Aberrant functional connectivity of resting state networks related to misperceptions and intra-individual variability in Parkinson's disease.

Patients with Parkinson's disease (PD) frequently suffer from visual misperceptions and hallucinations, which are difficult to objectify and quantify. We aimed to develop an image recognition task to objectify misperceptions and to assess performance fluctuations in PD patients with and without self-reported hallucinations. Thirty-two non-demented patients with Parkinson's disease (16 with and 16 without self-reported visual hallucinations) and 25 age-matched healthy controls (HC) were tested. Participants performed a dynamic image recognition task with real and scrambled images. We assessed misperception scores and intra-individual variability in recognition times. To gain insight into possible neural mechanisms related to misperceptions and performance fluctuations we correlated resting state network connectivity to the behavioral outcomes in a subsample of Parkinson's disease patients (N = 16). We found that PD patients with self-reported hallucinations (PD-VH) exhibited higher perceptual error rates, due to decreased perceptual sensitivity and not due to changed decision criteria. In addition, PD-VH patients exhibited higher intra-individual variability in recognition times than HC or PD-nonVH patients. Both, misperceptions and intra-individual variability were negatively correlated with resting state functional connectivity involving frontal and parietal brain regions, albeit in partly different subregions. Consistent with previous research suggesting that hallucinations arise from dysfunction in attentional networks, misperception scores correlated with reduced functional connectivity between the dorsal attention and salience network. Intra-individual variability correlated with decreased connectivity between somatomotor and right fronto-parietal networks. We conclude that our task can detect visual misperceptions that are more prevalent in PD-VH patients. In addition, fluctuating visual performance appear to be a signature of PD-VH patients, which might assist further studies of the underlying pathophysiological mechanisms and cognitive processes.

Cortical representation of auricular muscles in humans: A robot-controlled TMS mapping and fMRI study.

BACKGROUND: Most humans have the ability to activate the auricular muscles. Although (intentional) control suggests an involvement of higher cortical centers underlying posterior auricular muscle (PAM) activation, the cortical representation of the auricular muscles is still unknown. METHODS: With the purpose of identifying a possible cortical representation area we performed automated robotic and image-guided transcranial magnetic stimulation (TMS) mapping (n = 8) and functional magnetic resonance imaging (fMRI) (n = 13). For topographical comparison, a similar experimental protocol was applied for the first dorsal interosseus muscle (FDI) of the hand. RESULTS: The calculated centers of gravity (COGs) of both muscles were located on the precentral gyrus with the PAM COGs located more laterally compared to the FDI. The distance between the mean PAM and mean FDI COG was 26.3 mm. The TMS mapping results were confirmed by fMRI, which showed a dominance of cortical activation within the precentral gyrus during the corresponding motor tasks. The correspondence of TMS and fMRI results was high. CONCLUSION: The involvement of the primary motor cortex in PAM activation might point to an evolved function of the auricular muscles in humans and/or the ability of intentional (and selective) muscle activation.

Reach and grasp deficits following damage to the dorsal pulvinar.

Expansion of the dorsal pulvinar in humans and its anatomical connectivity suggests its involvement in higher-order cognitive and visuomotor functions. We investigated visuomotor performance in a 31 year old patient (M.B.) with a lesion centered on the medial portion of the dorsal pulvinar (left > right) due to an atypical Sarcoidosis manifestation. Unlike lesions with a vascular etiology, the lesion of M.B. did not include primary sensory or motor thalamic nuclei. Thus, this patient gave us the exceedingly rare opportunity to study the contribution of the dorsal pulvinar to visuomotor behavior in a human without confounding losses in primary sensory or motor domains. We investigated reaching, saccade and visual decision making performance. Patient data in each task was compared to at least seven age matched healthy controls. While saccades were hypometric towards both hemifields, the patient did not show any spatial choice bias or perceptual deficits. At the same time, he exhibited reach and grasp difficulties, which shared features with both, parietal and cerebellar damage. In particular, he had problems to form a precision grip and exhibited reach deficits expressed in decreased accuracy, delayed initiation and prolonged movement durations. Reach deficits were similar in foveal and extrafoveal viewing conditions and in both visual hemifields but were stronger with the right hand. These results suggest that dorsal pulvinar function in humans goes beyond its subscribed role in visual cognition and is critical for the programming of voluntary actions with the hands.

Structural connectivity of right frontal hyperactive areas scales with stuttering severity.

A neuronal sign of persistent developmental stuttering is the magnified coactivation of right frontal brain regions during speech production. Whether and how stuttering severity relates to the connection strength of these hyperactive right frontal areas to other brain areas is an open question. Scrutinizing such brain-behaviour and structure-function relationships aims at disentangling suspected underlying neuronal mechanisms of stuttering. Here, we acquired diffusion-weighted and functional images from 31 adults who stutter and 34 matched control participants. Using a newly developed structural connectivity measure, we calculated voxel-wise correlations between connection strength and stuttering severity within tract volumes that originated from functionally hyperactive right frontal regions. Correlation analyses revealed that with increasing speech motor deficits the connection strength increased in the right frontal aslant tract, the right anterior thalamic radiation, and in U-shaped projections underneath the right precentral sulcus. In contrast, with decreasing speech motor deficits connection strength increased in the right uncinate fasciculus. Additional group comparisons of whole-brain white matter skeletons replicated the previously reported reduction of fractional anisotropy in the left and right superior longitudinal fasciculus as well as at the junction of right frontal aslant tract and right superior longitudinal fasciculus in adults who stutter compared to control participants. Overall, our investigation suggests that right fronto-temporal networks play a compensatory role as a fluency enhancing mechanism. In contrast, the increased connection strength within subcortical-cortical pathways may be implied in an overly active global response suppression mechanism in stuttering. Altogether, this combined functional MRI-diffusion tensor imaging study disentangles different networks involved in the neuronal underpinnings of the speech motor deficit in persistent developmental stuttering.

To err is (perfectly) human: behavioural and neural correlates of error processing and perfectionism.

The attitude towards one's own imperfection strongly varies between individuals. Here, we investigated variations in error-related activity depending on two sub-traits of perfectionism, Personal Standard Perfectionism (PSP) and Evaluative Concern Perfectionism (ECP) in a large scale functional magnetic resonance imaging study (N = 75) using a digit-flanker task. Participants with higher PSP scores showed both more post-error slowing and more neural activity in the medial-frontal gyrus including anterior cingulate cortex after errors. Interestingly, high-EC perfectionists with low PSP showed no post-error slowing and the highest activity in the middle frontal gyrus, whereas high-EC perfectionists with high PSP showed the lowest activity in this brain area and more post-error slowing. Our findings are in line with the hypothesis that perfectionists with high concerns but low standards avoid performance monitoring to avoid the worry-inducing nature of detecting personal failure and the anticipation of poor evaluation by others. However, the stronger goal-oriented performance motivation of perfectionists with high concerns and high standards may have led to less avoidance of error processing and a more intense involvement with the imperfect behaviour, which is essential for improving future performance.

Simultaneous Transcranial Alternating Current Stimulation and Functional Magnetic Resonance Imaging.

Transcranial alternating current stimulation (tACS) is a promising tool for noninvasive investigation of brain oscillations. TACS employs frequency-specific stimulation of the human brain through current applied to the scalp with surface electrodes. Most current knowledge of the technique is based on behavioral studies; thus, combining the method with brain imaging holds potential to better understand the mechanisms of tACS. Because of electrical and susceptibility artifacts, combining tACS with brain imaging can be challenging, however, one brain imaging technique that is well suited to be applied simultaneously with tACS is functional magnetic resonance imaging (fMRI). In our lab, we have successfully combined tACS with simultaneous fMRI measurements to show that tACS effects are state, current, and frequency dependent, and that modulation of brain activity is not limited to the area directly below the electrodes. This article describes a safe and reliable setup for applying tACS simultaneously with visual task fMRI studies, which can lend to understanding oscillatory brain function as well as the effects of tACS on the brain.

Tinnitus- related distress: evidence from fMRI of an emotional stroop task.

BACKGROUND: Chronic tinnitus affects 5 % of the population, 17 % suffer under the condition. This distress seems mainly to be dependent on negative cognitive-emotional evaluation of the tinnitus and selective attention to the tinnitus. A well-established paradigm to examine selective attention and emotional processing is the Emotional Stroop Task (EST). Recent models of tinnitus distress propose limbic, frontal and parietal regions to be more active in highly distressed tinnitus patients. Only a few studies have compared high and low distressed tinnitus patients. Thus, this study aimed to explore neural correlates of tinnitus-related distress. METHODS: Highly distressed tinnitus patients (HDT, n = 16), low distressed tinnitus patients (LDT, n = 16) and healthy controls (HC, n = 16) underwent functional magnetic resonance imaging (fMRI) during an EST, that used tinnitus-related words and neutral words as stimuli. A random effects analysis of the fMRI data was conducted on the basis of the general linear model. Furthermore correlational analyses between the blood oxygen level dependent response and tinnitus distress, loudness, depression, anxiety, vocabulary and hypersensitivity to sound were performed. RESULTS: Contradictory to the hypothesis, highly distressed patients showed no Stroop effect in their reaction times. As hypothesized HDT and LDT differed in the activation of the right insula and the orbitofrontal cortex. There were no hypothesized differences between HDT and HC. Activation of the orbitofrontal cortex and the right insula were found to correlate with tinnitus distress. CONCLUSIONS: The results are partially supported by earlier resting-state studies and corroborate the role of the insula and the orbitofrontal cortex in tinnitus distress.

Neural Correlates Differ in High and Low Fear-Avoidant Chronic Low Back Pain Patients When Imagining Back-Straining Movements.

UNLABELLED: The fear-avoidance model postulates that in an initial acute phase chronic low back pain (CLBP) patients acquire a fear of movement that results in avoidance of physical activity and contributes to the pain becoming chronic. The current functional magnetic resonance imaging study investigated the neural correlates of imagining back-straining and neutral movements in CLBP patients with high (HFA) and low fear avoidance (LFA) and healthy pain-free participants. Ninety-three persons (62 CLBP patients, 31 healthy controls; age 49.7 ± 9.2 years) participated. The CLBP patients were divided into an HFA and an LFA group using the Tampa Scale of Kinesiophobia. The participants viewed pictures of back-straining and neutral movements and were instructed to imagine that they themselves were executing the activity shown. When imagining back-straining movements, HFA patients as well as healthy controls showed stronger anterior hippocampus activity than LFA patients. The neural activations of HFA patients did not differ from those of healthy controls. This may indicate that imagining back-straining movements triggered pain-related evaluations in healthy controls and HFA participants, but not in LFA participants. Although heightened pain expectancy in HFA compared with LFA patients fits well with the fear-avoidance model, the difference between healthy controls and LFA patients was unexpected and contrary to the fear-avoidance model. Possibly, negative evaluations of the back-straining movements are common but the LFA patients use some kind of strategy enabling them to react differently to the back-straining events. PERSPECTIVE: It appears that low fear-avoidant back pain patients use some kind of strategy or underlying mechanism that enables them to react with less fear in the face of potentially painful movements. This warrants further investigation because countering fear and avoidance provide an important advantage with respect to disability.

A DTI study on the corpus callosum of treatment-naïve boys with 'pure' Tourette syndrome.

Disturbances in the corpus callosum (CC) indicating altered interhemispheric connectivity have been associated with Tourette syndrome (TS). The objective of the present study was to refine knowledge about interhemispheric connectivity in TS by analyzing four different diffusion tensor imaging (DTI) parameters in a very homogeneous group of treatment-naïve boys with pure TS in comparison to male healthy controls (HC). Fractional anisotropy (FA), radial diffusivity (RD), axial diffusivity (AD) and mean diffusivity (MD) of five CC-segments were assessed from DTI of 26 treatment-naïve boys with pure TS and 24 HC. We observed no group differences in both FA and RD. However, we found a significant effect for AD and a trend for MD, being both reduced in boys with TS in comparison to HC. Moreover, a negative correlation between AD and the Yale Global Tic Severity Scale total score was observed. Reduced AD of the CC in treatment-naïve boys with pure TS in comparison to HC may indicate that significant alterations in white matter microstructure of the CC contribute to tic symptomatology per se and seem not to be related to confounders such as consequences of long-term medication, tic performance or tic suppression.

Transcranial alternating current stimulation affects the BOLD signal in a frequency and task-dependent manner.

Transcranial alternating current stimulation (tACS) has emerged as a promising tool for manipulating ongoing brain oscillations. While previous studies demonstrated frequency-specific effects of tACS on diverse cognitive functions, its effect on neural activity remains poorly understood. Here we asked how tACS modulates regional fMRI blood oxygenation level dependent (BOLD) signal as a function of frequency, current strength, and task condition. TACS was applied over the posterior cortex of healthy human subjects while the BOLD signal was measured during rest or task conditions (visual perception, passive video viewing and motor task). TACS was applied in a blockwise manner at different frequencies (10, 16, 60 and 80 Hz). The strongest tACS effects on BOLD activity were observed with stimulation at alpha (10 Hz) and beta (16 Hz) frequency bands, while effects of tACS at the gamma range were rather modest. Specifically, we found that tACS at 16 Hz induced BOLD activity increase in fronto-parietal areas. Overall, tACS effects varied as a function of frequency and task, and were predominantly seen in regions that were not activated by the task. Also, the modulated regions were poorly predicted by current density modeling studies. Taken together, our results suggest that tACS does not necessarily exert its strongest effects in regions below the electrodes and that region specificity might be achieved with tACS due to varying susceptibility of brain regions to entrain to a given frequency.

Neural Correlates of Empathy with Pain Show Habituation Effects. An fMRI Study.

BACKGROUND: Neuroimaging studies have demonstrated that the actual experience of pain and the perception of another person in pain share common neural substrates, including the bilateral anterior insular cortex and the anterior midcingulate cortex. As many fMRI studies include the exposure of participants to repeated, similar stimuli, we examined whether empathic neural responses were affected by habituation and whether the participants' prior pain experience influenced these habituation effects. METHOD: In 128 trials (four runs), 62 participants (31 women, 23.0 ± 4.2 years) were shown pictures of hands exposed to painful pressure (pain pictures) and unexposed (neutral pictures). After each trial, the participants rated the pain of the model. Prior to the experiment, participants were either exposed to the same pain stimulus (pain exposure group) or not (touch exposure group). In order to assess possible habituation effects, linear changes in the strength of the BOLD response to the pain pictures (relative to the neutral pictures) and in the ratings of the model's pain were evaluated across the four runs. RESULTS: Although the ratings of the model's pain remained constant over time, we found neural habituation in the bilateral anterior/midinsular cortex, the posterior midcingulate extending to dorsal posterior cingulate cortex, the supplementary motor area, the cerebellum, the right inferior parietal lobule, and the left superior frontal gyrus, stretching to the pregenual anterior cingulate cortex. The participant's prior pain experience did neither affect their ratings of the model's pain nor their maintenance of BOLD activity in areas associated with empathy. Interestingly, participants with high trait personal distress and fantasy tended to show less habituation in the anterior insula. CONCLUSION: Neural structures showed a decrease of the BOLD signal, indicating habituation over the course of 45 minutes. This can be interpreted as a neuronal mechanism responding to the repeated exposure to pain depictions, which may be regarded as functional in a range of contexts.

Neurocognitive functions and brain atrophy after proven neuroborreliosis: a case-control study.

BACKGROUND: Patients often report neurocognitive difficulties after neuroborreliosis (NB). The frequency and extent of cognitive problems in European patients have been studied incompletely. METHODS: Sixty patients received a neurological and neuropsychological work-up 6 months or longer after treatment for proven NB. Quality of life, psychiatric symptom load, and brain atrophy were measured. All results were compared with a group of 30 healthy control persons adapted for age, gender and education being serologically negative for Borrelia burgdorferi senso latu. A cognitive sum score and a global sum score including cognitive, psychological results and quality of life data was calculated for both groups. RESULTS: Patients after NB showed a lower (i.e. more impaired) score on the Scripps Neurological rating scale (SNRS), but the observed neurological deficits were generally mild (mean ± SD: 97.1 ± 4.7 vs. 99.1 ± 2.4, p = 0.02). The mean neuropsychological domain results of the NB group were all within the normal range. However, a lower performance was found for the frontal executive function z-values (mean ± SD -0.29 ± 0.60 vs. 0.09 ± 0.60; p = 0.0059) of NB patients. Comparing the global sum score (mean ± SD 11.3 ± 4.2 NB vs. 14.3 ± 2.9 control , p = 0.001) and the cognitive sum score of the NB group with those of the control group (mean ± SD -0.15 ± 0.42 NB vs. 0.08 ± 0.31 control , p = 0.0079), both differences were statistically different. The frequencies of impaired global sum scores and those of the pathological cognitive sum scores (p = 0.07) did not differ statistically. No significant differences were found for health-related quality of life (hrQoL), sleep, psychiatric symptom load, or brain atrophy. CONCLUSION: The mean cognitive functions of patients after proven NB were in the normal range. However, we were able to demonstrate a lower performance for the domain of frontal executive functions, for the mean cognitive sum score and the global sum score as a sign of subtle but measurable sequelae of neuroborreliosis. Brain atrophy is not a common consequence of neuroborreliosis.

Rhythmic gamma stimulation affects bistable perception.

When our brain is confronted with ambiguous visual stimuli, perception spontaneously alternates between different possible interpretations although the physical stimulus remains the same. Both alpha (8-12 Hz) and gamma (>30 Hz) oscillations have been reported to correlate with such spontaneous perceptual reversals. However, whether these oscillations play a causal role in triggering perceptual switches remains unknown. To address this question, we applied transcranial alternating current stimulation (tACS) over the posterior cortex of healthy human participants to boost alpha and gamma oscillations. At the same time, participants were reporting their percepts of an ambiguous structure-from-motion stimulus. We found that tACS in the gamma band (60 Hz) increased the number of spontaneous perceptual reversals, whereas no significant effect was found for tACS in alpha (10 Hz) and higher gamma (80 Hz) frequencies. Our results suggest a mechanistic role of gamma but not alpha oscillations in the resolution of perceptual ambiguity.

Egocentric virtual maze learning in adult survivors of childhood abuse with dissociative disorders: evidence from functional magnetic resonance imaging.

Present neuroimaging findings suggest two subtypes of trauma response, one characterized predominantly by hyperarousal and intrusions, and the other primarily by dissociative symptoms. The neural underpinnings of these two subtypes need to be better defined. Fourteen women with childhood abuse and the current diagnosis of dissociative amnesia or dissociative identity disorder but without posttraumatic stress disorder (PTSD) and 14 matched healthy comparison subjects underwent functional magnetic resonance imaging (fMRI) while finding their way in a virtual maze. The virtual maze presented a first-person view (egocentric), lacked any topographical landmarks and could be learned only by using egocentric navigation strategies. Participants with dissociative disorders (DD) were not impaired in learning the virtual maze when compared with controls, and showed a similar, although weaker, pattern of activity changes during egocentric learning when compared with controls. Stronger dissociative disorder severity of participants with DD was related to better virtual maze performance, and to stronger activity increase within the cingulate gyrus and the precuneus. Our results add to the present knowledge of preserved attentional and visuospatial mnemonic functioning in individuals with DD.

Effects of age on negative BOLD signal changes in the primary somatosensory cortex.

In addition to a contralateral activation of the primary and secondary somatosensory cortices, peripheral sensory stimulation has been shown to elicit responses in the ipsilateral primary somatosensory cortex (SI). In particular, evidence is accumulating that processes of interhemispheric inhibition as depicted by negative blood oxygenation level dependent (BOLD) signal changes are part of somatosensory processes. The aim of the study was to analyze age-related differences in patterns of cerebral activation in the somatosensory system in general and processes of interhemispheric inhibition in particular. For this, a functional magnetic resonance imaging (fMRI) study was performed including 14 younger (mean age 23.3±0.9years) and 13 healthy older participants (mean age 73.2±8.3years). All subjects were scanned during peripheral electrical median nerve stimulation (40Hz) to obtain BOLD responses in the somatosensory system. Moreover, the individual current perception threshold (CPT) as a quantitative measure of sensory function was determined in a separate psychophysical testing. Significant increases in BOLD signal across the entire group could be measured within the contralateral SI, in the bilateral secondary somatosensory cortex (SII), the contralateral supplementary motor area and the insula. Negative BOLD signal changes were delineated in ipsilateral SI/MI as well as in the ipsilateral thalamus and basal ganglia. After comparing the two groups, only the cortical deactivation in ipsilateral SI in the early stimulation phase as well as the activation in contralateral SI and SII in the late stimulation block remained as statistically significant differences between the two groups. The psychophysical experiments yielded a significant age-dependent effect of CPT change with less difference in the older group which is in line with the significantly smaller alterations in maximal BOLD signal change in the contra- and ipsilateral SI found between the two groups. Healthy aging seems to be associated with a decrease in intracerebral inhibition as reflected by smaller negative BOLD signal changes during fMRI tasks. This finding could constitute an important link between age-related neurophysiological changes and behavioral alterations in humans.

The effects of prior pain experience on neural correlates of empathy for pain: An fMRI study.

Neuroimaging studies have revealed partially shared neural substrates for both the actual experience of pain and empathy elicited by the pain of others. We examined whether prior pain exposure increased neural activity in the anterior midcingulate cortex (aMCC) and bilateral anterior insula (AI) as a correlate of empathy for pain. Participants (N=64: 32 women, 32 men) viewed pictures displaying exposure to pressure pain (pain pictures) and pictures without any cue of pain (neutral pictures). Prior to the experiment, half of the participants were exposed to the same pain stimulus as the one seen in the pain pictures (pain exposure condition); the other half had no such experience (touch exposure condition). A balanced sex ratio was kept, to investigate possible sex differences. In the region-of-interest analyses, participants of the pain exposure condition showed decreased activity in the right AI and the aMCC relative to participants of the touch exposure condition. While in men, no differences were found in relation to their exposure condition, women with pain exposure showed decreased activity in the aMCC and additionally, in bilateral AI. Based on the entire sample, whole brain analyses revealed stronger activation in the retrosplenial cortex, dorsomedial prefrontal cortex, and medial prefrontal cortex in the pain exposure condition. In conclusion, prior pain exposure did not increase, but decreased activity in regions regularly associated with empathy for pain. However, pain experience increased activity in regions associated with memory retrieval, perspective taking, and top-down emotion regulation, which might facilitate empathizing with others.

Neural correlates of tinnitus related distress: an fMRI-study.

Chronic tinnitus affects approximately 5% of the population. Severe distress due to the phantom noise is experienced by 20% of the tinnitus patients. This distress cannot be predicted by psychoacoustic features of the tinnitus. It is commonly assumed that negative cognitive emotional evaluation of the tinnitus and its expected consequences is a major factor that determines the impact of tinnitus-related distress. Models of tinnitus distress and recently conducted research propose differences in limbic, frontal and parietal processing between highly and low distressed tinnitus patients. An experimental paradigm using verbal material to stimulate cognitive emotional processing of tinnitus-related information was conducted. Age and sex matched highly (n = 16) and low (n = 16) distressed tinnitus patients and healthy controls (n = 16) underwent functional magnetic resonance imaging (fMRI) while sentences with neutral, negative or tinnitus-related content were presented. A random effects group analysis was performed on the basis of the general linear model. Tinnitus patients showed stronger activations to tinnitus-related sentences in comparison to neutral sentences than healthy controls in various limbic/emotion processing areas, such as the anterior cingulate cortex, midcingulate cortex, posterior cingulate cortex, retrosplenial cortex and insula and also in frontal areas. Highly and low distressed tinnitus patients differed in terms of activation of the left middle frontal gyrus. A connectivity analysis and correlational analysis between the predictors of the general linear model of relevant contrasts and tinnitus-related distress further supported the idea of a fronto-parietal-cingulate network, which seems to be more active in highly distressed tinnitus patients. This network may present an aspecific distress network. Based on the findings the left middle frontal gyrus and the right medial frontal gyrus are suggested as target regions for neuromodulatory approaches in the treatment of tinnitus. For future studies we recommend the use of idiosyncratic stimulus material.

Neural correlates of fear of movement in high and low fear-avoidant chronic low back pain patients: an event-related fMRI study.

The fear-avoidance model postulates that in chronic low back pain (CLBP) a fear of movement is acquired in the acute phase, which leads to subsequent avoidance of physical activity and contributes to the pain syndrome's becoming chronic. In the present event-related functional magnetic resonance imaging (fMRI) study of the neural correlates of the fear of movement, 60 women (30 CLBP patients, 15 healthy controls, and 15 women with spider phobia; mean age 46.8±9.8 years) participated. The CLBP patients were divided into a high and low fear-avoidant group on the basis of the Tampa Scale of Kinesiophobia. The participants viewed photographs depicting neutral and aversive (back-stressing) movements, generally fear-inducing and neutral pictures from the International Affective Picture System, and pictures of spiders while fMRI data were acquired. It was hypothesized that the high fear-avoidant CLBP patients would show fear-related activations when viewing the aversive movements and that they would differ from CLBP patients with low fear-avoidance and controls in this regard. No such activations were found for high or low fear-avoidant CLBP patients. The random-effects analysis showed no differences between high and low fear-avoidant CLBP patients or high fear-avoidant CLBP patients and controls. Normal fear-related activations were present in the high fear-avoidant CLBP patients for the generally fear-inducing pictures, demonstrating the validity of the stimulation paradigm and a generally unimpaired fear processing of the high fear-avoidant CLBP patients. Our findings do not support the fear component of the fear avoidance model.

Cerebrospinal fluid findings in adults with acute Lyme neuroborreliosis.

Presence of BB-specific antibodies in the cerebrospinal fluid (CSF) with evidence of their intrathecal production in conjunction with the white cell count in the CSF and typical clinical symptoms is the traditional diagnostic gold standard of Lyme neuroborreliosis (LNB). Few data are available on the CSF lactate concentration in European adults with the diagnosis of acute LNB. The objective of the study was to investigate the CSF changes during acute LNB. Routine CSF parameters [leukocyte count, protein, lactate and albumin concentrations, CSF/serum quotients of albumin (Q(Alb)), IgG, IgA and IgM, and oligoclonal IgG bands] and the Borrelia burgdorferi (BB)-specific antibody index were retrospectively studied in relation to the clinical presentation in patients diagnosed with acute LNB. A total of 118 patients with LNB were categorized into the following groups according to their symptoms at presentation; group 1: polyradiculoneuritis (Bannwarth's syndrome), group 2: isolated facial palsy and group 3: predominantly meningitic course of the disease. In addition to the CSF of patients with acute LNB, CSF of 19 patients with viral meningitis (VM) and 3 with neurolues (NL) were analyzed. There were 97 patients classified with definite LNB, and 21 as probable LNB. Neck stiffness and fever were reported by 15.3% of patients. Most of these patients were younger than 50 years. Polyradiculoneuritis was frequently found in patients older than 50 years. Lymphopleocytosis was found in all patients. Only 5 patients had a CSF lactate ≥3.5 mmol/l, and the mean CSF lactate level was not elevated (2.1 ± 0.6 mmol/l). The patients with definite LNB had significantly higher lactate levels than patients with probable LNB. Elevated lactate levels were accompanied by fever and headache. In the Reiber nomograms, intrathecal immunoglobulin synthesis was found for IgM in 70.2% followed by IgG in 19.5%. Isoelectric focussing detected an intrathecal IgG synthesis in 83 patients (70.3%). Elevated BB AIs in the CSF were found in 97 patients (82.2%). Patients with VM showed lower CSF protein concentration and CSF/serum quotients of albumin than LNB patients. In acute LNB, all patients had elevated cerebrospinal fluid (CSF) leukocyte counts. In contrast to infections by other bacteria, CSF lactate was lower than 3.5 mmol/l in all but 5 patients. The CSF findings did not differ between polyradiculoneuritis, facial palsy, and meningitis. The CSF in LNB patients strongly differed from CSF in VM patients with respect to protein concentration and the CSF/serum albumin quotient.

Altered motor network recruitment during finger tapping in boys with Tourette syndrome.

In Tourette syndrome (TS), not only the tics but also the findings on deficits in motor performance indicate motor system alterations. But our knowledge about the pathophysiology of the motor system in TS is still limited. To better understand the neuronal correlates of motor performance in TS, 19 treatment-naïve boys [age 12.5 (SD 1.4) years] with TS without comorbid symptomatology were compared to an age-matched healthy control group [n = 16; age 12.9 (SD 1.6) years] in regard to brain activation during right-hand index finger tapping by means of functional magnetic resonance imaging. Group differences were found mainly in the left (contralateral) precentral gyrus, which was less activated in boys suffering from TS and in caudate nucleus as well as in medial prefrontal cortex, which was more activated compared to healthy boys. These results show that even in the first years after the onset of the disorder, an altered brain network of motor performance is recruited. These alterations in brain regions frequently associated with TS are probably based on functional changes, which are discussed in terms of early compensatory mechanisms of the motor execution network.