Breathlessness amplifies amygdala responses during affective processing.

Breathlessness is an aversive symptom in many prevalent somatic and psychiatric diseases and is usually experienced as highly threatening. It is strongly associated with negative affect, but the underlying neural processes remain poorly understood. Therefore, using fMRI, the present study examined the effects of breathlessness on the neural processing of affective visual stimuli within candidate brain areas including the amygdala, insula, and anterior cingulate cortex (ACC). During scanning, 42 healthy volunteers, mean (SD) age: 29.0 (6.0) years, 14 female, were presented with affective picture series of negative, neutral, and positive valence while experiencing either no breathlessness (baseline conditions) or resistive-load induced breathlessness (breathlessness conditions). Respiratory measures and self-reports suggested successful induction of breathlessness and affective experiences. Self-reports of breathlessness intensity and unpleasantness were significantly higher during breathlessness conditions, mean (SD): 45.0 (16.6) and 32.3 (19.8), as compared to baseline conditions, mean (SD): 1.9 (3.0) and 2.9 (5.5). Compared to baseline conditions, stronger amygdala activations were observed during breathlessness conditions for both negative and positive affective picture series relative to neutral picture series, while no such effects were observed in insula and ACC. The present findings demonstrate that breathlessness amplifies amygdala responses during affective processing, suggesting an important role of the amygdala for mediating the interactions between breathlessness and affective states.

Dyspnea catastrophizing and neural activations during the anticipation and perception of dyspnea.

Dyspnea is an aversive symptom in various diseases. High levels of negative affectivity are typically associated with increased dyspnea and changes in its neural processing. Recently, more dyspnea-specific forms of negative affectivity such as dyspnea catastrophizing were suggested to contribute to increased perception of dyspnea beyond effects of rather unspecific negative affectivity such as general anxiety levels. The involved neural mechanisms have not yet been explored. Therefore, the present retrospective analysis examined the associations of dyspnea catastrophizing with neural activations during the anticipation and perception of dyspnea. Sixty-six healthy volunteers underwent 20 blocks of inspiratory resistive load breathing with parallel acquisition of fMRI data. Loads inducing either severe or mild dyspnea (dyspnea conditions) were presented in alternating order, with each condition being visually cued (anticipation conditions). Dyspnea catastrophizing and general trait anxiety were measured with the Breathlessness Catastrophizing Scale (BCS) and the State-Trait Anxiety Inventory, respectively. Correlating the BCS scores with neural activations during the perception of dyspnea yielded no significant results. However, during the anticipation of dyspnea, BCS scores correlated positively with activations of the anterior cingulate cortex (ACC), even after controlling for general anxiety levels. These activations in the ACC were not related to concurrent respiratory parameters. Results suggest that dyspnea catastrophizing in healthy volunteers is associated with stronger ACC recruitment during dyspnea anticipation. Given the established role of the ACC in processing affective states, affect regulation, and antinociception, this might reflect increased affective and/or top-down modulatory processing in individuals with higher dyspnea catastrophizing when anticipating dyspnea.

Brain Responses during the Anticipation of Dyspnea.

Dyspnea is common in many cardiorespiratory diseases. Already the anticipation of this aversive symptom elicits fear in many patients resulting in unfavorable health behaviors such as activity avoidance and sedentary lifestyle. This study investigated brain mechanisms underlying these anticipatory processes. We induced dyspnea using resistive-load breathing in healthy subjects during functional magnetic resonance imaging. Blocks of severe and mild dyspnea alternated, each preceded by anticipation periods. Severe dyspnea activated a network of sensorimotor, cerebellar, and limbic areas. The left insular, parietal opercular, and cerebellar cortices showed increased activation already during dyspnea anticipation. Left insular and parietal opercular cortex showed increased connectivity with right insular and anterior cingulate cortex when severe dyspnea was anticipated, while the cerebellum showed increased connectivity with the amygdala. Notably, insular activation during dyspnea perception was positively correlated with midbrain activation during anticipation. Moreover, anticipatory fear was positively correlated with anticipatory activation in right insular and anterior cingulate cortex. The results demonstrate that dyspnea anticipation activates brain areas involved in dyspnea perception. The involvement of emotion-related areas such as insula, anterior cingulate cortex, and amygdala during dyspnea anticipation most likely reflects anticipatory fear and might underlie the development of unfavorable health behaviors in patients suffering from dyspnea.

Structural Brain Changes in Patients With COPD.

BACKGROUND: Patients with COPD suffer from chronic dyspnea, which is commonly perceived as highly aversive and threatening. Moreover, COPD is often accompanied by disease-specific fears and avoidance of physical activity. However, little is known about structural brain changes in patients with COPD and respective relations with disease duration and disease-specific fears. METHODS: This study investigated structural brain changes in patients with COPD and their relation with disease duration, fear of dyspnea, and fear of physical activity. We used voxel-based morphometric analysis of MRI images to measure differences in generalized cortical degeneration and regional gray matter between 30 patients with moderate to severe COPD and 30 matched healthy control subjects. Disease-specific fears were assessed by the COPD anxiety questionnaire. RESULTS: Patients with COPD showed no generalized cortical degeneration, but decreased gray matter in posterior cingulate cortex (whole-brain analysis) as well as in anterior and midcingulate cortex, hippocampus, and amygdala (regions-of-interest analyses). Patients' reductions in gray matter in anterior cingulate cortex were negatively correlated with disease duration, fear of dyspnea, and fear of physical activity. Mediation analysis revealed that the relation between disease duration and reduced gray matter of the anterior cingulate was mediated by fear of physical activity. CONCLUSIONS: Patients with COPD demonstrated gray matter decreases in brain areas relevant for the processing of dyspnea, fear, and antinociception. These structural brain changes were partly related to longer disease duration and greater disease-specific fears, which might contribute to a less favorable course of the disease.

Pseudomonas helleri sp. nov. and Pseudomonas weihenstephanensis sp. nov., isolated from raw cow's milk.

Analysis of the microbiota of raw cow's milk and semi-finished milk products yielded seven isolates assigned to the genus Pseudomonas that formed two individual groups in a phylogenetic analysis based on partial rpoD and 16S rRNA gene sequences. The two groups could be differentiated from each other and also from their closest relatives as well as from the type species Pseudomonas aeruginosa by phenotypic and chemotaxonomic characterization and average nucleotide identity (ANIb) values calculated from draft genome assemblies. ANIb values within the groups were higher than 97.3 %, whereas similarity values to the closest relatives were 85 % or less. The major cellular lipids of strains WS4917T and WS4993T were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol; the major quinone was Q-9 in both strains, with small amounts of Q-8 in strain WS4917T. The DNA G+C contents of strains WS4917T and WS4993T were 58.08 and 57.30 mol%, respectively. Based on these data, strains WS4917T, WS4995 ( = DSM 29141 = LMG 28434), WS4999, WS5001 and WS5002 should be considered as representatives of a novel species of the genus Pseudomonas, for which the name Pseudomonas helleri sp. nov. is proposed. The type strain of Pseudomonas helleri is strain WS4917T ( = DSM 29165T = LMG 28433T). Strains WS4993T and WS4994 ( = DSM 29140 = LMG 28438) should be recognized as representing a second novel species of the genus Pseudomonas, for which the name Pseudomonas weihenstephanensis sp. nov. is proposed. The type strain of Pseudomonas weihenstephanensis is strain WS4993T ( = DSM 29166T = LMG 28437T).

Brain mechanisms of short-term habituation and sensitization toward dyspnea.

Dyspnea is a prevalent and threatening cardinal symptom in many diseases including asthma. Whether patients suffering from dyspnea show habituation or sensitization toward repeated experiences of dyspnea is relevant for both quality of life and treatment success. Understanding the mechanisms, including the underlying brain activation patterns, that determine the dynamics of dyspnea perception seems crucial for the improvement of treatment and rehabilitation. Toward this aim, we investigated the interplay between short-term changes of dyspnea perception and changes of related brain activation. Healthy individuals underwent repeated blocks of resistive load induced dyspnea with parallel acquisition of functional magnetic resonance imaging data. Late vs. early ratings on dyspnea intensity and unpleasantness were correlated with late vs. early brain activation for both, dyspnea anticipation and dyspnea perception. Individual trait and state anxiety were determined using questionnaire data. Our results indicate an involvement of the orbitofrontal cortex (OFC), midbrain/periaqueductal gray (PAG) and anterior insular cortex in habituation/sensitization toward dyspnea. Changes in the anterior insular cortex were particularly linked to changes in dyspnea unpleasantness. Changes of both dyspnea intensity and unpleasantness were positively correlated with state and trait anxiety. Our findings are in line with the suggested relationship between the anterior insular cortex and dyspnea unpleasantness. They further support the notion that habituation/sensitization toward dyspnea is influenced by anxiety. Our study extends the known role of the midbrain/PAG in anti-nociception to an additional involvement in habituation/sensitization toward dyspnea and suggests an interplay with the OFC.

Amygdala response to anticipation of dyspnea is modulated by 5-HTTLPR genotype.

Dyspnea anticipation and perception varies largely between individuals. To investigate whether genetic factors related to negative affect such as the 5-HTTLPR polymorphism impact this variability, we investigated healthy, 5-HTTLPR stratified volunteers using resistive load induced dyspnea together with fMRI. Alternating blocks of severe and mild dyspnea ("perception") were differentially cued ("anticipation") and followed by intensity and unpleasantness ratings. In addition, volunteers indicated their anticipatory fear during the anticipation periods. There were no genotype-based group differences concerning dyspnea intensity and unpleasantness or brain activation during perception of severe vs. mild dyspnea. However, in risk allele carriers, higher anticipatory fear was paralleled by stronger amygdala activation during anticipation of severe vs. mild dyspnea. These results suggest a role of the 5-HTTLPR genotype in fearful dyspnea anticipation.

Differential grey matter changes in sensorimotor cortex related to exceptional fine motor skills.

Functional changes in sensorimotor representation occur in response to use and lesion throughout life. Emerging evidence suggests that functional changes are paralleled by respective macroscopic structural changes. In the present study we used voxel-based morphometry to investigate sensorimotor cortex in subjects with congenitally malformed upper extremities. We expected increased or decreased grey matter to parallel the enlarged or reduced functional representations we reported previously. More specifically, we expected decreased grey matter values in lateral sensorimotor cortex related to compromised hand function and increased grey matter values in medial sensorimotor cortex due to compensatory foot use. We found a medial cluster of grey matter increase in subjects with frequent, hand-like compensatory foot use. This increase was predominantly seen for lateral premotor, supplementary motor, and motor areas and only marginally involved somatosensory cortex. Contrary to our expectation, subjects with a reduced number of fingers, who had shown shrinkage of the functional hand representation previously, did not show decreased grey matter values within lateral sensorimotor cortex. Our data suggest that functional plastic changes in sensorimotor cortex can be associated with increases in grey matter but may also occur in otherwise macroscopically normal appearing grey matter volumes. Furthermore, macroscopic structural changes in motor and premotor areas may be observed without respective changes in somatosensory cortex.

The role of ipsilateral primary motor cortex in movement control and recovery from brain damage.

The role of ipsilateral motor areas for movement control is not yet fully understood. The relevance of these areas to the recovery of motor function following a brain lesion is a matter of dispute. It has recently been stated that increased ipsilateral activation following brain damage is maladaptive and hindering the process of recovery. Others have presented evidence that ipsilateral motor areas subserve motor recovery. A recent study published in Experimental Neurology [Lotze, M., Sauseng, P., Staudt, M., 2009. Functional relevance of ipsilateral motor activation in congenital hemiparesis as tested by fMRI-navigated TMS. Exp. Neurol., 217, 440-443.] on patients with congenital hemiparesis presents evidence for the importance of ipsilateral primary motor cortex and dorsal premotor cortex to movement control even in the absence of direct ipsilateral descending output in this special set of patients. This comment briefly summarizes the relevant findings supporting both views and discusses potential causes for the prima facie contradictory findings.

Congenitally altered motor experience alters somatotopic organization of human primary motor cortex.

Human motor development is thought to result from a complex interaction between genes and experience. The well-known somatotopic organization of the primate primary motor cortex (M1) emerges postnatally. Although adaptive changes in response to learning and use occur throughout life, somatotopy is maintained as reorganization is restricted to modifications within major body part representations. We report of a unique opportunity to evaluate the influence of experience on the genetically determined somatotopic organization of motor cortex in humans. We examined the motor "foot" representation in subjects with congenitally compromised hand function and compensatory skillful foot use. Functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) of M1 revealed that the foot was represented in the classical medial foot area of M1 and was several centimetres away in nonadjacent cortex in the vicinity of the lateral "hand" area. Both areas had direct output to the spinal motor neurons innervating foot muscles and were behaviorally relevant because experimental disruption of either area by TMS altered reaction times. We demonstrate a unique, nonsomatotopically organized M1 in humans, which emerged as a function of grossly altered motor behavior from the earliest stages of development. Our results imply that during early motor development experience may play a more critical role in the shaping of genetically determined neural networks than previously assumed.

Reduced somatosensory hand representation in thalidomide-induced dysmelia as revealed by fMRI.

The concept of cerebral plasticity suggests that the hand representation in somatosensory cortex is abnormal in congenital malformation disorders. To investigate this issue we studied 11 subjects with different degrees of upper extremity dysmelia due to thalidomide embryopathy in comparison to 10 control subjects. In the affected subjects fingers are typically missing in radio-ulnar order beginning with the thumb. Haemodynamic responses to electrical stimulation of the radial-most and ulnar-most fingers were measured in each subject using functional magnetic resonance tomography. The size of the hand area in the primary somatosensory cortex was estimated by calculating the Euclidian distance between corresponding activation peaks on the lateral postcentral gyrus. The cortical somatosensory hand representation was found to be significantly smaller in dysmelic subjects as compared with the control subjects (P <0.001). The shrinkage of the hand area was not proportional to the number of missing fingers. Furthermore, the cortical representation of the ulnar fingers in the dysmelic subjects was shifted towards the cortical thumb representation of the control group. We suggest that the unproportional reduction of the hand area together with the observed shift may reflect use-dependent rather than malformation-induced reorganization of the somatosensory hand area.

Shrinkage of somatosensory hand area in subjects with upper extremity dysmelia revealed by magnetoencephalography.

The effect of peripheral lesions on cerebral somatosensory representations is well studied for experimentally induced amputations and deafferentations acquired later in life. However, few studies have investigated the brain's capacity for plastic changes in congenital malformations. We studied somatosensory-evoked fields to electrical stimulation of the bordering fingers in 10 subjects with upper extremity dysmelia in comparison with 10 control subjects using a 122-channel whole-head magnetometer. The number of developed fingers varied between two and four in the affected subjects. We localized finger representations in the primary somatosensory cortex and calculated Euclidian distances to estimate the size of the somatosensory hand area. Euclidian distances were significantly smaller in dysmelic subjects (5.7 mm) than in control subjects (11.6 mm) and were related to the number of the developed fingers on the contralateral hand. In contrast, individual finger representations were not found to be reduced. We suggest that the shrinkage of the somatosensory hand area might be related to the congenital nature of the malformation, to the smaller anatomical hand size in the affected subjects, and/or to use-dependent effects due to impaired hand function.

Left and right superior parietal lobule in tactile object discrimination.

Tactile object discrimination is one of the major manual skills of humans. While the exploring finger movements are not perceived explicitly, attention to the movement-evoked kinaesthetic information gates the tactile perception of object form. Using event-related functional magnetic resonance imaging in seven healthy subjects we found one area in the right superior parietal cortex, which was specifically activated by kinaesthetic attention during tactile object discrimination. Another area with similar location in the left hemisphere was related to the maintenance of tactile information for subsequent object discrimination. We conclude that kinaesthetic information is processed in the anterior portion of the superior parietal cortex (aSPL) with a right hemispheric predominance for discrimination and a left hemispheric predominance for information maintenance.

Use-dependent cortical plasticity in thalidomide-induced upper extremity dysplasia: evidence from somaesthesia and neuroimaging.

In this study cerebral reorganization was investigated in thalidomide-damaged subjects who use their feet to compensate for their malformed upper extremities. Tactile localization across toes was combined with fMRI to study use-dependent plasticity of the human somatosensory cortex. The manner of compensatory foot use was assessed by a questionnaire. In the behavioural experiment toes were stimulated with above threshold monofilaments and subjects had to report which toe was stimulated. When feet were employed for all everyday actions subjects made significantly fewer errors in the localization task. In subjects who use their feet only for specific actions such as grasping objects there were as many localization errors as in the control group of thalidomide-affected subjects with normal extremities. However, the patterns of mislocalizations were different with less errors occurring for the toe of the dominant foot involved in these actions. Functional MRI showed stronger haemodynamic responses to electrical stimulation of the toes in subjects using their feet for everyday actions as compared to controls. Our data show that long-term use of the feet for fine sensorimotor skills leads to better performance in tactile localization and changes in cerebral SI representation supporting the notion of use-dependent plasticity in the somatosensory cortex.

A fronto-parietal circuit for tactile object discrimination: an event-related fMRI study.

Previous studies of somatosensory object discrimination have been focused on the primary and secondary sensorimotor cortices. However, we expected the prefrontal cortex to also become involved in sequential tactile discrimination on the basis of its role in working memory and stimulus discrimination as established in other domains. To investigate the contributions of the different cerebral structures to tactile discrimination of sequentially presented objects, we obtained event-related functional magnetic resonance images from seven healthy volunteers. Our results show that right hand object exploration involved left sensorimotor cortices, bilateral premotor, parietal and temporal cortex, putamen, thalamus, and cerebellum. Tactile exploration of parallelepipeds for subsequent object discrimination activated further areas in the dorsal and ventral portions of the premotor cortex, as well as parietal, midtemporal, and occipital areas of both cerebral hemispheres. Discriminating a parallelepiped from the preceding one involved a bilateral prefrontal-anterior cingulate-superior temporal-posterior parietal circuit. While the prefrontal cortex was active with right hemisphere dominance during discrimination, there was left hemispheric prefrontal activation during the delay period between object presentations. Delay related activity was further seen in the anterior intraparietal area and the fusiform gyrus. The results reveal a prominent role of the human prefrontal cortex for somatosensory object discrimination in correspondence with recent models on stimulus discrimination and working memory.

Reorganization of motor representation in a patient with epilepsia partialis continua as shown by [O15]-labeled butanol positron emission tomography and functional magnetic resonance imaging.

The authors investigated a 38-year-old patient with focal cortical dysplasia in the right precentral cortex using positron emission tomography and functional magnetic resonance imaging to localize the hand and finger motor representations. The patient presented clinically with epilepsia partialis continua, supposed to originate from the perirolandic area harboring the cortical malformation. Both methods revealed an abnormal bilateral activation of motor cortex during left-hand finger movements. The results suggest that the so-called eloquent but nevertheless pathological dysplastic cortex accommodates motor representations.

Historadioautographic localization of oxytocin and V1a vasopressin binding sites in the kidney of developing and adult rabbit, mouse and merione and of adult human.

The localization of oxytocin (OT) binding sites and vasopressin (VP) binding sites of the V1a subtype was investigated by radioautography in kidneys of rabbits, mice and meriones during postnatal development and in the adult, and in the human kidney. Kidney sections were incubated in the presence of selective radioiodinated OT and V1a antagonists, respectively. The localizations were compared with those previously described in the rat. The main finding of the study was the almost constant presence in the cortex of V1a binding sites in the connecting tubule, the cortical collecting duct and in the juxtaglomerular apparatus (on the intra- and extraglomerular mesangium and the afferent arteriole). This distribution suggests an interaction of VP via V1a receptors and the kallikrein-kinin system in the kidney. OT binding sites, in comparison with V1a binding sites, were fewer and less constantly detectable in the kidney of the different species. In the mouse, their presence on the limbs of Henle's loop in the medulla points to the possibility of their involvement in the medullary concentrating process. In the kidneys of the various species, OT and V1a binding sites occurred always in differential structures. In contrast, in the human kidney cortex, a colocalization of OT and V1a binding sites was almost constantly observed. This raises the question as to the specificity of the neurohypophysial hormone receptors in the human kidney.

Tenascin and laminin function in target recognition and central synaptic differentiation.

The influence of the target cell-issued extracellular molecules tenascin-C and laminin on synaptogenesis was studied in mixed primary cultures of pituitary melanotrophs and hypothalamic neurons. We could demonstrate in this neuron-target co-culture system a new role for tenascin-C, which appeared to be expressed as an early and transitory signal of target recognition for selective afferent fibers. Tenascin-C expression disappeared from the melanotrophs soon after the establishment of neural contacts. Concomitantly, the melanotrophs became immunoreactive for laminins, and more specifically for the synaptic isoform beta2 chain-containing laminin. The laminin signal appeared to be involved in the induction of synaptic differentiation, selectively with fibers containing both dopamine and GABA, like those innervating the melanotrophs in situ.

The steroidogenic acute regulatory protein homolog MLN64, a late endosomal cholesterol-binding protein.

MLN64 is a transmembrane protein that shares homology with the cholesterol binding domain (START domain) of the steroidogenic acute regulatory protein. The steroidogenic acute regulatory protein is located in the inner membrane of mitochondria, where it facilitates cholesterol import into the mitochondria. Crystallographic analysis showed that the START domain of MLN64 is a cholesterol-binding domain. The present work was undertaken to determine which step of the intracellular cholesterol pathway MLN64 participates in. Using immunocytofluorescence, MLN64 colocalizes with LBPA, a lipid found specifically in late endosomes. Electron microscopy indicates that MLN64 is restricted to the limiting membrane of late endosomes. Microinjection or endocytosis of specific antibodies shows that the START domain of MLN64 is cytoplasmic. Deletion and mutagenesis experiments demonstrate that the amino-terminal part of MLN64 is responsible for its addressing. Although this domain does not contain conventional dileucine- or tyrosine-based targeting signals, we show that a dileucine motif (Leu(66)-Leu(67)) and a tyrosine residue (Tyr(89)) are critical for the targeting or the proper folding of the molecule. Finally, MLN64 colocalizes with cholesterol and Niemann Pick C1 protein in late endosomes. However, complementation assays show that MLN64 is not involved in the Niemann Pick C2 disease which, results in cholesterol lysosomal accumulation. Together, our results show that MLN64 plays a role at the surface of the late endosomes, where it might shuttle cholesterol from the limiting membrane to cytoplasmic acceptor(s).

Adventitia-derived nitric oxide in rat aortas exposed to endotoxin: cell origin and functional consequences.

The role of adventitial cells in bacterial lipopolysaccharide (LPS)-induced vascular nitric oxide (NO) overproduction has been largely ignored. In rat aortas exposed to LPS in vitro or in vivo, it was found that adventitia contained the major part of NO synthase (NOS)-2 protein (Western blot and immunohistochemistry) and generated the largest amount of NO (electron paramagnetic resonance spin trapping). NOS-2 immunoreactive cells were mainly resident macrophages at an early stage (5 h, in vitro or in vivo) and fibroblasts at a later stage (20 h, in vitro). Adventitial NOS-2 activity largely accounted for 1) the relaxing effect of L-arginine in rings exposed to LPS in vivo, 2) generation of an "NO store" revealed by N-acetylcysteine-induced relaxation, and 3) formation of protein-bound dinitrosyl iron complexes in the medial layer of aortic rings exposed to LPS in vitro. In conclusion, the adventitia is a powerful source of NO triggered by LPS in the rat aorta. This novel source of NO has an important impact on smooth muscle function and might be implicated in various inflammatory diseases.