The C-Band All-Sky Survey (C-BASS): Simulated parametric fitting in single pixels in total intensity and polarization.

The cosmic microwave background (CMB) B-mode signal is potentially weaker than the diffuse Galactic foregrounds over most of the sky at any frequency. A common method of separating the CMB from these foregrounds is via pixel-based parametric-model fitting. There are not currently enough all-sky maps to fit anything more than the most simple models of the sky. By simulating the emission in seven representative pixels, we demonstrate that the inclusion of a 5 GHz data point allows for more complex models of low-frequency foregrounds to be fitted than at present. It is shown that the inclusion of the C-BASS data will significantly reduce the uncertainties in a number of key parameters in the modelling of both the galactic foregrounds and the CMB. The extra data allow estimates of the synchrotron spectral index to be constrained much more strongly than is presently possible, with corresponding improvements in the accuracy of the recovery of the CMB amplitude. However, we show that to place good limits on models of the synchrotron spectral curvature will require additional low-frequency data.

Hyposensitivity to serotonergic stimulation in protein malnourished rats.

Rats subjected to early protein malnutrition have higher levels of brain serotonin (5-HT) than well-nourished rats. In the present study we asked whether the elevated 5-HT levels of associated with any changes in sensitivity to serotonergic stimulation. In four different behavioral tets the effects of the 5-HT agonist N,N-dimethyltryptamine (DMT) were, with only a few exceptions, smaller in rats malnourished during both pre- and postweaning stages of development or during just one period or the other. In Experiment 1 the 5-HT syndrome induced by DMT was weaker in malnourished rats than in well-nourished ones. In Experiments 2 and 3, DMT was not a disruptive to malnourished rats in two motor tasks, rotating rod and treadmill, as it was to rats reared under high protein conditions. In Experiment 4 reductions in acoustic startle amplitudes induced by DMT were not as large in malnourished as in well-nourished rats. The hyposensitivity to DMt in protein malnourished rats may reflect a diminished sensitivity of 5-HT receptors resulting from the abnormally high levels of the neurotransmitter.

The effects of protein malnutrition on the behavior of rats during the suckling period.

Observations of 2 groups of dams and their litters were made every 3 hr around the clock on Days 1-20 postpartum. The dams fed either an 8% or a 25% casein diet for 5 weeks before mating and during gestation and lactation. Dams on the low protein diet spent more time in the nest actively nursing their young than did high protein dams, and they exhibited no deficits in other maternal behaviors. Five of 11 kinds of behavior developed more slowly in the undernourished pups than in the well-nourished ones, but the developmental delays were no longer than a few days. Circadian fluctuations were apparent in all of the pups' activities during the 3rd postnatal week as well as in grooming and horizontal movement, 2 behaviors that were present earlier, by 6-10 days of age.

Utilization of 14C-tyrosine in brain and peripheral tissues of developmentally protein malnourished rats.

Prior studies of developmentally protein malnourished rats have reported substantial changes in brain and peripheral utilization of 14C-leucine, 14C-phenylalanine, and 14C-tryptophan. In the present study rats born to dams fed a low protein diet (8% casein) compared to the offspring of control rats fed a normal diet (25% casein) showed few significant differences in the uptake and incorporation of 14C-tyrosine into brain and peripheral tissues from birth to age 21 days. At birth, the 8% casein pups exhibited significant decreases in brain and peripheral tissue incorporation of tracer only at short post-injection times (10 and 20 min), but not at longer intervals (90 and 180 min). During ontogenetic development (Days 5-21), the 8% casein rats showed significant increases in uptake of 14C-tyrosine into the brain and peripheral tissues on Day 11 and a significantly higher percent incorporation of tracer into brain protein on Day 21 as compared to the 25% casein rats. For the most part, there were no significant changes in incorporation of radioactivity in peripheral tissues for the 2 diet groups on these post-birth days. Overall, the data indicates that developmental protein malnutrition causes relatively fewer changes in brain and peripheral utilization of the semi-essential amino acid tyrosine than those observed in previous studies with essential amino acids.

A neuropharmacological analysis of central nervous system catecholamine systems in development protein malnutrition.

Four experiments were performed to evaluate the effects of developmental protein deprivation on the behavioral response of adult rats to treatments known to affect central nervous system catecholamine systems. Results showed no group differences between protein malnourished and control animals in locomotor responsiveness to d- or l-amphetamine, recovery from behavioral asymmetry produced by a unilateral lesion of the substantia nigra, or in the development of response patterns indicative of denervation supersensitivity. However, a dose-dependent diminution in the ability of apomorphine to produce stereotyped behavior was noted in the malnourished group, suggesting that a class of brain dopamine receptors may be impaired or may have undergone homeostatic modification as a result of the undernutrition procedure.

Phenylalanine utilization in brain and peripheral tissues during development in normal and protein malnourished rats.

Rats born of mothers fed a low protein diet (8% casein) compared to control rats on a normal diet (25% casein) started 5 weeks prior to mating showed significant increases in uptake, incorporation and percent incorporation into protein of 14C-phynylalanine into brain and peripheral tissues. These effects were most pronounced on the day of birth. Also, different patterns of uptake of radioactive phenylalanine were observed between the two diet groups at birth. At ages 5, 11 and 21 days the 8% casein rats showed significant increases only in uptake and incorporation of 14C-phenylalanine into brain tissues as compared to the 25% casein animals with the percent incorporation of total radioactivity into brain protein being the same for both diet groups. For the most part, there were no significant changes in uptake and incorporation of radioactivity in peripheral tissues for the two diet groups on these post-birth days. Overall, the data indicate the possible presence of a brain specific effect whereby preferential utilization of an essential amino acid (phenylalanine) by the central nervous system occurs when rats are fed a low protein diet.

Power spectral analysis of EEG activity obtained from cortical and subcortical sites during the vigilance states of the cat.

There is considerable evidence that the raphé system and the region of the nucleus tractus solitarious (NTS), including the area postrema, play significant roles in slow-wave sleep mechanisms and in EEG synchronization. Studies of the interactions between these systems and the neocortex are much needed. If neuronal activity in these lower brainstem regions regulates the degree of cortical synchrony then a high degree of correspondence between the EEG of the area postrema or raphé complex with that of the cortex might be expected. In order to quantitate the reequency characteristics of the EEG obtained from these subcortical sites (nucleus raphé dorsalis, area postrema, as well as anatomical controls adjacent to these regions) during the different vigilance states (waking, slow-wave sleep, REM sleep) in the cat, power spectral analyses techniques were employed. Comparison of these subcortical spectral characteristic with those obtained from cortical (frontal and occipital) sites during the same vigilance state, show that the spectral measures elicited from the region of the area postrema closely correspond to that of the cortex, particularly during slow-wave sleep. On the other hand, the EEG of the anterior portion of the raphé region, although exhibiting a substantial low frequency component during slow-wave sleep in comparison to wakefulness does not show a statistically significant shift to low frequencies such as occurs in the area postrema or the cortex. These results suggest that the increases in the low frequency content of the cortical EEG sites during slow-wave sleep results from synchronizing inputs from the area postrema to a greater extent than from the raphé complex.

Sleep cycles in cats during chronic electrical stimulation of the area postrema and the anterior raphe.

Sleep-waking profiles were obtained from 130 7 hr stimulation-EEG recording sessions in a series of cats bearing chronically implanted stimulating electrodes in the regions of the area postrema and anterior raphe nuclei. The results indicated that: (a) during electrical stimulation of the region of the area postrema with 0.5 or 10 Hz at 1 and 2 mA there were significant increases in the occurrence of the deeper aspects of slow-wave sleep and in REM sleep. These elevations were significant in comparison to nonstimulation baselines and to sleep profiles obtained during stimulation of points located dorsal and anterior to the area postrema. (b) Stimulation of the medial reticular formation including the anterior raphe using the same parameters employed for the area postrema did not alter the occurrence of any stage of sleep. These findings indicate that the region of the area postrema may be more involved in the generation of sleep than the anterior raphe nuclei.

Effects of protein malnutrition during development on protein synthesis in brain and peripheral tissues.

Rats born of mothers fed a low protein diet (8% casein versus a normal 25% casein diet) starting 5 weeks prior to mating showed a 50-100% increase in protein synthesis in the brain and kidney on the day of birth. This effect was due to a 50-100% increase in the uptake of IP injected 14C-leucine in the malnourished rats. The proportion of total tissue radioactivity in the trichloroacetic acid-protein precipitates was the same in the 8% and 25% casein groups. For the most part, there were no significant diet related changes in uptake or incorporation of 14C-leucine in the brain, liver or kidney in the 8% and 25% casein groups on Days 5, 10-11 and 21. While the physiological basis of the diet related changes seen on the day of birth is unknown, the present data represent a previously undescribed effect of prenatal protein malnutrition.

Effect of 6-hydroxydopamine on electrical self stimulation of the brain.

In rats, after a single intracisternal injection of 6-hydroxydopamine (6-OHDA) electrical self stimulation was reduced by approximately 50%. The concentrations of noradrenaline and dopamine in the brain were reduced by 83%. A second injection of 6-OHDA reduced the concentration of these amines to 7% of control values and virtually eliminated self stimulation.