Piccolo genotype modulates neural correlates of emotion processing but not executive functioning

Major depressive disorder (MDD) is characterized by affective symptoms and cognitive impairments, which have been associated with changes in limbic and prefrontal activity as well as with monoaminergic neurotransmission. A genome-wide association study implicated the polymorphism rs2522833 in the piccolo (PCLO) gene—involved in monoaminergic neurotransmission—as a risk factor for MDD. However, the role of the PCLO risk allele in emotion processing and executive function or its effect on their neural substrate has never been studied. We used functional magnetic resonance imaging (fMRI) to investigate PCLO risk allele carriers vs noncarriers during an emotional face processing task and a visuospatial planning task in 159 current MDD patients and healthy controls. In PCLO risk allele carriers, we found increased activity in the left amygdala during processing of angry and sad faces compared with noncarriers, independent of psychopathological status. During processing of fearful faces, the PCLO risk allele was associated with increased amygdala activation in MDD patients only. During the visuospatial planning task, we found no genotype effect on performance or on BOLD signal in our predefined areas as a function of increasing task load. The PCLO risk allele was found to be specifically associated with altered emotion processing, but not with executive dysfunction. Moreover, the PCLO risk allele appears to modulate amygdala function during fearful facial processing in MDD and may constitute a possible link between genotype and susceptibility for depression via altered processing of fearful stimuli. The current results may therefore aid in better understanding underlying neurobiological mechanisms in MDD.     

Basal cerebral blood flow is dependent on the nitric oxide pathway in elderly but not in young healthy men

OBJECTIVE: Brain perfusion is tightly regulated over a wide range of blood pressures by local regulation of cerebral blood flow (CBF). Ageing is associated with impaired CBF and impaired nitric oxide mediated vasodilator responses. The role of nitric oxide in the regulation of basal CBF in young and older subjects was investigated, using the nitric oxide synthase inhibitor L-NMMA as pharmacological tool. METHODS: We used a gradient echo phase-contrast magnetic resonance imaging technique to investigate the role of nitric oxide in the regulation of cerebral blood flow in young (25+/-7.1 years; n=8) and old (78+/-6.6 years; n=7) volunteers. The study was performed in a double-blinded fashion and consisted of two study days. On one day the effects of the intravenously infused L-NMMA on CBF and blood pressure was measured and on the other day the effects of a matching placebo. RESULTS: Basal CBF was significantly lower in old compared to young subjects (590+/-20 vs 704+/-20 ml/min), while the cerebral vascular resistance (CVR) levels were significantly higher (0.15+/-0.01 (arbitrary units) vs 0.12+/-0.01, respectively). Infusion of L-NMMA significantly increased mean arterial pressure in both groups (2.8+/-1.2 mmHg; p=0.02 in the young and in the old subjects 5.6+/-1.1 mmHg; p<0.001). Infusion of L-NMMA significantly decreased CBF (49+/-12 ml/min; p<0.001) and increased CVR (0.02+/-0.004; p<0.001) in the old subjects but did not significantly influence cerebral circulation in the young subjects. CONCLUSION: We conclude that compared to young subjects, in old people CBF is impaired, and dependent on the intactness of the nitric oxide pathway.     

Interaction of neuropeptide Y genotype and childhood emotional maltreatment on brain activity during emotional processing

Neuropeptide Y (NPY) has been associated with stress reactivity in affective disorders and is most densely expressed in the amygdala. An important stressor associated with affective disorders is the experience of childhood emotional maltreatment (CEM). We investigated whether the interaction of NPY risk genotype and CEM would affect brain activation. From the Netherlands Study of Depression and Anxiety, 33 healthy controls and 85 patients with affective disorders were scanned with functional magnetic resonance imaging while making gender decisions of emotional facial expressions. Results showed interactions between genotype and CEM, within carriers of the risk genotype, CEM was associated with higher amygdala activation, whereas CEM did not influence activation in non-risk carriers. In the posterior cingulate cortex (PCC), less activation was seen in those with CEM and the risk genotype, whereas genotype did not influence PCC activation in those without CEM. In addition, those carrying the risk genotype and with experience of CEM made a faster gender decision than those without CEM. Thus, the combined effect of carrying NPY risk genotype and a history of CEM affected amygdala and PCC reactivity, areas related to emotion, self-relevance processing and autobiographical memory. These results are consistent with the notion that the combination of risk genotype and CEM may cause hypervigilance.     

Vascularization of head and neck paragangliomas: comparison of three MR angiographic techniques with digital subtraction angiography

BACKGROUND AND PURPOSE: MR angiography of the head and neck region has been studied widely, but few studies have been performed concerning the efficacy of MR angiography for the identification of the specific vascular supply of the highly vascular head and neck paragangliomas. In this study, we compared three MR angiography techniques with respect to visualization of branch arteries in the neck and identification of tumor feeders in patients with paragangliomas. METHODS: Fourteen patients with 29 paragangliomas were examined at 1.5 T using 3D phase-contrast (PC), 2D time-of-flight (2D TOF), and multi-slab 3D TOF MR angiography. In the first part of the study, two radiologists independently evaluated the visibility of first-, second-, and third-order branch arteries in the neck. In the second part of the study, the number of feeding arteries for every paraganglioma was determined and compared with digital subtraction angiography (DSA), the standard of reference in this study. RESULTS: Three-dimensional TOF angiography was superior to the other MR angiography techniques studied (P < .05) for depicting branch arteries of the external carotid artery in the neck, but only first- and second-order vessels were reliably shown. DSA showed a total of 78 feeding arteries in the group of patients with 29 paragangliomas, which was superior to what was revealed by all MR angiography techniques studied. More tumor feeders were identified with 3D TOF and 2D TOF angiography than with 3D PC MR angiography (P < .05), with a sensitivity/specificity of 61%/98%, 54%/95%, and 31%/95%, respectively. Sensitivity was lowest for carotid body tumors. CONCLUSION: Compared with intra-arterial DSA, the 3D TOF MR angiography technique was superior to 3D PC and 2D TOF MR angiography for identifying the first- and second-order vessels in the neck. With 3D TOF angiography, more tumor feeders were identified than with the other MR angiography techniques studied. The sensitivity of MR angiography, however, is not high enough to reveal important vascularization. The sensitivity of MR angiography is too low to replace DSA, especially in the presence of carotid body tumors.     

Incipient CADASIL

BACKGROUND: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is caused by mutations in the NOTCH3 gene. Knowledge of disease expression in young adult NOTCH3 mutation carriers (MCs) is limited. OBJECTIVE: To characterize clinical, neuropsychological, and radiological status in NOTCH3 MCs younger than 35 years. DESIGN: Clinical characterization and blinded survey comparing MCs with non-MCs. SETTING: Referral center. PARTICIPANTS: Individuals younger than 35 years who were at a 50% risk of a NOTCH3 mutation, from our CADASIL database. Thirteen individuals, from 8 families, met the criteria. METHODS: Comprehensive clinical, genetic, neuropsychological, and radiological investigations. Magnetic resonance images were scored according to a standardized white matter hyperintensities rating scale. RESULTS: Six individuals, from 5 families, were MCs. Clinical symptoms consisted of migraine (with aura), stroke, and stroke-like episodes. We did not find evidence for psychiatric disturbances, functional disability, or cognitive dysfunction, compared with non-MCs. Radiologically, a characteristic magnetic resonance imaging lesion pattern emerged for all MCs. This comprised white matter hyperintensities in the anterior temporal lobes, the frontal lobes, and the periventricular frontal caps. CONCLUSIONS: Migraine (with aura) and stroke can present in NOTCH3 MCs younger than 35 years; however, more importantly, physical function and cognition are intact. Possible subtle cognitive dysfunction needs to be assessed in a larger study. White matter hyperintensities on magnetic resonance imaging are characteristic, and are consistently visualized from the age of 21 years and onward. Awareness of the clinical and radiological features of CADASIL in those younger than 35 years should increase early diagnosis and allow for customized counseling of young adults from families with CADASIL.     

Cerebral microbleeds in CADASIL

BACKGROUND: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary arteriopathy leading to recurrent cerebral infarcts and dementia. Intracerebral hemorrhage (ICH) has been described sporadically in patients with CADASIL, suggesting that the affected arteries in CADASIL are not bleed-prone. However, the presence of cerebral microbleeds, which often remain undetected on conventional MRI, has not been determined in CADASIL. OBJECTIVE: To determine whether cerebral vessels in patients with CADASIL are prone to microbleeding. METHODS: T2*-weighted gradient echo MRI, which is highly sensitive for visualizing microbleeds, was performed in patients with CADASIL and their family members (n = 63). Known risk factors for ICH were determined for all individuals. On an exploratory basis, the presence of cerebral microbleeds was correlated with demographic variables, vascular risk factors, disease progression, ischemic MR lesions, and genotype. RESULTS: Cerebral microbleeds were present in 31% of symptomatic CADASIL mutation carriers, predominantly in the thalamus. Vascular risk factors such as hypertension did not account for the microbleeds in these patients. Factors associated with microbleeds were age (p = 0.008), Rankin disability score (p = 0.017), antiplatelet use (p = 0.025), number of lacunae on MRI (p = 0.009), and the Arg153Cys Notch3 mutation (p = 0.017). After correction for age, only the Arg153Cys mutation remained significantly associated with the presence of microbleeds. CONCLUSION: Patients with CADASIL have an age-related increased risk of intracerebral microbleeds. This implies that they may have an increased risk for ICH, which should be taken into account in CADASIL diagnosis and patient management.