Publications by authors named "J Pfannmöller"

11 Publications

  • Page 1 of 1

Tactile acuity of fingertips and hand representation size in human Area 3b and Area 1 of the primary somatosensory cortex.

Neuroimage 2021 May 27;232:117912. Epub 2021 Feb 27.

Functional Imaging Unit, Center for Diagnostic Radiology, University Medicine of Greifswald, Walther-Rathenau-Str.46, D-17475 Greifswald, Germany. Electronic address:

Intracortical mapping in monkeys revealed a full body map in all four cytoarchitectonic subdivisions of the contralateral primary somatosensory cortex (S1), as well as positive associations between spatio-tactile acuity performance of the fingers and their representation field size especially within cytoarchitectonic Area 3b and Area 1. Previous non-invasive investigations on these associations in humans assumed a monotonous decrease of representation field size from index finger to little finger although the field sizes are known to change in response to training or in disease. Recent developments improved noninvasive functional mapping of S1 by a) adding a cognitive task during repetitive stimulation to decrease habituation to the stimuli, b) smaller voxel size of fMRI-sequences, c) surface-based analysis accounting for cortical curvature, and d) increase of spatial specificity for fMRI data analysis by avoidance of smoothing, partial volume effects, and pial vein signals. We here applied repetitive pneumatic stimulation of digit 1 (D1; thumb) and digit 5 (D5; little finger) on both hands to investigate finger/hand representation maps in the complete S1, but also in cytoarchitectonic Areas 1, 2, 3a, and 3b separately, in 21 healthy volunteers using 3T fMRI. The distances between activation maxima of D1 and D5 were evaluated by two independent raters, blinded for performance parameters. The fingertip representations showed a somatotopy and were localized in the transition region between the crown and the anterior wall of the post central gyrus agreeing with Area 1 and 3b. Participants were comprehensively tested for tactile performance using von Freyhair filaments to determine cutaneous sensory thresholds (CST) as well as grating orientation thresholds (GOT) and two-point resolution (TPD) for spatio-tactile acuity testing. Motor performance was evaluated with pinch grip performance (Roeder test). We found bilateral associations of D1-D5 distance for GOT thresholds and partially also for TPD in Area 3b and in Area 1, but not if using the complete S1 mask. In conclusion, we here demonstrate that 3T fMRI is capable to map associations between spatio-tactile acuity and the fingertip representation in Area 3b and Area 1 in healthy participants.
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http://dx.doi.org/10.1016/j.neuroimage.2021.117912DOI Listing
May 2021

Laughter is in the air: involvement of key nodes of the emotional motor system in the anticipation of tickling.

Soc Cogn Affect Neurosci 2019 08;14(8):837-847

Faculty of Science and Medicine, Department of Neuroscience, Anatomy, University of Fribourg, 1700 Fribourg, Switzerland.

In analogy to the appreciation of humor, that of tickling is based upon the re-interpretation of an anticipated emotional situation. Hence, the anticipation of tickling contributes to the final outburst of ticklish laughter. To localize the neuronal substrates of this process, functional magnetic resonance imaging (fMRI) was conducted on 31 healthy volunteers. The state of anticipation was simulated by generating an uncertainty respecting the onset of manual foot tickling. Anticipation was characterized by an augmented fMRI signal in the anterior insula, the hypothalamus, the nucleus accumbens and the ventral tegmental area, as well as by an attenuated one in the internal globus pallidus. Furthermore, anticipatory activity in the anterior insula correlated positively with the degree of laughter that was produced during tickling. These findings are consistent with an encoding of the expected emotional consequences of tickling and suggest that early regulatory mechanisms influence, automatically, the laughter circuitry at the level of affective and sensory processing. Tickling activated not only those regions of the brain that were involved during anticipation, but also the posterior insula, the anterior cingulate cortex and the periaqueductal gray matter. Sequential or combined anticipatory and tickling-related neuronal activities may adjust emotional and sensorimotor pathways in preparation for the impending laughter response.
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http://dx.doi.org/10.1093/scan/nsz056DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6847157PMC
August 2019

Investigations on maladaptive plasticity in the sensorimotor cortex of unilateral upper limb CRPS I patients.

Restor Neurol Neurosci 2019 ;37(2):143-153

Functional Imaging Unit, Center for Diagnostic Radiology, University of Greifswald, Germany.

Background: Patients with a complex regional pain syndrome (CRPS) in the upper limb show a sensory and motor impairment of the hand. Decreased intra-cortical-inhibition (ICI) of the motor representation of the affected hand muscle and decreased somatosensory hand representation size were related to maladaptive plasticity.

Objective: To achieve new insights about CRPS we examined whether these alterations were present in a single cohort.

Methods: We used a multi-modal approach comprising behavioral testing, transcranial magnetic stimulation, and high resolution fMRI combined with a new analysis technique for improved neuronal specificity.

Results: We found a decreased pinch-grip performance, two-point discrimination on the fingertips, ICI in the motor cortex, and representation size of the hand in Brodmann Area 3b (BA3b) in the somatosensory cortex. Our analysis further showed that correlations with ICI on the non-affected side were absent on the affected side.

Conclusions: This study is the first to gather behavioral, neurophysiologic and imaging measurements for one patient cohort and it therefore enables a comprehensive view of collapsed associations of function and representation focused on the hemisphere contralateral to the affected hand.
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http://dx.doi.org/10.3233/RNN-180886DOI Listing
July 2019

Review on biomarkers in the resting-state networks of chronic pain patients.

Brain Cogn 2019 04 30;131:4-9. Epub 2018 Jun 30.

Functional Imaging Unit, Center for Diagnostic Radiology, University of Greifswald, Greifswald, Germany.

Biomarkers indicating characteristic alterations in the brains of pain patients would in comparison to behavioral examinations allow for earlier diagnoses of pain disease development, a more immediate monitoring of pain disease progression, and for the development of interventions to reverse or compensate for the alterations. To reveal causal relations between an observed alteration and the pain disease longitudinal examinations are essential. Resting-state fMRI examinations can readily be included in large longitudinal cohorts allowing to achieve sufficiently large patient samples even for rare diseases. Our literature review on longitudinal resting-state fMRI examinations of pain patients indicates that pain chronicity is predicted by alterations to the brain's reward system and default mode network. A brain wide reorganization of the resting-state networks is associated with the emergence of the chronic pain state. The functional connectivity of the left frontoparietal network predicts the evolution of pain intensity in the chronic state. Further investigations are necessary concerning the generalization of the biomarkers across the phases in pain development especially for the healthy state, across different pain etiologies, and their specificity to chronic pain. The currently acquired representative longitudinal cohorts will allow for clarification of those issues within the next decades.
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http://dx.doi.org/10.1016/j.bandc.2018.06.005DOI Listing
April 2019

High-resolution fMRI investigations of the fingertip somatotopy and variability in BA3b and BA1 of the primary somatosensory cortex.

Neuroscience 2016 Dec 21;339:667-677. Epub 2016 Oct 21.

Functional Imaging, Center for Diagnostic Radiology and Neuroradiology, University Medicine Greifswald, Walther-Rathenau-Straße 46, 17475 Greifswald, Germany. Electronic address:

The fingertip somatotopy in BA1 and BA3b of monkeys exhibits characteristic differences with a more discrete separation of the body parts in BA3b and a continuous orientation column-like structure in BA1. We present evidence for similar differences in the human somatotopy using BOLD fMRI for the investigations. Though the variability between the individual maps was large, we found a group-wide somatotopic representation in BA3b and BA1. The variability due to anatomical differences was small in our sample. This was demonstrated by comparing exact shortest distances in the individual brains and after nonlinear normalization to the group space template, for the removal of the individual anatomical variability. Distance mapping along Dijkstra paths was found to be a valid approximation to exact shortest paths only in the individual brains. The degree of fine-scale detail mapping was improved if valid surface distances instead of 3D Euclidean distances were applied. A further improvement was achieved by mapping the distances between all neighboring fingertips instead of only the outer fingertips. Taking into account all optimizations we found mirror symmetry of the somatotopy with respect to the interhemispheric gap.
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http://dx.doi.org/10.1016/j.neuroscience.2016.10.036DOI Listing
December 2016

Morphological and behavioral characterization of adult mice deficient for SrGAP3.

Cell Tissue Res 2016 10 17;366(1):1-11. Epub 2016 May 17.

Institut für Anatomie und Zellbiologie, Universitätsmedizin Greifswald, Friedrich-Löffler-Straße-23c, 17487, Greifswald, Germany.

SrGAP3 belongs to the family of Rho GTPase proteins. These proteins are thought to play essential roles in development and in the plasticity of the nervous system. SrGAP3-deficient mice have recently been created and approximately 10 % of these mice developed a hydrocephalus and died shortly after birth. The others survived into adulthood, but displayed neuroanatomical alteration, including increased ventricular size. We now show that SrGAP3-deficient mice display increased brain weight together with increased hippocampal volume. This increase was accompanied by an increase of the thickness of the stratum oriens of area CA1 as well as of the thickness of the molecular layer of the dentate gyrus (DG). Concerning hippocampal adult neurogenesis, we observed no significant change in the number of proliferating cells. The density of doublecortin-positive cells also did not vary between SrGAP3-deficient mice and controls. By analyzing Golgi-impregnated material, we found that, in SrGAP3-deficient mice, the morphology and number of dendritic spines was not altered in the DG. Likewise, a Sholl-analysis revealed no significant changes concerning dendritic complexity as compared to controls. Despite the distinct morphological alterations in the hippocampus, SrGAP3-deficient mice were relatively inconspicuous in their behavior, not only in the open-field, nest building but also in the Morris water-maze. However, the SrGAP3-deficient mice showed little to no interest in burying marbles; a behavior that is seen in some animal models related to autism, supporting the view that SrGAP3 plays a role in neurodevelopmental disorders.
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http://dx.doi.org/10.1007/s00441-016-2413-yDOI Listing
October 2016

Automated analysis protocol for high resolution BOLD-fMRI mapping of the fingertip somatotopy in brodmann area 3b.

J Magn Reson Imaging 2016 Feb 25;43(2):479-86. Epub 2015 Jun 25.

Functional Imaging Unit, Center for Diagnostic Radiology, University Medicine Greifswald, Germany.

Background: To introduce a standardized and automatized method for functional MRI (fMRI) examinations of the cortical sensory somatotopy in large samples for investigations of the fingertip somatotopy in the primary somatosensory cortex.

Methods: At 3 Tesla, T2* (spin-spin relaxation time) weighted images (gradient-echo echo planar imaging, voxel size 1.5 × 1.5 × 2 mm3) were acquired during stimulation of the finger tips for thumb, index and middle finger on both hands, in a group of 18 healthy participants. In addition, structural T1 weighted (magnetization prepared rapid gradient echo, isotropic voxel size 1 mm) and MR-angiography (time of flight, voxel size 0.26 × 0.26 × 0.5 mm3) images were recorded. Boundary based register served to combine movement correction and registration in FreeSurfer Functional analysis stream (FS-Fast), resulting in fine scale corrections, as revealed with FSL Possum (FSL FMRIB Software Library Physics-Oriented Simulated Scanner for Understanding MRI) simulations. Automated data analysis was achieved by inclusion of cytoarchitectonic probability maps for calculation of functional activation in Brodmann area 3b. Draining vessel artifacts were identified using the peak value approach and the MR-angiography. Distances were computed as the shortest connection within the gray matter.

Results: The fMRI somatotopic maps agreed with the expected fingertip somatotopy in 63% of the investigated subjects, an improvement of 34% compared with FS-Fast. Artifacts have been removed completely. Adjacent fingertips showed average distances of 8 ± 4.3 mm, and between thumb and middle finger 13.4 ± 4.8 mm was found. Distances for both hands were similar as expected from the characteristics of the fingertip spatial tactile resolution.

Conclusion: The introduced evaluation procedure allowed automated analysis of the fingertip representation in excellent agreement with preceding results.
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http://dx.doi.org/10.1002/jmri.24980DOI Listing
February 2016

Fear-potentiated startle processing in humans: Parallel fMRI and orbicularis EMG assessment during cue conditioning and extinction.

Int J Psychophysiol 2015 Dec 25;98(3 Pt 2):535-45. Epub 2015 Feb 25.

Department of Psychology, University of Greifswald, Germany.

Studying neural networks and behavioral indices such as potentiated startle responses during fear conditioning has a long tradition in both animal and human research. However, most of the studies in humans do not link startle potentiation and neural activity during fear acquisition and extinction. Therefore, we examined startle blink responses measured with electromyography (EMG) and brain activity measured with functional MRI simultaneously during differential conditioning. Furthermore, we combined these behavioral fear indices with brain network activity by analyzing the brain activity evoked by the startle probe stimulus presented during conditioned visual threat and safety cues as well as in the absence of visual stimulation. In line with previous research, we found a fear-induced potentiation of the startle blink responses when elicited during a conditioned threat stimulus and a rapid decline of amygdala activity after an initial differentiation of threat and safety cues in early acquisition trials. Increased activation during processing of threat cues was also found in the anterior insula, the anterior cingulate cortex (ACC), and the periaqueductal gray (PAG). More importantly, our results depict an increase of brain activity to probes presented during threatening in comparison to safety cues indicating an involvement of the anterior insula, the ACC, the thalamus, and the PAG in fear-potentiated startle processing during early extinction trials. Our study underlines that parallel assessment of fear-potentiated startle in fMRI paradigms can provide a helpful method to investigate common and distinct processing pathways in humans and animals and, thus, contributes to translational research.
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http://dx.doi.org/10.1016/j.ijpsycho.2015.02.025DOI Listing
December 2015

Usage of the middle finger shapes reorganization of the primary somatosensory cortex in patients with index finger amputation.

Restor Neurol Neurosci 2014 ;32(4):507-15

Functional Imaging Unit, Center for Diagnostic Radiology, University of Greifswald, Greifswald, Germany.

Purpose: The primary somatosensory cortex (S1) is somatotopically reorganized after limb amputation. The duration of the amputation, the intensity of phantom limb pain but also a multifactoral model of altered cerebral input have been discussed to be associated with cortical changes. Patients with finger amputation rarely show phantom limb pain, the deafferented cortical area is small but other fingers might well overtake function.

Method: We selected a group of index finger amputated patients and performed a high resolution (in plane: 1.5 mm2) S1-mapping during tactile stimulation of finger tips.

Result: We found an interhemispheric imbalance of the distance between the thumb and middle finger only for the patient-group. When patients used their middle finger more they showed less interhemispheric imbalance, increased spatial tactile discrimination and increased fMRI-activation in response to stimulation. Phantom limb pain was not associated with somatotopic representation parameters in S1.

Conclusions: Overall, our fMRI-data point to a usage dependent plasticity of Brodmann's area 3b in man.
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http://dx.doi.org/10.3233/RNN-130380DOI Listing
March 2015

Post-mortem magnetic resonance microscopy (MRM) of the murine brain at 7 Tesla results in a gain of resolution as compared to in vivo MRM.

Front Neuroanat 2014 13;8:47. Epub 2014 Jun 13.

Functional Imaging Unit, Center for Diagnostic Radiology, University of Greifswald Germany.

Small-animal MRI with high field strength allows imaging of the living animal. However, spatial resolution in in vivo brain imaging is limited by the scanning time. Measurements of fixated mouse brains allow longer measurement time, but fixation procedures are time consuming, since the process of fixation may take several weeks. We here present a quick and simple post-mortem approach without fixation that allows high-resolution MRI even at 7 Tesla (T2-weighted MRI). This method was compared to in vivo scans with optimized spatial resolution for the investigation of anesthetized mice (T1-weighted MRI) as well as to ex situ scans of fixed brains (T1- and T2-weighted scans) by using standard MRI-sequences, along with anatomic descriptions of areas observable in the MRI, analysis of tissue shrinkage and post-processing procedures (intensity inhomogeneity correction, PCNN3D brain extract, SPMMouse segmentation, and volumetric measurement). Post-mortem imaging quality was sufficient to determine small brain substructures on the morphological level, provided fast possibilities for volumetric acquisition and for automatized processing without manual correction. Moreover, since no fixation was used, tissue shrinkage due to fixation does not occur as it is, e.g., the case by using ex vivo brains that have been kept in fixatives for several days. Thus, the introduced method is well suited for comparative investigations, since it allows determining small structural alterations in the murine brain at a reasonable high resolution even by MRI performed at 7 Tesla.
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http://dx.doi.org/10.3389/fnana.2014.00047DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4056281PMC
July 2014

T1 bias in chemical shift-encoded liver fat-fraction: role of the flip angle.

J Magn Reson Imaging 2014 Oct 15;40(4):875-83. Epub 2013 Nov 15.

Department of Radiology and Neuroradiology, University Greifswald, Greifswald, Germany.

Purpose: To investigate flip angle (FA)-dependent T1 bias in chemical shift-encoded fat-fraction (FF) and to evaluate a strategy for correcting this bias to achieve accurate MRI-based estimates of liver fat with optimized signal-to-noise ratio (SNR).

Materials And Methods: Thirty-three obese patients, 14 men/19 women, aged 57.3 ± 13.9 years underwent 3 Tesla (T) liver MRI including MR-spectroscopy and four three-echo-complex chemical shift-encoded MRI sequences using different FAs (1°/3°/10°/20°). FF was estimated with R2* correction and multi-peak fat spectral modeling. The FF for each FA with and without T1 correction was compared with spectroscopy as a reference standard, using linear regression. Relative SNR of the magnitude data were assessed for each flip angle.

Results: The correlation between chemical shift-encoded MRI and spectroscopy was high (R(2) ≈ 0.9). Without T1 correction, the agreement of both techniques showed no significant differences in slope (PFlipAngle1 °  = 0.385/PFlipAngle3 °  = 0.289) using low FA. High FA resulted in significant different slopes (PFlipAngle10 °  = 0.016/PFlipAngle20 °  = 0.014. T1 bias was successfully corrected using the T1 correction strategy (slope:PFlipAngle10 °  = 0.387/PFlipAngle20 °  = 0.440). Additionally, the use of high FA (near the Ernst angle) improved the SNR of the magnitude data (FA1 vs. FA3; respectively FA1 vs. FA10 P ≤ 0.001).

Conclusion: T1 bias is a strong confounder in the assessment of liver fat using chemical shift imaging with high FA. However, using a larger flip angle with T1 correction leads to higher SNR, and residual error after T1 correction is very small.
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http://dx.doi.org/10.1002/jmri.24457DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4785023PMC
October 2014