Contextual Fear Conditioning Is Associated With Lateralized Expression of the Immediate Early Gene c-fos in the Central and Basolateral Amygdalar Nuclei.

Fos, the protein product of the immediate early gene c-fos, was used to map functional circuitry underlying contextual conditioned fear. Male rats were given footshocks in a distinctive context and later tested using freezing as the behavioral measure and compared with no-shock and no-retention-test control groups. An increased number of Fos-immunoreactive neurons was found in the lateral part of the central nucleus and in the anterior basolateral and lateral amygdalar nuclei in the brains of the conditioned-fear group compared with controls. Further, a greater number of Fos-immunoreactive neurons was observed in the right central and anterior basolateral nuclei compared with the number of labeled neurons in these structures on the left. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associative fear conditioning of enkephalin mRNA levels in central amygdalar neurons.

The central nucleus of the amygdala (CEA) is required for the expression of learned fear responses. This study used in situ hybridization to show that mRNA levels of the neuropeptide enkephalin are increased in CEA neurons after rats are placed in an environment that they associate with an unpleasant experience. In contrast, mRNA levels of another neuropeptide, corticotropin releasing hormone, do not change under the same conditions in the CEA of the same rats. Conditioned neuropeptide levels in amygdalar circuits may act as a reversible "gain control" for long-term modulation of subsequent fear responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The reentrant wide-band directional filter

A new type of a wide-band microwave filter is described and named the reentrant directional filter, in which resonance occurs in the form of a traveling wave rather than in the conventional form of a standing wave. This device is the network, which has the constant input impedance and is manufactured as the directional coupler's free construction. An analysis of the reentrant directional filter shows it to have advantages in the case of wide-bands when compared to previously used directional filters. This filter finds application in multiplexers, as well as in matched bandpass (band-stop) filters by using planar multilayer transmission-line technology. Experimental results verify the theoretical approach.     

Effect of saccharose and sorbit on indices of carbohydrate metabolism in mixed saliva of patients with diabetes mellitus and dental caries

The content of lactate in mixed saliva in severe diabetes mellitus associated with multiple caries was 5 times and in diabetes of medium severity 3.5 times greater than in caries-resistant subjects. This increase was largely caused by diabetes proper, since in multiple caries without diabetes, the lactate content was increased only 2-fold. The amount of pyruvate in saliva in multiple caries without diabetes was approximately the same as that in diabetes mellitus coupled with multiple caries. Preliminary administration to the oral cavity of 100 ml of 50% saccharose for 10 minutes (without swallowing) raised the saliva lactate content several times as compared to that in the same subjects before saccharose administration. The lactate content in saliva was particularly high in severe diabetes mellitus. Administration of 50% sorbitol of the oral cavity for 10 minutes did not increase the lactate content in saliva. Upon administration of saccharose lactate dehydrogenase activity in saliva significantly descended while sorbitol dehydrogenase activity significantly increased. Administration of sorbitol solution to the oral cavity did not produce any essential effect on sorbitol dehydrogenase activity in saliva.     

Organization of projections from the basomedial nucleus of the amygdala: a PHAL study in the rat

The organization of axonal projections from the basomedial nucleus of the amygdala (BMA) was examined with the Phaseolus vulgaris leucoagglutinin (PHAL) method in adult male rats. The anterior and posterior parts of the BMA, recognized on cytoarchitectonic grounds, display very different projection patterns. Within the amygdala, the anterior basomedial nucleus (BMAa) heavily innervates the central, medial, and anterior cortical nuclei. In contrast, the posterior basomedial nucleus (BMAp) sends a dense projection to the lateral nucleus, and to restricted parts of the central and medial nuclei. Extra-amygdalar projections from the BMA are divided into ascending and descending components. The former end in the cerebral cortex, striatum, and septum. The BMAa mainly innervates olfactory (piriform, transitional) and insular areas, whereas the BMAp also innervates inferior temporal (perirhinal, ectorhinal) and medial prefrontal (infralimbic, prelimbic) areas and the hippocampal formation. Within the striatum, the BMAa densely innervates the striatal fundus, whereas the nucleus accumbens receives a heavy input from the BMAp. Both parts of the BMA send massive projections to distinct regions of the bed nuclei of the stria terminalis. Descending projections from the BMA end primarily in the hypothalamus. The BMAa sends a major input to the lateral hypothalamic area, whereas the BMAp innervates the ventromedial nucleus particularly heavily. Injections were also placed in the anterior cortical nucleus (COAa), a cell group superficially adjacent to the BMAa. PHAL-labeled axons from this cell group mainly ascend into the amygdala and olfactory areas, and descend into the thalamus and lateral hypothalamic area. Based on connections, the COAa and BMAa are part of the same functional system. The results suggest that cytoarchitectonically distinct anterior and posterior parts of the BMA are also hodologically distinct and form parts of distinct anatomical circuits probably involved in mediating different behaviors (for example, feeding and social behaviors vs. emotion-related learning, respectively).     

Shielding calculations for a 100 MeV 30 mA proton beam

The Study and Production of Exotic Species (SPES) project employs a 100 MeV, 30 mA proton beam that strikes a primary target. The resulting high-energy neutron flux impinges on a secondary target of depleted uranium to produce, through fission, beams of short-lived, neutron-rich nuclei. This paper deals with some of the preliminary shielding calculations for the bunker. Monte Carlo is employed with MCNPX and, because of the deep penetrations involved, the in-house variance reduction optimiser, the direct statistical approach. The calculations exhibited a number of typical features that are addressed and discussed.     

Improving the performance of lightning-protection cables for overhead power lines

The influence of various factors on the performance of cables used for lightning protection of power lines is investigated. The guaranteed working life of the cables is considerably increased by applying a zinc coating of elevated density and by plastic compression of linear-contact cables.