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Zaidi AD, Birbaumer N, Fetz E, Logothetis N, Sitaram R. The hemodynamic initial-dip consists of both volumetric and oxymetric changes reflecting localized spiking activity. Front Neurosci 2023; 17:1170401. [PMID: 37304038 PMCID: PMC10248142 DOI: 10.3389/fnins.2023.1170401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 04/28/2023] [Indexed: 06/13/2023] Open
Abstract
The initial-dip is a transient decrease frequently observed in functional neuroimaging signals, immediately after stimulus onset, believed to originate from a rise in deoxy-hemoglobin (HbR) caused by local neural activity. It has been shown to be more spatially specific than the hemodynamic response, and is believed to represent focal neuronal activity. However, despite being observed in various neuroimaging modalities (such as fMRI, fNIRS, etc), its origins are disputed, and its precise neuronal correlates are unknown. Here we show that the initial-dip is dominated by a decrease in total-hemoglobin (HbT). We also find a biphasic response in deoxy-Hb (HbR), with an early decrease and later rebound. Both the HbT-dip and HbR-rebound were strongly correlated to highly localized spiking activity. However, HbT decreases were always large enough to counter the spiking-induced increase in HbR. We find that the HbT-dip counters spiking induced HbR increases, imposing an upper-limit to HbR concentration in the capillaries. Building on our results, we explore the possibility of active venule dilation (purging) as a possible mechanism for the HbT dip.
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Affiliation(s)
- Ali Danish Zaidi
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, United States
| | - Niels Birbaumer
- Center for Imaging Sciences, Biomedical Imaging Institute, University of Manchester, Manchester, United Kingdom
| | - Eberhard Fetz
- Institute of Biological and Medical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nikos Logothetis
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Department of Psychiatry and Section of Neuroscience, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Ranganatha Sitaram
- Institute of Biological and Medical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
- Department of Psychiatry and Section of Neuroscience, Pontificia Universidad Católica de Chile, Santiago, Chile
- Multimodal Functional Brain Imaging and Neurorehabilitation Hub, Diagnostic Imaging Department, St. Jude Children's Research Hospital, Memphis, TN, United States
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Janssen P, Isa T, Lanciego J, Leech K, Logothetis N, Poo MM, Mitchell AS. Visualizing advances in the future of primate neuroscience research. Curr Res Neurobiol 2022; 4:100064. [PMID: 36582401 PMCID: PMC9792703 DOI: 10.1016/j.crneur.2022.100064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 09/30/2022] [Accepted: 11/24/2022] [Indexed: 12/15/2022] Open
Abstract
Future neuroscience and biomedical projects involving non-human primates (NHPs) remain essential in our endeavors to understand the complexities and functioning of the mammalian central nervous system. In so doing, the NHP neuroscience researcher must be allowed to incorporate state-of-the-art technologies, including the use of novel viral vectors, gene therapy and transgenic approaches to answer continuing and emerging research questions that can only be addressed in NHP research models. This perspective piece captures these emerging technologies and some specific research questions they can address. At the same time, we highlight some current caveats to global NHP research and collaborations including the lack of common ethical and regulatory frameworks for NHP research, the limitations involving animal transportation and exports, and the ongoing influence of activist groups opposed to NHP research.
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Affiliation(s)
- Peter Janssen
- Laboratory for Neuro- and Psychophysiology, KU Leuven, Belgium
| | - Tadashi Isa
- Graduate School of Medicine, Kyoto University, Japan
| | - Jose Lanciego
- Department Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, CiberNed., Pamplona, Spain
| | - Kirk Leech
- European Animal Research Association, United Kingdom
| | - Nikos Logothetis
- International Center for Primate Brain Research, Shanghai, China
| | - Mu-Ming Poo
- International Center for Primate Brain Research, Shanghai, China
| | - Anna S. Mitchell
- School of Psychology, Speech and Hearing, University of Canterbury, Christchurch, New Zealand,Department of Experimental Psychology, University of Oxford, United Kingdom,Corresponding author. School of Psychology, Speech and Hearing, University of Canterbury, Christchurch, New Zealand.
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Hasanpour M, Mitricheva E, Logothetis N, Noori HR. Intensive longitudinal characterization of multidimensional biobehavioral dynamics in laboratory rats. Cell Rep 2021; 35:108987. [PMID: 33852865 DOI: 10.1016/j.celrep.2021.108987] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 01/04/2021] [Accepted: 03/23/2021] [Indexed: 11/26/2022] Open
Abstract
Rats have been used as animal models for human diseases for more than a century, yet a systematic understanding of basal biobehavioral phenotypes of laboratory rats is still missing. In this study, we utilize wireless tracking technology and videography, collect and analyze more than 130 billion data points to fill this gap, and characterize the evolution of behavior and physiology of group-housed male and female rats (n = 114) of the most commonly used strains (Lister Hooded, Long-Evans, Sprague-Dawley, and Wistar) throughout their development. The resulting intensive longitudinal data suggest the existence of strain and sex differences and bi-stable developmental states. Under standard laboratory 12-h light/12-h dark conditions, our study found the presence of multiple oscillations such as circatidal-like rhythms in locomotor activity. The overall findings further suggest that frequent movement along cage walls or thigmotaxic activity may be a physical feature of motion in constrained spaces, critically affecting the interpretation of basal behavior of rats in cages.
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Affiliation(s)
- Mehrdad Hasanpour
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Ekaterina Mitricheva
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany; International Center for Primate Brain Research, Center for Excellence in Brain Science and Intelligence Technology (CEBSIT)/Institute of Neuroscience (ION), Chinese Academy of Sciences, Shanghai, China
| | - Nikos Logothetis
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany; International Center for Primate Brain Research, Center for Excellence in Brain Science and Intelligence Technology (CEBSIT)/Institute of Neuroscience (ION), Chinese Academy of Sciences, Shanghai, China; Imaging Science and Biomedical Engineering, University of Manchester, Manchester, UK
| | - Hamid R Noori
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany; International Center for Primate Brain Research, Center for Excellence in Brain Science and Intelligence Technology (CEBSIT)/Institute of Neuroscience (ION), Chinese Academy of Sciences, Shanghai, China; McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA.
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Wang XJ, Hu H, Huang C, Kennedy H, Li CT, Logothetis N, Lu ZL, Luo Q, Poo MM, Tsao D, Wu S, Wu Z, Zhang X, Zhou D. Computational neuroscience: a frontier of the 21 st century. Natl Sci Rev 2020; 7:1418-1422. [PMID: 34691537 PMCID: PMC8288724 DOI: 10.1093/nsr/nwaa129] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
| | - Hailan Hu
- Center for Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, School of Medicine, Zhejiang University, China
| | - Chengcheng Huang
- Department of Neuroscience and Department of Mathematics, Center for the Neural Basis of Cognition, University of Pittsburgh, USA
| | - Henry Kennedy
- Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, France
| | - Chengyu Tony Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Chinese Academy of Sciences, CAS Center for Excellence in Brain Science and Intelligence Technology, China
| | - Nikos Logothetis
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Chinese Academy of Sciences, CAS Center for Excellence in Brain Science and Intelligence Technology, China
| | - Zhong-Lin Lu
- Division of Arts and Sciences, and NYU-ECNU Institute of Cognitive Neuroscience, NYU Shanghai, China
| | - Qingming Luo
- School of Biomedical Engineering, Hainan University, China
| | - Mu-Ming Poo
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Chinese Academy of Sciences, CAS Center for Excellence in Brain Science and Intelligence Technology, China
| | - Doris Tsao
- Division of Biology and Biological Engineering, California Institute of Technology, USA
| | - Si Wu
- School of Electronics Engineering and Computer Science, IDG/McGovern Institute for Brain Research, PKU-Tsinghua Center for Life Sciences, Peking University, China
| | - Zhaohui Wu
- College of Computer Science and Technology, Zhejiang University, China
| | - Xu Zhang
- Institute of Brain-Intelligence Science and Technology, Zhangjiang Lab, China
| | - Douglas Zhou
- School of Mathematical Sciences, MOE-LSC, and Institute of Natural Sciences, Shanghai Jiao Tong University, China
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Takemura H, Pestilli F, Weiner K, Keliris G, Landi S, Sliwa J, Ye F, Barnett M, Leopold D, Freiwald W, Logothetis N, Wandell B. Comparative neuroanatomy of occipital white matter tracts in human and macaque. J Vis 2017. [DOI: 10.1167/17.10.589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Hiromasa Takemura
- Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology, and Osaka UniversityGraduate School of Frontier Biosciences, Osaka University
| | - Franco Pestilli
- Department of Psychological and Brain Sciences, Indiana University
| | | | - Georgios Keliris
- Max Planck Institute for Biological CyberneticsBio-Imaging Lab, Department of Biomedical Sciences, University of Antwerp
| | | | | | - Frank Ye
- Neurophysiology Imaging Facility, National Institute of Mental Health, National Institute of Neurological Disorders and Stroke, National Eye Institute, National Institutes of Health
| | | | - David Leopold
- Neurophysiology Imaging Facility, National Institute of Mental Health, National Institute of Neurological Disorders and Stroke, National Eye Institute, National Institutes of Health
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Hartig R, Battal C, Chávez G, Vedoveli A, Steudel T, Krampe E, Öltermann A, Werner J, Logothetis N, Evrard H. Topographic mapping of the primate primary interoceptive cortex. Front Neurosci 2017. [DOI: 10.3389/conf.fnins.2017.94.00005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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7
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Smuda J, Klein C, Murayama Y, Steudel T, Krampe E, Oeltermann A, Werner J, Logothetis N, Evrard H. Local field potential activity in the macaque anterior insular cortex. Front Neurosci 2017. [DOI: 10.3389/conf.fnins.2017.94.00021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Zaidi AD, Munk MHJ, Schmidt A, Risueno-Segovia C, Bernard R, Fetz E, Logothetis N, Birbaumer N, Sitaram R. Simultaneous epidural functional near-infrared spectroscopy and cortical electrophysiology as a tool for studying local neurovascular coupling in primates. Neuroimage 2015; 120:394-9. [PMID: 26169323 DOI: 10.1016/j.neuroimage.2015.07.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 06/25/2015] [Accepted: 07/07/2015] [Indexed: 11/29/2022] Open
Abstract
Simultaneous measurements of intra-cortical electrophysiology and hemodynamic signals in primates are essential for relating human neuroimaging studies with intra-cortical electrophysiology in monkeys. Previously, technically challenging and resourcefully demanding techniques such as fMRI and intrinsic-signal optical imaging have been used for such studies. Functional near-infrared spectroscopy is a relatively less cumbersome neuroimaging method that uses near-infrared light to detect small changes in concentrations of oxy-hemoglobin (HbO), deoxy-hemoglobin (HbR) and total hemoglobin (HbT) in a volume of tissue with high specificity and temporal resolution. FNIRS is thus a good candidate for hemodynamic measurements in primates to acquire local hemodynamic signals during electrophysiological recordings. To test the feasibility of using epidural fNIRS with concomitant extracellular electrophysiology, we recorded neuronal and hemodynamic activity from the primary visual cortex of two anesthetized monkeys during visual stimulation. We recorded fNIRS epidurally, using one emitter and two detectors. We performed simultaneous cortical electrophysiology using tetrodes placed between the fNIRS sensors. We observed robust and reliable responses to the visual stimulation in both [HbO] and [HbR] signals, and quantified the signal-to-noise ratio of the epidurally measured signals. We also observed a positive correlation between stimulus-induced modulation of [HbO] and [HbR] signals and strength of neural modulation. Briefly, our results show that epidural fNIRS detects single-trial responses to visual stimuli on a trial-by-trial basis, and when coupled with cortical electrophysiology, is a promising tool for studying local hemodynamic signals and neurovascular coupling.
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Affiliation(s)
- Ali Danish Zaidi
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany; Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Germany.
| | - Matthias H J Munk
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany; Systems Neurophysiology, Fachbereich Biologie, Technische Universität Darmstadt, Germany
| | - Andreas Schmidt
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany; Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Germany
| | | | - Rebekka Bernard
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Eberhard Fetz
- Department of Physiology and Biophysics and Washington National Primate Research Center, University of WA, Seattle, USA
| | - Nikos Logothetis
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany; Center for Imaging Sciences, Biomedical Imaging Institute, University of Manchester, UK
| | - Niels Birbaumer
- Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Germany; Ospedale San Camillo, Istituto di Ricovero e Cura a Carattere Scientifico, Venezia-Lido, Italy; Department of Psychology, Biological Psychology, Universidad de las lslas Baleares, Spain
| | - Ranganatha Sitaram
- Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Germany; Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA.
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11
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Liewald D, Miller R, Logothetis N, Wagner HJ, Schüz A. Distribution of axon diameters in cortical white matter: an electron-microscopic study on three human brains and a macaque. Biol Cybern 2014; 108:541-57. [PMID: 25142940 PMCID: PMC4228120 DOI: 10.1007/s00422-014-0626-2] [Citation(s) in RCA: 182] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 08/05/2014] [Indexed: 05/18/2023]
Abstract
The aim of this study was to obtain information on the axonal diameters of cortico-cortical fibres in the human brain, connecting distant regions of the same hemisphere via the white matter. Samples for electron microscopy were taken from the region of the superior longitudinal fascicle and from the transitional white matter between temporal and frontal lobe where the uncinate and inferior occipitofrontal fascicle merge. We measured the inner diameter of cross sections of myelinated axons. For comparison with data from the literature on the human corpus callosum, we also took samples from that region. For comparison with well-fixed material, we also included samples from corresponding regions of a monkey brain (Macaca mulatta). Fibre diameters in human brains ranged from 0.16 to 9 μm. Distributions of diameters were similar in the three systems of cortico-cortical fibres investigated, both in humans and the monkey, with most of the average values below 1 μm diameter and a small population of much thicker fibres. Within individual human brains, the averages were larger in the superior longitudinal fascicle than in the transitional zone between temporal and frontal lobe. An asymmetry between left and right could be found in one of the human brains, as well as in the monkey brain. A correlation was also found between the thickness of the myelin sheath and the inner axon diameter for axons whose calibre was greater than about 0.6 μm. The results are compared to white matter data in other mammals and are discussed with respect to conduction velocity, brain size, cognition, as well as diffusion weighted imaging studies.
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Affiliation(s)
- Daniel Liewald
- Max Planck Institute for Biological Cybernetics, Spemannstr. 38/41, 72076 Tübingen, Germany
| | - Robert Miller
- Department of Psychological Medicine, University of Otago, Wellington, New Zealand
| | - Nikos Logothetis
- Max Planck Institute for Biological Cybernetics, Spemannstr. 38/41, 72076 Tübingen, Germany
| | | | - Almut Schüz
- Max Planck Institute for Biological Cybernetics, Spemannstr. 38/41, 72076 Tübingen, Germany
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Abstract
Despite the several-thousand-fold increase of brain volume during the course of mammalian evolution, the hierarchy of brain oscillations remains remarkably preserved, allowing for multiple-time-scale communication within and across neuronal networks at approximately the same speed, irrespective of brain size. Deployment of large-diameter axons of long-range neurons could be a key factor in the preserved time management in growing brains. We discuss the consequences of such preserved network constellation in mental disease, drug discovery, and interventional therapies.
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Affiliation(s)
- György Buzsáki
- The Neuroscience Institute, Center for Neural Science, School of Medicine, New York University, New York, NY 10016, USA.
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Sultan F, Augath M, Murayama Y, Tolias AS, Logothetis N. esfMRI of the upper STS: further evidence for the lack of electrically induced polysynaptic propagation of activity in the neocortex. Magn Reson Imaging 2011; 29:1374-81. [DOI: 10.1016/j.mri.2011.04.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 04/04/2011] [Accepted: 04/04/2011] [Indexed: 11/29/2022]
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Borchers S, Himmelbach M, Logothetis N, Karnath HO. Direct electrical stimulation of human cortex - the gold standard for mapping brain functions? Nat Rev Neurosci 2011; 13:63-70. [PMID: 22127300 DOI: 10.1038/nrn3140] [Citation(s) in RCA: 250] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Despite its clinical relevance, direct electrical stimulation (DES) of the human brain is surprisingly poorly understood. Although we understand several aspects of electrical stimulation at the cellular level, surface DES evokes a complex summation effect in a large volume of brain tissue, and the effect is difficult to predict as it depends on many local and remote physiological and morphological factors. The complex stimulation effects are reflected in the heterogeneity of behavioural effects that are induced by DES, which range from evocation to inhibition of responses - sometimes even when DES is applied at the same cortical site. Thus, it is a misconception that DES - in contrast to other neuroscience techniques - allows us to draw unequivocal conclusions about the role of stimulated brain areas.
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Affiliation(s)
- Svenja Borchers
- Center for Neurology, Division of Neuropsychology, University of Tübingen, 72076 Tübingen, Germany
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Watanabe M, Cheng K, Murayama Y, Ueno K, Asamizuya T, Tanaka K, Logothetis N. Attention but not awareness modulates the BOLD signal in the human V1 during binocular suppression. Science 2011; 334:829-31. [PMID: 22076381 DOI: 10.1126/science.1203161] [Citation(s) in RCA: 138] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Although recent psychophysical studies indicate that visual awareness and top-down attention are two distinct processes, it is not clear how they are neurally dissociated in the visual system. Using a two-by-two factorial functional magnetic resonance imaging design with binocular suppression, we found that the visibility or invisibility of a visual target led to only nonsignificant blood oxygenation level-dependent (BOLD) effects in the human primary visual cortex (V1). Directing attention toward and away from the target had much larger and robust effects across all study participants. The difference in the lower-level limit of BOLD activation between attention and awareness illustrates dissociated neural correlates of the two processes. Our results agree with previously reported V1 BOLD effects on attention, while they invite a reconsideration of the functional role of V1 in visual awareness.
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Li J, von Pföstl V, Zaldivar D, Zhang X, Logothetis N, Rauch A. Measuring multiple neurochemicals and related metabolites in blood and brain of the rhesus monkey by using dual microdialysis sampling and capillary hydrophilic interaction chromatography-mass spectrometry. Anal Bioanal Chem 2011; 402:2545-54. [PMID: 21956265 DOI: 10.1007/s00216-011-5427-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 08/25/2011] [Accepted: 09/17/2011] [Indexed: 01/15/2023]
Abstract
In vivo measurement of multiple functionally related neurochemicals and metabolites (NMs) is highly interesting but remains challenging in the field of basic neuroscience and clinical research. We present here an analytical method for determining five functionally and metabolically related polar substances, including acetylcholine (quaternary ammonium), lactate and pyruvate (organic acids), as well as glutamine and glutamate (amino acids). These NMs are acquired from samples of the brain and the blood of non-human primates in parallel by dual microdialysis, and subsequently analyzed by a direct capillary hydrophilic interaction chromatography (HILIC)-mass spectrometry (MS) based method. To obtain high sensitivity in electrospray ionization (ESI)-MS, lactate and pyruvate were detected in negative ionization mode whereas the other NMs were detected in positive ionization mode during each HILIC-MS run. The method was validated for linearity, the limits of detection and quantification, precision, accuracy, stability and matrix effect. The detection limit of acetylcholine, lactate, pyruvate, glutamine, and glutamate was 150 pM, 3 μM, 2 μM, 5 nM, and 50 nM, respectively. This allowed us to quantitatively and simultaneously measure the concentrations of all the substances from the acquired dialysates. The concentration ratios of both lactate/pyruvate and glutamine/glutamate were found to be higher in the brain compared to blood (p < 0.05). The reliable and simultaneous quantification of these five NMs from brain and blood samples allows us to investigate their relative distribution in the brain and blood, and most importantly paves the way for future non-invasive studies of the functional and metabolic relation of these substances to each other.
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Affiliation(s)
- Juan Li
- Max Planck Institute for Biological Cybernetics, Spemannstrasse 38, 72076 Tübingen, Germany
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Logothetis N. Minute-Accumulating Analysis and life testing. J Appl Stat 2011. [DOI: 10.1080/757582829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Sultan F, Hamodeh S, Murayama Y, Saleem KS, Logothetis N. Flat map areal topography in Macaca mulatta based on combined MRI and histology. Magn Reson Imaging 2010; 28:1159-64. [DOI: 10.1016/j.mri.2010.03.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 02/23/2010] [Accepted: 03/05/2010] [Indexed: 10/19/2022]
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Seymour K, Clifford C, Logothetis N, Bartels A. Examining the coding of colour-motion conjunctions in human visual cortex using pattern classifiers. J Vis 2010. [DOI: 10.1167/9.8.812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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22
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Tsuchiya N, Maier A, Logothetis N, Leopold D. Neuronal activity in area MT during perceptual stabilization of ambiguous structure-from-motion. J Vis 2010. [DOI: 10.1167/9.8.756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Iturria-Medina Y, Pérez Fernández A, Morris DM, Canales-Rodríguez EJ, Haroon HA, García Pentón L, Augath M, Galán García L, Logothetis N, Parker GJM, Melie-García L. Brain hemispheric structural efficiency and interconnectivity rightward asymmetry in human and nonhuman primates. ACTA ACUST UNITED AC 2010; 21:56-67. [PMID: 20382642 DOI: 10.1093/cercor/bhq058] [Citation(s) in RCA: 145] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Evidence for interregional structural asymmetries has been previously reported for brain anatomic regions supporting well-described functional lateralization. Here, we aimed to investigate whether the two brain hemispheres demonstrate dissimilar general structural attributes implying different principles on information flow management. Common left hemisphere/right hemisphere structural network properties are estimated and compared for right-handed healthy human subjects and a nonhuman primate, by means of 3 different diffusion-weighted magnetic resonance imaging fiber tractography algorithms and a graph theory framework. In both the human and the nonhuman primate, the data support the conclusion that, in terms of the graph framework, the right hemisphere is significantly more efficient and interconnected than the left hemisphere, whereas the left hemisphere presents more central or indispensable regions for the whole-brain structural network than the right hemisphere. From our point of view, in terms of functional principles, this pattern could be related with the fact that the left hemisphere has a leading role for highly demanding specific process, such as language and motor actions, which may require dedicated specialized networks, whereas the right hemisphere has a leading role for more general process, such as integration tasks, which may require a more general level of interconnection.
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Magri C, Whittingstall K, Singh V, Logothetis N, Panzeri S. Information breakdown analysis of simultaneous neural recordings: tools for the study of neural codes. Front Neuroinform 2009. [DOI: 10.3389/conf.neuro.11.2009.08.097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Wade A, Augath M, Logothetis N, Wandell B. fMRI measurements of color in macaque and human. J Vis 2008; 8:6.1-19. [PMID: 19146348 DOI: 10.1167/8.10.6] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Accepted: 07/17/2008] [Indexed: 11/24/2022] Open
Abstract
We have used fMRI to measure responses to chromatic and achromatic contrast in retinotopically defined regions of macaque and human visual cortex. We make four observations. Firstly, the relative amplitudes of responses to color and luminance stimuli in macaque area V1 are similar to those previously observed in human fMRI experiments. Secondly, the dorsal and ventral subdivisions of macaque area V4 respond in a similar way to opponent (L--M)-cone chromatic contrast suggesting that they are part of a single functional area. Thirdly, we find that macaque area V4, like area V1, responds preferentially to chromatic contrast compared to luminance contrast and the degree of preference is strongly influenced by the temporal frequency of the stimulus. Finally, we observe that while macaque V4d is a region on the dorsal surface of the macaque visual cortex that responds robustly to chromatic stimuli, human chromatic responses to identical stimuli are largely confined to the ventral surface suggesting a fundamental difference in the topographical organization of higher visual areas between humans and macaques.
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Affiliation(s)
- Alex Wade
- Smith-Kettlewell Eye Research Center, San Francisco, CA, USA.
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Yacoub E, Shmuel A, Logothetis N, Uğurbil K. Robust detection of ocular dominance columns in humans using Hahn Spin Echo BOLD functional MRI at 7 Tesla. Neuroimage 2007; 37:1161-77. [PMID: 17702606 PMCID: PMC2040323 DOI: 10.1016/j.neuroimage.2007.05.020] [Citation(s) in RCA: 212] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2007] [Revised: 05/01/2007] [Accepted: 05/10/2007] [Indexed: 11/23/2022] Open
Abstract
Cells in the mammalian brain tend to be grouped together according to their afferent and efferent connectivity, as well as their physiological properties. The columnar structures of neocortex are prominent examples of such modular organization, and have been studied extensively in anatomical and physiological experiments in rats, cats and monkeys. The importance of noninvasive study of such structures, in particular in human subjects, cannot be overemphasized. Not surprisingly, therefore, many attempts were made to map cortical columns using functional magnetic resonance imaging (fMRI). Yet, the robustness, repeatability, and generality of the hitherto used fMRI methodologies have been a subject of intensive debate. Using differential mapping in a high magnetic field magnet (7 T), we demonstrate here the ability of Hahn Spin-Echo (HSE) BOLD to map the ocular dominance columns (ODCs) of the human visual cortex reproducibly over several days with a high degree of accuracy, relative to expected spatial patterns from post-mortem data. On the other hand, the conventional Gradient-Echo (GE) blood oxygen level dependent (BOLD) signal in some cases failed to resolve ODCs uniformly across the selected gray matter region, due to the presence of non-specific signals. HSE signals uniformly resolved the ODC patterns, providing a more generalized mapping methodology (i.e. one that does not require adjusting experimental approaches based on prior knowledge or assumptions about functional organization and vascular structure in order to avoid confounding large vessel effects) to map unknown columnar systems in the human brain, potentially paving the way both for the study of the functional architecture of human sensory cortices, and of brain modules underlying specific cognitive processes.
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Affiliation(s)
- Essa Yacoub
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota Medical School, 2021 6th Street S.E., Minneapolis, MN 55455, USA.
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Sultan F, Augath M, Logothetis N. BOLD sensitivity to cortical activation induced by microstimulation: comparison to visual stimulation. Magn Reson Imaging 2007; 25:754-9. [PMID: 17482409 DOI: 10.1016/j.mri.2007.03.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/11/2007] [Indexed: 10/23/2022]
Abstract
Electrical microstimulation via intracortical electrodes is a widely used method for deducing functions of the brain. In this study, we compared the spatial extent and amplitude of BOLD responses evoked by intracortical electrical stimulation in primary visual cortex with BOLD activations evoked by visual stimulation. The experiments were performed in anesthetized rhesus monkeys. Visual stimulation yielded activities larger than predicted from the well-established visual magnification factor. However, electrical microstimulation yielded an even greater spread of the BOLD response. Our results confirm that the effects of electrical microstimulation extend beyond the brain region expected to be excited by direct current spread.
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Affiliation(s)
- Fahad Sultan
- Department of Cognitive Neurology, HIH for Clinical Brain Research, University Tuebingen, 72076 Tuebingen, Germany.
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Abstract
Attentional selection biases the processing of higher visual areas to particular parts of a scene. Recent experiments show how stimulation of neurons in the frontal eye fields can mimic this process.
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Affiliation(s)
- Christoph Kayser
- MPI for Biological Cybernetics, Spemannstrasse 38, 72076 Tuebingen, Germany
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Gretton A, Belitski A, Murayama Y, Schölkopf B, Logothetis N. The effect of artifacts on dependence measurement in fMRI. Magn Reson Imaging 2006; 24:401-9. [PMID: 16677946 DOI: 10.1016/j.mri.2005.12.036] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2005] [Accepted: 12/02/2005] [Indexed: 11/23/2022]
Abstract
The study of effective connectivity by means of neuroimaging depends on the measurement of similarity between activity patterns at different locations in the brain, without necessarily presupposing a particular model for this dependence. When these interactions are measured using functional magnetic resonance imaging (fMRI) techniques, however, imaging and physiological artifacts create patterns of dependence that may be unrelated to cortical activity. We demonstrate some of these effects through the measurement of short-range dependencies present in fMRI scans of the primary visual cortex (V1) in the anaesthetized macaque monkey. High-field (4.7 T) fMRI scans were conducted to measure responses based on the blood oxygen level-dependent contrast mechanism, during periods of no sensory stimulation and of visual stimulation with rotating polar-transformed checkerboard gratings. Dependence between the haemodynamic activity at different spatial locations (i.e., different voxels) was measured using correlation, mutual information and functional covariance. Particular attention was paid to understanding the sources of spurious dependence that may be observed during such investigations. Two main effects were detected: (a) short-range correlations introduced by the process of image reconstruction and (b) perturbations in the haemodynamic response caused by breathing. The image reconstruction artifacts were shown to create an artificially high short-range dependence in the readout direction of the scan, and the breathing artifacts caused enhanced short-range dependence in both the readout and phase-encode directions. Additional dependence in the phase-encode direction due to image-ghosting is also possible but will not be discussed in this report, as it can be alleviated by fine adjustment of preemphasis (elimination of eddy currents). A technique is described for removing breathing artifacts, and the effect of breathing on the apparent dependence between voxels is illustrated. The correlation of haemodynamic activity with the stimulus was found to be affected by breathing, although this effect can be neutralised by averaging the haemodynamic responses over many repetitions of the stimulus. Nonetheless, patterns of dependent activity between voxels may be lost in this averaging process, which makes the removal of breathing artifacts necessary if statistical dependence and the study of effective connectivity is the primary aim of an investigation.
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Affiliation(s)
- Arthur Gretton
- Max Planck Institute for Biological Cybernetics, 72076, Tübingen, Germany.
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Moutoussis K, Keliris G, Kourtzi Z, Logothetis N. A binocular rivalry study of motion perception in the human brain. Vision Res 2005; 45:2231-43. [PMID: 15924938 DOI: 10.1016/j.visres.2005.02.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2004] [Revised: 02/07/2005] [Accepted: 02/08/2005] [Indexed: 11/28/2022]
Abstract
The relationship between brain activity and conscious visual experience is central to our understanding of the neural mechanisms underlying perception. Binocular rivalry, where monocular stimuli compete for perceptual dominance, has been previously used to dissociate the constant stimulus from the varying percept. We report here fMRI results from humans experiencing binocular rivalry under a dichoptic stimulation paradigm that consisted of two drifting random dot patterns with different motion coherence. Each pattern had also a different color, which both enhanced rivalry and was used for reporting which of the two patterns was visible at each time. As the perception of the subjects alternated between coherent motion and motion noise, we examined the effect that these alternations had on the strength of the MR signal throughout the brain. Our results demonstrate that motion perception is able to modulate the activity of several of the visual areas which are known to be involved in motion processing. More specifically, in addition to area V5 which showed the strongest modulation, a higher activity during the perception of motion than during the perception of noise was also clearly observed in areas V3A and LOC, and less so in area V3. In previous studies, these areas had been selectively activated by motion stimuli but whether their activity reflects motion perception or not remained unclear; here we show that they are involved in motion perception as well. The present findings therefore suggest a lack of a clear distinction between 'processing' versus 'perceptual' areas in the brain, but rather that the areas involved in the processing of a specific visual attribute are also part of the neuronal network that is collectively responsible for its perceptual representation.
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Affiliation(s)
- K Moutoussis
- Max Planck Institute for Biological Cybernetics, Spemannstrasse 38, 72076 Tuebingen, Germany.
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Abstract
Spatiotemporally resolved functional MRI (fMRI) in animals can reveal how wide-spread neural networks are organized and accompanying electrophysiological recordings can show how small neural assemblies contribute to this organization. Here we present a novel technique that yields high-resolution structural and functional images of the monkey brain with small, tissue-compatible, intraosteally implantable radiofrequency coils. Voxel sizes as small as 0.0113 microl with high signal-to-noise and contrast-to-noise ratios were obtained, revealing both structural and functional cortical architecture in great detail. Up to a certain point, contrast sensitivity increased with decreasing voxel size, probably because of the decreased partial volume effects. Spatial specificity was demonstrated by the lamina-specific activation in experiments comparing responses to moving and flickering stimuli. The implications of this technique for combined fMRI/electrophysiology experiments and its limitations in terms of spatial coverage are discussed.
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Affiliation(s)
- Nikos Logothetis
- Max Planck Institute for Biological Cybernetics, Spemannstr. 38, Tuebingen, Germany.
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Abstract
Conscious experience involves perceiving, attending, remembering, and recognizing. Recent neuroscientific research has made significant contributions to our understanding of the mechanisms that mediate such capacities. Physiological and neuropsychological investigations have provided increasingly detailed descriptions of the location and functional properties of the brain structures involved in conscious perception, in attentive behavior and working memory, and in the recognition of objects. Such studies suggest that awareness of a visual stimulus probably reflects the interconnectivity and the type of cells involved in the representation of this stimulus, rather than the activity of specific circumscribed visual areas or processing streams.
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Affiliation(s)
- N Logothetis
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany.
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Logothetis N. Towards a quality management of education. Total Quality Man & Business Excellence 1995. [DOI: 10.1080/09544129500000005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Pöppel E, Stoerig P, Logothetis N, Fries W, Boergen KP, Oertel W, Zihl J. Plasticity and rigidity in the representation of the human visual field. Exp Brain Res 1987; 68:445-8. [PMID: 3691717 DOI: 10.1007/bf00248813] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Neuronal plasticity in the mammalian visual system has been studied with a variety of experimental methods like induction of artificial squint and eye rotation. To investigate neuronal plasticity in the human visual system, we examined a patient with a congenital convergent squint of his left eye, who later suffered a vascular lesion in his left occipital lobe that led to an incomplete hemianopia in his right visual field. The examination revealed that the visual field representation in the striate cortex is rigidly prewired with reference to the anatomical fovea. In contrast, plasticity in the oculomotor system enables the patient to use a functional visual axis that does not correspond to the anatomical fovea. Local alterations of sensitivity within the visual field that indicate interactions among non-corresponding retinal points provide additional evidence of functional plasticity.
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Affiliation(s)
- E Pöppel
- Institut für Medizinische Psychologie, Müchen, Federal Republic of Germany
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Pöppel E, Logothetis N. Neuronal oscillations in the human brain. Discontinuous initiations of pursuit eye movements indicate a 30-Hz temporal framework for visual information processing. Naturwissenschaften 1986; 73:267-8. [PMID: 3736678 DOI: 10.1007/bf00367781] [Citation(s) in RCA: 100] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Abstract
The 24 hr variations of plasma growth hormone (GH) and/or GH secretion provoked by oral glucose load or by insulin-induced hypoglycemia were studied in five microcephalic children. Low levels of GH and, especially, complete lack of secretory episodes were detected in three of the five children, two of whom were brothers. GH deficiency may constitute the principal or a contributing factor of impaired growth in some microcephalic children. A possible association between the cerebral abnomality and the pituitary hypofunction is suggested. An analogy is made between the present cases and the neuroendocrine complexes reported as Kallmann's and de Morsier's syndromes, respectively.
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