We propose an integral concept for tractography to describe crossing and splitting fibre bundles based on the orientation distribution function (ODF) estimated from high angular resolution diffusion imaging (HARDI). show that in order perform accurate probabilistic tractography, one needs use a ODF estimation not ODF. new obtained sharpening deconvolution transform (SDT) of reconstructed q-ball (QBI). This SDT provides insight into relationship between HARDI signal, ODF, demonstrate agrees...

It is generally agreed that the cerebral cortex can be segregated into structurally and functionally distinct areas. Anatomical subdivision of Broca's area has been achieved using different microanatomical criteria, such as cytoarchitecture distribution neuroreceptors. However, brain function also strongly depends upon anatomical connectivity, which therefore forms a sensible criterion for functio-anatomical segregation cortical Diffusion-weighted magnetic resonance (MR) imaging offers...

We used computer simulations to investigate finite element models of the layered structure human skull in EEG source analysis. Local models, where each location was modeled differently, and global assumed be homogeneous, were compared a reference model, which spongy compact bone explicitly accounted for. In both cases, isotropic anisotropic conductivity assumptions taken into account. considered sources entire brain determined errors forward calculation reconstructed dipole position. Our...

Despite the widespread use of transcranial magnetic stimulation (TMS), precise cortical locations underlying resulting physiological and behavioral effects are still only coarsely known. To date, mapping strategies have relied on projection approaches (often termed "center gravity" approaches) or maximum electric field value evaluation, therefore localize stimulated site approximately indirectly. Focusing motor cortex, we present validate a novel method to reliably determine effectively at...

Pianists often report that pure listening to a well-trained piece of music can involuntarily trigger the respective finger movements. We designed magnetoencephalography (MEG) experiment compare motor activation in pianists and nonpianists while piano pieces. For pianists, we found statistically significant increase activity above region contralateral cortex. Brain surface current density (BSCD) reconstructions revealed spatial dissociation this between notes preferably played by thumb little...

It has previously been demonstrated that enactment (i.e., performing representative gestures during encoding) enhances memory for concrete words, in particular action words. Here, we investigate the impact of on abstract word learning a foreign language. We further ask if novel words with facilitates sentence production. In within‐subjects paradigm, participants first learned 32 sentences from an artificial corpus conforming Italian phonotactics. Sixteen were encoded audiovisually. Another...

Abstract Anatomical MRI studies at 7T have demonstrated the ability to provide high‐quality images of human tissue in vivo. However, diffusion‐weighted imaging is limited by increased level artifact associated with standard, single‐shot, echo‐planar imaging, even when parallel techniques such as generalized autocalibrating partially acquisitions (GRAPPA) are used reduce effective echo spacing. Readout‐segmented conjunction has potential these artifacts allowing a further reduction spacing...

Functional integration in the brain rests on anatomical connectivity (the presence of axonal connections) and effective causal influences mediated by these connections). The deployment connections provides important constraints connectivity, but does not fully determine it, because synaptic can be expressed functionally a dynamic context-dependent fashion. Although it is generally assumed that data to guide construction neurobiologically realistic models connectivity; degree which actually...

Abstract In this study, we used invasive tracing to evaluate white matter tractography methods based on ex vivo diffusion‐weighted magnetic resonance imaging (dwMRI) data. A representative selection of were compared manganese a voxel‐wise basis, and more qualitative assessment examined whether, what extent, certain fiber tracts gray targets reached. While the agreement was very limited, revealed that is capable finding major tracts, although there some differences between methods. However,...

Uncertainty surrounding ohmic tissue conductivity impedes accurate calculation of the electric fields generated by non-invasive brain stimulation. We present an efficient and generic technique for uncertainty sensitivity analyses, which quantifies reliability field estimates identifies most influential parameters. For this purpose, we employ a non-intrusive generalized polynomial chaos expansion to compactly approximate multidimensional dependency on conductivities. demonstrate that proposed...

Stimulation with rhythmic light flicker (photic driving) plays an important role in the diagnosis of schizophrenia, mood disorder, migraine, and epilepsy. In particular, adjustment spontaneous brain rhythms to stimulus frequency (entrainment) is used assess functional flexibility brain. We aim gain deeper understanding mechanisms underlying this technique predict effects intensity. For purpose, a modified Jansen Rit neural mass model (NMM) cortical circuit used. This mean field has been...

The results of brain connectivity analysis using reconstructed source time courses derived from EEG and MEG data depend on a number algorithmic choices. While previous studies have investigated the influence choice estimation method or measure, effects head modeling errors simplifications not been studied sufficiently. In present simulation study, we particular properties model as well in MEG. Therefore, constructed realistic applied finite element to solve forward problems. We considered...

Transcranial magnetic stimulation (TMS) is a powerful tool to investigate causal structure-function relationships in the human brain. However, precise delineation of effectively stimulated neuronal populations notoriously impeded by widespread and complex distribution induced electric field. Here, we propose method that allows rapid feasible cortical localization at individual subject level. The functional relationship between field behavioral effect quantified combining experimental data...

Abstract Neither music nor spoken language form uniform auditory streams, rather, they are structured into phrases. For the perception of such structures, detection phrase boundaries is crucial. We discovered electroencephalography (EEG) and magnetoencephalography (MEG) correlates for in music. In EEG, this process was marked by a positive wave approximately between 500 600 ms after offset boundary with centroparietal maximum. MEG, we found major activity an even broader time window (400–700...

The human inferior parietal cortex convexity (IPCC) is an important association area, which integrates auditory, visual, and somatosensory information. However, the structural organization of IPCC a controversial issue. For example, cytoarchitectonic parcellations reported in literature range from 2 to 7 areas. Moreover, anatomical descriptions are often based on experiments macaque monkey. In this study, we used diffusion-weighted magnetic resonance imaging combined with probabilistic...

Abstract In modern neuroscience there is general agreement that brain function relies on networks and connectivity therefore of paramount importance for function. Accordingly, the delineation functional areas basis diffusion magnetic resonance imaging (dMRI) tractography may lead to highly relevant maps. Existing methods typically aim find a predefined number and/or are limited small regions grey matter. However, it in not likely single parcellation dividing into finite an adequate...