Janpeter Nickel

Neural correlates of religious experience.

The commonsense view of religious experience is that it is a preconceptual, immediate affective event. Work in philosophy and psychology, however, suggest that religious experience is an attributional cognitive phenomenon. Here the neural correlates of a religious experience are investigated using functional neuroimaging. During religious recitation, self‐identified religious subjects activated a frontal–parietal circuit, composed of the dorsolateral prefrontal, dorsomedial frontal and medial parietal cortex. Prior studies indicate that these areas play a profound role in sustaining reflexive evaluation of thought. Thus, religious experience may be a cognitive process which, nonetheless, feels immediate.

Functional clusters in the human parietal cortex as revealed by an observer-independent meta-analysis of functional activation studies

The human parietal cortex is a highly differentiated structure consisting of cytoarchitectonically defined subareas that are specifically connected with other cortical and subcortical areas. Based on evidence from neurophysiological studies in subhuman primates these subareas are supposed to be functionally highly specialized. Here, we reviewed 51 different neuroimaging studies on healthy subjects with activation of the parietal lobe in statistical parametric maps. Running a cluster analysis on the stereotactic coordinates of the centers of gravity of the activation areas and plotting them into Talairach space showed a high consistency of the mean activation foci for similar paradigms across different laboratories and functional imaging modalities. Our meta-analysis exposed seven distinct pairs of quite symmetrically distributed subareas of the parietal cortex of each hemisphere as well as three unpaired regions that are critically involved in the generation of limb and eye movements in egocentric and allocentric coordinates, but also in attention, memory and cognitive problem solving. These data highlights the modular organization of the human parietal lobe. By its locally interspersed distributed circuits it orchestrates specialized cognitive subfunctions interfacing perception and action. Our meta-analysis provides a new framework for understanding information processing in the human parietal cortex.

Pathological crying induced by deep brain stimulation

Pathological crying (PLC)—an affective gesture without any or an adequate emotion—occurs with various diseases. A recent theory suggests that PLC is caused by a disruption of higher order cortical association areas from the cerebellum which computes profiles of psychomotor responses. We report a patient with Parkinsons disease who developed PLC during stimulation of the subthalamic nucleus (STN) predominantly of the right hemisphere. Positron emission tomography imaging showed thalamo‐ponto‐cerebellar activation during such stimulation. These findings indicate that the STN and possibly also ponto‐cerebellar pathways are involved in psychomotor control and in the modulation of PLC.

Gender‐specific Differences of Hypometabolism in mTLE: Implication for Cognitive Impairments

Summary:  Purpose: To determine gender differences of hypometabolism and their implications for cognitive impairment in patients with medically refractory mesial temporal lobe epilepsy (mTLE).

Variability of Clinical Functional MR Imaging Results: A Multicenter Study

PURPOSE To investigate intersite variability of clinical functional magnetic resonance (MR) imaging, including influence of task standardization on variability and use of various parameters to inform the clinician whether the reliability of a given functional localization is high or low. MATERIALS AND METHODS Local ethics committees approved the study; all participants gave written informed consent. Eight women and seven men (mean age, 40 years) were prospectively investigated at three experienced functional MR sites with 1.5- (two sites) or 3-T (one site) MR. Nonstandardized motor and highly standardized somatosensory versions of a frequently requested clinical task (localization of the primary sensorimotor cortex) were used. Perirolandic functional MR variability was assessed (peak activation variability, center of mass [COM] variability, intraclass correlation values, overlap ratio [OR], activation size ratio). Data quality measures for functional MR images included percentage signal change (PSC), contrast-to-noise ratio (CNR), and head motion parameters. Data were analyzed with analysis of variance and a correlation analysis. RESULTS Localization of perirolandic functional MR activity differed by 8 mm (peak activity) and 6 mm (COM activity) among sites. Peak activation varied up to 16.5 mm (COM range, 0.4-16.5 mm) and 45.5 mm (peak activity range, 1.8-45.5 mm). Signal strength (PSC, CNR) was significantly lower for the somatosensory task (mean PSC, 1.0% ± 0.5 [standard deviation]; mean CNR, 1.2 ± 0.4) than for the motor task (mean PSC, 2.4% ± 0.8; mean CNR, 2.9 ± 0.9) (P < .001, both). Intersite variability was larger with low signal strength (negative correlations between signal strength and peak activation variability) even if the task was highly standardized (mean OR, 22.0% ± 18.9 [somatosensory task] and 50.1% ± 18.8 [motor task]). CONCLUSION Clinical practice and clinical functional MR biomarker studies should consider that the center of task-specific brain activation may vary up to 16.5 mm, with the investigating site, and should maximize functional MR signal strength and evaluate reliability of local results with PSC and CNR.

Between- and within-site variability of fMRI localizations

This study provides first data about the spatial variability of fMRI sensorimotor localizations when investigating the same subjects at different fMRI sites. Results are comparable to a previous patient study. We found a median between‐site variability of about 6 mm independent of task (motor or sensory) and experimental standardization (high or low). An intraclass correlation coefficient analysis using data quality measures indicated a major influence of the fMRI site on variability. In accordance with this, within‐site localization variability was considerably lower (about 3 mm). We conclude that the fMRI site is a considerable confound for localization of brain activity. However, when performed by experienced clinical fMRI experts, brain pathology does not seem to have a relevant impact on the reliability of fMRI localizations. Hum Brain Mapp 37:2151–2160, 2016.

Brain Tumors: Clinical Applications of Functional Magnetic Resonance Imaging and Diffusion Tensor Imaging

One of the most exciting methodologies in the clinical neurosciences evolving toward the end of the twentieth century was functional magnetic resonance imaging (fMRI). Whereas MRI is used to produce structural images of subjects’ brain the functional component allows an in vivo measurement of brain activity. fMRI has provided new insights into human cognitive functions. Till now it was mainly used for basic scientific questions and has provided foundations for at least five large-scale neurocognitive networks identified in the human brain, namely for spatial attention, language, memory-emotion, executive function, and face and object recognition. In addition, white matter tractography based on diffusion tensor imaging (DTI) has become a well-accepted noninvasive tool for exploring the white matter architecture of the human brain in vivo. These two MR techniques are complementary in describing functional and anatomical components of grey and white matters. Furthermore, fMRI is useful to define the seed regions for DTI, because large interindividual anatomical variations make it difficult to define tracking seed areas based reliably on macroanatomical landmarks. An accurate definition of seed regions for the reconstruction of a specific neuronal pathway becomes even more challenging in patients suffering from space occupying brain lesions due to the displacement of the tissue and the distortion of anatomical landmarks around the lesion. Therefore, fMRI and DTI play a growing role in clinical neuroimaging with increasing applications in neurosurgical planning using neuronavigation. By means of neuronavigational devices both modalities can intuitively be used during surgical procedures. The goal of tumor surgery is to optimize the extent of resection, while minimizing the risk of a permanent neurological deficit. Because the tumor may infiltrate eloquent areas and because of major intersubject anatomical and functional variability, cortical functional organization, subcortical connectivity and brain plasticity can be studied at an individual scale. Presurgical functional neuroimaging and tractography can show the relationships between eloquent regions and the tumor, and consequently the cortical and subcortical structures essential for brain functions can be identified and preserved. In addition, post-operative control and longitudinal neuroimaging studies are important to study adaptive changes in network behaviour and to monitor the effects of brain plasticity.