RESUMEN
Thalamocortical loops, connecting functionally segregated, higher order cortical regions, and basal ganglia, have been proposed not only for well described motor and sensory regions, but also for limbic and prefrontal areas relevant for affective and cognitive processes. These functions are, however, more specific to humans, rendering most invasive neuroanatomical approaches impossible and interspecies translations difficult. In contrast, non-invasive imaging of functional neuroanatomy using fMRI allows for the development of elaborate task paradigms capable of testing the specific functionalities proposed for these circuits. Until recently, spatial resolution largely limited the anatomical definition of functional clusters at the level of distinct thalamic nuclei. Since their anatomical distinction seems crucial not only for the segregation of cognitive and limbic loops but also for the detection of their functional interaction during cognitive-emotional integration, we applied high resolution fMRI on 7 Tesla. Using an event-related design, we could isolate thalamic effects for preceding attention as well as experience of erotic stimuli. We could demonstrate specific thalamic effects of general emotional arousal in mediodorsal nucleus and effects specific to preceding attention and expectancy in intralaminar centromedian/parafascicular complex. These thalamic effects were paralleled by specific coactivations in the head of caudate nucleus as well as segregated portions of rostral or caudal cingulate cortex and anterior insula supporting distinct thalamo-striato-cortical loops. In addition to predescribed effects of sexual arousal in hypothalamus and ventral striatum, high resolution fMRI could extent this network to paraventricular thalamus encompassing laterodorsal and parataenial nuclei. We could lend evidence to segregated subcortical loops which integrate cognitive and emotional aspects of basic human behavior such as sexual processing.
RESUMEN
UNLABELLED: The surface tension value (gamma min) of tracheal aspirate samples (TA) from newborns depends on lung maturity and is determined by concentrations of surfactant components (phospholipids, surfactant proteins, ions). During tracheal aspirate collecting the aspirate is diluted with physiological saline. Information about TA dilution is necessary for a standardized surface tension measurement. The purpose of this study was to establish an ELISA for determination of secretory IgA (SIgA), to determine the cutoff value of SIgA for surface tension measurement in tracheal aspirates and to test SIgA as marker for tracheal aspirate dilution. PATIENTS: In group 1 (normal range determination of gamma min) pharyngeal aspirates of 42 healthy newborns (nb) were investigated. In group 2 (determination of SIgA cutoff value) 15 TA and 8 pharyngeal aspirates of 23 pulmonary healthy nb (group 3) were used for validation of SIgA cutoff value. In group 4 36 TA of 22 nb with respiratory distress syndrome were studied. METHOD: The gamma min of group 1 were measured to establish the range of normal gamma min. The TA of group 2 were diluted stepwise and the dependence of gamma min on SIgA concentration were depicted in a diagram. The SIgA cutoff value was estimated by these dilution curves. Below this value the TA are very diluted and a measurement of gamma min is not useful. To test the reliability of SIgA as dilution marker the gamma min and SIgA values of TA from group 3 were determined. After exclusion of TA with reduced SIgA the gamma min of group 3 and 4 were compared. RESULTS: For the enzyme immunoassay following performance characteristics were determined: the accuracy (recovery): 95.6%, sensitivity: 4 ng/ml, and precision (intra- and interassay coefficient of variation): 9.8 and 19.1%, respectively. The range of normal gamma min (median (5th and 95th percentile)) amounts to 23.0 (14.8 and 28.7) mN/m. A SIgA cutoff value of 80 ng/ml was estimated. The gamma min from 8 of 27 TA (group 3) were above the normal range of gamma min during examination of the estimated SIgA cutoff value. 5 of these 8 TA had concentrations of SIgA below the cutoff point and could be excluded with the help of SIgA as dilution marker. The median of gamma min was significantly lower (p < 0.001) in group 3 (18.3 mN/m) in comparison to the median (35.8 mN/m) of group 4 (nb with respiratory distress syndrome). CONCLUSION: The performance characteristics of the SIgA enzyme immunoassay and the tested reliability of the SIgA cutoff value demonstrate, that a simple determination of surfactant deficiency by surface tension measurement of TA is possible using the concentration of SIgA as dilution marker.
