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PubMed2005

Spatiotemporal brain maps of delayed word repetition and recognition.

Whole-head magnetoencephalography (MEG) was used to spatiotemporally map the brain response underlying episodic retrieval of words studied a single time following a long delay (approximately 40 min). Recognition following a long delay occurs as a strong, sustained, differential response, within bilateral, ventral, and lateral prefrontal cortex, anterior temporal and medial parietal regions from approximately 500 ms onward, as well as ventral occipitotemporal regions from approximately 700 ms onward. In comparison with previous tasks using multiple repetitions at short delays, these effects were centered within the same areas (anteroventral temporal and ventral prefrontal) but were shifted to longer latencies (approximately 500 ms vs. approximately 200 ms), were less left-lateralized, and appear more in anterolateral prefrontal regions and less in lateral temporal cortex. Furthermore, comparison of correctly classified words with misclassified, novel and repeated words, suggests that these frontotemporal-parietocingulate responses are sensitive to actual as well as perceived repetition. The results also suggest that lateral prefrontal regions may participate more in controlled effortful retrieval, while left ventral frontal and anterior temporal responses may support sustained lexicosemantic processing. Additionally, left ventromedial temporal sites may be relatively more involved in episodic retrieval, while lateral temporal sites may participate more in automatic priming.

Adolescent↗
PubMed1997

Intraoperative brain mapping in a community setting--technical considerations.

Intraoperative brain mapping is a surgical adjunct used during lesionectomy or epilepsy surgery in functional cortex. This procedure is typically performed at academic institutions by fellowship trained neurosurgeons. However, most of the technology is straightforward and adaptable to the private practice setting. This paper outlines our intraoperative methodology for brain mapping during lesion resection in eloquent cortex.

Brain Mapping↗
PubMed1987

Stereotactic computer graphic system with brain maps.

We have developed a stereotactic computer graphic system with brain maps that runs on a personal computer. This system consists of three parts: 1. firmware for dizitizing radiological films with a TV camera or scanner (when digital image is not directly obtained from floppy disks); 2. software for introducing or processing brain maps by matching them with CT or NMR images; 3. hardware. Our system is designed to: 1. recognize the relevant frame points and calculate targets, their volume and surgical instrument trajectory; 2. match between brain maps of an ideal brain and patient's CT or NMR images with visible and invisible pathology; 3. monitor during surgery the position of the surgical instrument or target modification. The whole procedure and processed images are stored in a data-base for further study.

Brain Mapping↗
PubMed2001

Effect of stimulus intensity level on auditory middle latency response brain maps in human adults.

Auditory middle latency response (AMLR) brain maps were obtained in 11 young adults with normal hearing. AMLR waveforms were elicited with monaural clicks presented at three stimulus intensity levels (50, 70, and 90 dB nHL). Recordings were made for right and left ear stimulus presentations. All recordings were obtained in an eyes open/awake status for each subject. Peak-to-peak amplitudes and absolute latencies of the AMLR Pa and Pb waveforms were measured at the Cz electrode site. Pa and Pb waveforms were present 100 percent of the time in response to the 90 dB nHL presentation. The prevalence of Pa and Pb to the 70 dB nHL presentation varied from 86 to 95 percent. The prevalence of Pa and Pb to the 50 dB nHL stimulus never reached 100 percent, ranging in prevalence from 77 to 68 percent. No significant ear effect was seen for amplitude or latency measures of Pa or Pb. AMLR brain maps of the voltage field distributions of Pa and Pb waveforms showed different topographic features. Scalp topography of the Pa waveform was altered by a reduction in stimulus intensity level. At 90 dB nHL, the Pa brain map showed a large positivity midline over the frontal and central scalp areas. At lower stimulus intensity levels, frontal positivity was reduced, and scalp negativity over occipital regions was increased. Pb scalp topography was also altered by a reduction in stimulus intensity level. Varying the stimulus intensity significantly altered Pa and Pb distributions of amplitude and latency measures. Pa and Pb distributions were skewed regardless of stimulus intensity.

Adult↗
PubMed1990

Correlation of motor cortex brain mapping data with magnetic resonance imaging.

Brain maps derived intraoperatively from patients undergoing tumor resection were correlated retrospectively with magnetic resonance (MR) images with respect to the precise localization of the motor cortex in an attempt to identify useful preoperative MR imaging landmarks that correspond to functional brain regions. Superior axial T2-weighted MR images consistently localized the central sulcus, whereas parasagittal and farlateral sagittal images readily identified the rolandic (sensorimotor) cortex, as a functional unit, based on the cingulate-marginal sulcus and insula, respectively. It is therefore concluded that multiplanar MR images may serve as a useful preoperative planning aid prior to removing intrinsic brain tumors within or adjacent to the motor cortex.

Brain Mapping↗
PubMed1992

[Brain mapping in Parkinson disease treated by cryothalamotomy].

Brain mapping of the cerebral bioelectric activity was done by the BEAM method in 20 patients with Parkinson's disease treated by cryothalamotomy. Conventional egg examinations demonstrating relatively small changes of the type of local asymmetry of frequencies and/or amplitudes, sporadic focal changes, and sporadic generalized and disseminated generalized changes were analysed in a computer system in the domain of frequency and time. Brain mapping demonstrated very distinctly the asymmetry in the frequency bands alpha and beta. On the operated side a regular alpha rhythm of lower frequency but higher amplitude dominated in the brain hemisphere. On the intact side a quick beta rhythm prevailed and an irregular alpha rhythm was noticeable. This phenomenon described by analysis in the domain of frequency confirms the unilateral synchronizing influence of thalamotomy on the bioelectric activity of the operated brain hemisphere and may correlate with the functional motor improvement noted in the operated subjects. In three cases with a longer course of the disease analysis in the frequency domain demonstrated the presence of generalized diffused slow waves in both frontal regions. These changes correlated with mental insufficiency of the examined patients.

Adult↗
PubMed1990

Brain mapping in a case of multiple personality.

Brain maps were recorded on a patient with a multiple personality disorder (10 alternate personalities). Maps were recorded with eyes open and eyes closed during 2 different sessions, 2 months apart. Maps from each alternate personality were compared to those of the basic personality "S", some maps were similar and some were different, especially with eyes open. Findings that were replicated in the second session showed differences from 4 personalities, especially in theta and beta 2 frequencies on the left temporal and right posterior regions. A rank ordering of the differences in the brain maps of the alternate personalities from S were similar to the rank ordering of the differences in personality characteristics, as judged by the psychiatrist dealing with this patient. Maps from S acting like some of her personalities or from a professional actress portraying the different personalities did not reveal significant differences. Some of these findings are consistent with those in the literature, and the importance of detecting artifact in the raw EEG recording is emphasized.

Adult↗
PubMed1990

Brain maps and parallel computers.

It is well known that neural responses in many brain regions are organized in characteristic spatial patterns referred to as brain maps. It is likely that these patterns in some way reflect aspects of the neural computations being performed, but to date there are no general guiding principles for relating the structure of a brain map to the properties of the associated computation. In the field of parallel computing, maps similar to brain maps arise when computations are distributed across the multiple processors of a parallel computer. In this case, the relationship between maps and computations is well understood and general principles for optimally mapping computations onto parallel computers have been developed. In this paper we discuss how these principles may help illuminate the relationship between maps and computations in the nervous system.

Brain↗
PubMed1994

Integrating human brain maps.

Perception, action, cognition, and emotion can now be mapped in the brain by a growing family of techniques. Positron emission tomography, functional magnetic resonance imaging, event-related electrical potentials, event-related magnetic fields, and other non-invasive imaging techniques are rapidly evolving and providing an increasingly rich literature on the functional organization of the human brain. Although no two techniques map identical physiological processes or physical parameters, replications of functionally specific maps by different techniques indicate sufficient common ground for multimodality integration. The process of integration is multi-tiered. Recent advances in integration range from simple image fusion, to model-based synthetic analyses, to collective databases for neural-system modeling. Spatially, temporally, physiologically, and cognitively accurate computational models of the neural systems of human behavior are the ultimate objective of functional brain mapping. This objective will be reached only through integrating the diversity of modern brain-mapping methods.

Brain Mapping↗
PubMed1990

The development of EEG brain mapping.

The field of EEG brain mapping is a collection of many separate techniques for quantified EEG analysis. The most popular technique is the color-coded topographic mapping of frequency content, usually taken in the alert eyes-closed state. This field has developed progressively over 60 years and now is gradually entering use in clinical situations. Accepted clinical uses are still rather limited. A variety of substantial problems exists regarding artifacts, confounding clinical issues, the diversity of available techniques, and statistical interpretation. Clinically, the tests may demonstrate an abnormality but are generally nonspecific regarding the type of responsible pathology. They localize impairment far less well than neuroimaging tests. These digital EEG techniques should not be used separately from the polygraph EEG at this time and should be only used by persons who have sufficient skills, knowledge, and abilities in traditional polygraph EEG interpretation along with additional knowledge and experience in statistical and EEG computer-processing techniques.

Brain↗
PubMed1998

The 77-kDa echinoderm microtubule-associated protein (EMAP) shares epitopes with the mammalian brain MAPs, MAP-2 and tau.

Previous work has shown that the echinoderm microtubule-associated protein (EMAP) was a unique MAP with little sequence similarity with the brain MAPs. The purpose of this study was to determine whether there were any small domains within EMAP that were shared by the mammalian brain MAPs, MAP-2, and tau. It is reported here that EMAP and the heat-stable MAP-2 and tau share antigenic determinants. A polyclonal antisera, raised against SDS-PAGE denatured EMAP, reacted strongly with both MAP-2 and tau on Western blots. In addition, a detailed sequence comparison, using a window of 5 amino acids at a time, revealed several short domains with approximately 20 residues that shared sequence similarity. The regions of sequence similarity were all located in regions implicated in microtubule binding, suggesting that EMAP and the mammalian brain MAPs may share short structural and functional domains.

Amino Acid Sequence↗
PubMed1993

Brain mapping: a contribution to linear interpolation.

Topographic mapping of brain electrical activity has become a powerful tool in neurological diagnosis. Maps are obtained from a reduced number of actual measurements by means of mathematical interpolation. Most of these systems use linear combination of the values measured and, in spite of its importance, the choice of the exponent "n" in the weighting function is made ad hoc. In this paper we present a critical analysis of such method and propose an objective criterion for the estimation of that exponent. As well, we propose another criterion for determining the number of leads used in the interpolation of each point.

Algorithms↗
PubMed1975

The isocortex of the ox (Bos taurus). II. The cortical types, serial sections and brain map.

1. The cerebral hemispheres of the bovine brain have been studied by making serial sections in the different planes and employing Nissl, myelin and silver (protargol) methods. 2. Ten different cortical (architectural) types have been determined. 3. The somatomotor (Ms I, Ms II), somatosensory (Sm I, Sm II), auditory and visual areas of the cerebral cortex have been delimited. 4. A brain map with a symbolic scheme, has been prepared, based on the cyto- and myeloarchitectural findings and comparative experimental work on the nearest ungulates, other subprimates and primates including man. 5. The importance of the general eulaminate cortex, and its abundance in the frontal, temporal, and parietal lobes of man, which distinguish the human from the other brains are indicated. 6. It is concluded that the preparation of a brain map for this species, is the first step towards future experimental, neurophysiological and related fields of work.

Animals↗
PubMed2006

Preoperative endovascular brain mapping for intraoperative volumetric image guidance: preliminary concept and feasibility in animal models.

OBJECT: The authors describe a novel concept for brain mapping in which an endovascular approach is used, and they demonstrate its feasibility in animal models. The purpose of endovascular brain mapping is to delineate clearly the nonfunctional brain parenchyma when a craniotomy is performed for resection. The nonfunctional brain will be stained with sharp visual margins, differentiating it from the functional, nonstained brain. The authors list four essential criteria for developing an ideal endovascular mapping agent, and they describe seven potential approaches for accomplishing a successful endovascular brain map. METHODS: Four Sprague-Dawley rats and one New Zealand white rabbit were used to determine initial feasibility of the procedure. The animals were anesthetized, and the internal carotid artery was catheterized. Four potential brain mapping agents were infused into the right hemisphere of the five animals. Afterward, the brains were removed and each was analyzed both grossly and histologically. Fluorescein and FD&C Green No. 3 provided good visual clarity and margins, but required blood-brain barrier (BBB) manipulation. Tantalum particles enabled avoidance of BBB manipulation, but provided inadequate visual clarity, probably because of their size. A Sudan black "cocktail" provided excellent clarity and margins despite remaining in the brain capillaries. CONCLUSIONS: This is a novel application of the endovascular approach, and has broad potential for clinical neurosurgical brain mapping. The animal models in this study establish the feasibility of the procedure. However, further study is required to demonstrate safety, minimize toxicity, investigate stain durability, and improve the characteristics of potential mapping agents. The authors are planning to conduct future studies for identification of mapping agents that do not require BBB manipulation or vascular occlusion.

Angiography, Digital Subtraction↗
PubMedDate not supplied

[Awake craniotomy and brain mapping for eloquent cortex in patients with supratentorial tumors: a preliminary report].

Malignant brain tumours are incurable at present. Since none of the hitherto used treatment methods allows to significantly extend these patients' survival time, the basic aim is to improve their quality of life. Intraoperative brain mapping seems to be an approach enabling to minimize the risk of irreversible damages to functionally important structures of the brain. In the Department of Neurosurgery of the Medical University of Łódź awake craniotomy with stimulation of eloquent cortex was attempted from May 1999 to July 2000 in 13 patients aged 16 to 77 years. In two patients the attempt of intraoperative awakening was unsuccessful. In 8 out of the 11 awakened patients intraoperative brain mapping had a significant effect on the course of surgery (i.e. on the resection magnitude and "safe corridor"). Out of six patients with tumors situated in the neighbourhood of motor cortex--one developed a severe and permanent paresis of the upper limb. On the grounds of the literature and the authors' own experience an algorithm of awake craniotomy and intraoperative brain mapping was worked out.

Adolescent↗
PubMed1992

Intraoperative brain mapping techniques in neuro-oncology.

Intraoperative brain mapping techniques are utilized in neuro-oncology to maximize the extent of tumor resection and seizure control, and minimize the operative morbidity. Direct stimulation mapping of the cortex and subcortical descending motor pathways will localize the rolandic cortex, dominant language speech zones and motor tracts in the internal capsule, cerebral peduncle and corticospinal tract/anterior horn cells. Electrocorticography identifies epileptogenic areas that histologically are distinctly devoid of neoplastic infiltration. Seizure control is maximal when seizure foci are resected in addition to the tumor nidus.

Brain↗
PubMed1997

[Three-dimensional brain mapping using fMRI].

Functional mapping of the activated brain, the location and extent of the activated area were determined, during motor tasks and sensory stimulation using fMRI superimposed on 3 D anatomical MRI. Twelve volunteers were studied. The fMR images were acquired using a 2 D gradient echo echo planar imaging sequence. The 3D anatomical MR images of the whole brain were acquired using a conventional 3D gradient echo sequence. Motor tasks were sequential opposition of fingers, clenching a hand and elbow flexion. Somatosensory stimulation were administered by scrubbing the palm and sole with a washing sponge. Visual stimulation consisted of full visual field stimulation. Data were analyzed by the cross-correlation method. Transversal fMR images and anatomical images were reconstructed using both volume-, surface-rendering methods, and reconstructed for coronal and sagittal sections. Activated areas were expressed using the three primary colors. Motor tasks activated the contralateral primary motor area (M1), the primary somatosensory area (S1) and the supplementary motor area (SMA). Somatosensory tasks activated the contralateral S 1, M1 and secondary sensory area (S2). Activated areas during full visual field stimulation was observed in the bilateral occipital lobe, including both the primary cortex. Three-dimensional brain mapping allowed visualization of the anatomical location and extent of the activated brain during both motor task and sensory stimulation. Using this method we could obtain a functional map similar to the Penfield's schema.

Adult↗