Influence of the fusiform gyrus on amygdala response to emotional faces in the non-clinical range of social anxiety

BACKGROUND

Social anxiety often involves a combination of hypervigilance and avoidance to potentially warning signals including the facial expression of emotions. Functional imaging has demonstrated an increase in amygdala response to emotional faces in subjects with social anxiety. Nevertheless, it is unclear to what extent visual areas processing faces influence amygdala reactivity in different socially anxious individuals. We assessed the influence of the fusiform gyrus activation on amygdala response to emotional faces in the non-clinical range of social anxiety.

METHOD

Twenty-two normal subjects showing a wide range in social anxiety scores were examined using functional magnetic resonance imaging (fMRI) during the processing of happy and fearful faces. A dimensional analysis approach was used involving voxel-wise mapping of the correlation between subjects' social anxiety scores and amygdala activation, before and after controlling for fusiform gyrus activation.

RESULTS

We observed that only after controlling for subjects' level of activation of the fusiform gyrus was there an association between social anxiety ratings and amygdala response to both happy and fearful faces. The fusiform gyrus influence was more robust during the fear condition. Of note, fusiform gyrus response to fearful faces showed a negative correlation with additional behavioral assessments related to avoidance, including social anxiety scores, harm avoidance and sensitivity to punishment.

CONCLUSIONS

Relevant interactions among the emotional face-processing stages exist in the non-clinical range of social anxiety that may ultimately attenuate amygdala responses. Future research will help to establish the role of this effect in a clinical context.

Quantification and characterization of carotid calcium with multi-detector CT-angiography

OBJECTIVE

The aim of this study was to assess the accuracy of CT-angiography for identification and measurement of calcification of carotid atherosclerotic plaques and to characterise the content and distribution pattern of mineral calcium (hydroxyapatite, Ca) in carotid bifurcations and investigate its relationship with neurological symptoms.

METHODS

Twenty-six patients with ICA stenosis > 60% (13 symptomatic, 13 asymptomatic) were selected for study. Ca was estimated from the weight of the ashed remnants of carotid endarterectomy (CEA) specimens in 11 patients. Calcium content (calcification volume (mm3),CV), and average calcium density (Hounsfield units (HU),CD), were determined by CT-angiography. The distribution pattern of calcium within the lesion (base (posterior), shoulder or luminal surface) was assessed in all cases.

RESULTS

CT-derived estimation of CV and Ca mass (modified Agatston Score, (mAS) = CV x CD) showed a good correlation with its direct measurement in CEA specimens (r = 0.911 and 0.993 respectively, p < 0,005). Asymptomatic patients with ICA stenosis > 60% showed statistically significant higher content of Ca than those who were symptomatic (mAS: 122.6 +/- 138.0 HU mm3 vs 42.8 +/- 59.1 HU mm3, p = 0.04). Calcification on the surface of the plaque was observed more commonly in asymptomatic patients (9/12 vs 3/15, p = 0.006). Non-calcified or plaques with posterior calcification were 12 times more likely to be symptomatic (OR: 12, 95%CI 1.5-91.1, p = 0.021).

CONCLUSIONS

CT-angiography permits the reliable quantification of calcification of carotid plaques. A lower content of calcium in carotid plaques, as well as its distribution in the base of the lesion, was associated with a greater prevalence of neurological symptoms. These parameters may be useful to identify those patients at higher risk of stroke.

Reflex sympathetic dystrophy syndrome of the lower limbs in a renal transplant patient treated with tacrolimus

BACKGROUND

Recently, a previously unrecognized posttransplant syndrome known as reflex sympathetic dystrophy syndrome of the lower limbs has emerged in patients receiving cyclosporine as immunosuppression. We describe herein this complication observed in a patient treated with tacrolimus after kidney transplantation.

METHODS

A 49-year-old man received a kidney transplant from a cadaver donor and was treated with tacrolimus. Three months later, the patient complained of severe pain in the lower limbs that affected both knees and ankles. Bone scintigraphy and magnetic resonance were consistent with reflex sympathetic dystrophy syndrome.

RESULTS

Laboratory tests that included creatinine, glomerular filtration rate, calcium, phosphate, urate, alkaline phosphatase, and parathormone were normal or near normal. Tacrolimus levels were around 13 microg/ml. Clinical improvement appeared slowly and spontaneously during the following 3 months, without appreciable changes in the tacrolimus level.

CONCLUSIONS

In kidney transplant patients, tacrolimus could be a risk factor for the development of a reflex sympathetic dystrophy syndrome.