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5th International Conference on Functional Mapping of the Human Brain. Dusseldorf, Germany, June 22-26, 1999. Abstracts.
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Abstracts of the 5th International Symposium on Functional Neuroreceptor Mapping of the Living Brain. July 15-17, 2004, Vancouver, Canada.
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[The EEG and thinking].
The on-going EEG contains information on thinking strategies during cognitive and creative tasks and during listening to music. This was demonstrated by a method taking use of the fact that both the amount of local current production and the degree of electric coupling of brain regions is characteristically changed by mental tasks. In groups of volunteers the significant changes of absolute power and coherence caused by different mental tasks are computed and entered into schematic brain maps (EEG probability maps). The results indicate the existence of general brain strategies even in mental activities as specific as those referred to above. Moreover, several relationships between EEG, psychological test scores, degree of special education and intelligence were found. Studies with extreme value validation according to intelligence and creativity test scores yielded significant differences between the groups of the best and the poorest performers during a creative task in the EEG. The EEG thus can be conceived of as deterministic chaos with different degrees of organization according to its information content. In this context, the question arises as to a possible function of the EEG for the optimization of thinking processes.
Mapping of the mouse brain for screening procedures with the light microscope.
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Basic principles and neurosurgical applications of positron emission tomography.
Positron emission tomography (PET) is a technique for studying functional processes in the human body in vivo. The important clinical applications of PET in neurosurgery include localization of epileptic foci, diagnosis of brain tumors, preoperative brain mapping, and the study of plasticity of the brain following brain damage. The basic physics and neurosurgical applications of PET are presented.
2nd International Conference on Functional Mapping of the Human Brain. Boston, Massachusetts, June 17-21, 1996. Abstracts.
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3rd International Conference on Functional Mapping of the Human Brain. Copenhagen, Denmark, May 19-23, 1997. Abstracts.
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4th International Conference on Functional Mapping of the Human Brain. Montreal, Quebec, Canada. June 7-12, 1998. Abstracts.
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The time course of vasogenic oedema after focal human head injury--evidence from SPECT mapping of blood brain barrier defects.
We have tomographically mapped changes in the blood brain barrier (BBB) (99 mTc Pertechnetate) in 20 patients with acute contusions, and four with acute subdural haematomas in situ. The changes were related to regional CBF, (99 mTc HMPAO SPECT) T2 weighted MRI scans, CT abnormalities and the clinical features. Seventy-five percent of contusions were accompanied by a BBB abnormality, usually a "halo" around the lesion, which was more common in scans made after the second day. All contusions demonstrated "oedema" as a zone of "T2" signal on MRI or a zone of lucency on CT, and all were accompanied by a focal zone of low CBF on SPECT. Early contusional oedema appears to be cytotoxic but in certain cases, delayed blood brain barrier lesions develop, suggesting a vasogenic component.
Metabolic patterns associated with the clinical response to galantamine therapy: a fludeoxyglucose f 18 positron emission tomographic study.
BACKGROUND: Regional brain correlates of treatment with cholinesterase inhibitors in those with Alzheimer disease are unknown. OBJECTIVE: To map brain metabolism associated with the treatment response to galantamine with fludeoxyglucose F 18 positron emission tomography in patients with Alzheimer disease. DESIGN: This is a hypothesis-driven, prospective, open-label study of 19 patients with mild to moderate Alzheimer disease examined before and after treatment with the cholinesterase inhibitor galantamine. Clinical examinations included the cognitive portion of the Alzheimer Disease Assessment Scale, the Mini-Mental State Examination, and the Neuropsychiatric Inventory. Imaging was performed using fludeoxyglucose F 18 positron emission tomography. The positron emission tomographic data, registered to a probabilistic anatomical atlas, were subjected to a voxel-based analysis of 3 subgroups: total patient analysis, cognitive analysis, and behavioral analysis. Subvolume thresholding corrected random lobar noise to produce 3-dimensional significance maps. RESULTS: The total group analysis showed an increase in left caudate metabolism with no significant change in clinical outcomes for the total group with treatment. Subgroup analysis of cognitive and behavioral responders demonstrated a significant activation of a striatal-thalamofrontal network with galantamine treatment that was not present in patients whose condition worsened or was unchanged by therapy. In cognitive subgroups, change in left anterior cingulate metabolism significantly correlated with change in the cognitive portion of the Alzheimer Disease Assessment Scale (r = 0.70, P = .02); in behavioral subgroups, right cingulate metabolic change significantly correlated with improvement in depression and right ventral putamen metabolic change with improvement in apathy (r = 0.63, P<.05 for both). CONCLUSION: Cognitive and behavioral responders to galantamine therapy show clinically related improvements in prefrontal network metabolism along with thalamic activation.
An application of autoregressive model to pattern discrimination of brain electrical activity mapping.
Using the autoregressive model, we developed a method of illustrating significant regional differences between two records of brain electrical activity mapping. This new approach of brain electrical activity mapping analysis through a statistical taxonomy may be clinically useful for evaluation of the normal development of EEG in children and for localizing functional brain abnormality.
Coordinate-based versus structural approaches to brain image analysis.
A basic issue in neurosciences is to look for possible relationships between brain architecture and cognitive models. The lack of architectural information in magnetic resonance images, however, has led the neuroimaging community to develop brain mapping strategies based on various coordinate systems without accurate architectural content. Therefore, the relationships between architectural and functional brain organizations are difficult to study when analyzing neuroimaging experiments. This paper advocates that the design of new brain image analysis methods inspired by the structural strategies often used in computer vision may provide better ways to address these relationships. The key point underlying this new framework is the conversion of the raw images into structural representations before analysis. These representations are made up of data-driven elementary features like activated clusters, cortical folds or fiber bundles. Two classes of methods are introduced. Inference of structural models via matching across a set of individuals is described first. This inference problem is illustrated by the group analysis of functional statistical parametric maps (SPMs). Then, the matching of new individual data with a priori known structural models is described, using the recognition of the cortical sulci as a prototypical example.
Vestibular Evoked Potentials (VestEP) and Brain Electrical Activity Mapping - A Test of Vestibular Function - A Review (1990 - 1996).
Brain Electrical Activity Mapping of Vestibular Evoked Potentials (BEAM-VestEP) is a new technology for investigation of the spatial and temporal properties of a rotationally-induced brain electrical events. The method consists of multichannel EEG registration and mapping of the brain isoelectrical contours during short-lasting repetitive angular accelerations. A special data bank containing more than 400 BEAM-VestEP investigations on more than 300 persons, either symptom free volunteers or neurotological patients suffering from vertigo, tinnitus, sudden hearing loss, acoustic tumors, balance disorders, has been created for this study. The VestEP wave set consists of 5 - 7 positive/negative wave components, appearing within the time interval of 70 - 850 ms after the onset of the acceleratory step stimulus. The principle components analysis reveals that the shortest latencies and the highest amplitudes of the VestEPs can be registered from the central transversal line of electrodes, T3-C3-Cz-C4-T4. The later components are generated from the more frontally located cortical areas. The VestEP is a compound electrical phenomenon. The initial complex ( waves I - III) is related to the activation of specific (vestibular) cortical areas. The later complex (waves IV - VI) reflects the supramodal cortical proceedings with sensory information (cognitive components).
Mapping the human brain: past, present, and future.
The ability to map functional activity in the living human brain has rekindled interest in the organization of human neural circuitry specifically and in animal neural circuitry generally. Faced with incredible complexity, researchers are turning to the power of computer graphics for two- and three-dimensional interactive mapping, to the mathematical modeling of dynamics in proposed circuits, and to databases with powerful discovery engines.
Structural homology of microtubule-associated proteins 1 and 2 demonstrated by peptide mapping and immunoreactivity.
The major high molecular weight microtubule-associated polypeptides from hog brain (MAP-1 and MAP-2) were compared by one- and two-dimensional peptide mapping under varied conditions and by immunological techniques. Partial digestion of MAP-1 and MAP-2 with Staphylococcus aureus V8 protease and analysis in one dimension gave rise to very similar peptide maps independent of whether 125I-, 3H-, or 32P-labeled proteins were used. One-dimensional cleavage patterns of significant similarity were also obtained by partial digestion of MAP-1 and MAP-2 using trypsin or chymotrypsin. Furthermore, a pronounced similarity, although clear nonidentity, of MAP-1 and MAP-2 was also revealed after exhaustive digestion of 125I-labeled proteins with S. aureus V8 protease or trypsin followed by analysis of peptides in two dimensions. For immunological comparison, antisera were used that had been raised in rabbits using electrophoretically purified MAP-1 and MAP-2 components as immunogens. As determined by immunoprecipitation, the antiserum raised to MAP-1 was equally reactive with MAP-1 and MAP-2 components, whereas the antiserum to MAP-2 reacted primarily with MAP-2. Indicating the presence of common as well as unique antigenic determinants on MAP-1 and MAP-2, these results, therefore, were in agreement with the peptide mapping data. Implications of these results for biosynthetic mechanisms as well as differential distribution and functions of MAPs in cells are discussed.
Spatio-temporal dynamics of alpha brain electric fields, and cognitive modes.
Brain electric activity is viewed as sequences of momentary maps of potential distribution. Frequency-domain source modeling, estimation of the complexity of the trajectory of the mapped brain field distribution in state space, and microstate parsing were used as analysis tools. Input-presentation as well as task-free (spontaneous thought) data collection paradigms were employed. We found: Alpha EEG field strength is more affected by visualizing mentation than by abstract mentation, both input-driven as well as self-generated. There are different neuronal populations and brain locations of the electric generators for different temporal frequencies of the brain field. Different alpha frequencies execute different brain functions as revealed by canonical correlations with mentation profiles. Different modes of mentation engage the same temporal frequencies at different brain locations. The basic structure of alpha electric fields implies inhomogeneity over time-alpha consists of concatenated global microstates in the sub-second range, characterized by quasi-stable field topographics, and rapid transitions between the microstates. In general, brain activity is strongly discontinuous, indicating that parsing into field landscape-defined microstates is appropriate. Different modes of spontaneous and induced mentation are associated with different brain electric microstates; these are proposed as candidates for psychophysiological 'atoms of thought'.