Variation in the distribution of large-scale spatiotemporal patterns of activity across brain states.

A few large-scale spatiotemporal patterns of brain activity (quasiperiodic patterns or QPPs) account for most of the spatial structure observed in resting state functional magnetic resonance imaging (rs-fMRI). The QPPs capture well-known features such as the evolution of the global signal and the alternating dominance of the default mode and task positive networks. These widespread patterns of activity have plausible ties to neuromodulatory input that mediates changes in nonlocalized processes, including arousal and attention. To determine whether QPPs exhibit variations across brain conditions, the relative magnitude and distribution of the three strongest QPPs were examined in two scenarios. First, in data from the Human Connectome Project, the relative incidence and magnitude of the QPPs was examined over the course of the scan, under the hypothesis that increasing drowsiness would shift the expression of the QPPs over time. Second, using rs-fMRI in rats obtained with a novel approach that minimizes noise, the relative incidence and magnitude of the QPPs was examined under three different anesthetic conditions expected to create distinct types of brain activity. The results indicate that both the distribution of QPPs and their magnitude changes with brain state, evidence of the sensitivity of these large-scale patterns to widespread changes linked to alterations in brain conditions.

Variation in the Distribution of Large-scale Spatiotemporal Patterns of Activity Across Brain States.

A few large-scale spatiotemporal patterns of brain activity (quasiperiodic patterns or QPPs) account for most of the spatial structure observed in resting state functional magnetic resonance imaging (rs-fMRI). The QPPs capture well-known features such as the evolution of the global signal and the alternating dominance of the default mode and task positive networks. These widespread patterns of activity have plausible ties to neuromodulatory input that mediates changes in nonlocalized processes, including arousal and attention. To determine whether QPPs exhibit variations across brain conditions, the relative magnitude and distribution of the three strongest QPPs were examined in two scenarios. First, in data from the Human Connectome Project, the relative incidence and magnitude of the QPPs was examined over the course of the scan, under the hypothesis that increasing drowsiness would shift the expression of the QPPs over time. Second, using rs-fMRI in rats obtained with a novel approach that minimizes noise, the relative incidence and magnitude of the QPPs was examined under three different anesthetic conditions expected to create distinct types of brain activity. The results indicate that both the distribution of QPPs and their magnitude changes with brain state, evidence of the sensitivity of these large-scale patterns to widespread changes linked to alterations in brain conditions.

No support for Heincke's law in hagfish (Myxinidae): lack of an association between body size and the depth of species occurrence.

This study tests for interspecific evidence of Heincke's law among hagfishes and advances the field of research on body size and depth of occurrence in fishes by including a phylogenetic correction and by examining depth in four ways: maximum depth, minimum depth, mean depth of recorded specimens and the average of maximum and minimum depths of occurrence. Results yield no evidence for Heincke's law in hagfishes, no phylogenetic signal for the depth at which species occur, but moderate to weak phylogenetic signal for body size, suggesting that phylogeny may play a role in determining body size in this group.

Beyond fibrosis: stellate cells as liver stem cells.

The high regenerative potential of the liver is driven by parenchymal and non-parenchymal cells, which restore the original liver mass after injury by cell proliferation. The contribution of stem- and progenitor cells to liver regeneration is mainly observed when hepatocyte proliferation is impaired. However, the origin of stem/progenitor cells and their effectivity to restore injured liver is currently discussed controversially. Hepatic stellate cells, which are mainly known for their contribution to fibrosis in chronic liver diseases, were recently identified as mesenchymal stem cells (MSC) of the liver. Stellate cells are also involved in liver regeneration and fulfill a dual function by supporting neighboring cells and developing into liver epithelial cells. This demonstrates that stellate cells not only exhibit the same expression profile and differentiation potential but also functional similarities to MSC of other organs, which are at present intensively studied by many groups for their therapeutic use in liver diseases.

Neural evidence that suspense narrows attentional focus.

The scope of visual attention changes dynamically over time. Although previous research has reported conditions that suppress peripheral visual processing, no prior work has investigated how attention changes in response to the variable emotional content of audiovisual narratives. We used fMRI to test for the suppression of spatially peripheral stimuli and enhancement of narrative-relevant central stimuli at moments when suspense increased in narrative film excerpts. Participants viewed films presented at fixation, while flashing checkerboards appeared in the periphery. Analyses revealed that increasing narrative suspense caused reduced activity in peripheral visual processing regions in the anterior calcarine sulcus and in default mode network nodes. Concurrently, activity increased in central visual processing regions and in frontal and parietal regions recruited for attention and dynamic visual processing. These results provide evidence, using naturalistic stimuli, of dynamic spatial tuning of attention in early visual processing areas due to narrative context.

Effective connectivity in long-term EEG monitoring in preterm infants.

OBJECTIVE: Electroencephalogram (EEG) is commonly used to monitor brain activity in preterm neonates. Long-term EEG is used to predict outcomes by total band power. This study reports effective connectivity analyses in the fronto-parietal network in preterm infants. METHOD: Directed transfer functions (DTFs) were used in fully automated calculations of effective connectivity. Continuous eight-channel EEG recordings were performed for three full days starting at a median of 5.3h (2.5-11.2h) after birth. Analyses were performed using the channels Fp1, Fp2, P3 and P4. DTF were calculated every second in every connection and channel for all frequencies from 1 Hz to 30 Hz. The median connectivity was used in the connectivity assessment. RESULTS: Parieto-frontal connectivity was significantly higher (0.22) than fronto-parietal connectivity (0.05). There was a significant decrease in parieto-frontal connectivity between day one (0.18) and three. Conversely, there was a significant increase in fronto-parietal connectivity from day one to day three (0.07). CONCLUSION: Significant changes are seen in connectivity from day one to three, but there were no certain connectivity differences between gestational ages. SIGNIFICANCE: A rapid change in fronto-parietal connectivity was seen from day one to three which may indicate fast postpartum maturation.

The effect of blood glucose and pCO2 on spectral EEG of premature infants during the first three days of life.

BACKGROUND: Spectral EEG analysis using automated quantification of total absolute band power (tABP) expresses brain function. We hypothesized that pCO2 or blood glucose affects tABP during the critical first days of life in premature infants. OBJECTIVE: To use automated tABP quantification to determine whether EEG background activity in premature infants during the first 3 days of life is influenced by pCO2 or blood glucose levels. METHODS: Preterm infants, group 1 [gestational age (GA) = 24-27 weeks] and group 2 (GA = 28-30 weeks), underwent continuous EEG monitoring for 3 days after birth. Biochemical data were extracted from the observational datasheet used during monitoring. Blood samples were taken at the request of the attending physician. Statistical analyses were performed as repeated measurements using linear mixed models with a random intercept. The effect of time was treated as a fixed covariate and the GA groups as a fixed factor in all models. Continuous data were described using the mean ± SD or median and range, and categorical data were described using the number of patients and percentages unless otherwise indicated. RESULTS: There was an association between increased pCO2 and tABP and between increased blood glucose and tABP. Further, there were no differences in the responses between groups 1 and 2. CONCLUSION: Both hyperglycemia and hypercapnia showed a negative effect on brain activity decreasing tABP during the first 3 days of life in premature infants.

Automated spectral EEG analyses of premature infants during the first three days of life correlated with developmental outcomes at 24 months.

BACKGROUND: Spectral EEG analysis using automated quantification of total absolute band power (tABP) for long-term brain monitoring is reliable. We hypothesised that tABP during the first critical days of life could be a useful tool for predicting later developmental outcomes. OBJECTIVE: To determine whether measuring EEG background activity in premature infants with automated tABP quantification during the first 3 days of life correlated with their developmental outcomes at 24 months. METHODS: Preterm infants (group 1, gestational age, GA 24-28 weeks and group 2, GA 28-31 weeks) were continuously monitored by EEG for 3 days after birth. Their developmental outcomes were assessed using the Bayley-II and Peabody-2 developmental tests at 24 months. Their respective indices were calculated. Normal (index ≥85) and abnormal (index <85) outcomes were correlated with the tABP. RESULTS: In group 1, the tABP was significantly lower in the abnormal infants than in the normal infants. The specificity and negative predictive value were also high for all of the tests that were applied in this group. In group 2, there was no correlation between the tABP and developmental outcome. CONCLUSION: This study found that extremely premature infants with poor developmental outcomes had significantly lower tABP values in their first days of life compared to infants from the same group with normal outcomes. This method may be useful in predicting later outcomes in extremely premature infants and has the advantage of being automated.

Virtually perfect time sharing in dual-task performance: uncorking the central cognitive bottleneck.

A fundamental issue for psychological science concerns the extent to which people can simultaneously perform two perceptual-motor tasks. Some theorists have hypothesized that such dual-task performance is severely and persistently constrained by a central cognitive "bottle-neck," whereas others have hypothesized that skilled procedural decision making and response selection for two or more tasks can proceed at the same time under adaptive executive control. The three experiments reported here support this latter hypothesis. Their results show that after relatively modest amounts of practice, at least some participants achieve virtually perfect time sharing in the dual-task performance of basic choice reaction tasks. The results also show that observed interference between tasks can be modulated by instructions about differential task priorities and personal preferences for daring (concurrent) or cautious (successive) scheduling of tasks. Given this outcome, future research should investigate exactly when and how such sophisticated skills in dual-task performance are acquired.

[The effects of psychotherapy on Crohn's disease patients--results of a randomized multicenter study]. / Die Wirksamkeit psychotherapeutischer Massnahmen bei Morbus Crohn. Ergebnisse einer randomisierten, multizentrischen Studie.

In a prospective multicenter study of Crohn disease patients, the influence of psychotherapy on the course of the disease and on psychosocial variables (anxiety, depression, life satisfaction and data of the PSKB) was studied. Psychodynamic oriented psychotherapy was provided in addition to a standardized medical treatment and took place during the first year of the two-year observation period. 108 of 488 patients were recruited and randomly assigned to the psychotherapy and the control group. 84 patients completed the somatic and 81 the psychosocial follow up. 23% of the control group and 30% of the psychotherapy group showed episode-free courses, 29% and 17% respectively underwent surgery (worst outcome group). The ranking and comparisons of the disease course showed no significant difference (p = 0.125) between psychotherapy and control group. The psychosocial variables also showed no differences between these groups. Subjectively, the patients report favourable effects to psychotherapy.

[Radiofrequency catheter ablation of symptomatic isolated ventricular extrasystole in patients with a normal heart]. / Ablación por radiofrecuencia de extrasistolía ventricular aislada sintomática en corazón sano.

INTRODUCTION: Premature ventricular depolarizations (PVDs) in patients without heart disease, are a frequent clinical problem that can cause important symptoms. Most commonly, this benign arrhythmia responds to treatment with antiarrhythmic drugs. However, occasionally PVDs are refractory to pharmacological treatment but they can be eliminated with radiofrequency catheter ablation. AIM: To show our experience with four patients in whom we used this method. MATERIAL AND METHOD: We studied three men and a woman, twelve to forty six years old. All of them were symptomatic, their EKG and echocardiogram were normal and they had been treated with several drugs without response. In three of them the PVDs had left bundle-branch block morphology with inferior axis; the other patient had right bundle-branch block morphology with superior axis. The origin of the PVDs was determined using pace mapping. RESULTS: Two of the patients had spontaneous PVDs; in the other two isoproterenol infusion was used to induce them. In three patients the origin of the PVDs was located in right ventricular outflow and in the other in the anterolateral region of the left ventricle. None had sustained atrial or ventricular arrhythmia. In all of them PVDs were eliminated. A patient presented a second morphology that could not be treated. None of the patients had complications and they were discharged within the next 24 hours. Three noted symptomatic improvement and after 18 months, only one had a probable recurrence of the arrhythmia. CONCLUSIONS: Radiofrequency catheter ablation can be successfully used to eliminate PVDs in severely symptomatic and drug-resistant patients.

The production of health and the valuation of medical inputs in wage-amenity models.

Using a hedonic wage-amenity model, this paper examines the valuation of medical inputs into the production of health. The data used in this study include the incomes, demographics and measures of human capital for households in eastern North Carolina with county level medical input supply. These data allow an estimate of the marginal value of medical care inputs such as the physician to population ratio and the availability of specialized services in an area of the country where the lack of available medical care has been of particular concern to policy makers. Our results indicate that while health care inputs are not a significant determinant of earnings overall, they are important in counties that have been designated as medically underserved. In underserved counties each additional physician per 10,000 individuals in the county decreases earnings by about 11.6%. This suggests that physicians act as an amenity and workers are willing to accept lower wages to locate in counties with a higher physician to population ratio.

Aging and the psychological refractory period: task-coordination strategies in young and old adults.

The apparently deleterious effect of aging on dual-task performance is well established, but there is little agreement about the source of this effect. Studies of the psychological refractory period (PRP) indicate that young adults can flexibly control dual-task performance through task-coordination strategies. Thus, the performance of older adults might differ from young adults because older adults use different task-coordination strategies. To test this hypothesis, the executive-process interactive control (EPIC) architecture was applied to quantify the reaction time data from two PRP experiments conducted with young (age 18-26) and older (age 60-70) adults. The results show that participants' ability to coordinate the processing of two tasks did not decline with age. However, dual-task time costs were greater in the older adults. Three sources for this increase were found: generalized slowing, process-specific slowing, and the use of more cautious task-coordination strategies by the older adults.

Prevalence of magnesium and zinc deficiencies in nursing home residents in Germany.

In a multicentric study with 345 seniors over 70 years old we investigated magnesium and zinc levels in serum together with the prevalence of their typical symptoms of deficiency in nursing home residents (NHR) and non-nursing home residents (nNHR). In addition calcium, sodium and potassium levels in serum were determined as well as creatinine and albumin. Considering all seniors 33 per cent exhibited hypomagnesemia and 19 per cent hypozincemia. Zinc levels of female and male NHR were significantly lower than levels of nNHR. Hypomagnesemia was significantly associated with calf cramps and with diabetes mellitus. Hypozincemia was significantly associated with impaired wound healing.

The role of parietal cortex in verbal working memory.

Neuroimaging studies of normal subjects and studies of patients with focal lesions implicate regions of parietal cortex in verbal working memory (VWM), yet the precise role of parietal cortex in VWM remains unclear. Some evidence (; ) suggests that the parietal cortex mediates the storage of verbal information, but these studies and most previous ones included encoding and retrieval processes as well as storage and rehearsal of verbal information. A recent positron emission tomography (PET) study by isolated storage and rehearsal from other VWM processes and did not find reliable activation in parietal cortex. This result suggests that parietal cortex may not be involved in VWM storage, contrary to previous proposals. However, we report two behavioral studies indicating that some of the verbal material used by may not have required phonological representations in VWM. In addition, we report a PET study that isolated VWM encoding, retrieval, and storage and rehearsal processes in different PET scans and used material likely to require phonological codes in VWM. After subtraction of appropriate controls, the encoding condition revealed no reliable activations; the retrieval condition revealed reliable activations in dorsolateral prefrontal, anterior cingulate, posterior parietal, and extrastriate cortices, and the storage condition revealed reliable activations in dorsolateral prefrontal, inferior frontal, premotor, and posterior parietal cortices, as well as cerebellum. These results suggest that parietal regions are part of a network of brain areas that mediate the short-term storage and retrieval of phonologically coded verbal material.

Dendritic translocation of RC3/neurogranin mRNA in normal aging, Alzheimer disease and fronto-temporal dementia.

RC3/neurogranin is a postsynaptic protein kinase C (PKC)-/calmodulin-binding substrate implicated in long-term potentiation (LTP) forms of synaptic plasticity. Our previous digoxigenin in situ hybridization (DIG-ISH) studies detected RC3 mRNA in apical dendrites and cell bodies of neurons in the rat cerebral cortex and hippocampus. This observation suggested that RC3 mRNA is selectively translocated to dendrites, where it may be translated locally in response to synaptic activity. To test this hypothesis further, we isolated a full-length cDNA clone of the homologous human RC3 mRNA from a human cortex lambda GT11 library, determined its nucleotide and predicted amino acid sequences, and performed mRNA expression studies in cerebral cortex from normal human patients and from patients with Alzheimer disease (AD) and fronto-temporal dementia (FTD). The human cDNA clone detects a single approximately 1.3 kb mRNA whose nucleotide sequence is 73% similar to the rat nucleotide sequence and 96% similar to its amino acid sequence. DIG-ISH studies detect robust staining of RC3 mRNA in cell bodies of numerous neurons throughout Layers II-VI and in both apical and basal dendrites of pyramidal neurons in human neocortex (temporal/frontal). We conclude that dendritic targeting of RC3 mRNA is conserved in human brain. In AD neocortex tissue, there is little or no evidence for RC3 mRNA translocation to dendrites, while in FTD neocortex, targeting of RC3 mRNA to apical dendrites is preserved. Comparative studies in AD and FTD point to the potential importance of synapse integrity and the dendritic cytoskeleton in RC3 mRNA targeting in the human neocortex.

[Results of follow-up of mothers with previous surgical "total cervical cerclage" also with reference to neonatal data]. / Ergebnisse einer Nachuntersuchung von Müttern nach vorausgegangenen operativen "Totalen Muttermund-Verschlüssen" (TMV) unter Berücksichtigung auch der Daten ihrer Kinder.

From August 16, 1993 until March 6, 1995 a study was conducted at the Department of Obstetrics at the Berlin-Neukoelln Womens Hospital to evaluate the status of patients who had previously undergone total cervical occlusion (TCO) for the prevention of late abortion and premature birth. Special consideration was given to the possible effects of TCO on the patients' gynecologic status, the psychological circumstances associated with TCO and the developmental status of the infants. Fifty-four women participated in the study, their ages ranging between 26 and 53 years. The mean time-span between the TCO procedure and the present study was five years and five months. In the 54 women undergoing TCO, a total of 73 such procedures were performed. An extensive early TCO was performed in 63% and an extensive late TCO in 20.5%. The gestational age at the time of delivery was > or = 37 + 0 weeks in 67.1% of the women. More than half of the patients (54.9%) experienced a normal spontaneous vaginal delivery. In total, 84.5% of the infants were delivered vaginally; thus the cesarean section rate was only 15.5%. Regarding the patients' medical histories, the majority of the patients had no pathological findings on routine pap smears and pelvic examinations and, similarly, they had no complaints of menstrual irregularities. Only 10 patients (18.5%) underwent gynecological surgery in the interim; in these patients, the most common reason for surgery (in four cases) was sterilisation. The findings during speculum examination were tabulated. The majority of the patients (96%) exhibited a normal multiparous cervical portio. In 55% of the patients there was no evidence of scarring of the cervical portio. In 25% of the patients there was minor cervical scarring, in 13.5% it was moderate and in 5.8% it was severe. Except for a single case, the patients showed no evidence of vaginitis. During bimanual palpation on pelvic examination, in 82.7% of the patients the cervix was found to be at least 2 cm in length, a closed external cervical os was palpated in 65.4%, and an anteflexed/anteverted uterus that was normal in size and form was noted in 46.2%. In 95.4% of the patients, original squamous epithelium was seen colposcopically. The psychosocial status of each patient was evaluated on an individual basis. After taking all of the psychosocial circumstances associated with such a high-risk pregnancy into consideration, all the patients giving birth to a living infant described that event as a positive experience. However, this was not the case in the two patients whose premature infants did not survive. In 74.1% of the patients, the relationship with their domestic partners was described as "unchanged" when compared to the status of their relationship during the preceding pregnancy without TCO. The patients undergoing TCO described their own psychological status as "frequently strained" (61.1%) and "disturbed" (9.3%) antepartum. Postpartum, 90.7% of the patients described their psychological status as "good". In total, there were 74 births in the 54 patients included in this follow-up study. Of these 51 (68.9%) were living term infants, one stillborn (1.4%) and 22 (29.7%) premature infants. One infant weighed less than 1.000 grams while 4 (5.3%) weighed between 1.000 and 1.499 grams. Postpartum, 45.5% of the premature infants and 19.6% of the term infants were hospitalized. The primary indications for the transfer of the premature neonates were intensive care, hyperbilirubinemia and adaptation problems. The physical, emotional and mental development was unimpaired in 91.4% of the children. A capability for good social integration was displayed in 95.7% of the children. Based on the current investigation, it may be concluded that the total cervical occlusion procedure has no significant long-term negative effects.

Verbal Working Memory Load Affects Regional Brain Activation as Measured by PET.

We report an experiment that assesses the effect of variations in memory load on brain activations that mediate verbal working memory. The paradigm that forms the basis of this experiment is the "n-back" task in which subjects must decide for each letter in a series whether it matches the one presented n items back in the series. This task is of interest because it recruits processes involved in both the storage and manipulation of information in working memory. Variations in task difficulty were accomplished by varying the value of n. As n increased, subjects showed poorer behavioral performance as well as monotonically increasing magnitudes of brain activation in a large number of sites that together have been identified with verbal working-memory processes. By contrast, there was no reliable increase in activation in sites that are unrelated to working memory. These results validate the use of parametric manipulation of task variables in neuroimaging research, and they converge with the subtraction paradigm used most often in neuroimaging. In addition, the data support a model of working memory that includes both storage and executive processes that recruit a network of brain areas, all of which are involved in task performance.

[Total surgical cervical occlusion. Conclusions from data of several clinica, which use total surgical cervical occlusion]. / Der operative Totale Muttermund-Verschluss (TMV). Erhebungen von Daten einiger Kliniken, die den TMV einsetzen.

Operative Total Cervix Occlusion (TCO), and in particular early TCO (ETCO), which we introduced in 1980, continues to be an important part of the prematurity prevention program. We were therefore especially interested in obtaining not only a general idea of where, on what scale and with what results TCO is being performed, but also information on the operative technique used, the complication rate associated with it, and preoperative procedure. From the data of the 11 departments which participated in this inquiry it was established that the overall success rate of all TCO procedures performed was over 80% (659 out of 819). TCO thus enabled to substantially increase the number of infants who survived. This result is also reflected in a comparison of the pregnancies preceding and following TCO. The infant survival rate was increased from below 21% to over 74%. One surprising result was that late occlusion was performed more frequently than early occlusion at more than 50% of the clinics participating in the inquiry. This is presumably due to difficulties in defining early and late occlusion in retrospective data evaluation, and probably also explains why, based on our experience, the success rate with late occlusions was too high. Two occlusions were performed in 43 patients and three or more in 9 (including current TCO). With 14 cases (1.7%) identified the rate of complications associated with TCO is very low.

PET evidence for an amodal verbal working memory system.

Current models of verbal working memory assume that modality-specific representations are translated into phonological representations before entering the working memory system. We report an experiment that tests this assumption. Positron emission tomography measures were taken while subjects performed a verbal working memory task. Stimuli were presented either visually or aurally, and a visual or auditory search tasks, respectively, was used as a control. Results revealed an almost complete overlap between the active memory areas regardless of input modality. These areas included dorsolateral frontal, Broca's area, SMA, and premotor cortex in the left hemisphere; bilateral superior and posterior parietal cortices and anterior cingulate; and right cerebellum. These results correspond well with previous research and suggest that verbal working memory is modality independent and is mediated by a circuit involving frontal, parietal, and cerebellar mechanisms.