Psychology
Neuroimaging Techniques
Neuroimaging techniques are methods used to visualize the structure and function of the brain. These techniques include magnetic resonance imaging (MRI), functional MRI (fMRI), positron emission tomography (PET), and electroencephalography (EEG). They provide valuable insights into brain activity and are widely used in research to understand various psychological processes and disorders.
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11 Key excerpts on "Neuroimaging Techniques"
- Roger E Millsap, Alberto Maydeu-Olivares, Roger E Millsap, Alberto Maydeu-Olivares(Authors)
- 2009(Publication Date)
- SAGE Publications Ltd(Publisher)
28 Neuroimaging Analysis I: Electroencephalography Josep Marco-Pallarés, Estela Camara, Thomas F. Münte, and Antoni Rodríguez-Fornells COGNITIVE NEUROSCIENCE AND Neuroimaging Techniques Cognitive neuroscience has been termed the biology of mind. As such it is, to a large extent at least, a science about the human mind, as many of the higher cognitive func-tions, including language processing, episodic memory and executive functions, can best or exclusively be studied in human subjects. To fulfil its promise, cognitive neuroscience is in need of techniques that can serve as windows to the brain as it carries out the processes that make up the mind. Since human participants are under study, these techniques need to be non-invasive. In light of this, the recent success of cognitive neuroscience can be attributed to two factors: the increasingly sophisticated experimental designs that are borrowed from cognitive science and psychology, and, the methodological developments in neuroimag-ing techniques. In the present Chapter and the following one we will concentrate on the two major and most widely used Neuroimaging Techniques, namely methods derived from electroen-cephalography (EEG) and functional mag-netic resonance imaging (fMRI). While EEG has been around for about 80 years, recent methodological advances in signal analysis have led to a renewed interest in EEG-based experiments. Functional MRI, while having a much shorter history of little more than 15 years, has already reached a high level of sophistication, but more developments regarding analysis techniques are to be expected. For space reasons, we will not discuss other Neuroimaging Techniques here, but would like to point out that each of these possess unique properties that make them valuable tools in cognitive neuroscience. Near infra-red spectroscopy (NIRS) uses near-infra-red light to non-invasively measure changes in the concentration of oxygenated (O 2 Hb) and deoxygenated (HHb) hemoglobin.
- Linda J. Luecken, Linda C. Gallo(Authors)
- 2007(Publication Date)
- SAGE Publications, Inc(Publisher)
C H A P T E R 17 Neuroimaging Overview of Methods and Applications L EE R YAN G ENE E. A LEXANDER T he past few decades have seen enor-mous advances in the ability to visu-alize and measure aspects of brain anatomy and physiology in the living human being. The recent developments in neuroimag-ing techniques that provide measures of brain structure and function, as well as cerebral activity during cognitive processes such as per-ception, attention, and memory, have changed the face of cognitive neuroscience and allowed us to ask questions about the relation between the brain and behavior that were simply not possible only a decade or two ago. As these techniques have become more accessible and affordable for research use, they have been increasingly applied to a variety of research questions, having the potential to greatly enhance our understanding of the normal brain and its development throughout the lifespan. Even areas of research that have tradition-ally not been linked to neuroscience, such as social psychology, economics, and education, are increasingly making use of neuroimaging methods. From the beginning, evaluating the effects of health-related factors such as aging, neuro-logical and psychiatric illness, and brain injury has been an important and rapidly growing part of the neuroimaging field. Health psy-chology provides a potentially unique per-spective in the application of neuroimaging methods to study how brain-behavior rela-tionships are altered by disease states and other health-related factors. Neuroimaging provides a set of tools that can address a wide variety of questions.
eBook - PDFAssessment and Therapy
Specialty Articles from the Encyclopedia of Mental Health
- Howard S. Friedman(Author)
- 2001(Publication Date)
- Academic Press(Publisher)
Brain Scanning/Neuroimaging Richard J. Haier University of California, Irvine I. Basic Concepts II. Positron Emission Tomography (PET) III. Magnetic Resonance Imaging (MRI) IV. EEG and Magnetoencephalogram (MEG) V. Neuroimaging Findings and Normal Brain Function VI. Conclusions Co-Registration When one image is aligned, scaled and superimposed over another image so both fit the same space. EEG Electroencephalogram fMRI Functional Magnetic Resonance Imaging MEG Magnetoencephalogram MRI Magnetic Resonance Imaging PET Position Emission Tomography Pixel The smallest unit of an image; each pixel is quantified. Radiotracer A radioactive substance that imaging devices measure to show where the tracer goes. Region-of-Interest (ROI) Any brain area defined and located anatomically or mathematically. SPECT Single-Photon Emission Computed Tomog-raphy Stereotactic A method of defining brain area loca-tion using coordinates of a standard brain. Tomography Process of making a mathematical picture. A variety of MEDICAL IMAGING TECHNOLO-GIES show the brain in ways not possible previously. Functional imaging is especially useful for identifying brain areas involved in specific cognitive tasks and states. Each imaging method has different strengths and weaknesses. There are several core issues concern-ing image analysis that must be considered by re-searchers and clinicians. The combination of ad-vanced imaging technology with sophisticated psychological experiments is a powerful tool for help-ing understand the normal and abnormal brain. I. BASIC CONCEPTS A. Structural and Functional Imaging Through the 1970s researchers had access to the living human brain mostly through the study of blood, urine, and spinal fluid. Only electroencephalograph (EEG) methods and occasional probing during brain surgery provided direct data on human brain functioning.
eBook - ePub- Matt Carter, Jennifer C. Shieh(Authors)
- 2015(Publication Date)
- Academic Press(Publisher)
Table 1.1 compares the spatial and temporal resolutions, cost, and invasiveness of the various functional brain imaging techniques described previously. As mentioned before, many imaging laboratories now combine multiple techniques to make up for the inadequacies of any single technique. For example, fMRI offers excellent spatial resolution and is noninvasive, but it does not offer good temporal resolution of neural activity during experiments because the BOLD effect occurs over a period of 6–10 s. Therefore, some laboratories combine fMRI with MEG or EEG, in which signals can be detected within a fraction of a second.Figure 1.17 Optical imaging.Light is shined onto the surface of the brain. A portion of this light is reflected off the brain and detected by multiple optrodes. Changes in neural activity produce changes in the amount of light that is absorbed and reflected by the brain. Therefore, optical imaging can be used to indirectly detect changes in neural activity. These techniques can be either invasive (the skull is opened to reveal the surface of the brain) or noninvasive.Table 1.1 Comparison of Functional Imaging TechniquesSpatial resolution Temporal resolution Cost Invasiveness fMRI 1 mm 6–10 s Expensive Noninvasive PET 4 mm 1 min Very expensive Radioactive injection SPECT 8 mm 2–8 s Expensive Radioactive injection EEG 1 cm 1 ms Moderate Noninvasive MEG 1 mm 1 ms Very expensive Noninvasive Optical imaging 1 mm 2–8 s Inexpensive Can be invasive So far, this chapter has focused almost exclusively on the technology of structural and functional brain imaging. Of course, the utility of these technologies depends entirely on how they are used: the research hypotheses, experimental designs, and methods of data analysis. In the last part of this chapter, we will examine the approaches that can be taken in the design and analysis of functional imaging experiments.Functional Imaging Experimental Design and Analysis
Functional imaging technologies are particularly well suited to cognitive neuroscience
- Stephen F. Davis, William Buskist, Stephen F. Davis, William F. Buskist(Authors)
- 2007(Publication Date)
- SAGE Publications, Inc(Publisher)
139 16 I MAGING T ECHNIQUES FOR THE L OCALIZATION OF B RAIN F UNCTION B RENDA A NDERSON Stony Brook University T he incorporation of human imaging methods into the psychological sciences has been rapid and dramatic. The movement of behavioral research in this direction requires careful consideration of these methods and what they reveal about behavior and the brain. For this reason, the present chapter will highlight the basic assumptions that underlie these methodologies. The assumption that behavior is localized in the brain underlies the need for imaging methods in psychology. But these methods are only as good as the information they provide. Accordingly, we start with a review of the relation between neural activity and metabolism in the brain, and then proceed to describe the relation between blood flow and the signals measured, first with func-tional magnetic resonance imaging (fMRI). Because both positron emission tomography (PET) and fMRI utilize structural magnetic resonance (MR) images to identify the location of the activation, I will briefly discuss the basis of structural MRI and will illustrate its use to psychologists. The majority of the chapter will describe the basis of fMRI, which is the imaging method most widely used at the moment by psychologists. For com-parison purposes, there will be a brief description of PET functional imaging. Finally, I discuss the limits of these methodologies in relation to the questions of interest in psychology. ELEMENTAL FUNCTIONS LOCALIZED WITHIN THE BRAIN Behind the emergence of human imaging methods is the belief that function is localized in the brain. The belief that the mind and behavior are products of a biologi-cal machine, the brain, has emerged slowly over the last several centuries. These beliefs began with Galileo and Newton’s interpretation that the world is mechanical in nature (Schultz, 1981).
eBook - PDFDrugs and the Future
Brain Science, Addiction and Society
- David J. Nutt, Trevor W. Robbins, Gerald V. Stimson, Martin Ince, Andrew Jackson(Authors)
- 2006(Publication Date)
- Academic Press(Publisher)
These techniques have contributed much in the last decade or so to our understand- ing of this most challenging of social issues. But research effort in this area is not com- mensurate to the importance of the problem. This report reviews the application of neuroimaging to the study of drug addiction, beginning with the defining pharmacology and studies of craving before considering the more cognitive aspects. The availability of small imaging systems, particularly for magnetic resonance imaging (MRI), but also increasingly for PET and SPET, and in a few cases for combined MRI/PET, enables non-invasive methodologies to be applied to animal models, examples of which are given in Section 4. The development of PET as a molecular imaging tool is consid- ered in Section 5, and future developments in MRI, fMRI and their sister technique, magnetic resonance spectroscopy (MRS), in Section 6. Although not itself an imaging technique, transcranial magnetic stimulation (TMS) is increasingly being used in con- junction with Neuroimaging Techniques to explore the effects of inhibiting and mod- ulating neural circuits. This approach is described in Section 7. Although the vast majority of neuroimag- ing studies are based on fMRI, PET and SPET, these techniques lack temporal reso- lution. Where this is key, they are often sup- plemented by electroencephalography (EEG) or magnetoencephalography (MEG). A brief discussion of these is included in the final section. 2 FUNCTIONAL NEUROIMAGING IN THE STUDY OF DRUG ADDICTION: DEFINING PHARMACOLOGY AND CRAVING 2.1 Introduction The use of functional neuroimaging in the field of substance misuse has grown con- siderably over the past decade, as under- standing the neurobiology of addiction has become more of a clinical priority. There has been increased acceptance and development of drug treatments for addiction.
eBook - PDF- David C. Bellinger(Author)
- 2006(Publication Date)
- CRC Press(Publisher)
In addition, the techniques can be applied to animals, allowing further exploration of neurotoxicant effects following administration of toxicants or toxicant mixtures. Given the capacity of various imaging techniques to explore structural, functional, and neurochemical sequelae of exposure to neurotoxicants, their application to research in behavioral toxicology is an exciting development. In this chapter, we will first describe specific Neuroimaging Techniques, with a brief summary of their application to the study of child neurodevelopment in general. This will be followed by descriptions of the use of these techniques for the assessment of the central nervous system (CNS) effects of exposures to known neurotoxicants. Finally, data from a study that examined functional imaging in a cohort of children from the Faroe Islands with well characterized prenatal exposure to methylmercury (MeHg) and polychlorinated biphenyls (PCBs) will be described. Neuroimaging Techniques Computerized Tomography Computerized tomography (CT), invented in 1972 by Hounsfield and Cormack, is a technique that capitalizes on the fact that x-rays reflect the relative densities of the tissue through which they pass (6). During brain CT imaging, many x-rays are taken of the brain at an angle of 15-degrees to the canthomeatal line. Computing and mathematical techniques create the visual images of the brain that provide the concrete evidence of CT scan results. Because the gray matter, which is rich in cells, and the white matter, which is dominated by axons, have different densities, they reflect onto the x-ray film differently. This allows visualization of different brain structures. CT methodology is relatively inexpensive and fast. In the child neurodevelopment literature, CT techniques are most commonly described for clinical use. CT has been widely applied to the diagnosis, localization, surgical planning and post-operative surveillance of brain tumors (7–10).
eBook - PDFBiological Child Psychiatry
Recent Trends and Developments
- T. Banaschewski, L. A. Rohde, W. P. Kaschka, W. F. Gattaz(Authors)
- 2008(Publication Date)
- S. Karger(Publisher)
Examples from neuroimaging of ADHD will be used to illustrate the approaches discussed. Neuroimaging Methods for Investigating Human Brain and Cognitive Development MR techniques have introduced a new set of tools for capturing features of brain development in living, developing humans. The most common MR methods used in the study of human brain development include anatomical and functional MR imag-ing (fMRI). These methods have provided scientists with the opportunity to safely track the cognitive and neural processes underlying human development. Whereas anatomical MRI can be used to produce structural images of the brain useful for anatomical and morphometric studies, fMRI enables an in vivo measure of brain activity. fMRI measures changes in blood oxygenation in the brain that are assumed to reflect changes in neural activity [6] and eliminates the need for exogenous con-trast agents including radioactive isotopes [7, 8]. Diffusion tensor imaging is a rela-tively new MR technique that can detect changes in white matter microstructure based on properties of diffusion [9]. Diffusion of water in white matter tracts is affected by myelin and the orientation and regularity of fibers, and provides an index of brain connectivity. These three methods have advanced the field of developmental neuroscience by providing evidence of changes in structural architecture and func-tional organization in the developing brain in vivo. However, they provide only an indirect measure of brain structure and function: for example, changes in the volume of a structure or amount of activity as measured by fMRI methods lack the resolution to definitely characterize the mechanism of change. Histological evidence suggests that brain development is a dynamic process of regressive and progressive changes. As such, MRI-based cortical changes observed with development may be a combina-tion of myelination, dendritic pruning, and changes in the vascular, neuronal, and glial density.
- Talitha Best, Louise Dye, Talitha Best, Louise Dye(Authors)
- 2015(Publication Date)
- CRC Press(Publisher)
Similarly, PET also has great potential to increase our understanding of cerebral metabolic processes associated with nutraceuticals, yet the costs as well as the problems associ-ated with the use of radioisotopes continue to be a hindrance. Whilst not included in the current review, MEG is another imaging modality which has excellent temporal and spatial resolution. MEG has great potential to elucidate in vivo mechanisms of action of natural substances in the brain, yet the application of this technology to psychopharmacology is yet to eventuate. In future research, it is recommended that a greater effort be made on the part of disparate research labs to arrive at common methods, involving both cognitive activation tasks as well as analysis techniques, so that systematic review and meta-analysis of neuroimaging outcome measures (a necessary next step) can begin to occur. If current trends continue, then the next decade of human psychopharmacology research will enable robust and replicable in vivo neural effects to be established for a greatly augmented range of nutraceuti-cal nootropics. 332 Nutrition for Brain Health and Cognitive Performance TOP 6 SUMMARY POINTS FROM CHAPTER • A clear justification for the use of neuroimaging in a cognitive intervention study should precede its inclusion in the study. The major benefits of including neuroimaging in an intervention study include (1) to better under-stand in vivo mechanisms of action within the human brain and (2) to capture subtle neurocognitive effects that may be difficult to determine using standard behavioural measures. • EEG is the imaging modality that has been utilised most frequently in relation to psychopharmacological studies of nutraceutical and nutri-tional interventions. Power spectral analysis and ERP analysis have a long history of use in cognitive-affective neuroscience and are measures of cortical electrical activity which possess excellent temporal resolu-tion.
eBook - PDF- Kostas N. Fountas(Author)
- 2013(Publication Date)
- IntechOpen(Publisher)
Neuroimaging Techniques offer an important contribution to TMS mechanism comprehension through the description of the neural activation evoked by the electromagnetic pulse. For instance, electroencephalography (EEG) can detect the response of a cortical area to the TMS pulse (i.e., cerebral reactivity) based on the related electric markers of its activity, namely TMS-evoked potentials (TEPs). The analysis of TEP characteristics such as latency, amplitude, polarity, and waveform can offer an insight into the physiological state of the stimulated brain Novel Frontiers of Advanced Neuroimaging 144 area, allowing researchers to tackle inference with TMS mechanisms. On the other hand, techniques such as fMRI, PET, SPECT, and NIRS, which provide better spatial resolution than EEG, offer a detailed picture of responses to TMS throughout the brain. One of the most direct exemplifications of a neuroimaging contribution is the demonstration of the spread dynamics of TMS-evoked activity from the stimulated area to the connected regions. Ilmoniemi and colleagues ([17] – discussed below in section 2.2) were the first to provide direct evidence of this phenomenon. The authors mapped the ongoing activity evoked by the stimulation of the primary motor cortex and primary visual cortex in the ipsilateral and contralateral homologous regions. This evidence had a high novelty value in the field of TMS research, considering that traditionally its effects were evaluated only in regard to the stimulated area. Besides the elucidations on the general TMS mechanism, Neuroimaging Techniques can also provide direct evidence on the effect of a single TMS parameter. An example was provided by Käkhönen and colleagues [18]. The authors investigated reactivity variations of the prefrontal cortex and primary motor cortex across different stimulation intensity conditions.
eBook - PDF- Gert Rickheit, Ipke Wachsmuth(Authors)
- 2008(Publication Date)
- De Gruyter Mouton(Publisher)
The rapid development Neuroinformatic techniques 267 of new computation methods together with more powerful hardware, made it possible to analyze these huge databases with new, sophisticated methods from neuroinformatics, for example. Furthermore, it became possible to base analyses on only very few trials, which enabled researchers to perform on-line analyses of brain signals, opening up exciting new possibilities for Brain-Computer Interfaces (BCI) in order to control technical devices by brain signals. While intracortical elec- trodes were successfully employed to control e.g. robotic arms in animal studies (Chapin 1999; Nicolelis 2001), it is desirable to apply non-invasive techniques like EEG for human Brain-Computer Interfaces (Wolpaw et al., 2002; Birbaumer et al. 1999). Neuroinformatic techniques are capable of in- creasing the speed and accuracy of such devices: For instance, we have de- veloped a BCI for communicating letter sequences that improves upon re- ported communication bandwidths by employing recent machine learning techniques in conjunction with a P300-ERP based classification scheme (Kaper et al. 2004; Meinicke et al. 2003a). In this article we will describe how very similar methods can be employed to analyze brain activity with regard to neurolinguistic questions. In the following, we present several techniques, which we applied to EEG data in order to gain deeper insight into processing. Each method is briefly introduced before our results on EEG data, recorded in two experi- ments, are presented. As a first (rather ‘classic’) method, we briefly will describe principal component analysis (PCA) and demonstrate its use for the visualization of activity relationships between different scalp sites as a function of task con- ditions.
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