Assessment of T1, T1ρ, and T2 values of the ulnocarpal disc in healthy subjects at 3 tesla

OBJECTIVE

The purpose of this study was to implement clinically feasible imaging techniques for determination of T1, T1ρ, and T2 values of the ulnocarpal disc and to assess those values in a cohort of asymptomatic subjects at 3 tesla. Resulting values were compared between different age groups, since former histological findings of the ulnocarpal disc indicated frequent early degenerative changes of this tissue starting in the third decade of life, even in asymptomatic subjects.

MATERIALS AND METHODS

Twenty-seven healthy subjects were included in this study. T1 measurements were performed using 3D spoiled gradient-echo (GRE) sequence with variable flip angle. A series of T1ρ and T2-weighted images was acquired by a 3D GRE sequence after suitable magnetization preparation. T1,T1ρ, and T2 maps of the ulnocarpal disc were calculated pixel-wise. Representative mean values from extended regions were analysed.

RESULTS

Mean T1 values of the ulnocarpal disc ranged from 722 ms in a 39 year-old subject to 1264 ms in a 65 year-old subject, T1ρ ranged from 9.2 ms (26 year-old subject) to 25.9 ms (65 year-old subject). Calculated T2 values showed a large range from 4.1 ms to 22.3 ms. T1ρ and T1 values tended to increase with age (p<0.05), whereas T2 did not.

CONCLUSIONS

MR relaxometry of the ulnocarpal disc is feasible, and T1,T1ρ, and T2 values show modest variance in asymptomatic subjects. The potential of relaxation mapping to reveal relevant structural changes in patients has to be investigated in further studies.

Dissociated language functions: a matter of atypical language lateralization or cerebral plasticity?

BACKGROUND AND STUDY AIMS

The left hemisphere is generally considered to harbor language functions. Atypical cortical language lateralization is mainly demonstrated in left-handed and ambidextrous individuals, whereas dissociated language functions have been reported in association with brain injuries as a part of the reorganization process. We present a thoughtful discussion on the underlying mechanisms of dissociated language functions through an illustrative case of dissociated expressive language.

CASE REPORT

A 31-year-old left-handed woman presented with a recurrent left frontal glioma. Preoperative language functional magnetic resonance imaging (fMRI) panel revealed right-sided dominance for two different language tasks (verbal fluency and visual naming), and the word chain task demonstrated maximal activation in the left hemisphere at the posterior margin of the tumor. The patient was operated on awake to assess language functions intraoperatively. Preoperative fMRI findings were confirmed revealing a task-specific dissociation of expressive language functions. Surgical resection was taken to the functional boundaries. Postoperatively, no language dysfunction occurred.

CONCLUSIONS

Dissociated language functions are prone to occur in long-standing lesions. Different patterns of dissociation may be encountered due to interindividual particularities and cerebral plasticity. The presented patient is unique by demonstrating new insight into expressive language dissociation, emphasizing the role of a preoperative language fMRI panel and the capability of intraoperative language mapping for identifying special language networks.

Language aptitude for pronunciation in advanced second language (L2) learners: behavioural predictors and neural substrates

Individual differences in second language (L2) aptitude have been assumed to depend upon a variety of cognitive and personality factors. Especially, the cognitive factor phonological working memory has been conceptualised as language learning device. However, strong associations between phonological working memory and L2 aptitude have been previously found in early-stage learners only, not in advanced learners. The current study aimed at investigating the behavioural and neurobiological predictors of advanced L2 learning. Our behavioural results showed that phonetic coding ability and empathy, but not phonological working memory, predict L2 pronunciation aptitude in advanced learners. Second, functional neuroimaging revealed this behavioural trait to be correlated with hemodynamic responses of the cerebral network of speech motor control and auditory-perceptual areas. We suggest that the acquisition of L2 pronunciation aptitude is a dynamic process, requiring a variety of neural resources at different processing stages over time.

Non-verbal emotion communication training induces specific changes in brain function and structure

The perception of emotional cues from voice and face is essential for social interaction. However, this process is altered in various psychiatric conditions along with impaired social functioning. Emotion communication trainings have been demonstrated to improve social interaction in healthy individuals and to reduce emotional communication deficits in psychiatric patients. Here, we investigated the impact of a non-verbal emotion communication training (NECT) on cerebral activation and brain structure in a controlled and combined functional magnetic resonance imaging (fMRI) and voxel-based morphometry study. NECT-specific reductions in brain activity occurred in a distributed set of brain regions including face and voice processing regions as well as emotion processing- and motor-related regions presumably reflecting training-induced familiarization with the evaluation of face/voice stimuli. Training-induced changes in non-verbal emotion sensitivity at the behavioral level and the respective cerebral activation patterns were correlated in the face-selective cortical areas in the posterior superior temporal sulcus and fusiform gyrus for valence ratings and in the temporal pole, lateral prefrontal cortex and midbrain/thalamus for the response times. A NECT-induced increase in gray matter (GM) volume was observed in the fusiform face area. Thus, NECT induces both functional and structural plasticity in the face processing system as well as functional plasticity in the emotion perception and evaluation system. We propose that functional alterations are presumably related to changes in sensory tuning in the decoding of emotional expressions. Taken together, these findings highlight that the present experimental design may serve as a valuable tool to investigate the altered behavioral and neuronal processing of emotional cues in psychiatric disorders as well as the impact of therapeutic interventions on brain function and structure.

Isn't it ironic? Neural correlates of irony comprehension in schizophrenia

Ironic remarks are frequent in everyday language and represent an important form of social cognition. Increasing evidence indicates a deficit in comprehension in schizophrenia. Several models for defective comprehension have been proposed, including possible roles of the medial prefrontal lobe, default mode network, inferior frontal gyri, mirror neurons, right cerebral hemisphere and a possible mediating role of schizotypal personality traits. We investigated the neural correlates of irony comprehension in schizophrenia by using event-related functional magnetic resonance imaging (fMRI). In a prosody-free reading paradigm, 15 female patients with schizophrenia and 15 healthy female controls silently read ironic and literal text vignettes during fMRI. Each text vignette ended in either an ironic (n = 22) or literal (n = 22) statement. Ironic and literal text vignettes were matched for word frequency, length, grammatical complexity, and syntax. After fMRI, the subjects performed an off-line test to detect error rate. In this test, the subjects indicated by button press whether the target sentence has ironic, literal, or meaningless content. Schizotypal personality traits were assessed using the German version of the schizotypal personality questionnaire (SPQ). Patients with schizophrenia made significantly more errors than did the controls (correct answers, 85.3% vs. 96.3%) on a behavioural level. Patients showed attenuated blood oxygen level-dependent (BOLD) response during irony comprehension mainly in right hemisphere temporal regions (ironic>literal contrast) and in posterior medial prefrontal and left anterior insula regions (for ironic>visual baseline, but not for literal>visual baseline). In patients with schizophrenia, the parahippocampal gyrus showed increased activation. Across all subjects, BOLD response in the medial prefrontal area was negatively correlated with the SPQ score. These results highlight the role of the posterior medial prefrontal and right temporal regions in defective irony comprehension in schizophrenia and the mediating role of schizotypal personality traits.

Features of idebenone and related short-chain quinones that rescue ATP levels under conditions of impaired mitochondrial complex I

Short-chain quinones have been investigated as therapeutic molecules due to their ability to modulate cellular redox reactions, mitochondrial electron transfer and oxidative stress, which are pathologically altered in many mitochondrial and neuromuscular disorders. Recently, we and others described that certain short-chain quinones are able to bypass a deficiency in complex I by shuttling electrons directly from the cytoplasm to complex III of the mitochondrial respiratory chain to produce ATP. Although this energy rescue activity is highly interesting for the therapy of disorders associated with complex I dysfunction, no structure-activity-relationship has been reported for short-chain quinones so far. Using a panel of 70 quinones, we observed that the capacity for this cellular energy rescue as well as their effect on lipid peroxidation was influenced more by the physicochemical properties (in particular logD) of the whole molecule than the quinone moiety itself. Thus, the observed correlations allow us to explain the differential biological activities and therapeutic potential of short-chain quinones for the therapy of disorders associated with mitochondrial complex I dysfunction and/or oxidative stress.

Favorable gradients with the mitroflow aortic valve prosthesis in everyday surgery

BACKGROUND

The supra-annular Mitroflow valve has been implanted for over 20 years, preferably in small aortic roots. Early outcomes and gradients in unselected elderly patients receiving aortic valve surgery are reported in this study.

METHODS

Mitroflow valves were implanted in 190 consecutive patients (70% females). Mean age was 75.6 ± 5.5 years, body mass index was 28.2 ± 5.3 kg/m2, and logistic EuroSCORE 17.8 ± 16.5%. There were 170 single, 17 double, and 3 triple valve procedures. Of all, 46.8% of surgeries were performed with coronary artery bypass grafting and 39.5% were performed with isolated aortic valve replacement (AVR). Rates of redo and endocarditic cases were 14.2 and 4.7%.

RESULTS

The 19-mm (n = 14), 21-mm (n = 135), and 23-mm (n = 41) valves showed mean gradients of 16.1 ± 7.4 mm Hg, 15.8 ± 7.1 mm Hg, and 11.6 ± 4.1 mm Hg, respectively, before discharge. Maximum gradients were 27.5 ± 13.0, 28.4 ± 12.6, and 21.6 ± 7.6 mm Hg, respectively. Correlation between gradients and sizes was significant. In-hospital mortality was 12.6% overall (6.7% in isolated AVR). The rate of valve-related events was low (mild paravalvular leakage 2.1%, neurologic 3.2%, bleeding 3.2%, atrioventricular block 4.2%, no thrombosis).

CONCLUSION

The Mitroflow valve can be safely implanted in elderly patients undergoing advanced surgical procedures. Gradients were acceptably low even in the smallest valves.

Herbivore-induced plant volatiles can serve as host location cues for a generalist and a specialist egg parasitoid

Herbivore-induced plant volatiles are important host finding cues for larval parasitoids, and similarly, insect oviposition might elicit the release of plant volatiles functioning as host finding cues for egg parasitoids. We hypothesized that egg parasitoids also might utilize HIPVs of emerging larvae to locate plants with host eggs. We, therefore, assessed the olfactory response of two egg parasitoids, a generalist, Trichogramma pretiosum (Tricogrammatidae), and a specialist, Telenomus remus (Scelionidae) to HIPVs. We used a Y-tube olfactometer to tests the wasps' responses to volatiles released by young maize plants that were treated with regurgitant from caterpillars of the moth Spodoptera frugiperda (Noctuidae) or were directly attacked by the caterpillars. The results show that the generalist egg parasitoid Tr. pretiosum is innately attracted by volatiles from freshly-damaged plants 0-1 and 2-3 h after regurgitant treatment. During this interval, the volatile blend consisted of green leaf volatiles (GLVs) and a blend of aromatic compounds, mono- and homoterpenes, respectively. Behavioral assays with synthetic GLVs confirmed their attractiveness to Tr. pretiosum. The generalist learned the more complex volatile blends released 6-7 h after induction, which consisted mainly of sesquiterpenes. The specialist T. remus on the other hand was attracted only to volatiles emitted from fresh and old damage after associating these volatiles with oviposition. Taken together, these results strengthen the emerging pattern that egg and larval parasitoids behave in a similar way in that generalists can respond innately to HIPVs, while specialists seems to rely more on associative learning.

Neural correlates of metonymy resolution

Metonymies are exemplary models for complex semantic association processes at the sentence level. We investigated processing of metonymies using event-related functional magnetic resonance imaging (fMRI). During an 1.5Tesla fMRI scan, 14 healthy subjects (12 female) read 124 short German sentences with either literal (like "Africa is arid"), metonymic ("Africa is hungry"), or nonsense ("Africa is woollen") content. Sentences were constructed so that they obey certain grammatical, semantic, and plausibility conditions and were matched for word frequency, semantic association, length and syntactic structure. We concentrated on metonymies that were not yet fossilised; we also examined a wide variety of metonymic readings. Reading metonymies relative to literal sentences revealed signal changes in a predominantly left-lateralised fronto-temporal network with maxima in the left and right inferior frontal as well as left middle temporal gyri. Left inferior frontal activation may reflect both inference processes and access to world knowledge during metonymy resolution.

Individual differences in audio-vocal speech imitation aptitude in late bilinguals: functional neuro-imaging and brain morphology

An unanswered question in adult language learning or late bi and multilingualism is why individuals show marked differences in their ability to imitate foreign accents. While recent research acknowledges that more adults than previously assumed can still acquire a "native" foreign accent, very little is known about the neuro-cognitive correlates of this special ability. We investigated 140 German-speaking individuals displaying varying degrees of "mimicking" capacity, based on natural language text, sentence, and word imitations either in their second language English or in Hindi and Tamil, languages they had never been exposed to. The large subject pool was strictly controlled for previous language experience prior to magnetic resonance imaging. The late-onset (around 10 years) bilinguals showed significant individual differences as to how they employed their left-hemisphere speech areas: higher hemodynamic activation in a distinct fronto-parietal network accompanied low ability, while high ability paralleled enhanced gray matter volume in these areas concomitant with decreased hemodynamic responses. Finally and unexpectedly, males were found to be more talented foreign speech mimics.

Biological motion processing: the left cerebellum communicates with the right superior temporal sulcus

The cerebellum is thought to be engaged not only in motor control, but also in the neural network dedicated to visual processing of body motion. However, the pattern of connectivity within this network, in particular, between the cortical circuitry for observation of others' actions and the cerebellum remains largely unknown. By combining functional magnetic resonance imaging (fMRI) with functional connectivity analysis and dynamic causal modelling (DCM), we assessed cerebro-cerebellar connectivity during a visual perceptual task with point-light displays depicting human locomotion. In the left lateral cerebellum, regions in the lobules Crus I and VIIB exhibited increased fMRI response to biological motion. The outcome of the connectivity analyses delivered the first evidence for reciprocal communication between the left lateral cerebellum and the right posterior superior temporal sulcus (STS). Through communication with the right posterior STS that is a key node not only for biological motion perception but also for social interaction and visual tasks on theory of mind, the left cerebellum might be involved in a wide range of social cognitive functions.

Expertise modulates the neural basis of context dependent recognition of objects and their relations

Recognition of objects and their relations is necessary for orienting in real life. We examined cognitive processes related to recognition of objects, their relations, and the patterns they form by using the game of chess. Chess enables us to compare experts with novices and thus gain insight in the nature of development of recognition skills. Eye movement recordings showed that experts were generally faster than novices on a task that required enumeration of relations between chess objects because their extensive knowledge enabled them to immediately focus on the objects of interest. The advantage was less pronounced on random positions where the location of chess objects, and thus typical relations between them, was randomized. Neuroimaging data related experts' superior performance to the areas along the dorsal stream-bilateral posterior temporal areas and left inferior parietal lobe were related to recognition of object and their functions. The bilateral collateral sulci, together with bilateral retrosplenial cortex, were also more sensitive to normal than random positions among experts indicating their involvement in pattern recognition. The pattern of activations suggests experts engage the same regions as novices, but also that they employ novel additional regions. Expert processing, as the final stage of development, is qualitatively different than novice processing, which can be viewed as the starting stage. Since we are all experts in real life and dealing with meaningful stimuli in typical contexts, our results underline the importance of expert-like cognitive processing on generalization of laboratory results to everyday life.

Tissue specific resonance frequencies of water and metabolites within the human brain

Chemical shift imaging (CSI) without water suppression was used to examine tissue-specific resonance frequencies of water and metabolites within the human brain. The aim was to verify if there are any regional differences in those frequencies and to determine the influence of chemical shift displacement in slice-selection direction. Unsuppressed spectra were acquired at 3T from nine subjects. Resonance frequencies of water and after water signal removal of total choline, total creatine and NAA were estimated. Furthermore, frequency distances between the water and those resonances were calculated. Results were corrected for chemical shift displacement. Frequency distances between water and metabolites were consistent and greater for GM than for WM. The highest value of WM to GM difference (14ppb) was observed for water to NAA frequency distance. This study demonstrates that there are tissue-specific differences between frequency distances of water and metabolites. Moreover, the influence of chemical shift displacement in slice-selection direction is showed to be negligible.

The orally active melanocortin-4 receptor antagonist BL-6020/979: a promising candidate for the treatment of cancer cachexia

BACKGROUND: Under physiological conditions, the melanocortin system is a crucial part of the complex network regulating food intake and energy expenditure. In pathological states, like cachexia, these two parameters are deregulated, i.e., food intake is decreased and energy expenditure is increased-a vicious combination leading to catabolism. Agouti-related protein (AgRP), the endogenous antagonist at the melanocortin-4 receptor (MC-4R), was found to increase food intake and to reduce energy expenditure. This qualifies MC-4R blockade as an attractive mode of action for the treatment of cachexia. Based on this rationale, a novel series of small-molecule MC-4R antagonists was designed, from which the orally active compound BL-6020/979 (formerly known as SNT207979) emerged as the first promising development candidate showing encouraging pre-clinical efficacy and safety properties which are presented here. METHODS AND RESULTS: BL-6020/979 is an orally available, selective and potent MC-4R antagonist with a drug-like profile. It increased food intake and decreased energy expenditure in healthy wild-type but not in MC-4R deficient mice. More importantly, it ameliorated cachexia-like symptoms in the murine C26 adenocarcinoma model; with an effect on body mass and body composition and on the expression of catabolic genes. Moreover, BL-6020/979 showed antidepressant-like properties in the chronic mild stress model in rats and exhibits a favorable safety profile. CONCLUSION: The properties of BL-6020/979 demonstrated in animal models and presented here make it a promising candidate suitable for further development towards a first-in-class treatment option for cachexia that potentially opens up the opportunity to treat two hallmarks of the disease, i.e., decreased food intake and increased energy expenditure, with one drug.