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Florian Beissner

Journal articles

K J Bär, S Berger, C Schwier, U Wutzler, F Beissner (2012)  Insular dysfunction and descending pain inhibition in anorexia nervosa   Acta Psychiatrica Scandinavica  
Abstract: Objective: Reduced perception of pain is a well-established phenomenon in patients with anorexia nervosa (AN). We tested the hypothesis that altered processing of pain within the insula might account for reduced perception of pain. Method: Heat pain thresholds were obtained in nineteen patients with AN and matched controls. Thereafter, a thermode was used to deliver thermal painful stimuli to the right arm during functional magnetic resonance imaging (fMRI) measurements. Stimuli were initiated for 10 s from a baseline resting temperature (32°C) to three different levels (37, 42, 45°C). Results: Significantly increased heat pain thresholds were observed in patients. A stronger activation during heat pain perception was found in the left posterior insula in controls. In contrast, higher levels of activity were shown in the ipsilateral pons in patients when compared to controls. In patients, we found a significant interrelation between the depression score (Beck depression inventory) and heat pain activations. Conclusion: We suggest that reduced activity in the left posterior insula might contribute to increased pain thresholds in patients, while increased activations in the right anterior insula and pons mirror augmented sympathetic modulation putatively related to amplification of adrenergic descending pain inhibition. In addition, pain thresholds and brain activations were influenced by disease-inherent depressed mood.
F Beissner, Ralf Deichmann, Christian Henke, K J Bär (2012)  Acupuncture -€“ Deep pain with an autonomic dimension?   NeuroImage 60: 1. 653-660  
Abstract: Acupuncture point Pc6, located above the median nerve, has been shown to be effective in treating nausea and vomiting. Its stimulation frequently causes a heart rate reduction. The mechanism behind this autonomic reaction has not been clarified, so far. We combined brainstem-sensitive functional magnetic resonance imaging with heart rate recording and time-resolved rating of the needling sensation to measure neuronal correlates of sensations and autonomic reactions during acupuncture. On the cortical level, needling sensation activated typical pain-related areas, of which the ventromedial and dorsolateral prefrontal cortex and perigenual anterior cingulate cortex were further involved in mediating the heart rate response. In the brainstem, needling sensation activated nuclei of the descending pain control system, in which a network of hypothalamus, periaqueductal gray, rostral ventromedial medulla, and ventrolateral medulla was identified as the source of the heart rate changes. Our findings indicate that acupuncture may be a special pain stimulus, whose autonomic concomitants could explain its non-analgesic effects and in some cases even have a therapeutic potential.
Florian Beissner, Irene Marzolff (2012)  Investigation of Acupuncture Sensation Patterns under Sensory Deprivation Using a Geographic Information System.   Evidence-based complementary and alternative medicine: eCAM 2012: 591304.  
Abstract: The study of acupuncture-related sensations, like deqi and propagated sensations along channels (PSCs), has a long tradition in acupuncture basic research. The phenomenon itself, however, remains poorly understood. To study the connection between PSC and classical meridians, we applied a geographic information system (GIS) to analyze sketches of acupuncture sensations from healthy volunteers after laser acupuncture. As PSC can be subtle, we aimed at reducing the confounding impact of external stimuli by carrying out the experiment in a floatation tank under restricted environmental stimulation. 82.4% of the subjects experienced PSC, that is, they had line-like or 2-dimensional sensations, although there were some doubts that these were related to the laser stimulation. Line-like sensations on the same limb were averaged to calculate sensation mean courses, which were then compared to classical meridians by measuring the mean distance between the two. Distances ranged from 0.83 cm in the case of the heart (HT) and spleen (SP) meridian to 6.27 cm in the case of the kidney (KI) meridian. Furthermore, PSC was observed to "jump" between adjacent meridians. In summary, GIS has proven to be a valuable tool to study PSC, and our results suggest a close connection between PSC and classical meridians.
C Henke, F Beissner (2011)  Illustrationen zum ĂĽbertragenen Schmerz - Wie viel von Head steckt in den Headschen Zonen?   Schmerz 25: 2. 132-139  
Abstract: Beschäftigt man sich mit der Literatur zum Phänomen der Head-Zonen, so findet man in den gängigen Lehrbüchern der Anatomie, Physiologie und Neurologie stets den gleichen Typ von Abbildung vor. Aufgrund der Namensgebung könnte man annehmen, dass diese Abbildung auf Sir Henry Head zurückgehe. Verfolgt man jedoch die Referenzen etwa 100 Jahre zurück, so findet man das Originalbild letztlich in der deutschen Ausgabe des Chirurgie-Buches „Surgical Applied AnatomyÃ¢Â€Âś von Sir Frederick Treves aus dem Jahre 1914. Da weder die Autoren noch die Illustratoren des Buches experimentell über die Head-Zonen geforscht haben, muss diese Abbildung folglich auf Ergebnissen basieren, die aus älteren Quellen stammen. Bei Begutachtung der beiden groÃź en systematischen Arbeiten vor 1914, nämlich denen von Sir Henry Head und Sir James Mackenzie stellten wir fest, dass besagte Abbildung vorrangig auf den Arbeiten Mackenzies zu basieren scheint. Leider lassen sich die Quellen und Originalbilder, auf denen der Zeichner seiner Zeit die Abbildung begründet hat, heute nicht mehr nachvollziehen. Da der Zeichner keine der beiden Arbeiten exakt reproduziert hat, sind im Laufe der Zeit eine Reihe interessanter Fakten beider Autoren verloren gegangen. So wurde etwa das Phänomen der Headschen Maximalpunkte komplett ignoriert und ist daher heute fast vollständig in Vergessenheit geraten. Entsprechend muss man feststellen, dass die heutigen Darstellungen der Head-Zonen, die allesamt auf der Abbildung von 1914 basieren, eine Reduktion der exakt erarbeiteten und dokumentierten Ergebnisse von Head und Mackenzie darstellen. Deren Evidenzgrad ist daher als eher gering einzustufen.
F Beissner, Ulrike Nöth, Thomas Schockert (2011)  The Problem of Metal Needles in Acupuncture-fMRI Studies.   Evid Based Complement Alternat Med 2011: 808203. jan  
Abstract: Acupuncture is a therapy based on sensory stimulation of the human body by means of metal needles. The exact underlying mechanisms of acupuncture have not been clarified so far. Functional magnetic resonance imaging (fMRI) has become an important tool in acupuncture research. Standard acupuncture needles, which are made of ferromagnetic steel, however, are problematic in acupuncture-fMRI studies for several reasons, such as attraction by the scanner’s magnetic field, significant image distortions and signal-dropouts, when positioned close to the head or even heating due to absorption of radio frequency (RF). The aim of this study was to compare two novel types of acupuncture needles with a standard needle for their effect on MRI image quality. The standard needle severely reduced image quality, when located inside the RF coil. The nonferromagnetic metal needle may pose a risk due to RF heating, while the plastic needle has a significantly larger diameter. In conclusion, our recommendations are: (1) standard needles should not be used in MRI; (2) Nonferromagnetic metal needles seem to be the best choice for acupoints outside of the transmitter coil; and (3) only plastic needles are suited for points inside the coil. Laser acupuncture may be a safe alternative, too.
F Beissner, C Henke, P U Unschuld (2011)  Forgotten Features of Head Zones and Their Relation to Diagnostically Relevant Acupuncture Points   Evid Based Complement Alternat Med 2011: 240653. jan  
Abstract: In the 1890s Sir Henry Head discovered certain areas of the skin that develop tenderness (allodynia) in the course of visceral disease. These areas were later termed ’Head zones’. In addition, he also emphasized the existence of specific points within these zones, that he called ’maximum points’, a finding that seems to be almost forgotten today. We hypothesized that two important groups of acupuncture points, the diagnostically relevant Mu and Shu points, spatially and functionally coincide with these maximum points to a large extent. A comparison of Head’s papers with the Huang Di Neijing (Yellow Thearch’s Inner Classic) and the Zhen Jiu Jia Yi Jing (Systematic Classic of Acupuncture and Moxibustion), two of the oldest still extant Chinese sources on acupuncture, revealed astonishing parallels between the two concepts regarding both point locations and functional aspects. These findings suggest that the Chinese discovery of viscerocutaneous reflexes preceded the discovery in the West by more than 2000 years. Furthermore, the fact that Chinese medicine uses Mu and Shu points not only diagnostically but also therapeutically may give us new insights into the underlying mechanisms of acupuncture.
F Beissner, C Henke (2011)  Methodological problems in fMRI studies on acupuncture : A critical review with special emphasis on visual and auditory cortex activations   Evid Based Complement Alternat Med 2011: 607637.  
Abstract: Functional magnetic resonance imaging (fMRI) has been used for more than a decade to investigate possible supraspinal mechanisms of acupuncture stimulation. More than 60 studies and several review articles have been published on the topic. However, till now some acupuncture-fMRI studies have not adopted all methodological standards applied to most other fMRI studies. In this critical review, we comment on some of the problems including the choice of baseline, interpretation of deactivations, attention control and implications of different group statistics. We illustrate the possible impact of these problems by focussing on some early findings, namely activations of visual and auditory cortical areas, when acupoints were stimu- lated that are believed to have a therapeutic effect on vision or hearing in traditional Chinese medicine. While we are far from questioning the validity of using fMRI for the study of acupuncture effects, we think that activations reported by some of these studies were probably not a direct result of acupuncture stimulation but rather attributable to one or more of the methodological problems covered here. Finally, we try to offer solutions for these problems where possible.
F Beissner, R Deichmann, S Baudrexel (2011)  fMRI of the brainstem using dual-echo EPI   NeuroImage 55: 4. 1593-99  
Abstract: The brainstem is the part of the human brain that plays a pivotal role in the maintenance of many critical body functions. Due to the elevated level of cardiogenic noise, few fMRI studies have investigated the brainstem so far. Cardiac-gated echo-planar imaging with acquisition of two echoes per excitation (dual-echo EPI) is one method that significantly reduces cardiogenic noise and, thus, allows for fMRI measurements of the brainstem. As information on optimal preprocessing approaches for brainstem-fMRI data is still scarce, the goal of this study was to compare different combinations of normalization and smoothing procedures as implemented in standard fMRI software packages and to identify the combinations yielding optimal results for dual-echo EPI. 21 healthy subjects were measured while executing a simple motor paradigm to activate the facial and trigeminal motor nucleus in the brainstem. After motion correction and calculation of T2*-maps the data were preprocessed with 24 combinations of standard normalization (SPM classic, SPM unified, FSL, ABC) and smoothing procedures (pre-/post-smoothing with 3 mm-, 4.5 mm- and 6 mm-kernel) before undergoing first- and second-level statistical analysis. Activation results were compared for first-level and second-level statistics using two anatomically defined regions of interest. Five methods were found to be sensitive for activation of both nuclei. These included FSL normalization with 3 mm and 4.5 mm pre-smoothing as well as 3 mm post-smoothing, SPM unified normalization with 3 mm pre-smoothing and ABC normalization with 4.5 mm pre-smoothing. All these methods can be recommended for normalization and smoothing when analyzing fMRI data of the brainstem acquired by cardiac-gated dual-echo EPI.
F Beissner (2011)  fMRI studies of acupuncture mechanisms - a critique   Focus on Alternative and Complementary Therapies 16: 1. 3-11  
Abstract: Functional magnetic resonance imaging has been used extensively to study the underlying mechanisms of acupuncture. More than 80 studies and a dozen review articles have been published on this topic in the past 10 years. Emphasising the statistical quality of the studies, this critical review evaluates the results obtained so far by studies that have used a hypothesis-driven approach. A minimum sample size of 12 subjects, the application of random effects (or mixed effects) analyses, and a threshold corrected for multiple comparisons were defined as inclusion criteria for a meta-analysis of the reported cortical activations. Fourteen out of 71 studies met the inclusion criteria. The majority of these studies reported activations in cortical areas relevant to the processing of somatosensory, motor, or pain signals, as well as areas related to the special senses. From this type of study, it is so far impossible to say if cortical activations under acupuncture are part of an underlying mechanism, or if they simply reflect the brain’s processing of the somatosensory or pain stimulus from the acupuncture needle stimulation. In the future, the application of data-driven methods may lead to a more comprehensive understanding of neuronally mediated acupuncture effects.
Simon Baudrexel, Torsten Witte, Carola Seifried, Frederic von Wegner, F Beissner, Johannes C Klein, Helmuth Steinmetz, Ralf Deichmann, Jochen Roeper, RĂĽdiger Hilker (2011)  Resting state fMRI reveals increased subthalamic nucleus-motor cortex connectivity in Parkinson’s disease.   NeuroImage 55: 4. 1728-38  
Abstract: Parkinson’s disease (PD) is associated with abnormal hypersynchronicity in basal ganglia-thalamo-cortical loops. The clinical effectiveness of subthalamic nucleus (STN) high frequency stimulation indicates a crucial role of this nucleus within the affected motor networks in PD. Here we investigate alterations in the functional connectivity (FC) profile of the STN using resting state BOLD correlations on a voxel-by-voxel basis in functional magnetic resonance imaging (fMRI). We compared early stage PD patients (n=31) during the medication-off state with healthy controls (n=44). The analysis revealed increased FC between the STN and cortical motor areas (BA 4 and 6) in PD patients in accordance with electrophysiological studies. Moreover, FC analysis of the primary motor cortex (M1) hand area revealed that the FC increase was primarily found in the STN area within the basal ganglia. These findings are in good agreement with recent experimental data, suggesting that an increased STN-motor cortex synchronicity mediated via the so called hyperdirect motor cortex-subthalamic pathway might play a fundamental role in the pathophysiology of PD. An additional subgroup analysis was performed according to the presence (n=16) or absence (n=15) of tremor in patients. Compared to healthy controls tremor patients showed increased STN FC specifically in the hand area of M1 and the primary sensory cortex. In non-tremor patients, increased FC values were also found between the STN and midline cortical motor areas including the SMA. Taken together our results underline the importance of the STN as a key node for the modulation of BG-cortical motor network activity in PD patients.
F Beissner, S Baudrexel, Steffen Volz, R Deichmann (2010)  Dual-echo EPI for non-equilibrium fMRI - Implications of different echo combinations and masking procedures.   NeuroImage 52: 2. 524-31 apr  
Abstract: Dual-echo EPI is based on the acquisition of two images with different echo times per excitation, thus allowing for the calculation of purely T2(*) weighted data. The technique can be used for the measurement of functional activation whenever the prerequisite of constant equilibrium magnetization cannot be fulfilled due to variable inter-volume delays. The latter is the case when image acquisition is triggered by physiological parameters (e.g. cardiac gating) or by the subject’s response. Despite its frequent application, there is currently no standardized way of combining the information obtained from the two acquired echoes. The goal of this study was to quantify the implication of different echo combination methods (quotients of echoes and quantification of T(2)(*)) and calculation modalities, either pre-smoothing data before combination or subjecting unsmoothed combined data to masking (no masking, volume-wise masking, joint masking), on the theoretically predicted signal-to-noise ratio (SNR) of the BOLD response and on activation results of two fMRI experiments using finger tapping and visual stimulation in one group (n=5) and different motor paradigms to activate motor areas in the cortex and the brainstem in another group (n=21). A significant impact of echo combination and masking procedure was found for both SNR and activation results. The recommended choice is a direct calculation of T(2)(*) values, either using joint masking on unsmoothed data, or pre-smoothing images prior to T(2)(*) calculation. This method was most beneficial in areas close to the surface of the brain or adjacent to the ventricles and may be especially relevant to brainstem fMRI.
F Beissner, A Brandau, C Henke, L Felden, U Baumgärtner, Rolf-Detlef Treede, B G Oertel, J Lötsch (2010)  Quick discrimination of A(delta) and C fiber mediated pain based on three verbal descriptors.   PloS one 5: 9.  
Abstract: A(δ) and C fibers are the major pain-conducting nerve fibers, activate only partly the same brain areas, and are differently involved in pain syndromes. Whether a stimulus excites predominantly A(δ) or C fibers is a commonly asked question in basic pain research but a quick test was lacking so far.
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