Cortical Distribution of Eeg Activity for Component Processes During Mental Rotation

Alpha power (8–12 Hz) was monitored over the frontal, temporal, parietal and occipital lobes of the left and right cerebral hemispheres while participants mentally rotated three-dimensional shapes to match a specified target. By comparing the activational patterns generated during three experimental conditions, each designed to systematically isolate the involvement of the various subcomponents comprising this mental rotation task, it was suggested that the right frontal lobe mediates encoding and comparison/decision processes, while the left parietal and the left temporal region appear most involved in the generation of images and their mental rotation. A preliminary model describing the cooperative interaction of these cortical regions during mental rotation tasks is proposed.     

Agonist and antagonist interactions with D1 dopamine receptors: agonist-induced masking of D1 receptors depends on intrinsic activity.

The effects of agonist and antagonist compounds on the equilibrium binding of the D1 antagonist ligand [3H]SCH 23390 were examined in membranes from the striatum of the rat. The antagonist SK&F 83566 interacted with D1 receptors in the manner of a competitive antagonist, causing a decrease in the affinity of the binding of [3H]SCH 23390, without altering the maximum number of binding sites (Bmax). The interaction of agonist compounds with the D1 receptor appeared to be more complex. The drug SK&F 75670, a weak partial agonist, also acted competitively at D1 sites. However, agonists with moderate (SK&F 38393, CY 208-243) or full (dopamine) intrinsic activity to stimulate adenylate cyclase, interacted with D1 binding sites in a mixed competitive/non-competitive manner, causing both a decrease in ligand affinity and a decrease in Bmax. The benzazepine analogue, which also has full agonist activity, SK&F 82958, only caused a reduction in Bmax. Furthermore, there was a positive relationship between the intrinsic activity of agonists and the magnitude of the reductions in Bmax which they induced. In the presence of the GTP analogue, Gpp(NH)p, CY 208-243 no longer caused an apparent reduction in the number of receptors. These data suggests that the apparent loss of D1 receptors, induced by agonists, may result from an interaction with a guanine-nucleotide sensitive, high affinity agonist binding site and that the degree of interaction with this site depends on the intrinsic D1 activity of the agonist.     

The growth of Salmonella in rumen fluid from cattle at slaughter

The pH of the rument contents of cattle was recorded at slaughter; pH ranged from 5.5 to 7.8 and was not correlated with the period from saleyard to slaughter. Volatile fatty acids (VFA) were measured in 43 rumen samples; acetic, propionic and butyric were the major acids present, and the total VFA ranged from 75.9 mM/l for samples between pH 6-7, to 7.1 mM/l for samples of pH 8-9. Ten Salmonella strains belonging to 8 serotypes were grown in these 43 rumen samples. Where acid levels of these samples were high and pH low, most Salmonella sp. were inhibited; as the pH rose (pH 7-8) all Salmonella serotypes grew, some vigorously; as the total acid declined and pH continued to rise, growth of salmonella ceased. Serotypes and strains of the same serotype differed in their ability to grow in rumen contents, particularly when the pH was low.     

Premenstrual syndrome and locus of control

Seventy-six women completed a three-month prospective evaluation for premenstrual syndrome (PMS). As a part of the evaluation, they completed Rotter's Locus of Control (LOC) form in the follicular phase and premenstrually. It was found that the LOC scores of women meeting criteria for PMS rose significantly (became more "external") premenstrually, while scores of women without PMS did not show significant change. In addition, the premenstrual LOC scores of women meeting criteria for PMS were significantly higher than were scores of the non-PMS women. The results are consistent with the idea that cycle related changes in self-perception occur in women demonstrating PMS symptomatology.