD). These studies suggest a potential role of posterior brain regions in both the neurocognitive deficits of Alzheimer’s patients and STM binding in general. Thereupon, we surmised that stimulation of the posterior parietal cortex (PPC) might be a successful approach to tackle working memory deficits in this condition, especially at early stages. To date, no causal evidence exists of the role of the parietal cortex in STM binding. A unique approach to assess this issue is afforded by single-subject direct intracranial electrical stimulation of specific brain regions during a relevant cognitive task. Electrical stimulation has been used both for clinical purposes and to causally probe brain mechanisms. Previous evidence of electrical currents spreading through white matter along well defined functional circuits indicates that visual working memory mechanisms are subserved by a specific widely distributed network. Here, we stimulated the parietal cortex of a subject with intracranial electrodes as he performed the visual STM task. We compared the ensuing results to those from a non-stimulated condition and to the performance of a matched control group. In brief, direct stimulation of the parietal cortex induced a selective improvement in STM. These results, together with previous studies, provide very preliminary but promising ground to examine behavioral changes upon parietal stimulation in AD. We discuss our results regarding: (a) the usefulness of the task to target prodromal stages of AD; (b) the role of a posterior network in STM binding and in AD; and (c) the potential opportunity to improve STM binding through brain stimulation.
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Affiliation(s)
- Agustina Birba
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro UniversityBuenos Aires, Argentina.,National Scientific and Technical Research Council (CONICET)Buenos Aires, Argentina
| | - Eugenia Hesse
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro UniversityBuenos Aires, Argentina.,National Scientific and Technical Research Council (CONICET)Buenos Aires, Argentina.,Instituto de Ingeniería Biomédica, Facultad de Ingeniería, Universidad de Buenos AiresBuenos Aires, Argentina
| | - Lucas Sedeño
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro UniversityBuenos Aires, Argentina.,National Scientific and Technical Research Council (CONICET)Buenos Aires, Argentina
| | - Ezequiel P Mikulan
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro UniversityBuenos Aires, Argentina.,National Scientific and Technical Research Council (CONICET)Buenos Aires, Argentina
| | | | - Juan Ávalos
- Hospital Italiano de Buenos AiresBuenos Aires, Argentina
| | - Federico Adolfi
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro UniversityBuenos Aires, Argentina.,National Scientific and Technical Research Council (CONICET)Buenos Aires, Argentina
| | - Agustina Legaz
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro UniversityBuenos Aires, Argentina
| | - Tristán A Bekinschtein
- Consciousness and Cognition Laboratory, Department of Psychology, University of CambridgeCambridge, United Kingdom
| | - Máximo Zimerman
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro UniversityBuenos Aires, Argentina
| | - Mario Parra
- Department of Psychology, School of Social Sciences, Heriot-Watt UniversityEdinburgh, United Kingdom.,Human Cognitive Neuroscience, Centre for Cognitive Ageing and Cognitive Epidemiology, Alzheimer Scotland Dementia Research Centre, Department of Psychology, University of EdinburghEdinburgh, United Kingdom.,Neuroprogressive and Dementia Network, NHS Research ScotlandEdinburgh, United Kingdom.,Facultad de Psicología, Universidad Autónoma del CaribeBarranquilla, Colombia
| | - Adolfo M García
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro UniversityBuenos Aires, Argentina.,National Scientific and Technical Research Council (CONICET)Buenos Aires, Argentina.,Faculty of Education, National University of Cuyo (UNCuyo)Mendoza, Argentina
| | - Agustín Ibáñez
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro UniversityBuenos Aires, Argentina.,National Scientific and Technical Research Council (CONICET)Buenos Aires, Argentina.,Facultad de Psicología, Universidad Autónoma del CaribeBarranquilla, Colombia.,Center for Social and Cognitive Neuroscience (CSCN), School of Psychology, Universidad Adolfo IbañezSantiago, Chile.,Centre of Excellence in Cognition and its Disorders, Australian Research Council (ARC)Sydney, NSW, Australia
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70
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Intracortical microstimulation differentially activates cortical layers based on stimulation depth. Brain Stimul 2017; 10:684-694. [DOI: 10.1016/j.brs.2017.02.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 01/23/2017] [Accepted: 02/24/2017] [Indexed: 12/22/2022] Open
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71
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Jazayeri M, Afraz A. Navigating the Neural Space in Search of the Neural Code. Neuron 2017; 93:1003-1014. [DOI: 10.1016/j.neuron.2017.02.019] [Citation(s) in RCA: 158] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 02/08/2017] [Accepted: 02/08/2017] [Indexed: 01/10/2023]
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72
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Oya H, Howard MA, Magnotta VA, Kruger A, Griffiths TD, Lemieux L, Carmichael DW, Petkov CI, Kawasaki H, Kovach CK, Sutterer MJ, Adolphs R. Mapping effective connectivity in the human brain with concurrent intracranial electrical stimulation and BOLD-fMRI. J Neurosci Methods 2017; 277:101-112. [PMID: 28012852 PMCID: PMC5534177 DOI: 10.1016/j.jneumeth.2016.12.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 11/22/2016] [Accepted: 12/20/2016] [Indexed: 12/27/2022]
Abstract
BACKGROUND Understanding brain function requires knowledge of how one brain region causally influences another. This information is difficult to obtain directly in the human brain, and is instead typically inferred from resting-state fMRI. NEW METHOD Here, we demonstrate the safety and scientific promise of a novel and complementary approach: concurrent electrical stimulation and fMRI (es-fMRI) at 3T in awake neurosurgical patients with implanted depth electrodes. RESULTS We document the results of safety testing, actual experimental setup, and stimulation parameters, that safely and reliably evoke activation in distal structures through stimulation of amygdala, cingulate, or prefrontal cortex. We compare connectivity inferred from the evoked patterns of activation with that estimated from standard resting-state fMRI in the same patients: while connectivity patterns obtained with each approach are correlated, each method produces unique results. Response patterns were stable over the course of 11min of es-fMRI runs. COMPARISON WITH EXISTING METHOD: es-fMRI in awake humans yields unique information about effective connectivity, complementing resting-state fMRI. Although our stimulations were below the level of inducing any apparent behavioral or perceptual effects, a next step would be to use es-fMRI to modulate task performances. This would reveal the acute network-level changes induced by the stimulation that mediate the behavioral and cognitive effects seen with brain stimulation. CONCLUSIONS es-fMRI provides a novel and safe approach for mapping effective connectivity in the human brain in a clinical setting, and will inform treatments for psychiatric and neurodegenerative disorders that use deep brain stimulation.
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Affiliation(s)
- Hiroyuki Oya
- Department of Neurosurgery, Human Brain Research Laboratory, University of Iowa, Iowa City, IA 52241, USA.
| | - Matthew A Howard
- Department of Neurosurgery, Human Brain Research Laboratory, University of Iowa, Iowa City, IA 52241, USA
| | - Vincent A Magnotta
- Department of Radiology, University of Iowa College of Medicine, Iowa City, IA 52241, USA
| | - Anton Kruger
- Department of Electrical and Computer Engineering, University of Iowa College of Engineering, USA
| | | | - Louis Lemieux
- UCL Institute of Neurology, University College London, London, UK
| | | | | | - Hiroto Kawasaki
- Department of Neurosurgery, Human Brain Research Laboratory, University of Iowa, Iowa City, IA 52241, USA
| | - Christopher K Kovach
- Department of Neurosurgery, Human Brain Research Laboratory, University of Iowa, Iowa City, IA 52241, USA
| | - Matthew J Sutterer
- Department of Neurosurgery, Human Brain Research Laboratory, University of Iowa, Iowa City, IA 52241, USA
| | - Ralph Adolphs
- Division of Biology and Biological Engineering, California Institute of Technology, USA
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73
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Hao Y, Riehle A, Brochier TG. Mapping Horizontal Spread of Activity in Monkey Motor Cortex Using Single Pulse Microstimulation. Front Neural Circuits 2016; 10:104. [PMID: 28018182 PMCID: PMC5159418 DOI: 10.3389/fncir.2016.00104] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 12/01/2016] [Indexed: 12/13/2022] Open
Abstract
Anatomical studies have demonstrated that distant cortical points are interconnected through long range axon collaterals of pyramidal cells. However, the functional properties of these intrinsic synaptic connections, especially their relationship with the cortical representations of body movements, have not been systematically investigated. To address this issue, we used multielectrode arrays chronically implanted in the motor cortex of two rhesus monkeys to analyze the effects of single-pulse intracortical microstimulation (sICMS) applied at one electrode on the neuronal activities recorded at all other electrodes. The temporal and spatial distribution of the evoked responses of single and multiunit activities was quantified to determine the properties of horizontal propagation. The typical responses were characterized by a brief excitatory peak followed by inhibition of longer duration. Significant excitatory responses to sICMS could be evoked up to 4 mm away from the stimulation site, but the strength of the response decreased exponentially and its latency increased linearly with the distance. We then quantified the direction and strength of the propagation in relation to the somatotopic organization of the motor cortex. We observed that following sICMS the propagation of neural activity is mainly directed rostro-caudally near the central sulcus but follows medio-lateral direction at the most anterior electrodes. The fact that these interactions are not entirely symmetrical may characterize a critical functional property of the motor cortex for the control of upper limb movements. Overall, these results support the assumption that the motor cortex is not functionally homogeneous but forms a complex network of interacting subregions.
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Affiliation(s)
- Yaoyao Hao
- Institut de Neurosciences de la Timone, CNRS - Aix-Marseille Université, UMR7289 Marseille, France
| | - Alexa Riehle
- Institut de Neurosciences de la Timone, CNRS - Aix-Marseille Université, UMR7289Marseille, France; RIKEN Brain Science InstituteSaitama, Japan; Institute of Neuroscience and Medicine, Forschungszentrum JülichJülich, Germany
| | - Thomas G Brochier
- Institut de Neurosciences de la Timone, CNRS - Aix-Marseille Université, UMR7289 Marseille, France
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74
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Kim S, Callier T, Bensmaia SJ. A computational model that predicts behavioral sensitivity to intracortical microstimulation. J Neural Eng 2016; 14:016012. [PMID: 27977419 DOI: 10.1088/1741-2552/14/1/016012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECTIVE Intracortical microstimulation (ICMS) is a powerful tool to investigate the neural mechanisms of perception and can be used to restore sensation for patients who have lost it. While sensitivity to ICMS has previously been characterized, no systematic framework has been developed to summarize the detectability of individual ICMS pulse trains or the discriminability of pairs of pulse trains. APPROACH We develop a simple simulation that describes the responses of a population of neurons to a train of electrical pulses delivered through a microelectrode. We then perform an ideal observer analysis on the simulated population responses to predict the behavioral performance of non-human primates in ICMS detection and discrimination tasks. MAIN RESULTS Our computational model can predict behavioral performance across a wide range of stimulation conditions with high accuracy (R 2 = 0.97) and generalizes to novel ICMS pulse trains that were not used to fit its parameters. Furthermore, the model provides a theoretical basis for the finding that amplitude discrimination based on ICMS violates Weber's law. SIGNIFICANCE The model can be used to characterize the sensitivity to ICMS across the range of perceptible and safe stimulation regimes. As such, it will be a useful tool for both neuroscience and neuroprosthetics.
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Affiliation(s)
- Sungshin Kim
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, USA
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75
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Premereur E, Taubert J, Janssen P, Vogels R, Vanduffel W. Effective Connectivity Reveals Largely Independent Parallel Networks of Face and Body Patches. Curr Biol 2016; 26:3269-3279. [DOI: 10.1016/j.cub.2016.09.059] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 09/04/2016] [Accepted: 09/28/2016] [Indexed: 10/20/2022]
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76
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Boychuk JA, Farrell JS, Palmer LA, Singleton AC, Pittman QJ, Teskey GC. HCN channels segregate stimulation-evoked movement responses in neocortex and allow for coordinated forelimb movements in rodents. J Physiol 2016; 595:247-263. [PMID: 27568501 DOI: 10.1113/jp273068] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Accepted: 08/17/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The present study tested whether HCN channels contribute to the organization of motor cortex and to skilled motor behaviour during a forelimb reaching task. Experimental reductions in HCN channel signalling increase the representation of complex multiple forelimb movements in motor cortex as assessed by intracortical microstimulation. Global HCN1KO mice exhibit reduced reaching accuracy and atypical movements during a single-pellet reaching task relative to wild-type controls. Acute pharmacological inhibition of HCN channels in forelimb motor cortex decreases reaching accuracy and increases atypical movements during forelimb reaching. ABSTRACT The mechanisms by which distinct movements of a forelimb are generated from the same area of motor cortex have remained elusive. Here we examined a role for HCN channels, given their ability to alter synaptic integration, in the expression of forelimb movement responses during intracortical microstimulation (ICMS) and movements of the forelimb on a skilled reaching task. We used short-duration high-resolution ICMS to evoke forelimb movements following pharmacological (ZD7288), experimental (electrically induced cortical seizures) or genetic approaches that we confirmed with whole-cell patch clamp to substantially reduce Ih current. We observed significant increases in the number of multiple movement responses evoked at single sites in motor maps to all three experimental manipulations in rats or mice. Global HCN1 knockout mice were less successful and exhibited atypical movements on a skilled-motor learning task relative to wild-type controls. Furthermore, in reaching-proficient rats, reaching accuracy was reduced and forelimb movements were altered during infusion of ZD7288 within motor cortex. Thus, HCN channels play a critical role in the separation of overlapping movement responses and allow for successful reaching behaviours. These data provide a novel mechanism for the encoding of multiple movement responses within shared networks of motor cortex. This mechanism supports a viewpoint of primary motor cortex as a site of dynamic integration for behavioural output.
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Affiliation(s)
- Jeffery A Boychuk
- Department of Physiology, University of Kentucky, Lexington, Kentucky, USA.,Epilepsy Center, University of Kentucky, Lexington, Kentucky, USA.,Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada.,Department of Neuroscience, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Jordan S Farrell
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada.,Department of Neuroscience, University of Calgary, Calgary, Alberta, Canada
| | - Laura A Palmer
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada.,Department of Neuroscience, University of Calgary, Calgary, Alberta, Canada
| | - Anna C Singleton
- Department of Neuroscience, University of Calgary, Calgary, Alberta, Canada
| | - Quentin J Pittman
- Department of Neuroscience, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, Calgary, Alberta, Canada
| | - G Campbell Teskey
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada.,Department of Neuroscience, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, Calgary, Alberta, Canada
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77
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Abstract
UNLABELLED Comprehensive analysis of brain function depends on understanding the dynamics of diverse neural signaling processes over large tissue volumes in intact animals and humans. Most existing approaches to measuring brain signaling suffer from limited tissue penetration, poor resolution, or lack of specificity for well-defined neural events. Here we discuss a new brain activity mapping method that overcomes some of these problems by combining MRI with contrast agents sensitive to neural signaling. The goal of this "molecular fMRI" approach is to permit noninvasive whole-brain neuroimaging with specificity and resolution approaching current optical neuroimaging methods. In this article, we describe the context and need for molecular fMRI as well as the state of the technology today. We explain how major types of MRI probes work and how they can be sensitized to neurobiological processes, such as neurotransmitter release, calcium signaling, and gene expression changes. We comment both on past work in the field and on challenges and promising avenues for future development. SIGNIFICANCE STATEMENT Brain researchers currently have a choice between measuring neural activity using cellular-level recording techniques, such as electrophysiology and optical imaging, or whole-brain imaging methods, such as fMRI. Cellular level methods are precise but only address a small portion of mammalian brains; on the other hand, whole-brain neuroimaging techniques provide very little specificity for neural pathways or signaling components of interest. The molecular fMRI techniques we discuss have particular potential to combine the specificity of cellular-level measurements with the noninvasive whole-brain coverage of fMRI. On the other hand, molecular fMRI is only just getting off the ground. This article aims to offer a snapshot of the status and future prospects for development of molecular fMRI techniques.
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Mendoza G, Peyrache A, Gámez J, Prado L, Buzsáki G, Merchant H. Recording extracellular neural activity in the behaving monkey using a semichronic and high-density electrode system. J Neurophysiol 2016; 116:563-74. [PMID: 27169505 PMCID: PMC4978789 DOI: 10.1152/jn.00116.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/04/2016] [Indexed: 11/22/2022] Open
Abstract
We describe a technique to semichronically record the cortical extracellular neural activity in the behaving monkey employing commercial high-density electrodes. After the design and construction of low cost microdrives that allow varying the depth of the recording locations after the implantation surgery, we recorded the extracellular unit activity from pools of neurons at different depths in the presupplementary motor cortex (pre-SMA) of a rhesus monkey trained in a tapping task. The collected data were processed to classify cells as putative pyramidal cells or interneurons on the basis of their waveform features. We also demonstrate that short time cross-correlogram occasionally yields unit pairs with high short latency (<5 ms), narrow bin (<3 ms) peaks, indicative of monosynaptic spike transmission from pre- to postsynaptic neurons. These methods have been verified extensively in rodents. Finally, we observed that the pattern of population activity was repetitive over distinct trials of the tapping task. These results show that the semichronic technique is a viable option for the large-scale parallel recording of local circuit activity at different depths in the cortex of the macaque monkey and other large species.
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Affiliation(s)
- Germán Mendoza
- Instituto de Neurobiología, National Autonomous University of Mexico, Querétaro, México; and
| | - Adrien Peyrache
- The Neuroscience Institute, School of Medicine and Center for Neural Science, New York University, New York, New York
| | - Jorge Gámez
- Instituto de Neurobiología, National Autonomous University of Mexico, Querétaro, México; and
| | - Luis Prado
- Instituto de Neurobiología, National Autonomous University of Mexico, Querétaro, México; and
| | - György Buzsáki
- The Neuroscience Institute, School of Medicine and Center for Neural Science, New York University, New York, New York
| | - Hugo Merchant
- Instituto de Neurobiología, National Autonomous University of Mexico, Querétaro, México; and
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79
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Lee HJ, Weitz AJ, Bernal-Casas D, Duffy BA, Choy M, Kravitz AV, Kreitzer AC, Lee JH. Activation of Direct and Indirect Pathway Medium Spiny Neurons Drives Distinct Brain-wide Responses. Neuron 2016; 91:412-24. [PMID: 27373834 DOI: 10.1016/j.neuron.2016.06.010] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 04/06/2016] [Accepted: 05/27/2016] [Indexed: 12/28/2022]
Abstract
A central theory of basal ganglia function is that striatal neurons expressing the D1 and D2 dopamine receptors exert opposing brain-wide influences. However, the causal influence of each population has never been measured at the whole-brain scale. Here, we selectively stimulated D1 or D2 receptor-expressing neurons while visualizing whole-brain activity with fMRI. Excitation of either inhibitory population evoked robust positive BOLD signals within striatum, while downstream regions exhibited significantly different and generally opposing responses consistent with-though not easily predicted from-contemporary models of basal ganglia function. Importantly, positive and negative signals within the striatum, thalamus, GPi, and STN were all associated with increases and decreases in single-unit activity, respectively. These findings provide direct evidence for the opposing influence of D1 and D2 receptor-expressing striatal neurons on brain-wide circuitry and extend the interpretability of fMRI studies by defining cell-type-specific contributions to the BOLD signal.
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Affiliation(s)
- Hyun Joo Lee
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA
| | - Andrew J Weitz
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - David Bernal-Casas
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA
| | - Ben A Duffy
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA
| | - ManKin Choy
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA
| | - Alexxai V Kravitz
- National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA; Gladstone Institute of Neurological Disease, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Anatol C Kreitzer
- Gladstone Institute of Neurological Disease, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jin Hyung Lee
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA; Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA.
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80
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Werginz P, Rattay F. The impact of calcium current reversal on neurotransmitter release in the electrically stimulated retina. J Neural Eng 2016; 13:046013. [DOI: 10.1088/1741-2560/13/4/046013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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81
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Hadar R, Vengeliene V, Barroeta Hlusicke E, Canals S, Noori HR, Wieske F, Rummel J, Harnack D, Heinz A, Spanagel R, Winter C. Paradoxical augmented relapse in alcohol-dependent rats during deep-brain stimulation in the nucleus accumbens. Transl Psychiatry 2016; 6:e840. [PMID: 27327255 PMCID: PMC4931598 DOI: 10.1038/tp.2016.100] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 04/14/2016] [Accepted: 04/20/2016] [Indexed: 12/24/2022] Open
Abstract
Case reports indicate that deep-brain stimulation in the nucleus accumbens may be beneficial to alcohol-dependent patients. The lack of clinical trials and our limited knowledge of deep-brain stimulation call for translational experiments to validate these reports. To mimic the human situation, we used a chronic-continuous brain-stimulation paradigm targeting the nucleus accumbens and other brain sites in alcohol-dependent rats. To determine the network effects of deep-brain stimulation in alcohol-dependent rats, we combined electrical stimulation of the nucleus accumbens with functional magnetic resonance imaging (fMRI), and studied neurotransmitter levels in nucleus accumbens-stimulated versus sham-stimulated rats. Surprisingly, we report here that electrical stimulation of the nucleus accumbens led to augmented relapse behavior in alcohol-dependent rats. Our associated fMRI data revealed some activated areas, including the medial prefrontal cortex and caudate putamen. However, when we applied stimulation to these areas, relapse behavior was not affected, confirming that the nucleus accumbens is critical for generating this paradoxical effect. Neurochemical analysis of the major activated brain sites of the network revealed that the effect of stimulation may depend on accumbal dopamine levels. This was supported by the finding that brain-stimulation-treated rats exhibited augmented alcohol-induced dopamine release compared with sham-stimulated animals. Our data suggest that deep-brain stimulation in the nucleus accumbens enhances alcohol-liking probably via augmented dopamine release and can thereby promote relapse.
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Affiliation(s)
- R Hadar
- Department of Psychiatry and Psychotherapy, University Hospital Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - V Vengeliene
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - E Barroeta Hlusicke
- Department of Psychiatry and Psychotherapy, University Hospital Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - S Canals
- Cellular and Systems Neurobiology Unit, Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas and Universidad Miguel Hernández, Sant Joan d'Alacant, Spain
| | - H R Noori
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - F Wieske
- Department of Psychiatry and Psychotherapy, University Hospital Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - J Rummel
- Department of Psychiatry and Psychotherapy, University Hospital Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - D Harnack
- Department of Neurology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - A Heinz
- Department of Psychiatry and Psychotherapy, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - R Spanagel
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - C Winter
- Department of Psychiatry and Psychotherapy, University Hospital Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany,Department of Psychiatry and Psychotherapy, University Hospital Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden 01307, Germany. E-mail:
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82
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Cleeren E, Premereur E, Casteels C, Goffin K, Janssen P, Van Paesschen W. The effective connectivity of the seizure onset zone and ictal perfusion changes in amygdala kindled rhesus monkeys. NEUROIMAGE-CLINICAL 2016; 12:252-61. [PMID: 27489773 PMCID: PMC4959940 DOI: 10.1016/j.nicl.2016.05.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 04/04/2016] [Accepted: 05/31/2016] [Indexed: 12/22/2022]
Abstract
Epileptic seizures are network-level phenomena. Hence, epilepsy may be regarded as a circuit-level disorder that cannot be understood outside this context. Better insight into the effective connectivity of the seizure onset zone and the manner in which seizure activity spreads could lead to specifically-tailored therapies for epilepsy. We applied the electrical amygdala kindling model in two rhesus monkeys until these animals displayed consistent stage IV seizures. At this stage, we investigated the effective connectivity of the amygdala by means of electrical microstimulation during fMRI (EM-fMRI). In addition, we imaged changes in perfusion during a seizure using ictal SPECT perfusion imaging. The spatial overlap between the connectivity network and the ictal perfusion network was assessed both at the regional level, by calculating Dice coefficients using anatomically defined regions of interest, and at the voxel level. The kindled amygdala was extensively connected to bilateral cortical and subcortical structures, which in many cases were connected multisynaptically to the amygdala. At the regional level, the spatial extents of many of these fMRI activations and deactivations corresponded to the respective increases and decreases in perfusion imaged during a stage IV seizure. At the voxel level, however, some regions showed residual seizure-specific activity (not overlapping with the EM-fMRI activations) or fMRI-specific activation (not overlapping with the ictal SPECT activations), indicating that frequently, only a part of a region anatomically connected to the seizure onset zone participated in seizure propagation. Thus, EM-fMRI in the amygdala of electrically-kindled monkeys reveals widespread areas that are often connected multisynaptically to the seizure focus. Seizure activity appears to spread, to a large extent, via these connected areas.
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Affiliation(s)
- Evy Cleeren
- Laboratory for Neuro- and Psychophysiology, KU Leuven, O&N II Herestraat 49 - bus 1021, 3000 Leuven, Belgium; Laboratory for Epilepsy Research, KU Leuven, UZ Herestraat 49 - bus 7003 48, 3000 Leuven, Belgium
| | - Elsie Premereur
- Laboratory for Neuro- and Psychophysiology, KU Leuven, O&N II Herestraat 49 - bus 1021, 3000 Leuven, Belgium
| | - Cindy Casteels
- Nuclear Medicine & Molecular Imaging, Department of Imaging and Pathology, UZ Herestraat 49 - bus 7003 59, 3000 Leuven, Belgium; Molecular Small Animal Imaging Center (MoSAIC), O&N I Herestraat 49 - bus 505, 3000 Leuven, Belgium
| | - Karolien Goffin
- Nuclear Medicine & Molecular Imaging, Department of Imaging and Pathology, UZ Herestraat 49 - bus 7003 59, 3000 Leuven, Belgium
| | - Peter Janssen
- Laboratory for Neuro- and Psychophysiology, KU Leuven, O&N II Herestraat 49 - bus 1021, 3000 Leuven, Belgium
| | - Wim Van Paesschen
- Laboratory for Epilepsy Research, KU Leuven, UZ Herestraat 49 - bus 7003 48, 3000 Leuven, Belgium
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83
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Neural correlates of the LSD experience revealed by multimodal neuroimaging. Proc Natl Acad Sci U S A 2016; 113:4853-8. [PMID: 27071089 DOI: 10.1073/pnas.1518377113] [Citation(s) in RCA: 413] [Impact Index Per Article: 51.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Lysergic acid diethylamide (LSD) is the prototypical psychedelic drug, but its effects on the human brain have never been studied before with modern neuroimaging. Here, three complementary neuroimaging techniques: arterial spin labeling (ASL), blood oxygen level-dependent (BOLD) measures, and magnetoencephalography (MEG), implemented during resting state conditions, revealed marked changes in brain activity after LSD that correlated strongly with its characteristic psychological effects. Increased visual cortex cerebral blood flow (CBF), decreased visual cortex alpha power, and a greatly expanded primary visual cortex (V1) functional connectivity profile correlated strongly with ratings of visual hallucinations, implying that intrinsic brain activity exerts greater influence on visual processing in the psychedelic state, thereby defining its hallucinatory quality. LSD's marked effects on the visual cortex did not significantly correlate with the drug's other characteristic effects on consciousness, however. Rather, decreased connectivity between the parahippocampus and retrosplenial cortex (RSC) correlated strongly with ratings of "ego-dissolution" and "altered meaning," implying the importance of this particular circuit for the maintenance of "self" or "ego" and its processing of "meaning." Strong relationships were also found between the different imaging metrics, enabling firmer inferences to be made about their functional significance. This uniquely comprehensive examination of the LSD state represents an important advance in scientific research with psychedelic drugs at a time of growing interest in their scientific and therapeutic value. The present results contribute important new insights into the characteristic hallucinatory and consciousness-altering properties of psychedelics that inform on how they can model certain pathological states and potentially treat others.
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84
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Kim K, Ekstrom AD, Tandon N. A network approach for modulating memory processes via direct and indirect brain stimulation: Toward a causal approach for the neural basis of memory. Neurobiol Learn Mem 2016; 134 Pt A:162-177. [PMID: 27066987 DOI: 10.1016/j.nlm.2016.04.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 03/15/2016] [Accepted: 04/05/2016] [Indexed: 12/22/2022]
Abstract
Electrical stimulation of the brain is a unique tool to perturb endogenous neural signals, allowing us to evaluate the necessity of given neural processes to cognitive processing. An important issue, gaining increasing interest in the literature, is whether and how stimulation can be employed to selectively improve or disrupt declarative memory processes. Here, we provide a comprehensive review of both invasive and non-invasive stimulation studies aimed at modulating memory performance. The majority of past studies suggest that invasive stimulation of the hippocampus impairs memory performance; similarly, most non-invasive studies show that disrupting frontal or parietal regions also impairs memory performance, suggesting that these regions also play necessary roles in declarative memory. On the other hand, a handful of both invasive and non-invasive studies have also suggested modest improvements in memory performance following stimulation. These studies typically target brain regions connected to the hippocampus or other memory "hubs," which may affect endogenous activity in connected areas like the hippocampus, suggesting that to augment declarative memory, altering the broader endogenous memory network activity is critical. Together, studies reporting memory improvements/impairments are consistent with the idea that a network of distinct brain "hubs" may be crucial for successful memory encoding and retrieval rather than a single primary hub such as the hippocampus. Thus, it is important to consider neurostimulation from the network perspective, rather than from a purely localizationalist viewpoint. We conclude by proposing a novel approach to neurostimulation for declarative memory modulation that aims to facilitate interactions between multiple brain "nodes" underlying memory rather than considering individual brain regions in isolation.
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Affiliation(s)
- Kamin Kim
- Department of Neurosurgery, University of Texas Medical School at Houston, Houston, TX, USA
| | - Arne D Ekstrom
- Center for Neuroscience and Department of Psychology, University of California Davis, Davis, CA, USA
| | - Nitin Tandon
- Department of Neurosurgery, University of Texas Medical School at Houston, Houston, TX, USA.
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85
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Vincent M, Rossel O, Hayashibe M, Herbet G, Duffau H, Guiraud D, Bonnetblanc F. The difference between electrical microstimulation and direct electrical stimulation – towards new opportunities for innovative functional brain mapping? Rev Neurosci 2016; 27:231-58. [DOI: 10.1515/revneuro-2015-0029] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 10/17/2015] [Indexed: 11/15/2022]
Abstract
AbstractBoth electrical microstimulation (EMS) and direct electrical stimulation (DES) of the brain are used to perform functional brain mapping. EMS is applied to animal fundamental neuroscience experiments, whereas DES is performed in the operating theatre on neurosurgery patients. The objective of the present review was to shed new light on electrical stimulation techniques in brain mapping by comparing EMS and DES. There is much controversy as to whether the use of DES during wide-awake surgery is the ‘gold standard’ for studying the brain function. As part of this debate, it is sometimes wrongly assumed that EMS and DES induce similar effects in the nervous tissues and have comparable behavioural consequences. In fact, the respective stimulation parameters in EMS and DES are clearly different. More surprisingly, there is no solid biophysical rationale for setting the stimulation parameters in EMS and DES; this may be due to historical, methodological and technical constraints that have limited the experimental protocols and prompted the use of empirical methods. In contrast, the gap between EMS and DES highlights the potential for new experimental paradigms in electrical stimulation for functional brain mapping. In view of this gap and recent technical developments in stimulator design, it may now be time to move towards alternative, innovative protocols based on the functional stimulation of peripheral nerves (for which a more solid theoretical grounding exists).
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Affiliation(s)
- Marion Vincent
- 1INRIA, Université de Montpellier, LIRMM, équipe DEMAR, F-34095 Montpellier, France
| | - Olivier Rossel
- 1INRIA, Université de Montpellier, LIRMM, équipe DEMAR, F-34095 Montpellier, France
| | - Mitsuhiro Hayashibe
- 1INRIA, Université de Montpellier, LIRMM, équipe DEMAR, F-34095 Montpellier, France
| | | | | | - David Guiraud
- 1INRIA, Université de Montpellier, LIRMM, équipe DEMAR, F-34095 Montpellier, France
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86
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Ethological Action Maps: A Paradigm Shift for the Motor Cortex. Trends Cogn Sci 2016; 20:121-132. [PMID: 26628112 DOI: 10.1016/j.tics.2015.10.008] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 10/20/2015] [Accepted: 10/28/2015] [Indexed: 11/21/2022]
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87
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Chernov MM, Chen G, Torre-Healy LA, Friedman RM, Roe AW. Microelectrode array stimulation combined with intrinsic optical imaging: A novel tool for functional brain mapping. J Neurosci Methods 2016; 263:7-14. [PMID: 26820903 DOI: 10.1016/j.jneumeth.2016.01.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Revised: 12/24/2015] [Accepted: 01/16/2016] [Indexed: 02/03/2023]
Abstract
BACKGROUND Functional brain mapping via cortical microstimulation is a widely used clinical and experimental tool. However, data are traditionally collected point by point, making the technique very time consuming. Moreover, even in skilled hands, consistent penetration depths are difficult to achieve. Finally, the effects of microstimulation are assessed behaviorally, with no attempt to capture the activity of the local cortical circuits being stimulated. NEW METHOD We propose a novel method for functional brain mapping, which combines the use of a microelectrode array with intrinsic optical imaging. The precise spacing of electrodes allows for fast, accurate mapping of the area of interest in a regular grid. At the same time, the optical window allows for visualization of local neural connections when stimulation is combined with intrinsic optical imaging. RESULTS We demonstrate the efficacy of our technique using the primate motor cortex as a sample application, using a combination of microstimulation, imaging and electrophysiological recordings during wakefulness and under anesthesia. Comparison with current method: We find the data collected with our method is consistent with previous data published by others. We believe that our approach enables data to be collected faster and in a more consistent fashion and makes possible a number of studies that would be difficult to carry out with the traditional approach. CONCLUSIONS Our technique allows for simultaneous modulation and imaging of cortical sensorimotor networks in wakeful subjects over multiple sessions which is highly desirable for both the study of cortical organization and the design of brain machine interfaces.
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Affiliation(s)
- Mykyta M Chernov
- Department of Psychology, Vanderbilt University, 111 21st Ave S, Nashville, TN 37240, United States.
| | - Gang Chen
- Department of Psychology, Vanderbilt University, 111 21st Ave S, Nashville, TN 37240, United States
| | - Luke A Torre-Healy
- Department of Psychology, Vanderbilt University, 111 21st Ave S, Nashville, TN 37240, United States
| | - Robert M Friedman
- Department of Psychology, Vanderbilt University, 111 21st Ave S, Nashville, TN 37240, United States
| | - Anna W Roe
- Department of Psychology, Vanderbilt University, 111 21st Ave S, Nashville, TN 37240, United States
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88
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Roe AW, Chernov MM, Friedman RM, Chen G. In Vivo Mapping of Cortical Columnar Networks in the Monkey with Focal Electrical and Optical Stimulation. Front Neuroanat 2015; 9:135. [PMID: 26635539 PMCID: PMC4644798 DOI: 10.3389/fnana.2015.00135] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 10/12/2015] [Indexed: 11/30/2022] Open
Abstract
There are currently largescale efforts to understand the brain as a connection machine. However, there has been little emphasis on understanding connection patterns between functionally specific cortical columns. Here, we review development and application of focal electrical and optical stimulation methods combined with optical imaging and fMRI mapping in the non-human primate. These new approaches, when applied systematically on a large scale, will elucidate functionally specific intra-areal and inter-areal network connection patterns. Such functionally specific network data can provide accurate views of brain network topology.
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Affiliation(s)
- Anna Wang Roe
- Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University Hangzhou, China
| | - Mykyta M Chernov
- Department of Psychology, Vanderbilt University, Nashville TN, USA
| | | | - Gang Chen
- Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University Hangzhou, China
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89
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Spherical statistics for characterizing the spatial distribution of deep brain stimulation effects on neuronal activity. J Neurosci Methods 2015; 255:52-65. [PMID: 26275582 DOI: 10.1016/j.jneumeth.2015.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 07/29/2015] [Accepted: 08/01/2015] [Indexed: 11/24/2022]
Abstract
BACKGROUND Computational models of deep brain stimulation (DBS) have played a key role in understanding its physiological mechanisms. By estimating a volume of tissue directly modulated by DBS, one can relate the neuronal pathways within those volumes to the therapeutic efficacy of a particular DBS setting. NEW METHOD A spherical statistical framework is described to quantify and determine salient features of such morphologies using visualization techniques, empirical shape analysis, and formal hypothesis testing. This framework is shown using a 3D model of thalamocortical neurons surrounding a radially-segmented DBS array. RESULTS We show that neuronal population volumes modulated by various DBS electrode configurations can be characterized by parametric distribution models, such as Kent and Watson girdle models. Distribution parameters were found to change with stimulus settings, including amplitude and radial distance from the DBS array. Increasing stimulation amplitude through a single electrode resulted in more diffuse neuronal activation and increased rotational symmetry about the mean direction of the activated population. When stimulation amplitude was held constant, the activated neuronal population distribution was more concentrated with distance from the DBS array and was also more rotationally asymmetric. We also show how data representation (e.g. stimulus-entrained cell body vs. axon node) can significantly alter model distribution shape. COMPARISON TO EXISTING METHODS This statistical framework provides a quantitative method to analyze the spatial morphologies of DBS-induced effects on neuronal activity. CONCLUSIONS The application of spherical statistics to assess spatial distributions of neuronal activity has potential usefulness for numerous other recording, labeling, and stimulation modalities.
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90
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Adab HZ, Vogels R. Perturbation of Posterior Inferior Temporal Cortical Activity Impairs Coarse Orientation Discrimination. Cereb Cortex 2015; 26:3814-3827. [PMID: 26250777 DOI: 10.1093/cercor/bhv178] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
It is reasonable to assume that the discrimination of simple visual stimuli depends on the activity of early visual cortical neurons, because simple visual features are supposedly coded in these areas whereas more complex features are coded in late visual areas. Recently, we showed that training monkeys in a coarse orientation discrimination task modified the response properties of single neurons in the posterior inferior temporal (PIT) cortex, a late visual area. Here, we examined the contribution of PIT to coarse orientation discrimination using causal perturbation methods. Electrical stimulation (ES) of PIT with currents of at least 100 µA impaired coarse orientation discrimination in monkeys. The performance deterioration did not exclusively reflect a general impairment to perform a difficult perceptual task. However, high current (650 µA) but not low-current (100 µA) ES also impaired fine color discrimination. ES of temporal regions dorsal or anterior to PIT produced less impairment of coarse orientation discrimination than ES of PIT. Injections of the GABA agonist muscimol into PIT also impaired performance. These data suggest that the late cortical area PIT is part of the network that supports coarse orientation discrimination of a simple grating stimulus, at least after extensive training in this task at threshold.
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Affiliation(s)
- Hamed Zivari Adab
- Laboratorium voor Neuro- en Psychofysiologie, KU Leuven Medical School, Leuven 3000, Belgium
| | - Rufin Vogels
- Laboratorium voor Neuro- en Psychofysiologie, KU Leuven Medical School, Leuven 3000, Belgium
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91
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Hussin AT, Boychuk JA, Brown AR, Pittman QJ, Teskey GC. Intracortical Microstimulation (ICMS) Activates Motor Cortex Layer 5 Pyramidal Neurons Mainly Transsynaptically. Brain Stimul 2015; 8:742-50. [PMID: 25892002 DOI: 10.1016/j.brs.2015.03.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 02/08/2015] [Accepted: 03/19/2015] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Intracortical microstimulation (ICMS) is a technique used for a number of purposes including the derivation of cortical movement representations (motor maps). Its application can activate the output layer 5 of motor cortex and can result in the elicitation of body movements depending upon the stimulus parameters used. OBJECTIVE The extent to which pyramidal tract projection neurons of the motor cortex are activated transsynaptically or directly by ICMS remains an open question. Given this uncertainty in the mode of activation, we used a preparation that combined patch clamp whole-cell recordings from single layer 5 pyramidal neurons and extracellular ICMS in slices of motor cortex as well as a standard in vivo mapping technique to ask how ICMS activated motor cortex pyramidal neurons. METHODS We measured changes in synaptic spike threshold and spiking rate to ICMS in vitro and movement threshold in vivo in the presence or absence of specific pharmacological blockers of glutamatergic (AMPA, NMDA and Kainate) receptors and GABAA receptors. RESULTS With major excitatory and inhibitory synaptic transmission blocked (with DNQX, APV and bicuculline methiodide), we observed a significant increase in the ICMS current intensity required to elicit a movement in vivo as well as to the first spike and an 85% reduction in spiking responses in vitro. Subsets of neurons were still responsive after the synaptic block, especially at higher current intensities, suggesting a modest direct activation. CONCLUSION Taken together our data indicate a mainly synaptic mode of activation to ICMS in layer 5 of rat motor cortex.
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Affiliation(s)
- Ahmed T Hussin
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada T2N 4N1; Department of Neuroscience, University of Calgary, Alberta, Canada T2N 4N1
| | - Jeffery A Boychuk
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada T2N 4N1; Department of Neuroscience, University of Calgary, Alberta, Canada T2N 4N1; Department of Physiology and Pharmacology, University of Calgary, Alberta, Canada T2N 4N1; Department of Cell Biology and Anatomy, University of Calgary, Alberta, Canada T2N 4N1
| | - Andrew R Brown
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada T2N 4N1; Department of Neuroscience, University of Calgary, Alberta, Canada T2N 4N1
| | - Quentin J Pittman
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada T2N 4N1; Department of Neuroscience, University of Calgary, Alberta, Canada T2N 4N1; Department of Physiology and Pharmacology, University of Calgary, Alberta, Canada T2N 4N1
| | - G Campbell Teskey
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada T2N 4N1; Department of Neuroscience, University of Calgary, Alberta, Canada T2N 4N1; Department of Physiology and Pharmacology, University of Calgary, Alberta, Canada T2N 4N1; Department of Cell Biology and Anatomy, University of Calgary, Alberta, Canada T2N 4N1.
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92
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Moreno A, Morris RGM, Canals S. Frequency-Dependent Gating of Hippocampal-Neocortical Interactions. Cereb Cortex 2015; 26:2105-2114. [PMID: 25761637 DOI: 10.1093/cercor/bhv033] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
How and where hippocampal-neocortical interactions required for memory formation take place is a major issue of current research. Using a combined in vivo functional magnetic resonance imaging/electrophysiology approach, we have investigated whether specific frequencies of CA3 neuronal activation, inducing different forms of short-term plasticity at CA1 synapses, contribute to differential activity propagation in brain-wide networks connected to the hippocampus. We report that localized activation of CA3 neurons in dorsal hippocampus produced activity propagation within the hippocampal formation, including the subiculum and entorhinal cortex, which increased monotonically with frequency to a maximum at 20-40 Hz. However, robust extrahippocampal propagation was seen specifically at theta-beta frequencies (10-20 Hz), reaching a network of midline neocortical and mesolimbic structures. Activation in those regions correlated with a frequency-dependent facilitation of spiking activity recorded in CA1. These results provide a mechanistic link between the dynamic properties of short-term plasticity in the efferent synapses of CA3 neurons in CA1 and activity propagation in brain-wide networks, and identify polysynaptic information channels segregated in the frequency domain.
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Affiliation(s)
- Andrea Moreno
- Centre for Cognitive and Neural Systems, Edinburgh Neuroscience, University of Edinburgh, Edinburgh EH8 9JZ, UK.,Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, Sant Joan d'Alacant 03550, Spain
| | - Richard G M Morris
- Centre for Cognitive and Neural Systems, Edinburgh Neuroscience, University of Edinburgh, Edinburgh EH8 9JZ, UK
| | - Santiago Canals
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, Sant Joan d'Alacant 03550, Spain
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93
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Cocchi L, Sale MV, Lord A, Zalesky A, Breakspear M, Mattingley JB. Dissociable effects of local inhibitory and excitatory theta-burst stimulation on large-scale brain dynamics. J Neurophysiol 2015; 113:3375-85. [PMID: 25717162 DOI: 10.1152/jn.00850.2014] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 02/21/2015] [Indexed: 12/12/2022] Open
Abstract
Normal brain function depends on a dynamic balance between local specialization and large-scale integration. It remains unclear, however, how local changes in functionally specialized areas can influence integrated activity across larger brain networks. By combining transcranial magnetic stimulation with resting-state functional magnetic resonance imaging, we tested for changes in large-scale integration following the application of excitatory or inhibitory stimulation on the human motor cortex. After local inhibitory stimulation, regions encompassing the sensorimotor module concurrently increased their internal integration and decreased their communication with other modules of the brain. There were no such changes in modular dynamics following excitatory stimulation of the same area of motor cortex nor were there changes in the configuration and interactions between core brain hubs after excitatory or inhibitory stimulation of the same area. These results suggest the existence of selective mechanisms that integrate local changes in neural activity, while preserving ongoing communication between brain hubs.
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Affiliation(s)
- Luca Cocchi
- Queensland Brain Institute, The University of Queensland, Brisbane, Australia;
| | - Martin V Sale
- Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Anton Lord
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Andrew Zalesky
- Melbourne Neuropsychiatry Centre and Melbourne School of Engineering, The University of Melbourne, Melbourne, Australia; and
| | | | - Jason B Mattingley
- Queensland Brain Institute, The University of Queensland, Brisbane, Australia; School of Psychology, The University of Queensland, Brisbane, Australia
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94
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Premereur E, Van Dromme IC, Romero MC, Vanduffel W, Janssen P. Effective connectivity of depth-structure-selective patches in the lateral bank of the macaque intraparietal sulcus. PLoS Biol 2015; 13:e1002072. [PMID: 25689048 PMCID: PMC4331519 DOI: 10.1371/journal.pbio.1002072] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 01/09/2015] [Indexed: 12/04/2022] Open
Abstract
Extrastriate cortical areas are frequently composed of subpopulations of neurons encoding specific features or stimuli, such as color, disparity, or faces, and patches of neurons encoding similar stimulus properties are typically embedded in interconnected networks, such as the attention or face-processing network. The goal of the current study was to examine the effective connectivity of subsectors of neurons in the same cortical area with highly similar neuronal response properties. We first recorded single- and multi-unit activity to identify two neuronal patches in the anterior part of the macaque intraparietal sulcus (IPS) showing the same depth structure selectivity and then employed electrical microstimulation during functional magnetic resonance imaging in these patches to determine the effective connectivity of these patches. The two IPS subsectors we identified-with the same neuronal response properties and in some cases separated by only 3 mm-were effectively connected to remarkably distinct cortical networks in both dorsal and ventral stream in three macaques. Conversely, the differences in effective connectivity could account for the known visual-to-motor gradient within the anterior IPS. These results clarify the role of the anterior IPS as a pivotal brain region where dorsal and ventral visual stream interact during object analysis. Thus, in addition to the anatomical connectivity of cortical areas and the properties of individual neurons in these areas, the effective connectivity provides novel key insights into the widespread functional networks that support behavior.
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Affiliation(s)
- Elsie Premereur
- Lab. voor Neuro- en Psychofysiologie, KU Leuven, Leuven, Belgium
| | | | - Maria C. Romero
- Lab. voor Neuro- en Psychofysiologie, KU Leuven, Leuven, Belgium
| | - Wim Vanduffel
- Lab. voor Neuro- en Psychofysiologie, KU Leuven, Leuven, Belgium
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Peter Janssen
- Lab. voor Neuro- en Psychofysiologie, KU Leuven, Leuven, Belgium
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95
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Different forms of effective connectivity in primate frontotemporal pathways. Nat Commun 2015; 6:6000. [PMID: 25613079 PMCID: PMC4306228 DOI: 10.1038/ncomms7000] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 11/28/2014] [Indexed: 01/03/2023] Open
Abstract
It is generally held that non-primary sensory regions of the brain have a strong impact on frontal cortex. However, the effective connectivity of pathways to frontal cortex is poorly understood. Here we microstimulate sites in the superior temporal and ventral frontal cortex of monkeys and use functional magnetic resonance imaging to evaluate the functional activity resulting from the stimulation of interconnected regions. Surprisingly, we find that, although certain earlier stages of auditory cortical processing can strongly activate frontal cortex, downstream auditory regions, such as voice-sensitive cortex, appear to functionally engage primarily an ipsilateral temporal lobe network. Stimulating other sites within this activated temporal lobe network shows strong activation of frontal cortex. The results indicate that the relative stage of sensory processing does not predict the level of functional access to the frontal lobes. Rather, certain brain regions engage local networks, only parts of which have a strong functional impact on frontal cortex. Neural pathways to frontal cortex areas of the brain enable communication, but their connectivity is unclear. Petkov et al. use electrical microstimulation and brain imaging to describe different forms of hierarchical effective connectivity that exist between the primate frontal and temporal cortex.
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96
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Jones SE, Zhang M, Avitsian R, Bhattacharyya P, Bulacio J, Cendes F, Enatsu R, Lowe M, Najm I, Nair D, Phillips M, Gonzalez-Martinez J. Functional magnetic resonance imaging networks induced by intracranial stimulation may help defining the epileptogenic zone. Brain Connect 2015; 4:286-98. [PMID: 24735069 DOI: 10.1089/brain.2014.0225] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Patients with medically intractable epilepsy often undergo invasive evaluation and surgery, with a 50% success rate. The low success rate is likely due to poor identification of the epileptogenic zone (EZ), the brain area causing seizures. This work introduces a new method using functional magnetic resonance imaging (fMRI) with simultaneous direct electrical stimulation of the brain that could help localize the EZ, performed in five patients with medically intractable epilepsy undergoing invasive evaluation with intracranial depth electrodes. Stimulation occurred in a location near the hypothesized EZ and a location away. Electrical recordings in response to stimulation were recorded and compared to fMRI. Multiple stimulation parameters were varied, like current and frequency. The brain areas showing fMRI response were compared with the areas resected and the success of surgery. Robust fMRI maps of activation networks were easily produced, which also showed a significant but weak positive correlation between quantitative measures of blood-oxygen-level-dependent (BOLD) activity and measures of electrical activity in response to direct electrical stimulation (mean correlation coefficient of 0.38 for all acquisitions that produced a strong BOLD response). For four patients with outcome data at 6 months, successful surgical outcome is consistent with the resection of brain areas containing high local fMRI activity. In conclusion, this method demonstrates the feasibility of simultaneous direct electrical stimulation and fMRI in humans, which allows the study of brain connectivity with high resolution and full spatial coverage. This innovative technique could be used to better define the localization and extension of the EZ in intractable epilepsies, as well as for other functional neurosurgical procedures.
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97
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Abstract
In 1998 several groups reported the feasibility of fMRI experiments in monkeys, with the goal to bridge the gap between invasive nonhuman primate studies and human functional imaging. These studies yielded critical insights in the neuronal underpinnings of the BOLD signal. Furthermore, the technology has been successful in guiding electrophysiological recordings and identifying focal perturbation targets. Finally, invaluable information was obtained concerning human brain evolution. We here provide a comprehensive overview of awake monkey fMRI studies mainly confined to the visual system. We review the latest insights about the topographic organization of monkey visual cortex and discuss the spatial relationships between retinotopy and category- and feature-selective clusters. We briefly discuss the functional layout of parietal and frontal cortex and continue with a summary of some fascinating functional and effective connectivity studies. Finally, we review recent comparative fMRI experiments and speculate about the future of nonhuman primate imaging.
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Affiliation(s)
- Wim Vanduffel
- Laboratory for Neuro- and Psychophysiology, KU Leuven Medical School, Campus Gasthuisberg, Leuven, 3000, Belgium; Department of Radiology, Harvard Medical School, Boston, MA 02129, USA; A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, USA.
| | - Qi Zhu
- Laboratory for Neuro- and Psychophysiology, KU Leuven Medical School, Campus Gasthuisberg, Leuven, 3000, Belgium
| | - Guy A Orban
- Laboratory for Neuro- and Psychophysiology, KU Leuven Medical School, Campus Gasthuisberg, Leuven, 3000, Belgium; Department of Neuroscience, University of Parma, Parma, 43125, Italy
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98
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Glutamate mediated astrocytic filtering of neuronal activity. PLoS Comput Biol 2014; 10:e1003964. [PMID: 25521344 PMCID: PMC4270452 DOI: 10.1371/journal.pcbi.1003964] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 10/06/2014] [Indexed: 02/02/2023] Open
Abstract
Neuron-astrocyte communication is an important regulatory mechanism in various brain functions but its complexity and role are yet to be fully understood. In particular, the temporal pattern of astrocyte response to neuronal firing has not been fully characterized. Here, we used neuron-astrocyte cultures on multi-electrode arrays coupled to Ca2+ imaging and explored the range of neuronal stimulation frequencies while keeping constant the amount of stimulation. Our results reveal that astrocytes specifically respond to the frequency of neuronal stimulation by intracellular Ca2+ transients, with a clear onset of astrocytic activation at neuron firing rates around 3-5 Hz. The cell-to-cell heterogeneity of the astrocyte Ca2+ response was however large and increasing with stimulation frequency. Astrocytic activation by neurons was abolished with antagonists of type I metabotropic glutamate receptor, validating the glutamate-dependence of this neuron-to-astrocyte pathway. Using a realistic biophysical model of glutamate-based intracellular calcium signaling in astrocytes, we suggest that the stepwise response is due to the supralinear dynamics of intracellular IP3 and that the heterogeneity of the responses may be due to the heterogeneity of the astrocyte-to-astrocyte couplings via gap junction channels. Therefore our results present astrocyte intracellular Ca2+ activity as a nonlinear integrator of glutamate-dependent neuronal activity.
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99
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Ritaccio A, Brunner P, Gunduz A, Hermes D, Hirsch LJ, Jacobs J, Kamada K, Kastner S, Knight RT, Lesser RP, Miller K, Sejnowski T, Worrell G, Schalk G. Proceedings of the Fifth International Workshop on Advances in Electrocorticography. Epilepsy Behav 2014; 41:183-92. [PMID: 25461213 PMCID: PMC4268064 DOI: 10.1016/j.yebeh.2014.09.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 09/05/2014] [Indexed: 11/30/2022]
Abstract
The Fifth International Workshop on Advances in Electrocorticography convened in San Diego, CA, on November 7-8, 2013. Advancements in methodology, implementation, and commercialization across both research and in the interval year since the last workshop were the focus of the gathering. Electrocorticography (ECoG) is now firmly established as a preferred signal source for advanced research in functional, cognitive, and neuroprosthetic domains. Published output in ECoG fields has increased tenfold in the past decade. These proceedings attempt to summarize the state of the art.
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Affiliation(s)
| | - Peter Brunner
- Albany Medical College, Albany, NY, USA; Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | | | | | | | | | | | | | | | - Ronald P Lesser
- Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | | | | | - Gerwin Schalk
- Albany Medical College, Albany, NY, USA; Wadsworth Center, New York State Department of Health, Albany, NY, USA
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100
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Georgieva P, Brugger D, Schwarz C. Are spatial frequency cues used for whisker-based active discrimination? Front Behav Neurosci 2014; 8:379. [PMID: 25404903 PMCID: PMC4217502 DOI: 10.3389/fnbeh.2014.00379] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 10/16/2014] [Indexed: 11/13/2022] Open
Abstract
Rats are highly skilled in discriminating objects and textures by palpatory movements of their whiskers. If they used spatial frequency cues, they would be able to optimize performance in a stimulus dependent way-by moving their whisker faster or slower across the texture surface, thereby shifting the frequency content of the neuronal signal toward an optimal working range for perception. We tested this idea by measuring discrimination performance of head-fixed rats that were trained to actively sample from virtual grids. The virtual grid mimicked discrete and repetitive whisker deflections generated by real objects (e.g., grove patterns) with single electrical microstimulation pulses delivered directly to the barrel cortex, and provided the critical advantage that stimuli could be controlled at highest precision. Surprisingly, rats failed to use the spatial frequency cue for discrimination as a matter of course, and also failed to adapt whisking patterns in order to optimally exploit frequency differences. In striking contrast they could be easily trained to discriminate stimuli differing in electrical pulse amplitudes, a stimulus property that is not malleable by whisking. Intermingling these "easy-to-discriminate" discriminanda with others that solely offered frequency/positional cues, rats could be guided to base discrimination on frequency and/or position, albeit on a lower level of performance. Following this training, abolishment of electrical amplitude cues and reducing positional cues led to initial good performance which, however, was unstable and ran down to very low levels over the course of hundreds of trials. These results clearly demonstrate that frequency cues, while definitely perceived by rats, are of minor importance and they are not able to support consistent modulation of whisking patterns to optimize performance.
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Affiliation(s)
- Petya Georgieva
- Systems Neurophysiology, Werner Reichardt Center for Integrative Neuroscience, University Tübingen Tübingen, Germany ; Department for Cognitive Neurology, Hertie-Institute for Clinical Brain Research, University Tübingen Tübingen, Germany
| | - Dominik Brugger
- Systems Neurophysiology, Werner Reichardt Center for Integrative Neuroscience, University Tübingen Tübingen, Germany ; Department for Cognitive Neurology, Hertie-Institute for Clinical Brain Research, University Tübingen Tübingen, Germany
| | - Cornelius Schwarz
- Systems Neurophysiology, Werner Reichardt Center for Integrative Neuroscience, University Tübingen Tübingen, Germany ; Department for Cognitive Neurology, Hertie-Institute for Clinical Brain Research, University Tübingen Tübingen, Germany
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