1
|
Peña-Casanova J, Sánchez-Benavides G, Sigg-Alonso J. Updating functional brain units: Insights far beyond Luria. Cortex 2024; 174:19-69. [PMID: 38492440 DOI: 10.1016/j.cortex.2024.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 01/15/2024] [Accepted: 02/15/2024] [Indexed: 03/18/2024]
Abstract
This paper reviews Luria's model of the three functional units of the brain. To meet this objective, several issues were reviewed: the theory of functional systems and the contributions of phylogenesis and embryogenesis to the brain's functional organization. This review revealed several facts. In the first place, the relationship/integration of basic homeostatic needs with complex forms of behavior. Secondly, the multi-scale hierarchical and distributed organization of the brain and interactions between cells and systems. Thirdly, the phylogenetic role of exaptation, especially in basal ganglia and cerebellum expansion. Finally, the tripartite embryogenetic organization of the brain: rhinic, limbic/paralimbic, and supralimbic zones. Obviously, these principles of brain organization are in contradiction with attempts to establish separate functional brain units. The proposed new model is made up of two large integrated complexes: a primordial-limbic complex (Luria's Unit I) and a telencephalic-cortical complex (Luria's Units II and III). As a result, five functional units were delineated: Unit I. Primordial or preferential (brainstem), for life-support, behavioral modulation, and waking regulation; Unit II. Limbic and paralimbic systems, for emotions and hedonic evaluation (danger and relevance detection and contribution to reward/motivational processing) and the creation of cognitive maps (contextual memory, navigation, and generativity [imagination]); Unit III. Telencephalic-cortical, for sensorimotor and cognitive processing (gnosis, praxis, language, calculation, etc.), semantic and episodic (contextual) memory processing, and multimodal conscious agency; Unit IV. Basal ganglia systems, for behavior selection and reinforcement (reward-oriented behavior); Unit V. Cerebellar systems, for the prediction/anticipation (orthometric supervision) of the outcome of an action. The proposed brain units are nothing more than abstractions within the brain's simultaneous and distributed physiological processes. As function transcends anatomy, the model necessarily involves transition and overlap between structures. Beyond the classic approaches, this review includes information on recent systemic perspectives on functional brain organization. The limitations of this review are discussed.
Collapse
Affiliation(s)
- Jordi Peña-Casanova
- Integrative Pharmacology and Systems Neuroscience Research Group, Neuroscience Program, Hospital del Mar Medical Research Institute, Barcelona, Spain; Department of Psychiatry and Legal Medicine, Autonomous University of Barcelona, Bellaterra, Barcelona, Spain; Test Barcelona Services, Teià, Barcelona, Spain.
| | | | - Jorge Sigg-Alonso
- Department of Behavioral and Cognitive Neurobiology, Institute of Neurobiology, National Autonomous University of México (UNAM), Queretaro, Mexico
| |
Collapse
|
2
|
Soloukey S, Vincent AJPE, Smits M, De Zeeuw CI, Koekkoek SKE, Dirven CMF, Kruizinga P. Functional imaging of the exposed brain. Front Neurosci 2023; 17:1087912. [PMID: 36845427 PMCID: PMC9947297 DOI: 10.3389/fnins.2023.1087912] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 01/19/2023] [Indexed: 02/11/2023] Open
Abstract
When the brain is exposed, such as after a craniotomy in neurosurgical procedures, we are provided with the unique opportunity for real-time imaging of brain functionality. Real-time functional maps of the exposed brain are vital to ensuring safe and effective navigation during these neurosurgical procedures. However, current neurosurgical practice has yet to fully harness this potential as it pre-dominantly relies on inherently limited techniques such as electrical stimulation to provide functional feedback to guide surgical decision-making. A wealth of especially experimental imaging techniques show unique potential to improve intra-operative decision-making and neurosurgical safety, and as an added bonus, improve our fundamental neuroscientific understanding of human brain function. In this review we compare and contrast close to twenty candidate imaging techniques based on their underlying biological substrate, technical characteristics and ability to meet clinical constraints such as compatibility with surgical workflow. Our review gives insight into the interplay between technical parameters such sampling method, data rate and a technique's real-time imaging potential in the operating room. By the end of the review, the reader will understand why new, real-time volumetric imaging techniques such as functional Ultrasound (fUS) and functional Photoacoustic Computed Tomography (fPACT) hold great clinical potential for procedures in especially highly eloquent areas, despite the higher data rates involved. Finally, we will highlight the neuroscientific perspective on the exposed brain. While different neurosurgical procedures ask for different functional maps to navigate surgical territories, neuroscience potentially benefits from all these maps. In the surgical context we can uniquely combine healthy volunteer studies, lesion studies and even reversible lesion studies in in the same individual. Ultimately, individual cases will build a greater understanding of human brain function in general, which in turn will improve neurosurgeons' future navigational efforts.
Collapse
Affiliation(s)
- Sadaf Soloukey
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
- Department of Neurosurgery, Erasmus MC, Rotterdam, Netherlands
| | | | - Marion Smits
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, Netherlands
| | - Chris I. De Zeeuw
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
- Netherlands Institute for Neuroscience, Royal Dutch Academy for Arts and Sciences, Amsterdam, Netherlands
| | | | | | | |
Collapse
|
3
|
Polanski WH, Oelschlägel M, Juratli TA, Wahl H, Krukowski PM, Morgenstern U, Koch E, Steiner G, Schackert G, Sobottka SB. Topographic Mapping of the Primary Sensory Cortex Using Intraoperative Optical Imaging and Tactile Irritation. Brain Topogr 2023; 36:1-9. [PMID: 36446998 PMCID: PMC9834102 DOI: 10.1007/s10548-022-00925-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 10/30/2022] [Indexed: 11/30/2022]
Abstract
The determination of exact tumor boundaries within eloquent brain regions is essential to maximize the extent of resection. Recent studies showed that intraoperative optical imaging (IOI) combined with median nerve stimulation is a helpful tool for visualization of the primary sensory cortex (PSC). In this technical note, we describe a novel approach of using IOI with painless tactile irritation to demonstrate the feasibility of topographic mapping of different body regions within the PSC. In addition, we compared the IOI results with preoperative functional MRI (fMRI) findings. In five patients with tumors located near the PSC who received tumor removal, IOI with tactile irritation of different body parts and fMRI was applied. We showed that tactile irritation of the hand in local and general anesthesia leads to reliable changes of cerebral blood volume during IOI. Hereby, we observed comparable IOI activation maps regarding the median nerve stimulation, fMRI and tactile irritation of the hand. The tactile irritation of different body areas revealed a plausible topographic distribution along the PSC. With this approach, IOI is also suitable for awake surgeries, since the tactile irritation is painless compared with median nerve stimulation and is congruent to fMRI findings. Further studies are ongoing to standardize this method to enable a broad application within the neurosurgical community.
Collapse
Affiliation(s)
- Witold H. Polanski
- Department of Neurosurgery, University Hospital of Dresden, Fiedlerstr. 74, 01307 Dresden, Germany
| | - Martin Oelschlägel
- Clinical Sensoring and Monitoring, Faculty of Medicine, University Hospital Carl Gustav Carus, Dresden University of Technology, 01307 Dresden, Germany
| | - Tareq A. Juratli
- Department of Neurosurgery, University Hospital of Dresden, Fiedlerstr. 74, 01307 Dresden, Germany
| | - Hannes Wahl
- Institute of Diagnostic and Interventional Neuroradiology, University Hospital Carl Gustav Carus, Technical University of Dresden, Fetscherstr. 74, 01307 Dresden, Germany
| | - Pawel M. Krukowski
- Institute of Diagnostic and Interventional Neuroradiology, University Hospital Carl Gustav Carus, Technical University of Dresden, Fetscherstr. 74, 01307 Dresden, Germany
| | - Ute Morgenstern
- Institute of Biomedical Engineering, Faculty of Electrical and Computer Engineering, Technische Universität Dresden, 01307 Dresden, Germany
| | - Edmund Koch
- Clinical Sensoring and Monitoring, Faculty of Medicine, University Hospital Carl Gustav Carus, Dresden University of Technology, 01307 Dresden, Germany
| | - Gerald Steiner
- Clinical Sensoring and Monitoring, Faculty of Medicine, University Hospital Carl Gustav Carus, Dresden University of Technology, 01307 Dresden, Germany
| | - Gabriele Schackert
- Department of Neurosurgery, University Hospital of Dresden, Fiedlerstr. 74, 01307 Dresden, Germany
| | - Stephan B. Sobottka
- Department of Neurosurgery, University Hospital of Dresden, Fiedlerstr. 74, 01307 Dresden, Germany
| |
Collapse
|
4
|
Mitsuhashi D, Hishida R, Oishi M, Hiraishi T, Natsumeda M, Shibuki K, Fujii Y. Visualization of cortical activation in human brain by flavoprotein fluorescence imaging. J Neurosurg 2022; 137:1105-1113. [PMID: 35180697 DOI: 10.3171/2022.1.jns212542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/07/2022] [Indexed: 11/06/2022]
Abstract
OBJECTIVE To develop an innovative brain mapping and neuromonitoring method during neurosurgery, the authors set out to establish intraoperative flavoprotein fluorescence imaging (iFFI) to directly visualize cortical activations in human brain. The significance of iFFI was analyzed by comparison with intraoperative perfusion-dependent imaging (iPDI), which is considered the conventional optical imaging, and by performing animal experiments. METHODS Seven patients with intracerebral tumors were examined by iFFI and iPDI following craniotomy, using a single operative microscope equipped with a laser light source for iFFI and xenon lamp for iPDI. Images were captured by the same charge-coupled device camera. Responses to bipolar stimulation at selected points on the cortical surface were analyzed off-line, and relative signal changes were visualized by overlaying pseudocolor intensity maps onto cortical photographs. Signal changes exceeding 3 SDs from baseline were defined as significant. The authors also performed FFI and PDI on 10 mice using similar settings, and then compared signal patterns to intraoperative studies. RESULTS Signals acquired by iFFI exhibited biphasic spatiotemporal changes consisting of an early positive signal peak (F1) and a delayed negative signal peak (F2). In contrast, iPDI signals exhibited only 1 negative peak (P1) that was significantly delayed compared to F1 (p < 0.02) and roughly in phase with F2. Compared to F2 and P1, F1 was of significantly lower amplitude (p < 0.02) and located closer to the bipolar stimulus center (p < 0.03), whereas F2 and P1 were more widespread, irregular, and partially overlapping. In mice, the spatiotemporal characteristics of FFI and PDI resembled those of iFFI and iPDI, but the early positive signal was more robust than F1. CONCLUSIONS This is the first report in humans of successful intraoperative visualization of cortical activations by using iFFI, which showed rapid evoked cortical activity prior to perfusion-dependent signal changes. Further technical improvements can lead to establishment of iFFI as a real-time intraoperative tool.
Collapse
Affiliation(s)
| | - Ryuichi Hishida
- 2Department of Neurophysiology, Brain Research Institute, Niigata University, Niigata, Japan
| | | | | | | | - Katsuei Shibuki
- 2Department of Neurophysiology, Brain Research Institute, Niigata University, Niigata, Japan
| | | |
Collapse
|
5
|
Mangraviti A, Volpin F, Cha J, Cunningham SI, Raje K, Brooke MJ, Brem H, Olivi A, Huang J, Tyler BM, Rege A. Intraoperative Laser Speckle Contrast Imaging For Real-Time Visualization of Cerebral Blood Flow in Cerebrovascular Surgery: Results From Pre-Clinical Studies. Sci Rep 2020; 10:7614. [PMID: 32376983 PMCID: PMC7203106 DOI: 10.1038/s41598-020-64492-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 04/01/2020] [Indexed: 01/04/2023] Open
Abstract
Cerebrovascular surgery can benefit from an intraoperative system that conducts continuous monitoring of cerebral blood flow (CBF). Such a system must be handy, non-invasive, and directly integrated into the surgical workflow. None of the currently available techniques, considered alone, meets all these criteria. Here, we introduce the SurgeON™ system: a newly developed non-invasive modular tool which transmits high-resolution Laser Speckle Contrast Imaging (LSCI) directly onto the eyepiece of the surgical microscope. In preclinical rodent and rabbit models, we show that this system enabled the detection of acute perfusion changes as well as the recording of temporal response patterns and degrees of flow changes in various microvascular settings, such as middle cerebral artery occlusion, femoral artery clipping, and complete or incomplete cortical vessel cautery. During these procedures, a real-time visualization of vasculature and CBF was available in high spatial resolution through the eyepiece as a direct overlay on the live morphological view of the surgical field. Upon comparison with indocyanine green angiography videoangiography (ICG-VA) imaging, also operable via SurgeON, we found that direct-LSCI can produce greater information than ICG-VA and that continuous display of data is advantageous for performing immediate LSCI-guided adjustments in real time.
Collapse
Affiliation(s)
- Antonella Mangraviti
- Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, United States
| | - Francesco Volpin
- Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, United States
| | - Jaepyeong Cha
- Vasoptic Medical, Inc., Baltimore, MD, United States
| | | | - Karan Raje
- Vasoptic Medical, Inc., Baltimore, MD, United States
| | | | - Henry Brem
- Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, United States.,Department of Oncology, Johns Hopkins University, Baltimore, MD, United States.,Department of Ophthalmology, Johns Hopkins University, Baltimore, MD, United States.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States
| | - Alessandro Olivi
- Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, United States.,Department of Oncology, Johns Hopkins University, Baltimore, MD, United States.,Department of Neurosurgery, Catholic University School of Medicine, Rome, Italy
| | - Judy Huang
- Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, United States
| | - Betty M Tyler
- Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, United States.
| | - Abhishek Rege
- Vasoptic Medical, Inc., Baltimore, MD, United States
| |
Collapse
|
6
|
Oelschlägel M, Meyer T, Morgenstern U, Wahl H, Gerber J, Reiß G, Koch E, Steiner G, Kirsch M, Schackert G, Sobottka SB. Mapping of language and motor function during awake neurosurgery with intraoperative optical imaging. Neurosurg Focus 2020; 48:E3. [PMID: 32006940 DOI: 10.3171/2019.11.focus19759] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 11/15/2019] [Indexed: 11/06/2022]
Abstract
Intraoperative optical imaging (IOI) is a marker-free, contactless, and noninvasive imaging technique that is able to visualize metabolic changes of the brain surface following neuronal activation. Although it has been used in the past mainly for the identification of functional brain areas under general anesthesia, the authors investigated the potential of the method during awake surgery. Measurements were performed in 10 patients who underwent resection of lesions within or adjacent to cortical language or motor sites. IOI was applied in 3 different scenarios: identification of motor areas by using finger-tapping tasks, identification of language areas by using speech tasks (overt and silent speech), and a novel approach-the application of IOI as a feedback tool during direct electrical stimulation (DES) mapping of language. The functional maps, which were calculated from the IOI data (activity maps), were qualitatively compared with the functional MRI (fMRI) and the electrophysiological testing results during the surgical procedure to assess their potential benefit for surgical decision-making.The results reveal that the intraoperative identification of motor sites with IOI in good agreement with the preoperatively acquired fMRI and the intraoperative electrophysiological measurements is possible. Because IOI provides spatially highly resolved maps with minimal additional hardware effort, the application of the technique for motor site identification seems to be beneficial in awake procedures. The identification of language processing sites with IOI was also possible, but in the majority of cases significant differences between fMRI, IOI, and DES were visible, and therefore according to the authors' findings the IOI results are too unspecific to be useful for intraoperative decision-making with respect to exact language localization. For this purpose, DES mapping will remain the method of choice.Nevertheless, the IOI technique can provide additional value during the language mapping procedure with DES. Using a simple difference imaging approach, the authors were able to visualize and calculate the spatial extent of activation for each stimulation. This might enable surgeons in the future to optimize the mapping process. Additionally, differences between tumor and nontumor stimulation sites were observed with respect to the spatial extent of the changes in cortical optical properties. These findings provide further evidence that the method allows the assessment of the functional state of neurovascular coupling and is therefore suited for the delineation of pathologically altered tissue.
Collapse
Affiliation(s)
- Martin Oelschlägel
- 1Clinical Sensoring and Monitoring, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden
| | - Tobias Meyer
- 2ABX-CRO Advanced Pharmaceutical Services Forschungsgesellschaft mbH, Dresden
| | - Ute Morgenstern
- 3Institute of Biomedical Engineering, Faculty of Electrical and Computer Engineering, Technische Universität Dresden
| | - Hannes Wahl
- 4Institute and Polyclinic of Diagnostic and Interventional Neuroradiology, Carl Gustav Carus University Hospital, Technische Universität Dresden
| | - Johannes Gerber
- 4Institute and Polyclinic of Diagnostic and Interventional Neuroradiology, Carl Gustav Carus University Hospital, Technische Universität Dresden
| | - Gilfe Reiß
- 6Department of Neurosurgery, Carl Gustav Carus University Hospital, Technische Universität Dresden, Saxony, Germany
| | - Edmund Koch
- 1Clinical Sensoring and Monitoring, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden
| | - Gerald Steiner
- 1Clinical Sensoring and Monitoring, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden
| | - Matthias Kirsch
- 5Department of Neurosurgery, Asklepios Kliniken Schildautal Seesen; and
| | - Gabriele Schackert
- 6Department of Neurosurgery, Carl Gustav Carus University Hospital, Technische Universität Dresden, Saxony, Germany
| | - Stephan B Sobottka
- 6Department of Neurosurgery, Carl Gustav Carus University Hospital, Technische Universität Dresden, Saxony, Germany
| |
Collapse
|
7
|
Sato K, Nariai T, Momose-Sato Y, Kamino K. Intraoperative intrinsic optical imaging of human somatosensory cortex during neurosurgical operations. NEUROPHOTONICS 2017; 4:031205. [PMID: 28018935 PMCID: PMC5162804 DOI: 10.1117/1.nph.4.3.031205] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 11/28/2016] [Indexed: 05/19/2023]
Abstract
Intrinsic optical imaging as developed by Grinvald et al. is a powerful technique for monitoring neural function in the in vivo central nervous system. The advent of this dye-free imaging has also enabled us to monitor human brain function during neurosurgical operations. We briefly describe our own experience in functional mapping of the human somatosensory cortex, carried out using intraoperative optical imaging. The maps obtained demonstrate new additional evidence of a hierarchy for sensory response patterns in the human primary somatosensory cortex.
Collapse
Affiliation(s)
- Katsushige Sato
- Komazawa Women’s University, Department of Health and Nutrition Sciences, Faculty of Human Health, 238 Sakahama, Inagi-shi, Tokyo 206-8511, Japan
| | - Tadashi Nariai
- Tokyo Medical and Dental University, Graduate School, Department of Neurosurgery, Faculty of Medicine, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Yoko Momose-Sato
- Kanto Gakuin University, College of Nutrition, Department of Nutrition and Dietetics, 1-50-1 Mutsuura-higashi, Kanazawa-ku, Yokohama 236-8503, Japan
| | - Kohtaro Kamino
- Tokyo Medical and Dental University, School of Medicine,1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| |
Collapse
|
8
|
Morone KA, Neimat JS, Roe AW, Friedman RM. Review of functional and clinical relevance of intrinsic signal optical imaging in human brain mapping. NEUROPHOTONICS 2017; 4:031220. [PMID: 28630881 PMCID: PMC5466092 DOI: 10.1117/1.nph.4.3.031220] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 05/12/2017] [Indexed: 05/30/2023]
Abstract
Intrinsic signal optical imaging (ISOI) within the first decade of its use in humans showed its capacity as a precise functional mapping tool. It is a powerful tool that can be used intraoperatively to help a surgeon to directly identify functional areas of the cerebral cortex. Its use is limited to the intraoperative setting as it requires a craniotomy and durotomy for direct visualization of the brain. It has been applied in humans to study language, somatosensory and visual cortices, cortical hemodynamics, epileptiform activity, and lesion delineation. Despite studies showing clear evidence of its usefulness in clinical care, its clinical use in humans has not grown. Impediments imposed by imaging in a human operating room setting have hindered such work. However, recent studies have been aimed at overcoming obstacles in clinical studies establishing the benefits of its use to patients. This review provides a description of ISOI and its use in human studies with an emphasis on the challenges that have hindered its widespread use and the recent studies that aim to overcome these hurdles. Clinical studies establishing the benefits of its use to patients would serve as the impetus for continued development and use in humans.
Collapse
Affiliation(s)
- Katherine A. Morone
- Vanderbilt University Medical Center, Department of Neurology, Nashville, Tennessee, United States
| | - Joseph S. Neimat
- University of Louisville School of Medicine, Department of Neurosurgery, Louisville, Kentucky, United States
| | - Anna W. Roe
- Oregon Health and Science University, Division of Neuroscience, Oregon National Primate Research Center, Beaverton, Oregon, United States
- Zhejiang University, Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, HuaJiaChi Campus, Hangzhou, China
| | - Robert M. Friedman
- Oregon Health and Science University, Division of Neuroscience, Oregon National Primate Research Center, Beaverton, Oregon, United States
| |
Collapse
|
9
|
Rao VR, Leonard MK, Kleen JK, Lucas BA, Mirro EA, Chang EF. Chronic ambulatory electrocorticography from human speech cortex. Neuroimage 2017; 153:273-282. [PMID: 28396294 DOI: 10.1016/j.neuroimage.2017.04.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 03/15/2017] [Accepted: 04/04/2017] [Indexed: 01/07/2023] Open
Abstract
Direct intracranial recording of human brain activity is an important approach for deciphering neural mechanisms of cognition. Such recordings, usually made in patients with epilepsy undergoing inpatient monitoring for seizure localization, are limited in duration and depend on patients' tolerance for the challenges associated with recovering from brain surgery. Thus, typical intracranial recordings, similar to most non-invasive approaches in humans, provide snapshots of brain activity in acute, highly constrained settings, limiting opportunities to understand long timescale and natural, real-world phenomena. A new device for treating some forms of drug-resistant epilepsy, the NeuroPace RNS® System, includes a cranially-implanted neurostimulator and intracranial electrodes that continuously monitor brain activity and respond to incipient seizures with electrical counterstimulation. The RNS System can record epileptic brain activity over years, but whether it can record meaningful, behavior-related physiological responses has not been demonstrated. Here, in a human subject with electrodes implanted over high-level speech-auditory cortex (Wernicke's area; posterior superior temporal gyrus), we report that cortical evoked responses to spoken sentences are robust, selective to phonetic features, and stable over nearly 1.5 years. In a second subject with RNS System electrodes implanted over frontal cortex (Broca's area, posterior inferior frontal gyrus), we found that word production during a naming task reliably evokes cortical responses preceding speech onset. The spatiotemporal resolution, high signal-to-noise, and wireless nature of this system's intracranial recordings make it a powerful new approach to investigate the neural correlates of human cognition over long timescales in natural ambulatory settings.
Collapse
Affiliation(s)
- Vikram R Rao
- University of California, San Francisco, Department of Neurology, San Francisco, CA 94143, United States.
| | - Matthew K Leonard
- University of California, San Francisco, Department of Neurosurgery, San Francisco, CA 94143, United States; Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, United States
| | - Jonathan K Kleen
- University of California, San Francisco, Department of Neurology, San Francisco, CA 94143, United States
| | - Ben A Lucas
- University of California, San Francisco, Department of Neurosurgery, San Francisco, CA 94143, United States; Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, United States
| | - Emily A Mirro
- NeuroPace, Inc., Mountain View, CA 94043, United States
| | - Edward F Chang
- University of California, San Francisco, Department of Neurosurgery, San Francisco, CA 94143, United States; Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, United States
| |
Collapse
|
10
|
Valdés PA, Roberts DW, Lu FK, Golby A. Optical technologies for intraoperative neurosurgical guidance. Neurosurg Focus 2016; 40:E8. [PMID: 26926066 DOI: 10.3171/2015.12.focus15550] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Biomedical optics is a broadly interdisciplinary field at the interface of optical engineering, biophysics, computer science, medicine, biology, and chemistry, helping us understand light-tissue interactions to create applications with diagnostic and therapeutic value in medicine. Implementation of biomedical optics tools and principles has had a notable scientific and clinical resurgence in recent years in the neurosurgical community. This is in great part due to work in fluorescence-guided surgery of brain tumors leading to reports of significant improvement in maximizing the rates of gross-total resection. Multiple additional optical technologies have been implemented clinically, including diffuse reflectance spectroscopy and imaging, optical coherence tomography, Raman spectroscopy and imaging, and advanced quantitative methods, including quantitative fluorescence and lifetime imaging. Here we present a clinically relevant and technologically informed overview and discussion of some of the major clinical implementations of optical technologies as intraoperative guidance tools in neurosurgery.
Collapse
Affiliation(s)
- Pablo A Valdés
- Departments of 1 Neurosurgery and.,Department of Neurosurgery, Harvard Medical School, Boston Children's Hospital, Boston
| | - David W Roberts
- Section of Neurosurgery, Geisel School of Medicine at Dartmouth, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | | | - Alexandra Golby
- Departments of 1 Neurosurgery and.,Radiology, and.,Dana Farber Cancer Institute, Harvard Medical School, Brigham and Women's Hospital
| |
Collapse
|
11
|
Song Y, Riera JJ, Bhatia S, Ragheb J, Garcia C, Weil AG, Jayakar P, Lin WC. Intraoperative optical mapping of epileptogenic cortices during non-ictal periods in pediatric patients. Neuroimage Clin 2016; 11:423-434. [PMID: 27104137 PMCID: PMC4827725 DOI: 10.1016/j.nicl.2016.02.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 02/19/2016] [Accepted: 02/22/2016] [Indexed: 01/27/2023]
Abstract
Complete removal of epileptogenic cortex while preserving eloquent areas is crucial in patients undergoing epilepsy surgery. In this manuscript, the feasibility was explored of developing a new methodology based on dynamic intrinsic optical signal imaging (DIOSI) to intraoperatively detect and differentiate epileptogenic from eloquent cortices in pediatric patients with focal epilepsy. From 11 pediatric patients undergoing epilepsy surgery, negatively-correlated hemodynamic low-frequency oscillations (LFOs, ~ 0.02-0.1 Hz) were observed from the exposed epileptogenic and eloquent cortical areas, as defined by electrocorticography (ECoG), using a DIOSI system. These LFOs were classified into multiple groups in accordance with their unique temporal profiles. Causal relationships within these groups were investigated using the Granger causality method, and 83% of the ECoG-defined epileptogenic cortical areas were found to have a directed influence on one or more cortical areas showing LFOs within the field of view of the imaging system. To understand the physiological origins of LFOs, blood vessel density was compared between epileptogenic and normal cortical areas and a statistically-significant difference (p < 0.05) was detected. The differences in blood-volume and blood-oxygenation dynamics between eloquent and epileptogenic cortices were also uncovered using a stochastic modeling approach. This, in turn, yielded a means by which to separate epileptogenic from eloquent cortex using hemodynamic LFOs. The proposed methodology detects epileptogenic cortices by exploiting the effective connectivity that exists within cortical regions displaying LFOs and the biophysical features contributed by the altered vessel networks within the epileptogenic cortex. It could be used in conjunction with existing technologies for epileptogenic/eloquent cortex localization and thereby facilitate clinical decision-making.
Collapse
Affiliation(s)
- Yinchen Song
- Department of Biomedical Engineering, Florida International University, 10555 West Flagler Street, EC 2600, Miami, FL 33174, United States
| | - Jorge J Riera
- Department of Biomedical Engineering, Florida International University, 10555 West Flagler Street, EC 2600, Miami, FL 33174, United States
| | - Sanjiv Bhatia
- Division of Neurosurgery, Nicklaus Children's Hospital, 3100 SW 62nd Ave, Miami, FL 33155, United States
| | - John Ragheb
- Division of Neurosurgery, Nicklaus Children's Hospital, 3100 SW 62nd Ave, Miami, FL 33155, United States
| | - Claudia Garcia
- Division of Neurosurgery, Nicklaus Children's Hospital, 3100 SW 62nd Ave, Miami, FL 33155, United States
| | - Alexander G Weil
- Division of Neurosurgery, Nicklaus Children's Hospital, 3100 SW 62nd Ave, Miami, FL 33155, United States
| | - Prasanna Jayakar
- Division of Neurosurgery, Nicklaus Children's Hospital, 3100 SW 62nd Ave, Miami, FL 33155, United States
| | - Wei-Chiang Lin
- Department of Biomedical Engineering, Florida International University, 10555 West Flagler Street, EC 2600, Miami, FL 33174, United States.
| |
Collapse
|
12
|
Abstract
A number of studies have focused on the role of specific brain regions, such as the dorsal anterior cingulate cortex during trials on which participants make errors, whereas others have implicated a host of more widely distributed regions in the human brain. Previous work has proposed that there are multiple cognitive control networks, raising the question of whether error-related activity can be found in each of these networks. Thus, to examine error-related activity broadly, we conducted a meta-analysis consisting of 12 tasks that included both error and correct trials. These tasks varied by stimulus input (visual, auditory), response output (button press, speech), stimulus category (words, pictures), and task type (e.g., recognition memory, mental rotation). We identified 41 brain regions that showed a differential fMRI BOLD response to error and correct trials across a majority of tasks. These regions displayed three unique response profiles: (1) fast, (2) prolonged, and (3) a delayed response to errors, as well as a more canonical response to correct trials. These regions were found mostly in several control networks, each network predominantly displaying one response profile. The one exception to this "one network, one response profile" observation is the frontoparietal network, which showed prolonged response profiles (all in the right hemisphere), and fast profiles (all but one in the left hemisphere). We suggest that, in the place of a single localized error mechanism, these findings point to a large-scale set of error-related regions across multiple systems that likely subserve different functions.
Collapse
|
13
|
Sobottka SB, Meyer T, Kirsch M, Koch E, Steinmeier R, Morgenstern U, Schackert G. Intraoperative optical imaging of intrinsic signals: a reliable method for visualizing stimulated functional brain areas during surgery. J Neurosurg 2013; 119:853-63. [DOI: 10.3171/2013.5.jns122155] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Intraoperative optical imaging (IOI) is an experimental technique used for visualizing functional brain areas after surgical exposure of the cerebral cortex. This technique identifies areas of local changes in blood volume and oxygenation caused by stimulation of specific brain functions. The authors describe a new IOI method, including innovative data analysis, that can facilitate intraoperative functional imaging on a routine basis. To evaluate the reliability and validity of this approach, they used the new IOI method to demonstrate visualization of the median nerve area of the somatosensory cortex.
Methods
In 41 patients with tumor lesions adjacent to the postcentral gyrus, lesions were surgically removed by using IOI during stimulation of the contralateral median nerve. Optical properties of the cortical tissue were measured with a sensitive camera system connected to a surgical microscope. Imaging was performed by using 9 cycles of alternating prolonged stimulation and rest periods of 30 seconds. Intraoperative optical imaging was based on blood volume changes detected by using a filter at an isosbestic wavelength (λ = 568 nm). A spectral analysis algorithm was used to improve computation of the activity maps. Movement artifacts were compensated for by an elastic registration algorithm. For validation, intraoperative conduction of the phase reversal over the central sulcus and postoperative evaluation of the craniotomy site were used.
Results
The new method and analysis enabled significant differentiation (p < 0.005) between functional and nonfunctional tissue. The identification and visualization of functionally intact somatosensory cortex was highly reliable; sensitivity was 94.4% and specificity was almost 100%. The surgeon was provided with a 2D high-resolution activity map within 12 minutes. No method-related side effects occurred in any of the 41 patients.
Conclusions
The authors' new approach makes IOI a contact-free and label-free optical technique that can be used safely in a routine clinical setup. Intraoperative optical imaging can be used as an alternative to other methods for the identification of sensory cortex areas and offers the added benefit of a high-resolution map of functional activity. It has great potential for visualizing and monitoring additional specific functional brain areas such as the visual, motor, and speech cortex. A prospective national multicenter clinical trial is currently being planned.
Collapse
Affiliation(s)
| | - Tobias Meyer
- 1Department of Neurosurgery, University Hospital Carl Gustav Carus
- 2Institute for Biomedical Engineering
| | - Matthias Kirsch
- 1Department of Neurosurgery, University Hospital Carl Gustav Carus
| | - Edmund Koch
- 3Clinical Sensoring and Monitoring, Faculty of Medicine Carl Gustav Carus, Technical University of Dresden, Dresden; and
| | - Ralf Steinmeier
- 4Department of Neurosurgery, Klinikum Chemnitz gGmbH, Chemnitz, Germany
| | | | | |
Collapse
|
14
|
Hecht N, Woitzik J, König S, Horn P, Vajkoczy P. Laser speckle imaging allows real-time intraoperative blood flow assessment during neurosurgical procedures. J Cereb Blood Flow Metab 2013; 33:1000-7. [PMID: 23512134 PMCID: PMC3705427 DOI: 10.1038/jcbfm.2013.42] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 01/17/2013] [Accepted: 02/11/2013] [Indexed: 11/09/2022]
Abstract
Currently, there is no adequate technique for intraoperative monitoring of cerebral blood flow (CBF). To evaluate laser speckle imaging (LSI) for assessment of relative CBF, LSI was performed in 30 patients who underwent direct surgical revascularization for treatment of arteriosclerotic cerebrovascular disease (ACVD), Moyamoya disease (MMD), or giant aneurysms, and in 8 control patients who underwent intracranial surgery for reasons other than hemodynamic compromise. The applicability and sensitivity of LSI was investigated through baseline perfusion and CO2 reactivity testing. The dynamics of LSI were assessed during bypass test occlusion and flow initiation procedures. Laser speckle imaging permitted robust (pseudo-) quantitative assessment of relative microcirculatory flow and standard bypass grafting resulted in significantly higher postoperative baseline perfusion values in ACVD and MMD. The applicability and sensitivity of LSI was shown by a significantly reduced CO2 reactivity in ACVD (9.6±9%) and MMD (8.5±8%) compared with control (31.2±5%; P<0.0001). In high- and intermediate-flow bypass patients, LSI was characterized by a dynamic real-time response to acute perfusion changes and ultimately confirmed a sufficient flow substitution through the bypass graft. Thus, LSI can be used for sensitive and continuous, non-invasive real-time visualization and measurement of relative cortical CBF in excellent spatial-temporal resolution.
Collapse
Affiliation(s)
- Nils Hecht
- Department of Neurosurgery and Center for Stroke-research Berlin (CSB), Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Johannes Woitzik
- Department of Neurosurgery and Center for Stroke-research Berlin (CSB), Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Susanne König
- Department of Anesthesiology and Operative Intensive Care Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Peter Horn
- Department of Neurosurgery and Center for Stroke-research Berlin (CSB), Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Peter Vajkoczy
- Department of Neurosurgery and Center for Stroke-research Berlin (CSB), Charité-Universitätsmedizin Berlin, Berlin, Germany
| |
Collapse
|
15
|
Haglund MM. Optical imaging of visual cortex epileptic foci and propagation pathways. Epilepsia 2012; 53 Suppl 1:87-97. [DOI: 10.1111/j.1528-1167.2012.03479.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
16
|
Rezaie R, Simos PG, Fletcher JM, Cirino PT, Vaughn S, Papanicolaou AC. Engagement of temporal lobe regions predicts response to educational interventions in adolescent struggling readers. Dev Neuropsychol 2012; 36:869-88. [PMID: 21978010 DOI: 10.1080/87565641.2011.606404] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Brain activation profiles obtained using magnetoencephalography were compared between middle-school students experiencing reading difficulties and non-reading-impaired students during performance of a continuous printed word recognition task. Struggling readers underwent small-group remedial instruction, and students who showed significant gains in word reading efficiency at a one-year follow-up assessment were classified as Adequate Responders whereas those not demonstrating such gains as Inadequate Responders. At baseline, compared to Inadequate Responders, the activation profiles of Adequate Responders featured increased activity in the left middle, superior temporal, and ventral occipitotemporal regions, as well as in the right mesial temporal cortex. The degree of activity in these regions was a significant predictor of improvement in word reading efficiency beyond the prediction afforded by baseline reading accuracy or fluency measures. The engagement of brain areas that typically serve as key components of the brain circuit for reading may be an important factor in predicting response to intervention in older students who experience reading difficulties.
Collapse
Affiliation(s)
- Roozbeh Rezaie
- Department of Pediatrics, Children's Learning Institute, University of Texas Health Science Center, Houston, Texas 77030, USA.
| | | | | | | | | | | |
Collapse
|
17
|
Rezaie R, Simos PG, Fletcher JM, Juranek J, Cirino PT, Li Z, Passaro AD, Papanicolaou AC. The timing and strength of regional brain activation associated with word recognition in children with reading difficulties. Front Hum Neurosci 2011; 5:45. [PMID: 21647211 PMCID: PMC3098420 DOI: 10.3389/fnhum.2011.00045] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 04/27/2011] [Indexed: 12/04/2022] Open
Abstract
The study investigates the relative degree and timing of cortical activation across parietal, temporal, and frontal regions during performance of a continuous visual-word recognition task in children who experience reading difficulties (N = 44, RD) and typical readers (N = 40, NI). Minimum norm estimates of regional neurophysiological activity were obtained from magnetoencephalographic recordings. Children with RD showed bilaterally reduced neurophysiological activity in the superior and middle temporal gyri, and increased activity in rostral middle frontal and ventral occipitotemporal cortices, bilaterally. The temporal profile of activity in the RD group, featured near-simultaneous activity peaks in temporal, inferior parietal, and prefrontal regions, in contrast to a clear temporal progression of activity among these areas in the NI group. These results replicate and extend previous MEG and fMRI results demonstrating atypical, latency-dependent attributes of the brain circuit involved in word reading in children with reading difficulties.
Collapse
Affiliation(s)
- Roozbeh Rezaie
- Department of Pediatrics, Children's Learning Institute, University of Texas Health Science Center at Houston Houston, TX, USA
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Parthasarathy AB, Weber EL, Richards LM, Fox DJ, Dunn AK. Laser speckle contrast imaging of cerebral blood flow in humans during neurosurgery: a pilot clinical study. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:066030. [PMID: 21198204 PMCID: PMC9113397 DOI: 10.1117/1.3526368] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 10/26/2010] [Accepted: 11/05/2010] [Indexed: 05/18/2023]
Abstract
Monitoring cerebral blood flow (CBF) during neurosurgery can provide important physiological information for a variety of surgical procedures. CBF measurements are important for assessing whether blood flow has returned to presurgical baseline levels and for assessing postsurgical tissue viability. Existing techniques for intraoperative monitoring of CBF based on magnetic resonance imaging are expensive and often impractical, while techniques such as indocyanine green angiography cannot produce quantitative measures of blood flow. Laser speckle contrast imaging (LSCI) is an optical technique that has been widely used to quantitatively image relative CBF in animal models in vivo. In a pilot clinical study, we adapted an existing neurosurgical operating microscope to obtain LSCI images in humans in real time during neurosurgery under baseline conditions and after bipolar cautery. Simultaneously recorded ECG waveforms from the patient were used to develop a filter that helped reduce measurement variabilities due to motion artifacts. Results from this study demonstrate the feasibility of using LSCI to obtain blood flow images during neurosurgeries and its capability to produce full field CBF image maps with excellent spatial resolution in real-time with minimal disruption to the surgical procedure.
Collapse
Affiliation(s)
- Ashwin B. Parthasarathy
- The University of Texas at
Austin, Department of Biomedical Engineering, Austin, Texas
78712
| | - Erica L. Weber
- The University of Texas at
Austin, Department of Biomedical Engineering, Austin, Texas
78712
| | - Lisa M. Richards
- The University of Texas at
Austin, Department of Biomedical Engineering, Austin, Texas
78712
| | - Douglas J. Fox
- St. David's Hospital, NeuroTexas
Institute, Austin, Texas 78705
| | - Andrew K. Dunn
- The University of Texas at
Austin, Department of Biomedical Engineering, Austin, Texas
78712
- Address all correspondence to: Andrew K. Dunn, The University of
Texas at Austin, Department of Biomedical Engineering, Austin, Texas 78712; Tel:
512-232-2808; E-mail:
| |
Collapse
|
19
|
Liao SM, Gregg NM, White BR, Zeff BW, Bjerkaas KA, Inder TE, Culver JP. Neonatal hemodynamic response to visual cortex activity: high-density near-infrared spectroscopy study. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:026010. [PMID: 20459255 PMCID: PMC2874048 DOI: 10.1117/1.3369809] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 01/14/2010] [Accepted: 01/26/2010] [Indexed: 05/18/2023]
Abstract
The neurodevelopmental outcome of neonatal intensive care unit (NICU) infants is a major clinical concern with many infants displaying neurobehavioral deficits in childhood. Functional neuroimaging may provide early recognition of neural deficits in high-risk infants. Near-infrared spectroscopy (NIRS) has the advantage of providing functional neuroimaging in infants at the bedside. However, limitations in traditional NIRS have included contamination from superficial vascular dynamics in the scalp. Furthermore, controversy exists over the nature of normal vascular, responses in infants. To address these issues, we extend the use of novel high-density NIRS arrays with multiple source-detector distances and a superficial signal regression technique to infants. Evaluations of healthy term-born infants within the first three days of life are performed without sedation using a visual stimulus. We find that the regression technique significantly improves brain activation signal quality. Furthermore, in six out of eight infants, both oxy- and total hemoglobin increases while deoxyhemoglobin decreases, suggesting that, at term, the neurovascular coupling in the visual cortex is similar to that found in healthy adults. These results demonstrate the feasibility of using high-density NIRS arrays in infants to improve signal quality through superficial signal regression, and provide a foundation for further development of high-density NIRS as a clinical tool.
Collapse
Affiliation(s)
- Steve M Liao
- Washington University School of Medicine, Department of Pediatrics and Department of Neurology and Department of Radiology, St. Louis, Missouri 63110, USA
| | | | | | | | | | | | | |
Collapse
|
20
|
Szycik GR, Jansma H, Münte TF. Audiovisual integration during speech comprehension: an fMRI study comparing ROI-based and whole brain analyses. Hum Brain Mapp 2009; 30:1990-9. [PMID: 18711707 DOI: 10.1002/hbm.20640] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Visual information (lip movements) significantly contributes to speech comprehension raising the question for the neural implementation of audiovisual (AV) integration during speech processing. To replicate and extend earlier neuroimaging findings, we compared two different analysis approaches in a slow event-related fMRI study of healthy native speakers of German who were exposed to AV speech stimuli (disyllabic nouns) with audio and visual signals being either congruent or incongruent. First, data was subjected to whole brain general linear model analysis after transformation of all individual data sets into standard space. Second, a region of interest (ROI) approach based on individual anatomy was used with ROI defined in areas identified previously as being important for AV processing. Standard space analysis revealed a widespread cortical network including the posterior part of the left superior temporal sulcus, Broca's region and its right hemispheric counterpart showing increased activity for incongruent stimuli. The ROI approach allowed to identify differences in activity between Brodmann areas 44 and 45, within Broca's area for incongruent stimulation, and also allowed to study activity of subdivisions of superior temporal regions. The complementary strengths and weaknesses of the two analysis approaches are discussed.
Collapse
Affiliation(s)
- Gregor R Szycik
- Department of Neuropsychology, University of Magdeburg, Magdeburg, Germany
| | | | | |
Collapse
|
21
|
Prakash N, Uhlemann F, Sheth SA, Bookheimer S, Martin N, Toga AW. Current trends in intraoperative optical imaging for functional brain mapping and delineation of lesions of language cortex. Neuroimage 2009; 47 Suppl 2:T116-26. [PMID: 18786643 PMCID: PMC2782948 DOI: 10.1016/j.neuroimage.2008.07.066] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Revised: 07/19/2008] [Accepted: 07/30/2008] [Indexed: 10/21/2022] Open
Abstract
Resection of a cerebral arteriovenous malformation (AVM), epileptic focus, or glioma, ideally has a prerequisite of microscopic delineation of the lesion borders in relation to the normal gray and white matter that mediate critical functions. Currently, Wada testing and functional magnetic resonance imaging (fMRI) are used for preoperative mapping of critical function, whereas electrical stimulation mapping (ESM) is used for intraoperative mapping. For lesion delineation, MRI and positron emission tomography (PET) are used preoperatively, whereas microscopy and histological sectioning are used intraoperatively. However, for lesions near eloquent cortex, these imaging techniques may lack sufficient resolution to define the relationship between the lesion and language function, and thus not accurately determine which patients will benefit from neurosurgical resection of the lesion without iatrogenic aphasia. Optical techniques such as intraoperative optical imaging of intrinsic signals (iOIS) show great promise for the precise functional mapping of cortices, as well as delineation of the borders of AVMs, epileptic foci, and gliomas. Here we first review the physiology of neuroimaging, and then progress towards the validation and justification of using intraoperative optical techniques, especially in relation to neurosurgical planning of resection AVMs, epileptic foci, and gliomas near or in eloquent cortex. We conclude with a short description of potential novel intraoperative optical techniques.
Collapse
Affiliation(s)
- Neal Prakash
- University of California, Los Angeles, Laboratory of Neuro Imaging, Los Angeles, CA 90095, USA.
| | | | | | | | | | | |
Collapse
|
22
|
Xiang HD, Fonteijn HM, Norris DG, Hagoort P. Topographical functional connectivity pattern in the perisylvian language networks. Cereb Cortex 2009; 20:549-60. [PMID: 19546155 DOI: 10.1093/cercor/bhp119] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We performed a resting-state functional connectivity study to investigate directly the functional correlations within the perisylvian language networks by seeding from 3 subregions of Broca's complex (pars opercularis, pars triangularis, and pars orbitalis) and their right hemisphere homologues. A clear topographical functional connectivity pattern in the left middle frontal, parietal, and temporal areas was revealed for the 3 left seeds. This is the first demonstration that a functional connectivity topology can be observed in the perisylvian language networks. The results support the assumption of the functional division for phonology, syntax, and semantics of Broca's complex as proposed by the memory, unification, and control (MUC) model and indicated a topographical functional organization in the perisylvian language networks, which suggests a possible division of labor for phonological, syntactic, and semantic function in the left frontal, parietal, and temporal areas.
Collapse
Affiliation(s)
- Hua-Dong Xiang
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
| | | | | | | |
Collapse
|
23
|
Lee BH, Bai SJ. Functional Mapping of Nervous System Using Optical Imaging Techniques. JOURNAL OF THE KOREAN MEDICAL ASSOCIATION 2009. [DOI: 10.5124/jkma.2009.52.1.69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Bae Hwan Lee
- Department of Physiology, Yonsei University College of Medicine, Korea
| | - Sun Joon Bai
- Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, Korea.
| |
Collapse
|
24
|
Glasser MF, Rilling JK. DTI tractography of the human brain's language pathways. ACTA ACUST UNITED AC 2008; 18:2471-82. [PMID: 18281301 DOI: 10.1093/cercor/bhn011] [Citation(s) in RCA: 428] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Diffusion Tensor Imaging (DTI) tractography has been used to detect leftward asymmetries in the arcuate fasciculus, a pathway that links temporal and inferior frontal language cortices. In this study, we more specifically define this asymmetry with respect to both anatomy and function. Twenty right-handed male subjects were scanned with DTI, and the arcuate fasciculus was reconstructed using deterministic tractography. The arcuate was divided into 2 segments with different hypothesized functions, one terminating in the posterior superior temporal gyrus (STG) and another terminating in the middle temporal gyrus (MTG). Tractography results were compared with peak activation coordinates from prior functional neuroimaging studies of phonology, lexical-semantic processing, and prosodic processing to assign putative functions to these pathways. STG terminations were strongly left lateralized and overlapped with phonological activations in the left but not the right hemisphere, suggesting that only the left hemisphere phonological cortex is directly connected with the frontal lobe via the arcuate fasciculus. MTG terminations were also strongly left lateralized, overlapping with left lateralized lexical-semantic activations. Smaller right hemisphere MTG terminations overlapped with right lateralized prosodic activations. We combine our findings with a recent model of brain language processing to explain 6 aphasia syndromes.
Collapse
Affiliation(s)
- Matthew F Glasser
- Department of Anthropology, Emory University, 1557 Dickey Drive, Atlanta, GA 30322, USA
| | | |
Collapse
|
25
|
Asthagiri AR, Pouratian N, Sherman J, Ahmed G, Shaffrey ME. Advances in brain tumor surgery. Neurol Clin 2008; 25:975-1003, viii-ix. [PMID: 17964023 DOI: 10.1016/j.ncl.2007.07.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Advances in the fields of molecular and translational research, oncology, and surgery have emboldened the medical community to believe that intrinsic brain tumors may be treatable. Intraoperative imaging and brain mapping allow operations adjacent to eloquent cortex and more radical resection of tumors with increased confidence and safety. Despite these advances, the infiltrating edge of a neoplasm and distant microscopic satellite lesions will never be amendable to a surgical cure. Indeed, it is continued research into the delivery of an efficacious chemobiologic agent that will eventually allows us to manage this primary cause of treatment failure.
Collapse
|
26
|
Hamberger MJ. Cortical language mapping in epilepsy: a critical review. Neuropsychol Rev 2007; 17:477-89. [PMID: 18004662 DOI: 10.1007/s11065-007-9046-6] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Accepted: 10/03/2007] [Indexed: 11/29/2022]
Abstract
One challenge in dominant hemisphere epilepsy surgery is to remove sufficient epileptogenic tissue to achieve seizure freedom without compromising postoperative language function. Electrical stimulation mapping (ESM) of language was developed specifically to identify essential language cortex in pharmacologically intractable epilepsy patients undergoing left hemisphere resection of epileptogenic cortex. Surprisingly, the procedure remains unstandardized, and limited data support its clinical validity. Nevertheless, ESM for language mapping has likely minimized postoperative language decline in numerous patients, and has generated a wealth of data elucidating brain-language relations. This article reviews the literature on topographical patterns of language organization inferred from ESM, and the influence of patient characteristics on these patterns, including baseline ability level, age, gender, pathology, degree of language lateralization and bilingualism. Questions regarding clinical validity and limitations of ESM are discussed. Finally, recommendations for clinical practice are presented, and theoretical questions regarding ESM and the findings it has generated are considered.
Collapse
Affiliation(s)
- Marla J Hamberger
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
| |
Collapse
|
27
|
Abstract
AbstractA parieto-frontal integration theory (P-FIT) model of human intelligence has been proposed based on a review of neuroimaging literature and lesion studies. The P-FIT model provides an important basis for future research. Future studies involving connectivity analyses and an integrative approach of imaging modalities using the P-FIT model should provide vastly increased understanding of the biological bases of intelligence.
Collapse
|
28
|
Zeff BW, White BR, Dehghani H, Schlaggar BL, Culver JP. Retinotopic mapping of adult human visual cortex with high-density diffuse optical tomography. Proc Natl Acad Sci U S A 2007; 104:12169-74. [PMID: 17616584 PMCID: PMC1924577 DOI: 10.1073/pnas.0611266104] [Citation(s) in RCA: 229] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Indexed: 11/18/2022] Open
Abstract
Functional neuroimaging is a vital element of neuroscience and cognitive research and, increasingly, is an important clinical tool. Diffuse optical imaging is an emerging, noninvasive technique with unique portability and hemodynamic contrast capabilities for mapping brain function in young subjects and subjects in enriched or clinical environments. We have developed a high-performance, high-density diffuse optical tomography (DOT) system that overcomes previous limitations and enables superior image quality. We show herein the utility of the DOT system by presenting functional hemodynamic maps of the adult human visual cortex. The functional brain images have a high contrast-to-noise ratio, allowing visualization of individual activations and highly repeatable mapping within and across subjects. With the improved spatial resolution and localization, we were able to image functional responses of 1.7 cm in extent and shifts of <1 cm. Cortical maps of angle and eccentricity in the visual field are consistent with retinotopic studies using functional MRI and positron-emission tomography. These results demonstrate that high-density DOT is a practical and powerful tool for mapping function in the human cortex.
Collapse
Affiliation(s)
- Benjamin W. Zeff
- *Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Brian R. White
- Department of Physics and School of Medicine, Washington University, St. Louis, MO 63130; and
| | - Hamid Dehghani
- Department of Physics, University of Exeter, Exeter EX4 4QJ, United Kingdom
| | - Bradley L. Schlaggar
- *Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Joseph P. Culver
- *Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110
| |
Collapse
|
29
|
Prakash N, Biag JD, Sheth SA, Mitsuyama S, Theriot J, Ramachandra C, Toga AW. Temporal profiles and 2-dimensional oxy-, deoxy-, and total-hemoglobin somatosensory maps in rat versus mouse cortex. Neuroimage 2007; 37 Suppl 1:S27-36. [PMID: 17574868 PMCID: PMC2227950 DOI: 10.1016/j.neuroimage.2007.04.063] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Revised: 04/20/2007] [Accepted: 04/25/2007] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Mechanisms of neurovascular coupling-the relationship between neuronal chemoelectrical activity and compensatory metabolic and hemodynamic changes-appear to be preserved across species from rats to humans despite differences in scale. However, previous work suggests that the highly cellular dense mouse somatosensory cortex has different functional hemodynamic changes compared to other species. METHODS We developed novel hardware and software for 2-dimensional optical spectroscopy (2DOS). Optical changes at four simultaneously recorded wavelengths were measured in both rat and mouse primary somatosensory cortex (S1) evoked by forepaw stimulation to create four spectral maps. The spectral maps were converted to maps of deoxy-, oxy-, and total-hemoglobin (HbR, HbO, and HbT) concentration changes using the modified Beer-Lambert law and phantom HbR and HbO absorption spectra. RESULTS : Functional hemodynamics were different in mouse versus rat neocortex. On average, hemodynamics were as expected in rat primary somatosensory cortex (S1): the fractional change in the log of HbT concentration increased monophasically 2 s after stimulus, whereas HbO changes mirrored HbR changes, with HbO showing a small initial dip at 0.5 s followed by a large increase 3.0 s post stimulus. In contrast, mouse S1 showed a novel type of stimulus-evoked hemodynamic response, with prolonged, concurrent, monophasic increases in HbR and HbT and a parallel decrease in HbO that all peaked 3.5-4.5 s post stimulus onset. For rats, at any given time point, the average size and shape of HbO and HbR forepaw maps were the same, whereas surface veins distorted the shape of the HbT map. For mice, HbO, HbR, and HbT forepaw maps were generally the same size and shape at any post-stimulus time point. CONCLUSIONS 2DOS using image splitting optics is feasible across species for brain mapping and quantifying the map topography of cortical hemodynamics. These results suggest that during physiologic stimulation, different species and/or cortical architecture may give rise to different hemodynamic changes during neurovascular coupling.
Collapse
Affiliation(s)
- Neal Prakash
- University of California, Los Angeles, David Geffen School of Medicine, Department of Neurology, Laboratory of Neuro Imaging, Los Angeles, CA 90095, USA.
| | | | | | | | | | | | | |
Collapse
|
30
|
Hammers A, Chen CH, Lemieux L, Allom R, Vossos S, Free SL, Myers R, Brooks DJ, Duncan JS, Koepp MJ. Statistical neuroanatomy of the human inferior frontal gyrus and probabilistic atlas in a standard stereotaxic space. Hum Brain Mapp 2007; 28:34-48. [PMID: 16671082 PMCID: PMC6871382 DOI: 10.1002/hbm.20254] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2005] [Accepted: 12/27/2005] [Indexed: 11/10/2022] Open
Abstract
We manually defined the inferior frontal gyrus (IFG) on high-resolution MRIs in native space in 30 healthy subjects (15 female, median age 31 years; 15 male, median age 30 years), resulting in 30 individual atlases. Using standard software (SPM99), these were spatially transformed to a widely used stereotaxic space (MNI/ICBM 152) to create probabilistic maps. In native space, the total IFG volume was on average 5%, and the gray matter (GM) portion 12% larger in women (not significant). Expressed as a percentage of ipsilateral frontal lobe volume (i.e., correcting for brain size), the IFG was an average of 20%, and the GM portion of the IFG 27%, larger in women (P < 0.005). Correcting for total lobar volume yielded the same result. No asymmetry was found in IFG volumes. There were significant positional differences between the right and left IFGs, with the right IFG being further lateral in both native and stereotaxic space. Variability was similar on the left and right, but more pronounced anteriorly and superiorly. We show differences in IFG volume, composition, and position between sexes and between hemispheres. Applications include probabilistic determination of location in group studies, automatic labeling of new scans, and detection of anatomical abnormalities in patients.
Collapse
Affiliation(s)
- Alexander Hammers
- MRC Clinical Sciences Centre and Division of Neuroscience, Faculty of Medicine, Imperial College, Hammersmith Hospital, London, UK.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Karunanayaka PR, Holland SK, Schmithorst VJ, Solodkin A, Chen EE, Szaflarski JP, Plante E. Age-related connectivity changes in fMRI data from children listening to stories. Neuroimage 2006; 34:349-60. [PMID: 17064940 DOI: 10.1016/j.neuroimage.2006.08.028] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Revised: 08/02/2006] [Accepted: 08/08/2006] [Indexed: 11/20/2022] Open
Abstract
The way humans comprehend narrative speech plays an important part in human development and experience. A group of 313 children with ages 5-18 were subjected to a large-scale functional magnetic resonance imaging (fMRI) study in order to investigate the neural correlates of auditory narrative comprehension. The results were analyzed to investigate the age-related brain activity changes involved in the narrative language comprehension circuitry. We found age-related differences in brain activity which may either reflect changes in local neuroplasticity (of the regions involved) in the developing brain or a more global transformation of brain activity related to neuroplasticity. To investigate this issue, Structural Equation Modeling (SEM) was applied to the results obtained from a group independent component analysis (Schmithorst, V.J., Holland, S.K., et al., 2005. Cognitive modules utilized for narrative comprehension in children: a functional magnetic resonance imaging study. NeuroImage) and the age-related differences were examined in terms of changes in path coefficients between brain regions. The group Independent Component Analysis (ICA) had identified five bilateral task-related components comprising the primary auditory cortex, the mid-superior temporal gyrus, the most posterior aspect of the superior temporal gyrus, the hippocampus, the angular gyrus and the medial aspect of the parietal lobule (precuneus/posterior cingulate). Furthermore, a left-lateralized network (sixth component) was also identified comprising the inferior frontal gyrus (including Broca's area), the inferior parietal lobule, and the medial temporal gyrus. The components (brain regions) for the SEM were identified based on the ICA maps and the results are discussed in light of recent neuroimaging studies corroborating the functional segregation of Broca's and Wernicke's areas and the important role played by the right hemisphere in narrative comprehension. The classical Wernicke-Geschwind (WG) model for speech processing is expanded to a two-route model involving a direct route between Broca's and Wernicke's area and an indirect route involving the parietal lobe.
Collapse
Affiliation(s)
- Prasanna R Karunanayaka
- Imaging Research Center, Children's Hospital Medical Center, 3333 Burnet Ave. ML 5031, Cincinnati, OH 45229, USA.
| | | | | | | | | | | | | |
Collapse
|
32
|
Vihla M, Laine M, Salmelin R. Cortical dynamics of visual/semantic vs. phonological analysis in picture confrontation. Neuroimage 2006; 33:732-8. [PMID: 16934492 DOI: 10.1016/j.neuroimage.2006.06.040] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Accepted: 06/23/2006] [Indexed: 10/24/2022] Open
Abstract
Picture naming covers the main stages of word production from concept retrieval to articulation. Cortical correlates of picture naming have been characterized with both haemodynamic and neurophysiological methods but the association of specific activation patterns with the hypothesized processing stages remains elusive. Here we used categorization tasks to selectively highlight different components of picture confrontation, from visual analysis (VIS) to semantic (SEM) and phonological access (PHON), and compared these time courses of activation with that obtained during picture naming (NAM). Brain activity was recorded with whole-head magnetoencephalography (MEG). Following the initially similar activation patterns in occipital and parietal areas, task effects (stronger activation in NAM/PHON than in SEM/VIS) emerged after 300 ms, in the sustained activation of the left posterior temporal and bilateral inferior frontal cortex, apparently reflecting enhancement of phonological and phonetic/articulatory processing.
Collapse
Affiliation(s)
- Minna Vihla
- Brain Research Unit, Low Temperature Laboratory, Helsinki University of Technology, PO Box 2200, 02015 TKK, Espoo, Finland
| | | | | |
Collapse
|
33
|
Nariai T, Sato K, Hirakawa K, Ohta Y, Tanaka Y, Ishiwata K, Ishii K, Kamino K, Ohno K. Imaging of somatotopic representation of sensory cortex with intrinsic optical signals as guides for brain tumor surgery. J Neurosurg 2005; 103:414-23. [PMID: 16235671 DOI: 10.3171/jns.2005.103.3.0414] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Intrinsic optical signals in response to somatosensory stimuli were intraoperatively recorded during brain tumor surgery. In the present study, the authors report on the use of this technique as an intraoperative guide for the safe resection of tumors adjacent to or within the sensorimotor cortex. METHODS In 14 patients with tumors adjacent to or within the sensorimotor cortex, intrinsic optical signals in response to somatosensory stimuli were recorded by illuminating the brain surface with Xe white light and imaging the reflected light passing through a bandpass filter (605 nm). Results were compared with intraoperative recordings of sensory evoked potentials in all 14 patients and with noninvasive mapping modalities such as magnetoencephalography and positron emission tomography in selected patients. In all but two patients, the somatosensory optical signals were recorded on the primary sensory cortex. Optical signals elicited by stimulation of the first and fifth digits and the three branches of the trigeminal nerve were recorded at different locations on the sensory strip. This somatotopic information was useful in determining the resection border in patients with glioma located in the sensorimotor cortex. CONCLUSIONS Optical imaging of intrinsic signals is a useful technique with superior spatial resolution for delineating the somatotopic representation of human primary sensory cortex. Furthermore, it can be used as an intraoperative monitoring tool to improve the safety and accuracy of resections of brain tumors adjacent to or within the sensorimotor cortex.
Collapse
Affiliation(s)
- Tadashi Nariai
- Department of Neurosurgery and Physiology, Tokyo Medical and Dental University, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Abstract
In a brain composed of localized but connected specialized areas, disconnection leads to dysfunction. This simple formulation underlay a range of 19th century neurological disorders, referred to collectively as disconnection syndromes. Although disconnectionism fell out of favour with the move against localized brain theories in the early 20th century, in 1965, an American neurologist brought disconnection to the fore once more in a paper entitled, 'Disconnexion syndromes in animals and man'. In what was to become the manifesto of behavioural neurology, Norman Geschwind outlined a pure disconnectionist framework which revolutionized both clinical neurology and the neurosciences in general. For him, disconnection syndromes were higher function deficits that resulted from white matter lesions or lesions of the association cortices, the latter acting as relay stations between primary motor, sensory and limbic areas. From a clinical perspective, the work reawakened interest in single case studies by providing a useful framework for correlating lesion locations with clinical deficits. In the neurosciences, it helped develop contemporary distributed network and connectionist theories of brain function. Geschwind's general disconnectionist paradigm ruled clinical neurology for 20 years but in the late 1980s, with the re-emergence of specialized functional roles for association cortex, the orbit of its remit began to diminish and it became incorporated into more general models of higher dysfunction. By the 1990s, textbooks of neurology were devoting only a few pages to classical disconnection theory. Today, new techniques to study connections in the living human brain allow us, for the first time, to test the classical formulation directly and broaden it beyond disconnections to include disorders of hyperconnectivity. In this review, on the 40th anniversary of Geschwind's publication, we describe the changing fortunes of disconnection theory and adapt the general framework that evolved from it to encompass the entire spectrum of higher function disorders in neurology and psychiatry.
Collapse
Affiliation(s)
- Marco Catani
- Centre for Neuroimaging Sciences, Institute of Psychiatry, De Crespigny Park, London, UK.
| | | |
Collapse
|
35
|
Schmithorst VJ, Holland SK, Plante E. Cognitive modules utilized for narrative comprehension in children: a functional magnetic resonance imaging study. Neuroimage 2005; 29:254-66. [PMID: 16109491 PMCID: PMC1357541 DOI: 10.1016/j.neuroimage.2005.07.020] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2005] [Revised: 06/30/2005] [Accepted: 07/08/2005] [Indexed: 10/25/2022] Open
Abstract
The ability to comprehend narratives constitutes an important component of human development and experience. The neural correlates of auditory narrative comprehension in children were investigated in a large-scale functional magnetic resonance imaging (fMRI) study involving 313 subjects ages 5-18. Using group independent component analysis (ICA), bilateral task-related components were found comprising the primary auditory cortex, the mid-superior temporal gyrus, the hippocampus, the angular gyrus, and medial aspect of the parietal lobule (precuneus/posterior cingulate). In addition, a right-lateralized component was found involving the most posterior aspect of the superior temporal gyrus, and a left-lateralized component was found comprising the inferior frontal gyrus (including Broca's area), the inferior parietal lobule, and the medial temporal gyrus. Using a novel data-driven analysis technique, increased task-related activity related to age was found in the components comprising the mid-superior temporal gyrus (Wernicke's area) and the posterior aspect of the superior temporal gyrus, while decreased activity related to age was found in the component comprising the angular gyrus. The results are discussed in light of recent hypotheses involving the functional segregation of Wernicke's area and the specific role of the mid-superior temporal gyrus in speech comprehension.
Collapse
Affiliation(s)
- Vincent J Schmithorst
- Imaging Research Center, Children's Hospital Medical Center, 3333 Burnet Ave. ML 5031, Cincinnati, OH 45229, USA.
| | | | | |
Collapse
|
36
|
Sato K, Nariai T, Tanaka Y, Maehara T, Miyakawa N, Sasaki S, Momose-Sato Y, Ohno K. Functional representation of the finger and face in the human somatosensory cortex: intraoperative intrinsic optical imaging. Neuroimage 2005; 25:1292-301. [PMID: 15850747 DOI: 10.1016/j.neuroimage.2004.12.049] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2004] [Revised: 12/13/2004] [Accepted: 12/17/2004] [Indexed: 11/26/2022] Open
Abstract
We applied the intrinsic optical imaging technique to the human primary somatosensory cortex during brain tumor/epilepsy surgery for nine patients. The cortical surface was illuminated with a Xenon light through an operating microscope, and the reflected light, which passed through a 605 nm bandpass filter, was detected by a CCD camera-based optical imaging system. Individual electrical stimulation of five digits induced changes in the reflected light intensities. Visualizing the intrinsic optical responses, we constructed maps of finger representation in Brodmann's area 1. In the maps, response areas of Digits I to V were sequentially aligned along the central sulcus in the crown of the postcentral gyrus from the latero-inferior region (Digit I) to the medio-superior region (Digit V). The neighboring response areas partially overlapped each other, as previously described in the monkey somatosensory cortex. Similar results were obtained in the face region with stimulation of the three branches of the trigeminal nerve. These results suggest that the overlap of the response areas is a common feature in the somatosensory cortex not only in monkeys, but also in humans.
Collapse
Affiliation(s)
- Katsushige Sato
- Department of Physiology, Tokyo Medical and Dental University Graduate School and Faculty of Medicine, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
37
|
Abstract
Early anatomically based models of language consisted of an arcuate tract connecting Broca's speech and Wernicke's comprehension centers; a lesion of the tract resulted in conduction aphasia. However, the heterogeneous clinical presentations of conduction aphasia suggest a greater complexity of perisylvian anatomical connections than allowed for in the classical anatomical model. This article re-explores perisylvian language connectivity using in vivo diffusion tensor magnetic resonance imaging tractography. Diffusion tensor magnetic resonance imaging data from 11 right-handed healthy male subjects were averaged, and the arcuate fasciculus of the left hemisphere reconstructed from this data using an interactive dissection technique. Beyond the classical arcuate pathway connecting Broca's and Wernicke's areas directly, we show a previously undescribed, indirect pathway passing through inferior parietal cortex. The indirect pathway runs parallel and lateral to the classical arcuate fasciculus and is composed of an anterior segment connecting Broca's territory with the inferior parietal lobe and a posterior segment connecting the inferior parietal lobe to Wernicke's territory. This model of two parallel pathways helps explain the diverse clinical presentations of conduction aphasia. The anatomical findings are also relevant to the evolution of language, provide a framework for Lichtheim's symptom-based neurological model of aphasia, and constrain, anatomically, contemporary connectionist accounts of language.
Collapse
Affiliation(s)
- Marco Catani
- Centre for Neuroimaging Sciences, Institute of Psychiatry, King's College London, DeCrespigny Park, London SE5 8AZ, United Kingdom.
| | | | | |
Collapse
|
38
|
Schwartz TH. The Application of Optical Recording of Intrinsic Signals to Simultaneously Acquire Functional, Pathological and Localizing Information and Its Potential Role in Neurosurgery. Stereotact Funct Neurosurg 2005; 83:36-44. [PMID: 15821368 DOI: 10.1159/000085025] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
INTRODUCTION The accurate intraoperative localization of epileptic foci and surrounding functional architecture is critical to a successful surgical outcome. Current techniques are limited either by their inability to simultaneously sample large areas of cortex with high spatial resolution or account for dynamic alterations in cortical morphology. Optical recording of intrinsic signals can map neuronal activity in a large area of cortex with a spatial resolution in the order of <100 mum. We explored methods of simultaneously representing localizing information, functional architecture and the border of an epileptic focus in vivo with intrinsic signal imaging. METHODS The functional architecture of V1 was mapped using optical imaging of intrinsic signals in the ferret at 707 nm (n = 9). Interictal and ictal foci were then generated with focal iontophoresis of bicuculline methiodide and 4-aminopyridine into V1 and mapped optically. Blood vessel architecture was mapped using light acquired at 540 nm. RESULTS Epilepsy maps could be superimposed on maps of the underlying functional architecture and surface blood vessel pattern to produce composite pathological-functional maps. Sufficient data for localization as well as identification of both pathological and functional architecture could be conveyed in a single image. CONCLUSIONS Cortical maps generated with intrinsic signal imaging can combine topographic and localizing information about normal functional architecture and interictal and ictal onset zones with extremely high spatial resolution. These maps may be useful in guiding surgical resections and multiple subpial transections to minimize unnecessary damage to functional brain surrounding neocortical pathology.
Collapse
|
39
|
Yokoyama K, Watanabe M, Watanbe Y, Okada E. Interpretation of principal components of the reflectance spectra obtained from multispectral images of exposed pig brain. JOURNAL OF BIOMEDICAL OPTICS 2005; 10:11005. [PMID: 15847571 DOI: 10.1117/1.1854671] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The spatial variation in reflectance such as the blood-vessel pattern can be observed in the image of cerebral cortex. This spatial variation is mainly caused by the difference in concentrations of oxy- and deoxyhemoglobin in the tissue. We analyze the reflectance spectra obtained from multispectral images of pig cortex by principal component analysis to extract information that relates to physiological parameters such as the concentrations of oxy- and deoxyhemoglobin and physical parameters such as mean optical path length. The light propagation in a model of exposed pig cortex is predicted by Monte Carlo simulation to estimate the interpretation of physiological and physical meanings of the principal components. The spatial variance of reflectance spectra of the pig cortex can be approximately described by the first principal component. The first principal component reflects the spectrum of hemoglobin in the cortical tissue multiplied by the mean optical path length. These results imply that the wavelength dependence of mean optical path length can be experimentally estimated from the first principal component of the reflectance spectra obtained from multispectral image of cortical tissue.
Collapse
Affiliation(s)
- Kentaro Yokoyama
- Keio University, Department of Electronics and Electrical Engineering, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan
| | | | | | | |
Collapse
|
40
|
Cannestra AF, Pouratian N, Forage J, Bookheimer SY, Martin NA, Toga AW. Functional Magnetic Resonance Imaging and Optical Imaging for Dominant-hemisphere Perisylvian Arteriovenous Malformations. Neurosurgery 2004; 55:804-12; discussion 812-4. [PMID: 15458588 DOI: 10.1227/01.neu.0000137654.27826.71] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2003] [Accepted: 05/28/2004] [Indexed: 11/19/2022] Open
Abstract
Abstract
OBJECTIVE:
In this study, we developed an a priori system to stratify surgical intervention of perisylvian arteriovenous malformations (AVMs) in 20 patients. We stratified the patients into three categories based on preoperative functional magnetic resonance imaging (fMRI) language activation pattern and relative location of the AVM.
METHODS:
In Group I (minimal risk), the AVM was at least one gyrus removed from language activation, and patients subsequently underwent asleep resection. In Group II (high risk), the AVM and language activation were intimately associated. Because the risk of postoperative language deficit was high, these patients were then referred to radiosurgery. In Group III (indeterminate risk), the AVM and language were adjacent to each other. The risk of language deficit could not be predicted on the basis of the fMRI alone. These patients underwent awake craniotomy with electrocortical stimulation mapping and optical imaging of intrinsic signals for language mapping.
RESULTS:
All patients from Group I (minimal risk) underwent asleep resection without deficit. All Group II (high-risk) patients tolerated radiosurgery without complication. In Group III (indeterminate risk), three patients underwent successful resection, whereas two underwent aborted resection after intracranial mapping.
CONCLUSION:
We advocate the use of fMRI to assist in the preoperative determination of operability by asleep versus awake craniotomy versus radiosurgery referral. In addition, we advocate the use of all three functional mapping (fMRI, electrocortical stimulation mapping, and optical imaging of intrinsic signals) techniques to clarify the eloquence score of the Spetzler-Martin system before definitive treatment (anesthetized resection versus radiosurgery versus intraoperative resection versus intraoperative closure and radiosurgery referral).
Collapse
Affiliation(s)
- Andrew F Cannestra
- Laboratory of Neuro Imaging, Department of Neurology, and Division of Neurosurgery, University of California at Los Angeles School of Medicine, 90095-1769, USA
| | | | | | | | | | | |
Collapse
|
41
|
Schwartz TH, Chen LM, Friedman RM, Spencer DD, Roe AW. Intraoperative optical imaging of human face cortical topography: a case study. Neuroreport 2004; 15:1527-31. [PMID: 15194889 DOI: 10.1097/01.wnr.0000131006.59315.2f] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We used intrinsic signal optical imaging to obtain maps of human somatosensory cortex during electrocutaneous stimulation of the face during a neurosurgical procedure for epilepsy. We found that human face somatotopy is organized like the macaque or cebus monkey, with peri-orbital skin located medial to peri-buccal skin, and that cortical magnification in the human is comparable to that in non-human primates. This study demonstrates that intrinsic signal imaging can be performed on humans during operative procedures with sufficient spatial resolution to reveal high-resolution topographic maps.
Collapse
Affiliation(s)
- Theodore H Schwartz
- Department of Neurosurgery,Yale University School of Medicine, New Haven, CT, USA.
| | | | | | | | | |
Collapse
|
42
|
Zepeda A, Arias C, Sengpiel F. Optical imaging of intrinsic signals: recent developments in the methodology and its applications. J Neurosci Methods 2004; 136:1-21. [PMID: 15126041 DOI: 10.1016/j.jneumeth.2004.02.025] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2004] [Indexed: 11/20/2022]
Abstract
Since optical imaging (OI) of intrinsic signals was first developed in the 1980s, significant advances have been made regarding our understanding of the origins of the recorded signals. The technique has been refined and the range of its applications has been broadened considerably. Here we review recent developments in methodology and data analysis as well as the latest findings on how intrinsic signals are related to metabolic cost and electrophysiological activity in the brain. We give an overview of what optical imaging has contributed to our knowledge of the functional architecture of sensory cortices, their development and plasticity. Finally, we discuss the utility of OI for functional studies of the human brain as well as in animal models of neuropathology.
Collapse
Affiliation(s)
- Angelica Zepeda
- Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México, DF, Mexico
| | | | | |
Collapse
|
43
|
Uludağ K, Steinbrink J, Kohl-Bareis M, Wenzel R, Villringer A, Obrig H. Cytochrome-c-oxidase redox changes during visual stimulation measured by near-infrared spectroscopy cannot be explained by a mere cross talk artefact. Neuroimage 2004; 22:109-19. [PMID: 15110001 DOI: 10.1016/j.neuroimage.2003.09.053] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2003] [Revised: 09/22/2003] [Accepted: 09/26/2003] [Indexed: 10/26/2022] Open
Abstract
The detection of redox changes in cytochrome-c-oxidase ([Cyt-ox]) in response to cerebral activation by non-invasive NIRS is hampered by methodological spectroscopic issues related to the modification of the Beer-Lambert law. Also, the question whether a change in the enzyme's redox-state is elicited by functional stimulation is unresolved. In a previous study, we found physiological evidence in favour of an activation-induced increase in oxidation of the enzyme [J. Cereb. Blood Flow Metab. 19 (1999) 592], while in a second study on spectroscopic cross talk, we found that the [Cyt-ox] changes to potentially be an artefact of the spectroscopic approach [J. Biomed. Opt. 7 (2002) 51]. Here, we use two different stimuli which differentially activate areas either rich or poor in [Cyt-ox] content (blob/interblob in visual cortex V1 and pale/thin stripes in V2) to further clarify this apparent discrepancy. In a first experiment, two stimuli were presented in an alternating fashion for 20 s and all stimulation periods were separated by resting periods of 40 s. We observed similar changes in [Cyt-ox] for both stimuli. To become more sensitive to the potentially very small optical changes related to changes in [Cyt-ox], we tried to minimise global haemodynamic and metabolic effects in a second experiment by omitting the resting periods. Our hypothesis was that [Cyt-ox] changes could be fully explained by cross talk as it is predicted from our last study [J. Biomed. Opt. 7 (2002) 51]. However, in more than half of the experiments, we were not able to model the changes in Cyt-ox calculated from measured attenuation spectra as a cross talk artefact. We interpret this finding as an argument in favour of the existence of [Cyt-ox] changes in response to functional stimulation. This finding, however, does not lessen the liability of the [Cyt-ox] changes to cross talk and calls for great caution when [Cyt-ox] changes are derived from NIRS measurements based on the modified Beer-Lambert approach. Further (invasive) validation studies are required.
Collapse
Affiliation(s)
- Kâmil Uludağ
- Department of Neurology, Charité, Humboldt University, Berlin 10117, Germany.
| | | | | | | | | | | |
Collapse
|
44
|
|
45
|
Cannestra AF, Wartenburger I, Obrig H, Villringer A, Toga AW. Functional assessment of Broca’s area using near infrared spectroscopy in humans. Neuroreport 2003; 14:1961-5. [PMID: 14561929 DOI: 10.1097/00001756-200310270-00016] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We used near-infrared spectroscopy (NIRS) to compare functional hemoglobin concentration changes (delta[oxy-Hb] and delta[deoxy-Hb]) over human language and motor cortices. Eight subjects performed finger opposition, tongue movement, and covert visual object naming in an interleaved block paradigm design. NIRS revealed paradigm specific patterns of delta[oxy-Hb] and delta[deoxy-Hb] providing cortical localization of each function. During each task, significant response overlap was observed when comparing the [oxy-Hb] signals, whereas delta[deoxy-Hb] seemed more localized. Furthermore, by applying magnitude and time to significance measures to the delta[deoxy-Hb] response profile, Broca's area was easily distinguished from neighboring tongue (and hand) motor representation. Delta[oxy-Hb] did not provide this level of specificity. These findings suggest delta[deoxy-Hb] as the preferential NIRS parameter to map language cortices.
Collapse
Affiliation(s)
- Andrew F Cannestra
- Department of Neurology, UCLA School of Medicine, 710 Westwood Plaza, Los Angeles, CA 90095-1769, USA
| | | | | | | | | |
Collapse
|
46
|
Pouratian N, Sheth SA, Martin NA, Toga AW. Shedding light on brain mapping: advances in human optical imaging. Trends Neurosci 2003; 26:277-82. [PMID: 12744845 DOI: 10.1016/s0166-2236(03)00070-5] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Several functional brain imaging techniques have been used to study human cortical organization. Optical imaging of intrinsic signals (OIS) offers perhaps the best combination of spatial coverage, resolution and speed for mapping the functional topography of human cortex. In this review, we discuss recent advances in optical imaging technology and methodology that have made human OIS easier to implement and more accessible, including improvements in detector characteristics and the development of sophisticated algorithms for reducing motion artifact. Moreover, we discuss how these advances have helped enhance our understanding of the functional organization of the human brain. We also review newly developed analyses for interpreting and validating optical signals, including refined signal analysis techniques and multimodality comparisons. Combined, these advances have enabled the study of not only primary sensory and motor cortices, but also higher cognitive processes such as language production and comprehension. Continued improvement and implementation of this technique promises to shed new light on the functional organization of human cortex.
Collapse
Affiliation(s)
- Nader Pouratian
- Laboratory of Neuro Imaging, Department of Neurology, David Geffen School of Medicine at UCLA, 710 Westwood Plaza Room 4238, Los Angeles, CA 90095-1769, USA
| | | | | | | |
Collapse
|
47
|
Abstract
Optical approaches to investigate cerebral function and metabolism have long been applied in invasive studies. From the neuron cultured to the exposed cortex in the human during neurosurgical procedures, high spatial resolution can be reached and several processes such as membrane potential, cell swelling, metabolism of mitochondrial chromophores, and vascular response can be monitored, depending on the respective preparation. The authors focus on an extension of optical methods to the noninvasive application in the human. Starting with the pioneering work of Jöbsis 25 years ago, near-infrared spectroscopy (NIRS) has been used to investigate functional activation of the human cerebral cortex. Recently, several groups have started to use imaging systems that allow the generation of images of a larger area of the subject's head and, thereby, the production of maps of cortical oxygenation changes. Such images have a much lower spatial resolution compared with the invasively obtained optical images. The noninvasive NIRS images, however, can be obtained in undemanding set-ups that can be easily combined with other functional methods, in particular EEG. Moreover, NIRS is applicable to bedside use. The authors briefly review some of the abundant literature on intrinsic optical signals and the NIRS imaging studies of the past few years. The weaknesses and strengths of the approach are critically discussed. The authors conclude that NIRS imaging has two major advantages: it can address issues concerning neurovascular coupling in the human adult and can extend functional imaging approaches to the investigation of the diseased brain.
Collapse
Affiliation(s)
- Hellmuth Obrig
- Department of Neurology, Charité, Humboldt University, Berlin, Germany.
| | | |
Collapse
|
48
|
Sasaki S, Yazawa I, Miyakawa N, Mochida H, Shinomiya K, Kamino K, Momose-Sato Y, Sato K. Optical imaging of intrinsic signals induced by peripheral nerve stimulation in the in vivo rat spinal cord. Neuroimage 2002; 17:1240-55. [PMID: 12414264 DOI: 10.1006/nimg.2002.1286] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We examined neural response patterns evoked by peripheral nerve stimulation in in vivo rat spinal cords using an intrinsic optical imaging technique to monitor neural activity. Adult rats were anesthetized by urethane, and laminectomy was performed between C5 and Th1 to expose the dorsal surface of the cervical spinal cord. The median, ulnar, and radial nerves were dissected, and bipolar electrodes were implanted in the forelimb. Changes in optical reflectance were recorded from the dorsal cervical spinal cord in response to simultaneous stimulation of the median and ulnar nerves using a differential video acquisition system. In the region of the cervical spinal cord, intrinsic optical signals were detected between C5 and Th1 at wavelengths of 605, 630, 730, 750, and 850 nm: the image with the largest signal intensity and highest contrast was obtained at 605 nm. The signal intensity and response area expanded with an increase in the stimulation intensity and varied with the depth of the focal plane of the macroscope. The intrinsic optical response was mostly eliminated by Cd(2+), suggesting that the detected signals were mainly mediated by postsynaptic mechanisms activated by sensory nerve fibers. Furthermore, we succeeded in imaging neural activity evoked by individual peripheral nerve stimulation. We found that the response areas related to each peripheral nerve exhibited different spatial distribution patterns and that there were animal-to-animal variations in the evoked neural responses in the spinal cord. The results obtained in this study confirmed that intrinsic optical imaging is a very useful technique for acquiring fine functional maps of the in vivo spinal cord.
Collapse
Affiliation(s)
- Shinichi Sasaki
- Department of Physiology, Tokyo Medical and Dental University Graduate School and Faculty of Medicine, Bunkyo-ku, Tokyo 113-8519, Japan
| | | | | | | | | | | | | | | |
Collapse
|
49
|
Pouratian N, Cannestra AF, Martin NA, Toga AW. Intraoperative optical intrinsic signal imaging: a clinical tool for functional brain mapping. Neurosurg Focus 2002; 13:e1. [PMID: 15771400 DOI: 10.3171/foc.2002.13.4.2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Optical imaging of intrinsic signals (OIS) is a well-established neuroimaging modality by which functional cortical activity is mapped by detecting activity-related changes in cortical light reflectance. Light reflectance changes are detected by a charged-coupled device camera that captures images of the exposed cortex both at rest and during activity. Although to date OIS has only been used for research purposes, intraoperative OIS (iOIS) holds promise as a clinical mapping tool. In general, iOIS demonstrates good spatial correlation with electrocortical stimulation mapping (ECSM) and other electrophysiological modalities. Additionally, iOIS offers high spatial resolution (in microns), does not make contact with the surface of the brain, and introduces no potentially harmful compounds. Moreover, mapping is relatively rapid. The authors review the potential contribution of iOIS to the intraoperative environment. Specifically, they review iOIS methodology, discuss signal origin, compare OIS with other functional mapping modalities, and explain its potential benefits and limitations. They propose that iOIS may, in the future, be used in conjunction with ECSM to improve the resolution and accuracy of intraoperative mapping, decrease total time of intraoperative mapping, and possibly improve neurological outcomes. Additional studies will be required to quantify the sensitivity and specificity of optical maps relative to ECSM before it can be implemented clinically.
Collapse
Affiliation(s)
- Nader Pouratian
- Laboratory of Neuro Imaging, Division of Brain Mapping, Department of Neurology, University of California, Los Angeles, California, USA
| | | | | | | |
Collapse
|
50
|
Kujala A, Alho K, Valle S, Sivonen P, Ilmoniemi RJ, Alku P, Näätänen R. Context modulates processing of speech sounds in the right auditory cortex of human subjects. Neurosci Lett 2002; 331:91-4. [PMID: 12361848 DOI: 10.1016/s0304-3940(02)00843-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using whole-head magnetoencephalography, we studied how context affects processing of speech sounds by recording the magnetic counterpart (MMNm) of the mismatch negativity (MMN) event-related potential, which is elicited in the auditory cortex by a contrast between infrequent and frequent auditory stimuli. In Experiment 1, in the right, but not in the left, hemisphere auditory cortex, a contrast of consonant-vowel syllables elicited a stronger MMNm when presented within a word context than when occurring alone. Further, in Experiment 2, these same syllable contrasts were processed in the right auditory cortex more strongly when embedded in a non-speech sound context than when presented alone. This facilitation thus was insensitive to the phonetic and semantic features of the context but might nevertheless reflect the participation of the right hemisphere in speech perception.
Collapse
Affiliation(s)
- Anu Kujala
- Cognitive Brain Research Unit, Department of Psychology, PO Box 13, University of Helsinki, FIN-00014, Helsinki, Finland.
| | | | | | | | | | | | | |
Collapse
|