Interoceptive threat leads to defensive mobilization in highly anxiety sensitive persons

To study defensive mobilization elicited by the exposure to interoceptive arousal sensations, we exposed highly anxiety sensitive students to a symptom provocation task. Symptom reports, autonomic arousal, and the startle eyeblink response were monitored during guided hyperventilation and a recovery period in 26 highly anxiety sensitive persons and 22 controls. Normoventilation was used as a non-provocative comparison condition. Hyperventilation led to autonomic arousal and a marked increase in somatic symptoms. While high and low anxiety sensitive persons did not differ in their defensive activation during hyperventilation, group differences were detected during early recovery. Highly anxiety sensitive students exhibited a potentiation of startle response magnitudes and increased autonomic arousal after hyper- as compared to after normoventilation, indicating defensive mobilization evoked by the prolonged presence of feared somatic sensations.     

Antinociceptive effects of ethanolic extract from the flowers of Acmella oleracea (L.) R.K. Jansen in mice

Ethnopharmacological relevance

In Brazil, Acmella oleracea (L.) R.K. Jansen, popularly known as “jambu”, has been used by some communities from Amazon region to treat toothache. In this study we examined the antinociceptive effect of the ethanolic extract obtained from the flowers of Acmella oleracea (EEAO) in animal models of nociceptive (chemical and thermal) and neuropathic (partial sciatic nerve ligation) pain.

Materials and methods

Adult male mice were treated by intraperitoneal route (i.p.) with EEAO before the induction of nociceptive response by formalin, capsaicin and cinnamaldehyde, thermal heat hyperalgesia (hot plate test) and mechanical allodynia (traumatic sciatic nerve injury). Acute toxicity and non-specific sedative effects were evaluated.

Results

EEAO (10, 30 and 100 mg/kg) reduced both neurogenic and inflammatory phases of the formalin- and also capsaicin- and cinnamaldehyde-induced orofacial nociception. Interestingly, EEAO at 100 mg/kg (i.p.) also reversed capsaicin-induced heat hyperalgesia assessed as the latency to paw withdrawal in the hot plate test. Also in the hot plate test, paw withdrawal latency was increased by EEAO (100 mg/kg) and this response was only partially reversed by naloxone. Furthermore, EEAO (100 mg/kg) also reduced mechanical allodynia caused by partial sciatic nerve ligation for 3 h. The estimated LD50 value was 889.14 mg/kg and EEAO did not alter the locomotion of animals in the open-field test.

Conclusion

Taken together, our data show that EEAO produces prevalent antinociceptive effects and does not cause adverse effects. The presence of N-alkylamides, including spilanthol, suggests that the therapeutic effect of EEAO is related to its highest anesthetic activity.     

Mechanisms of change: Effects of repetitive exposure to feared stimuli on the brain's fear network

Repetitive exposure to feared stimuli is considered as the essential element in therapy with phobic patients. However, the mechanisms mediating symptom reduction and their underlying neurobiological processes are poorly understood. Therefore, we presented the same fear‐relevant and neutral stimuli repeatedly to individuals with high and low fear of animals during fMRI scanning. High‐, but not low‐fearful individuals showed an initial fear‐stimulus‐related potentiation of amygdala and insula activity. Potentiation of the amygdala in the high‐fearful group habituated quickly, but insula activity was still potentiated during later repetition trials. Both groups showed an initial potentiation of the dorsomedial prefrontal cortex (dmPFC) that continuously decreased in low‐, but not in high‐fearful participants. Thus, within‐session habituation may occur on an automatic processing level (amygdala), but does not cause lasting neural changes on a higher order cortical level (dmPFC).     

Modulation of the ERP repetition effects during exposure to phobia-relevant and other affective pictures in spider phobia

In the present study, dense sensor event-related potentials were measured in spider-phobic individuals and non-anxious controls during incidental encoding of phobia-relevant spider and standard neutral, unpleasant and pleasant pictures. Stimulus repetition effects were assessed by presenting each picture twice--in the first and in the second half of the session. Repeated presentation of standard pleasant, unpleasant and neutral pictures resulted in a late ERP repetition effect that was similarly pronounced in both experimental groups and for all picture categories. Moreover, relative to non-fearful controls spider-phobic individuals showed an overall greater early ERP repetition effect starting at 180 ms after picture onset. At later stages of evaluative processing, repeated as compared with initial presentation of phobia-relevant spider pictures elicited reduced ERP amplitudes over centro-parietal sites (480-580 ms) in spider-phobic but not in control individuals. This pattern of results indicates that in small animal phobics long lasting exposure to their feared pictures leads to an increased mobilization of the perceptual analysis system, an effect that might help to improve emotional control and/or facilitate strategic avoidance of threat resulting in a diminished evaluative threat processing. This phobia-specific processing mechanism might prevent effective stimulus processing and hinder the habituation process during treatment.     

Bone marrow-derived cells contribute to cell turnover in aging murine hearts

The paradigm that cardiac myocytes are non-proliferating, terminally differentiated cells was recently challenged by studies reporting the ability of bone marrow-derived cells (BMCs) to differentiate into cardiomyocytes after myocardial damage. However, little knowledge exists about the role of BMCs in the heart during physiological aging. Twelve-week-old mice (n=36) were sublethally irradiated and bone marrow from littermates transgenic for enhanced green fluorescent protein (eGFP) was transplanted. After 4 weeks, 18 mice were sacrificed at the age of 4 months and served as controls (group A); the remaining mice were sacrificed at the age of 18 months (group B). Group A did not exhibit a significant number of eGFP+ cells, whereas 9.4±2.8 eGFP+ cells/mm2 was documented in group B. In total, only five eGFP+ cardiomyocytes were detected in 20 examined hearts, excluding a functional role of BM differentiation in cardiomyocytes. Similarly, a relevant differentiation of BMCs in endothelial or smooth muscle cells was excluded. In contrast, numerous BM-derived fibroblasts and myofibroblasts were observed in group B, but none were detected in group A. The present study demonstrates that BMCs transdifferentiate into fibroblasts and myofibroblasts in the aging murine myocardium, suggesting their contribution to the preservation of the structural integrity of the myocardium, while they do not account for regenerative processes of the heart.     

Alpha oscillations and the control of voluntary saccadic behavior

The purpose of this review is to explore the dynamic properties of alpha oscillations as biological covariates of intra- and inter-individual variance in saccadic behavior. A preponderance of research suggests that oscillatory dynamics in the alpha band co-vary with performance on a number of visuo-spatial cognitive tasks. Here we discuss a growing body of research relating these measures to saccadic behavior, focusing also on how task related and spontaneous measures of alpha oscillations may serve as potential biomarkers for ocular motor dysfunction in clinical populations.     

In vivo high-resolution magnetic resonance elastography of the uterine corpus and cervix

Objectives

To apply 3D multifrequency MR elastography (3DMMRE) to the uterus and analyse the viscoelasticity of the uterine tissue in healthy volunteers considering individual variations and variations over the menstrual cycle.

Methods

Sixteen healthy volunteers participated in the study, one of whom was examined 12 times over two menstrual cycles. Pelvic 3DMMRE was performed on a 1.5-T scanner with seven vibration frequencies (30–60 Hz) using a piezoelectric driver. Two mechanical parameter maps were obtained corresponding to the magnitude (|G ^* |) and the phase angle (φ) of the complex shear modulus.

Results

On average, the uterine corpus had higher elasticity, but similar viscosity compared with the cervix, reflected by |G ^* |_{uterine corpus}?=?2.58?±?0.52 kPa vs. |G ^* |_cervix?=?2.00?±?0.34 kPa (p?φ _{uterine corpus}?=?0.54?±?0.08, φ _cervix?=?0.57?±?0.12 (p?=?0.428). With 2.23?±?0.26 kPa, |G ^* | of the myometrium was lower in the secretory phase (SP) compared with that of the proliferative phase (PP, |G ^* |?=?3.01?±?0.26 kPa). For the endometrium, the value of |G ^* | in SP was 68 % lower than during PP (PP, |G ^* |?=?3.34?±?0.42 kPa; SP, |G ^* |?=?1.97?±?0.34 kPa; p?=?0.0061).

Conclusion

3DMMRE produces high-resolution mechanical parameter maps of the uterus and cervix and shows sensitivity to structural and functional changes of the endometrium and myometrium during the menstrual cycle.

Key Points

? MR elastography provided for the first time spatially resolved viscoelasticity maps of uterus. ? Uterine corpus had a higher elasticity, but similar viscosity compared with cervix. ? The stiffness of both endometrium and myometrium decreases during the menstrual cycle.     

Postinterventional MRI findings following MRI-guided laser ablation of osteoid osteoma

Objective

To evaluate postinterventional magnetic resonance imaging (MRI) characteristics following MRI-guided laser ablation of osteoid osteoma (OO).

Materials and methods

35 patients treated with MRI-guided laser ablation underwent follow-up MRI immediately after the procedure, after 3, 6, 12, 24, 36, and up to 48 months. The imaging protocol included multiplanar fat-saturated T2w TSE, unenhanced and contrast-enhanced T1w SE, and subtraction images. MR images were reviewed regarding the appearance and size of treated areas, and presence of periablation bone and soft tissue changes. Imaging was correlated with clinical status.

Results

Mean follow-up time was 13.6 months. 28/35 patients (80%) showed a postinterventional “target-sign” appearance consisting of a fibrovascular rim zone and a necrotic core area. After an initial increase in total lesion diameter after 3 months, a subsequent progressive inward remodeling process of the zonal compartments was observed for up to 24 months. Periablation bone and soft tissue changes showed a constant decrease over time. MR findings correlated well with the clinical status. Clinical success was achieved in 32/35 (91%).

Conclusions

Evaluation of long-term follow-up MRI after laser ablation of OO identified typical postinterventional changes and thus may contribute to the interpretation of therapeutic success and residual or recurrent OO in suspected cases.