CNTNAP2 is a gene on chromosome 7 that has shown associations with autism and schizophrenia, and there is evidence that it plays an important role for neuronal synchronization and brain connectivity. In this study, we assessed the relationship between Diffusion Tensor Imaging (DTI), a putative marker of anatomical brain connectivity, and multiple single nucleotide polymorphisms (SNPs) spread out over this large gene. 81 healthy controls and 44 patients with schizophrenia (all Caucasian) underwent DTI and genotyping of 31 SNPs within CNTNAP2. We employed Tract-based Spatial Statistics (TBSS) for inter-subject brain registration and computed average diffusivity values for six major white matter tracts. Analyses of Covariance (ANCOVAs) were computed to test for possible associations with genotypes. The strongest association, which survived rigorous Bonferroni correction, was between rs2710126 genotype and Fractional Anisotropy (FA) in the uncinate fasciculus (p = .00003). This anatomical location is particularly interesting given the enriched fronto-temporal expression of CNTNAP2 in the developing brain. For this SNP, no phenotype association has been reported before. There were several further genotype-DTI associations that were nominally significant but did not survive Bonferroni correction, including an association between axial diffusivity in the dorsal cingulum bundle and a region in intron 13 (represented by rs2710102, rs759178, rs2538991), which has previously been reported to be associated with anterior-posterior functional connectivity. We present new evidence about the effects of CNTNAP2 on brain connectivity, whose disruption has been hypothesized to be central to schizophrenia pathophysiology.
High-capacity adenoviral vectors (HC-AdVs) lacking all viral coding sequences were shown to result in long-term transgene expression and phenotypic correction in small and large animal models. It has been established that HC-AdVs show significantly reduced toxicity profiles compared with early-generation adenoviral vectors. Furthermore, with capsid-modified HC-AdV becoming available, we are just starting to understand the full potential of this vector system. However, for many researchers, the wide-scale use of HC-AdV is hampered by labor-intensive and complex production procedures. Herein, we provide a feasible and detailed protocol for efficient generation of HC-AdV. We introduce an efficient cloning strategy for the generation of recombinant HC-AdV vector genomes. Infection and amplification of the HC-AdV are performed in a spinner culture system. For purification, we routinely apply cesium chloride gradients. Finally, we describe various methods for establishing vector titers. Generation of high-titer HC-AdV can be achieved in 3 weeks.
The concept of 'willed' actions has attracted attention during the last few years. Free choices have been associated with activations on the medial frontal surface, the dorsolateral prefrontal cortex and the parietal lobe. Self-paced movements and free selection between various motor responses were typically used to investigate voluntary behavior. The aim of the present study was to determine neural correlates of voluntary motor responses and the voluntary inhibition of motor responses in a group of healthy subjects. Hence, a go/nogo/voluntary selection paradigm was used. In the voluntary selection condition subjects decided freely whether or not to respond with a button press after stimulus presentation. Functional MRI data and event-related potentials were acquired simultaneously in order to reliably investigate spatial and temporal characteristics of these responses. The results showed decision-related enhanced neural responses predominantly in the medial frontal gyrus/supplementary motor area, lateral frontal brain regions and the inferior parietal gyrus. Additional activations associated with voluntary movements were detected in the frontal eye field as well as brain regions directly linked to motor responses (e.g. somatosensory cortical areas). Altogether, decision processes were shown to be relatively independent of the kind of response chosen.
Studies of schizophrenia with functional MRI have shown hyper- and hypoactivations in various brain regions including the prefrontal cortex. Functional anomalies have also been reported in first-degree relatives of schizophrenic patients. The aim of this study was to examine working memory related brain functions in healthy subjects, schizophrenic patients and unaffected relatives and to determine the influence of psychopathology on these processes. A parametric n-back working memory task and functional MRI were used to examine 61 patients with schizophrenia, 11 nonpsychotic relatives of schizophrenic patients and a comparison group of 61 healthy subjects. The results indicated increased as well as decreased brain functions in schizophrenic patients compared to the control group depending on the task difficulty and the performance: during the attention task (0-back), which served as control condition, behavioral responses of patients and healthy subjects hardly differed but BOLD responses were considerably enhanced in schizophrenic patients. With increasing task difficulty differences between groups in BOLD responses diminished whereas behavioral deficits of patients increased. The examination of attention-independent working memory-functions (2- vs. 0-back) produced hypoactivations in patients, especially in frontal, temporal and subcortical brain regions. Furthermore, positive symptoms were associated with parietal dysfunctions. Behavioral performance and neural responses of unaffected relatives of schizophrenic patients were intermediate between schizophrenic patients and controls indicating slight brain dysfunctions. In addition, compensatory strategies were demonstrated. These findings suggest that the genetic risk for schizophrenia is accompanied by neural inefficiency which is associated with cognitive deficits, especially in difficult tasks.
High-resolution (HR) multislice computed tomography (MSCT) has become the essential tool for the evaluation of malformations, trauma, and especially tumors of the midface and head and neck region. Important for an adequate evaluation of pathologic findings in the head and neck region is a profound knowledge of the organization of the anatomic compartments and their neighboring relation. Therefore, CT scanning of different head and neck regions should be fitted for the special needs of the anatomic region under investigation, for example, particular adjusted protocols for the evaluation of the larynx. The rapid technical improvement of MSCT in recent years has made CT the first-choice imaging modality in many clinical conditions. The thinner slice collimation with improved anatomic detail visualization, the considerably reduced scanning time, and the possibility to calculate multiplanar reconstructions (MPR) from the scanned volume data set have contributed to the ascent of CT scanning in head and neck oncology. Especially helpful is the ability of cross-sectional imaging to reveal pathologic conditions that are not detectable by endoscopy or in the setting of staging underestimated due to submucosal spread. The aim of this article is to provide protocol suggestions for MSCT of the head and neck regions on the basis of a tailored review of the most important anatomic structures and their pathologic conditions.
Liver-based gene therapy approaches demonstrated that high-capacity adenoviral vectors (HC-AdVs) can persist life-long in mice and for 2 years or longer in rats, dogs, and nonhuman primates. However, the molecular status of episomal HC-AdV DNA molecules and the mechanism of vector genome maintenance have not been analyzed. HC-AdV lacks all viral coding sequences including early gene region 4 (E4), which prevents concatemerization in wild-type adenovirus. Therefore, we addressed whether concatemerization or circularization of HC-AdV DNA occurs in transduced cells. We employed pulsed-field gel electrophoresis and a sensitive concatemer/circle-specific polymerase chain reaction (PCR). To test for replication as a potential mechanism for maintenance, we developed a methylase/restriction endonuclease-based system using methylation-marked HC-AdV. We found that unlike DeltaE4 mutant virus, only monomers of HC-AdV genomes were observable in vitro. Using our methylase/restriction endonuclease-based system, no replication of HC-AdV was sensed in various cell lines. However, concatemer formation of HC-AdV could be induced after coinfection with an E4-deleted helper virus, indicating that linkage of genomes may be supported by replication. To examine HC-AdV DNA molecules in vivo, C57BL/6 mice were injected and vector DNA in liver was analyzed. In concordance with our in vitro results, exclusively linear monomers were detected. To sense the replication status of HC-AdV genomes, we established a sensitive real-time PCR. Our results indicated that the input transduced DNA genomes were the persistent molecules in murine liver. In summary, we demonstrated that HC-AdV genomes persist predominantly as replication-defective monomeric genomes.
OBJECTIVE:To use a combination of magnetic resonance diffusion-tensor imaging (MR-DTI) and MR imaging of voxel-based morphometry (MR-VBM) in patients with fibromyalgia syndrome (FMS) to determine microstructural and volume changes in the central neuronal networks involved in the sensory-discriminative and affective-motivational characteristics of pain, anxiety, memory, and regulation of the stress response.METHODS:Thirty female patients with FMS and 30 healthy female control subjects were studied. Predefined areas of the brain were measured for volume of gray matter by MR-VBM and for diffusivity and fractional anisotropy (FA) by MR-DTI. Higher FA values and reduced diffusivity are thought to reflect increased complexity of brain-tissue microstructure.RESULTS:MR-VBM and MR-DTI demonstrated a striking pattern of changes in brain morphology in patients with FMS. Both thalami, the thalamocortical tracts, and both insular regions showed significant decreases in FA. In contrast, increases in FA and decreases in gray matter volume were seen in the postcentral gyri, amygdalae, hippocampi, superior frontal gyri, and anterior cingulate gyri. Increased pain intensity scores were correlated with changes in MR-DTI measurements in the right superior frontal gyrus. Increased fatigue was correlated with changes in the left superior frontal and left anterior cingulate gyrus, and self-perceived physical impairment was correlated with changes in the left postcentral gyrus. Higher intensity scores for stress symptoms were correlated negatively with diffusivity in the thalamus and FA in the left insular cortex. No relationship was found between MR-VBM measurements and symptom intensity scores.CONCLUSION:MR-DTI allows the visualization of microstructural changes in the brain of patients with FMS, appears to be more sensitive than MR-VBM, and may serve as an additional diagnostic technique in FMS and probably other dysfunctional pain syndromes.
While the precise role of the anterior cingulate cortex (ACC) is still being discussed, it has been suggested that ACC activity might reflect the amount of mental effort associated with cognitive processing. So far, not much is known about the temporal dynamics of ACC activity in effort-related decision making or auditory attention, because fMRI is limited concerning its temporal resolution and electroencephalography (EEG) is limited concerning its spatial resolution. Single-trial coupling of EEG and fMRI can be used to predict the BOLD signal specifically related to amplitude variations of electrophysiological components. The striking feature of single-trial coupling is its ability to separate different aspects of the BOLD signal according to their specific relationship to a distinct neural process. In the present study we investigated 10 healthy subjects with a forced choice reaction task under both low and high effort conditions and a control condition (passive listening) using simultaneous EEG and fMRI. We detected a significant effect of mental effort only for the N1 potential, but not for the P300 potential. In the fMRI analysis, ACC activation was present only in the high effort condition. We used single-trial coupling of EEG and fMRI in order to separate information specific to N1-amplitude variations from the unrelated BOLD response. Under high effort conditions we were able to detect circumscribed BOLD activations specific to the N1 potential in the ACC (t=4.7) and the auditory cortex (t=6.1). Comparing the N1-specific BOLD activity of the high effort condition versus the control condition we found only activation of the ACC (random effects analysis, corrected for multiple comparisons, t=4.4). These findings suggest a role of early ACC activation in effort-related decision making and provide a direct link between the N1 component and its corresponding BOLD signal.
Anxiety disorders are highly prevalent in patients with alcohol use disorder. The purpose of the present study was to examine the neural correlates of behavioral inhibition in alcohol-dependent patients (ICD-10: F 10.2), and in healthy controls and to determine the influence of anxiety on these processes. Therefore, behavioral responses (reaction times; error rates) and event-related potentials of 16 patients with alcohol dependence syndrome and 16 age-and gender-matched healthy controls were recorded while the participants performed an auditory go/no-go task. The patient group was stratified according to their self-rated trait anxiety (STAI) with scores above and below median. We hypothesized that patients suffering from alcohol dependence would show reduced no-go P3 amplitudes involved in response inhibition compared to healthy subjects. In patients with alcoholism and high trait anxiety the decline of no-go P3 amplitudes was expected to be less distinct. The estimation of effect size based on the reaction times of patients with high and low anxiety ratings revealed a cohen's d of 0.61 indicating a small effect. High trait anxiety ratings were also associated with slightly enhanced no-go P3 amplitudes in central brain regions (Mean no-go P3 amplitude at Cz: 10.43 μV) compared to patients with low anxiety scores (Mean 8.98 μV). The effect size (cohen's d) revealed a small effect. Using the Mann-Whitney-U-test for independent samples of the comparison of high- and low-anxious patients, however, did not reveal any significant differences concerning no-go P3 amplitudes. Patients with alcohol use disorder and healthy controls did not differ significantly with regard to reaction time, error rate and no-go P3 amplitudes. This study suggests that no-go P3 amplitudes in patients with alcohol use disorder might be affected to some degree by habitual anxiety. The results emphasize the importance of monitoring trait anxiety in studies regarding cognitive functions in subjects with alcohol use disorder.
Alcohol-dependence is often associated with comorbid psychiatric symptoms. However, the results concerning the influence of these symptoms on cognitive functioning in alcoholism are still inconsistent. The aim of this study was to determine performance monitoring in healthy volunteers and alcohol-dependent patients, and to assess the influence of trait anxiety on these processes. Sixteen healthy volunteers and 16 detoxified alcohol-dependent patients completed an auditory go/nogo paradigm. Functional magnetic resonance imaging, event-related potentials and behavioral data were acquired simultaneously. The patients were classified by median split based on level of self-rated trait anxiety (state-trait anxiety inventory; STAI). The results showed no significant differences regarding inhibition-associated electrophysiological and behavioral responses between alcohol-dependent patients with high-trait anxiety scores and alcohol-addicts with low-STAI scores. However, the functional MRI data revealed elevated activations during the response inhibition task especially in the middle frontal gyrus (BA 6/9), the superior frontal gyrus (BA 6/8/9) and the right inferior frontal gyrus, as well as temporo-parietal brain regions in patients with high-trait anxiety compared to non-anxious alcohol-addicts. Patients and healthy controls showed comparable results with regard to neural and behavioral responses. These results suggest that inhibitory control capacities of alcohol-dependent patients are not consistent: alcohol-addicts with high-trait anxiety ratings showed elevated neural responses compared to patients without any comorbid psychiatric symptoms. This may indicate that comorbid psychiatric symptoms need to be considered when assessing brain responses in alcohol-dependent patients.
Patienten mit Alkoholabhängigkeit zeigen häufig kognitive Defizite vor allem in den Bereichen Gedächtnis und exekutive Fähigkeiten (Parsons OA, Alcohol Clin Exp Res; 1998:22(4): 954–61). Unklar ist, ob bzw. inwieweit komorbide psychiatrische Erkrankungen an der Ausprägung der kognitiven Beeinträchtigungen beteiligt sind. Untersucht wurden die neuronalen Korrelate der Verhaltensinhibition bei Patienten mit Alkoholabhängigkeit und gesunden Kontrollpersonen sowie der Einfluss einer komorbiden Angsterkrankung auf diese Prozesse.
Currently, there is evidence demonstrating that schizophrenia is an illness characterized by multiple deficits in cognitive processes such as attention and memory. It is assumed that these are the consequence of functional and anatomical variations especially comprising frontal and temporo-parietal brain regions as well as abnormal interactions between these areas. These variations may result in altered neuronal contribution of affected brain regions during cognitive processes not only concerning the intensity of neuronal reactivity but also regarding their temporal aspects. We simultaneously recorded ERP and functional MRI data to examine brain regions involved in information processing and examined differences in the intensity of neuronal activity as well as temporal aspects of neuronal participation in schizophrenics and healthy controls.
Der mediale präfrontale Cortex (mPFC) und der anteriore cinguläre Cortex (ACC) sind bei vielen kognitiven Prozessen beteiligt, u.a. bei Aufmerksamkeitsprozessen und Verhaltenskontrolle. Darüber hinaus spielen beide Regionen eine zentrale Rolle bei vielen psychiatrischen Krankheiten. Zwei Paradigmen wurden bisher häufig in elektrophysiologischen Studien eingesetzt, um mediale Frontallappenanteile zu untersuchen: Zum einen das Wahlreaktionsparadigma und zum anderen das Go-/Nogo-Paradigma. In Lokalisationsuntersuchungen mittels Low Resolution Electromagnetic Tomography (LORETA) wurden Aktivierungsmuster im Bereich der frontalen Mittellinie entdeckt. Allerdings ist die räumliche Auflösung elektrophysiologischer Lokalisationsmethoden mit der LORETA limitiert. Diese Einschränkungen hinsichtlich der räumlichen Auflösung existieren nicht für die funktionelle Magnetresonanztomographie (fMRT).
Recent drawbacks in treating patients with severe combined immunodeficiency disorders with retroviral vectors underline the importance of generating novel tools for stable transduction of mammalian cells. Substantial progress has been made over the recent years which may offer important steps towards stable and more importantly safer correction of genetic diseases. This article discusses recent advances for stable transduction of target cells based on adenoviral gene transfer. There is accumulating evidence that recombinant adenoviral vectors (AdVs) based on various human serotypes with a broad cellular tropism and adenoviruses (Ads) from different species will play an important role in future gene therapy applications. In combination with recombinant AdVs for somatic integration these gene transfer vectors offer high transduction efficiencies with potentially safer integration patterns. Other approaches for persistent transgene expression include excision of stable episomes from the adenoviral vector genome, but also long-term persistence of the complete adenoviral vector genome as an episomal DNA molecule was demonstrated and exemplified by the treatment of various genetic diseases in small and large animal models. This review displays advantages but also limitations of these Ad based vector systems. This is the perfect time to pursue such approaches because alternative strategies for stable transduction of mammalian cells undergoing many cell divisions are urgently needed. Looking into the future, we believe that a combination of different components from different viral vectors in concert with non-viral vector systems will be successful in designing significantly optimized transfer vehicles for a broad range of different genetic diseases.
Funktionelle Bildgebungs- und elektrophysiologische Studien beschäftigen sich seit langem mit dem anterioren cingulären Cortex (ACC) als mögliche Schlüsselregion für die in der Schizophrenie bekannten Aufmerksamkeits- und Motivationsdefizite. Wir untersuchten in der vorliegenden Studie mittels einer konzentrationsabhängigen auditorischen Wahlreaktionsaufgabe, bei der eine Beteiligung des ACC bereits bekannt ist, den Einfluss von Belohnung auf die Hirnaktivität und die kognitiven Leistungen im Vergleich zwischen Patienten mit Schizophrenie und gesunden Kontrollprobanden.
Cerebrale Funktionsdefizite bei Patienten mit Alkoholabhängigkeit sind vielfach beschrieben worden. Elektrophysiologisch wurden häufig verminderte Amplituden des ereigniskorrelierten Potentials P300 als neurophysiologisches Korrelat einer Informationsverarbeitungsstörung gefunden. Eine genaue neuroanatomische Zuordnung dieser Befunde basierend alleine auf Skalp-Potential-Daten ist jedoch nicht ohne weiteres möglich. Die funktionelle Magnetresonanztomographie (fMRT) erlaubt eine valide und präzise Lokalisation hirnfunktioneller Prozesse.
RATIONALE AND OBJECTIVES:During aging, there is evidence of microstructural changes in certain cortical and subcortical brain regions. Diffusion tensor imaging (DTI) is used to study age related microstructural changes in the acoustic pathway. MATERIALS AND METHODS:Twenty healthy volunteers (mean age 28.5 years) and 15 healthy volunteers (mean age 61.3 years) were examined using a 1.5-T MR system with a high-resolution T1-weighted sequence and an integrated parallel imaging technique DTI Echo-planar-imaging (EPI) sequence. For reliability, 10 subjects underwent a second examination 2 days later. The fractional anisotropy (FA) and the apparent diffusion coefficient (ADC) were measured in six brain regions of the auditory pathway. RESULTS:We found no left/right asymmetry in the selected brain structures. There were no significant differences (P < .05) in the ADC and FA in the lateral lemniscus and medial geniculate body of young and elderly subjects. However, FA was significantly increased (P < .05) in the inferior colliculus and decreased in the auditory radiation, the superficial temporal gyrus, and the transverse temporal gyrus in the elder subjects than in the younger ones. There were no significant differences in anisotropy in subsequent examinations in the younger individuals. CONCLUSIONS:These findings suggest evidence of age-related changes in the acoustic pathway. These changes are associated with a decrease in anisotropy mainly in the cortical grey and white matter rather than in the subcortical regions. Our DTI measurements were reproducible.
Das Arbeitsgedächtnis umfasst die Fähigkeit,bei der Bearbeitung kognitiver Aufgaben Informationen gleichzeitig zu verarbeiten und zu speichern. Defizite im Bereich des Arbeitsgedächtnisses werden häufig bei Patienten mit Schizophrenie beschrieben (z.B. Callicott et al. (2003) Am J Psychiatry;160(12):2209–15).
Das akustisch evozierte P300-Potential gilt als ein Indikator zentraler Neurotransmission im Rahmen kognitiver Informationsverarbeitung. Ein Einfluss von Alter und Reaktionszeiten auf das P300-Potential ist vielfach beschrieben worden. Die genauen neuroanatomischen Strukturen, die für Alters- und Reaktionszeiteffekte verantwortlich sind, wurden jedoch bisher nicht näher untersucht. An der Generierung des P300-Potentials sind verschiedene kortiko-limbische Strukturen beteiligt. Allerdings ist die genaue neuroanatomische Zuordnung von auf Skalp-Ableitungen basierenden EEG-Daten nicht ohne weiteres möglich. Gleichwohl kann eine valide und präzise Lokalisation des BOLD-Korrelats des P300-Potentials bei simultaner fMRT/EEG-Messung erreicht werden. Ziel dieser Studie war es, die neuroanatomischen Grundlagen der Alters- und Reaktionszeitabhängigkeit des P300-Potentials durch eine simultane EEG/fMRT-Untersuchung darzustellen.