The Savannah River Site's Groundwater Monitoring Program second quarter 1999 (April through June 1999)

This report summarizes the Groundwater Monitoring Program conducted by Savannah River Site during first quarter 1999. It includes the analytical data, field data, data review, quality control, and other documentation for this program; provides a record of the program's activities; and serves as an official record of the analytical results

Brain aromatase activity and plasma testosterone levels are elevated in aggressive male mice during early ontogeny

Testosterone (T) and estradiol (E(2)) are involved in intraspecific aggressive behavior. Both steroids exert their effects on behavior via the hypothalamus and the amygdala (Am) of the central nervous system (CNS). In these brain areas T is converted to E(2), by the enzyme aromatase. Both the levels of brain aromatase activity (AA) and the effects of T and E(2) on aggressive behavior in adulthood depend on steroidal organization of the CNS during ontogeny. In this study we measured plasma T and in vitro brain AA of male fetuses and neonates derived from two strains of wild house mice, which had been genetically selected for aggression, based upon attack latency. There were no differences in preoptic area (POA) AA levels between selection lines on either embryonic day (E) 17 or 18, or the day after birth (day 1). In the non-aggressive long attack latency (LAL) males the POA AA increases with age, i.e. was higher on E18 than on E17, which is correlated with brain weight (BrW). This was in contrast to aggressive short attack latency (SAL) fetuses, which only showed a slight, but not significant difference between embryonic days or, a correlation with BrW. Neonatally, the POA AA of LAL males tended to decrease in contrast to SAL males. However, SAL neonates had a higher AA in the amygdala (Am) than LAL neonates, whereas no differences exist in the anterior hypothalamus. Thus, a differential brain AA distribution exists in SAL and LAL pups. At day 1 SAL: males show higher AA in the Am than in the hypothalamus (POA + AH), whereas in the LAL strain the AA did not differ between these brain areas. In the LAL males plasma T levels decreased from E17 to day 1, whereas the SAL neonates (day 1) exhibited higher circulating T concentrations than LAL neonates. These results suggest a T-independent aromatase induction prenatally in both selection lines, whereas neonatally the higher plasma T level in the SAL line coincides with higher AA levels:in the Am. Accordingly, a differential pattern of E(2) formation exists in the brains of the two selection lines during ontogeny. The variation in circulating T and maximal brain E(2) formation around birth might result in a differential organization of adult CNS sensitivity to sex steroids and accordingly differences in aggressive behavior.</p

Distinct developmental origins manifest in the specialized encoding of movement by adult neurons of the external globus pallidus

SummaryTranscriptional codes initiated during brain development are ultimately realized in adulthood as distinct cell types performing specialized roles in behavior. Focusing on the mouse external globus pallidus (GPe), we demonstrate that the potential contributions of two GABAergic GPe cell types to voluntary action are fated from early life to be distinct. Prototypic GPe neurons derive from the medial ganglionic eminence of the embryonic subpallium and express the transcription factor Nkx2-1. These neurons fire at high rates during alert rest, and encode movements through heterogeneous firing rate changes, with many neurons decreasing their activity. In contrast, arkypallidal GPe neurons originate from lateral/caudal ganglionic eminences, express the transcription factor FoxP2, fire at low rates during rest, and encode movements with robust increases in firing. We conclude that developmental diversity positions prototypic and arkypallidal neurons to fulfil distinct roles in behavior via their disparate regulation of GABA release onto different basal ganglia targets

The Savannah River Site's Groundwater Monitoring Program First Quarter 1999 (January through March 1999)

This report summarizes the Groundwater Monitoring Program conducted by Savannah River Site during first quarter 1999. It includes the analytical data, field data, data review, quality control, and other documentation for this program; provides a record of the program's activities; and serves as an official record of the analytical results

The Savannah River Site's Groundwater Monitoring Program - Third Quarter 1999 (July through September 1999)

This report summarizes the Savannah River Site Groundwater Monitoring Program during the third quarter 1999. It includes the analytical data, field data, data review, quality control, and other documentation for this program; provides a record of the program activities; and serves as an official record of the analytical results

The Savannah River Site's Groundwater Monitoring Program - Fourth Quarter 1999 (October through December 1999)

This report summarizes the Groundwater Monitoring Program conducted by the Savannah River site during fourth quarter 1999. It includes the analytical data, field data, data review, quality control, and other documentation for this program; provides a record of the program's activities; and serves as an official records of the analytical results

The Savannah River Site's Groundwater Monitoring Program Third Quarter 1998 (July through September 1998)

This report summarizes the Groundwater Monitoring Program conducted by SRS during third quarter 1998. It includes the analytical data, field data, data review, quality control, and other documentation for this program; provides a record of the program's activities; and serves as an official record of the analytical results

The Savannah River Site's Groundwater Monitoring Program First Quarter 1998 (January through March 1998)

This report summarizes the Groundwater Monitoring Program conducted by the Savannah River Site during first quarter 1998. It includes the analytical data, field data, data review, quality control, and other documentation for this program; provides a record of the program's activities; and serves as an official record of the analytical results