The Oxford Handbook of Functional Brain Imaging in Neuropsychology and Cognitive Neurosciences

A large part of the contemporary literature involves functional neuroimaging. Yet few readers are sufficiently familiar with the various imaging methods, their capabilities and limitations, to appraise it correctly. To fulfill that need is the purpose of this Handbook, which consists of an accessible description of the methods and their clinical and research applications. The Handbook begins with an overview of basic concepts of functional brain imaging, magnetoencephalography and the use of magnetic source imaging (MSI), positron emission tomography (PET), diffusion tensor imaging (DTI), and transcranial magnetic stimulation (TMS). The authors then discuss the various research applications of imaging, such as white matter connectivity; the function of the default mode network; the possibility and the utility of imaging of consciousness; the search for mnemonic traces of concepts the mechanisms of the encoding, consolidation, and retrieval of memories; executive functions and their neuroanatomical mechanisms; voluntary actions, human will and decision-making; motor cognition; language and the mechanisms of affective states and pain. The final chapter discusses the uses of functional neuroimaging in the presurgical mapping of the brain.

2003 ◽  
Vol 16 (4-5) ◽  
pp. 255-275 ◽  
Author(s):  
Rebecca L Billingsley ◽  
Panagiotis G Simos ◽  
Eduardo M Castillo ◽  
Fernando Maestú ◽  
Shirin Sarkari ◽  
...  

2001 ◽  
Vol 24 (3) ◽  
pp. 189-203 ◽  
Author(s):  
Todd L. Richards

This tutorial/review covers functional brain-imaging methods and results used to study language and reading disabilities. Although the main focus is on functional MRI and functional MR spectroscopy, other imaging techniques are discussed briefly such as positron emission tomography (PET), electroencephalography (EEG), magnetoencepholography (MEG), and MR diffusion imaging. These functional brain-imaging studies have demonstrated that dyslexia is a brain-based disorder and that serial imaging studies can be used to study the effect of treatment on functional brain activity.


2021 ◽  
Vol 12 ◽  
Author(s):  
Mohammed Bermo ◽  
Mohammed Saqr ◽  
Hunter Hoffman ◽  
David Patterson ◽  
Sam Sharar ◽  
...  

Functional neuroimaging modalities vary in spatial and temporal resolution. One major limitation of most functional neuroimaging modalities is that only neural activation taking place inside the scanner can be imaged. This limitation makes functional neuroimaging in many clinical scenarios extremely difficult or impossible. The most commonly used radiopharmaceutical in Single Photon Emission Tomography (SPECT) functional brain imaging is Technetium 99 m-labeled Ethyl Cysteinate Dimer (ECD). ECD is a lipophilic compound with unique pharmacodynamics. It crosses the blood brain barrier and has high first pass extraction by the neurons proportional to regional brain perfusion at the time of injection. It reaches peak activity in the brain 1 min after injection and is then slowly cleared from the brain following a biexponential mode. This allows for a practical imaging window of 1 or 2 h after injection. In other words, it freezes a snapshot of brain perfusion at the time of injection that is kept and can be imaged later. This unique feature allows for designing functional brain imaging studies that do not require the patient to be inside the scanner at the time of brain activation. Functional brain imaging during severe burn wound care is an example that has been extensively studied using this technique. Not only does SPECT allow for imaging of brain activity under extreme pain conditions in clinical settings, but it also allows for imaging of brain activity modulation in response to analgesic maneuvers whether pharmacologic or non-traditional such as using virtual reality analgesia. Together with its utility in extreme situations, SPECTS is also helpful in investigating brain activation under typical pain conditions such as experimental controlled pain and chronic pain syndromes.


2001 ◽  
Vol 7 (3) ◽  
pp. 181-188 ◽  
Author(s):  
Klaus P. Ebmeier ◽  
Julia M. Lappin

One hundred years ago, D'Arsonval and Beer first described the effects of magnetic fields on human brain function. Placing one's head into a powerful magnet produced phosphenes, vertigo or even syncopes (George & Belmaker, 2000). However, only since 1985 has the technology of fast discharging capacitors developed sufficiently to generate reproducible effects across the intact skull, with peak magnetic field strengths of about 1–2 tesla (Barker et al, 1985). The headline-grabbing news has been about therapeutic applications of transcranial magnetic stimulation (TMS), but in the meantime a revolution in functional brain research has taken place, based on the manipulation of brain activity by focused magnetic fields. TMS applied in this way is, in a manner of speaking, brain imaging in the reverse. While common modes of functional brain imaging, such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), demonstrate associations between brain metabolic activity and ‘brain tasks', the causal interpretation of such associations can be difficult. Is the frontal lobe activation observed during a memory task, for example, necessary for performing the task, or does it correspond to monitoring activity that runs parallel to task performance proper? If, on the other hand, focal brain activation during TMS results in a muscle twitch, there is no doubt that stimulation of at least some of the neurons within the magnetic field is sufficient cause for the observed movement. Functional neuroimaging is now often combined with TMS, carried out in the same session in order to exploit the complementary strengths of the methods. Although direct stimulation of association (as opposed to motor or sensory) cortex does not usually result in an observable response, TMS applied in repetitive trains can produce reversible ‘lesions'. By interfering with tasks that are dependent on the functioning of the stimulated neurons, it can thus contribute to the localisation of brain function.


2007 ◽  
Vol 107 (3) ◽  
pp. 488-494 ◽  
Author(s):  
Jeffrey I. Berman ◽  
Mitchel S. Berger ◽  
Sungwon Chung ◽  
Srikantan S. Nagarajan ◽  
Roland G. Henry

Object Resecting brain tumors involves the risk of damaging the descending motor pathway. Diffusion tensor (DT)–imaged fiber tracking is a noninvasive magnetic resonance (MR) technique that can delineate the subcortical course of the motor pathway. The goal of this study was to use intraoperative subcortical stimulation mapping of the motor tract and magnetic source imaging to validate the utility of DT-imaged fiber tracking as a tool for presurgical planning. Methods Diffusion tensor-imaged fiber tracks of the motor tract were generated preoperatively in nine patients with gliomas. A mask of the resultant fiber tracks was overlaid on high-resolution T1- and T2-weighted anatomical MR images and used for stereotactic surgical navigation. Magnetic source imaging was performed in seven of the patients to identify functional somatosensory cortices. During resection, subcortical stimulation mapping of the motor pathway was performed within the white matter using a bipolar electrode. Results A total of 16 subcortical motor stimulations were stereotactically identified in nine patients. The mean distance between the stimulation sites and the DT-imaged fiber tracks was 8.7 ±3.1 mm (±standard deviation). The measured distance between subcortical stimulation sites and DT-imaged fiber tracks combines tracking technique errors and all errors encountered with stereotactic navigation. Conclusions Fiber tracks delineated using DT imaging can be used to identify the motor tract in deep white matter and define a safety margin around the tract.


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