Comparison of scotopic sensitivity in diurnal (Anas platyrhynchos) and crepuscular (Dendrocygna autumnalis) ducks.

Obtained scotopic visual adaptation curves from 4 mallard ducks. A curve of best fit was used to compare the mallards' mean adaptation curve to the curve previously reported for the black-bellied tree duck, a crepuscular species. The curves did not differ significantly in either their slopes or base levels (thresholds). The mallards' curve had a rod-cone "break" at approximately 25 min. This break was evident in the scotopic curve for pigeons but was absent from the black-bellied tree ducks' curve. Examination of retinal tissues indicated that the black-bellied tree ducks had significantly more rods and cones, and a larger rod-cone ratio than the mallards. The mallards' scotopic visual threshold was exceeded by the natural illumination present under several nocturnal conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New studies and considerations on the pathology of the primate skull. A contribution to the "Gundu" problem

The problem of 'Gundu' in primates is discussed. Cases of so-called 'Gundu' in the literature, two cases in Gorilla and one in Lagothrix, are dealt with. Histological and X-ray techniques are used. One case (Lagothrix) represents the so-called simian bone disease, which is metabolic disorder and is due to a secondary nutritional hyperparathyroidism. The other two cases (Gorilla) show symmetrical bony tumors of the maxilla. The origin is uncertain. Gundu, Paget's disease and primary hyperparathyroidism Recklinghausen have not been observed in primates so far.     

The mutual relations of structures in the growing bill of chick (Gallus domesticus L.) and duck (Anas platyrhynchos L.) Embryos. IV. The size, shape, and position of the upper and lower bills in unilaterally microphthalmic duck embryos

Unilaterally microphthalmic duck (DUM) embryos studied in stage 39 were obtained by damaging the right eye in stage 17. The development between stages 19 and 39 was observed in samples. After prolonged incubation, one duck hatched and reached adulthood. In DUM embryos partial crossbeak develops. Both the upper and lower bills deviate lateralwards, the upper bill more than the lower. In stage 39 a small orbit is present on the treated side. In stained and cleared heads most of the elements of the skull (the bones surrounding the orbit, the brain-case, and the upper and lower bill elements) are translated in the direction of the rudimentary orbit on the treated side. The bills are twisted around each other at the tip. Measurements of external dimensions as well as those made in stained and cleared stage-39 DUM heads show elongation of the left part of the lower bill. Except for the crossed bills, the changes found in the embryos persisted in the adult. The findings support a hypothesis concerning the mutual influence of bills during morphogenesis. The coherence of the functional cranial components in the embryo is discussed.     

The effects of surface and structural feature matches on the access of story analogs.

Competing theories of analogical reasoning have disagreed on the relative contributions of surface and structural features to the access of previously read base stories when one is reading a current cue story. A key limitation of the prior work was that surface and structural feature overlap between bases and cues was not manipulated precisely. The present study systematically manipulated the number of surface and structural matches to determine their relative effect on access. Results involving reminding and reading time measures suggest that surface and lower-order structural features affected access about equally, at least when a higher-order relation (HOR) was shared between a base and cue story. When a HOR was not shared, surface feature overlap continued to affect access while lower-order structural features had a less reliable effect. Models of access might need to be adjusted to account for these phenomena. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

"Arousal hypothesis" and the effects of music on purchasing behavior.

Replicates, in a naturalistic setting, a prior finding which supported that portion of the "arousal hypothesis" which predicts that a certain degree of noise will actually increase activity. Music was varied from loud to soft in 8 counterbalanced experimental sessions in 2 large supermarkets (N = 1100). The "arousal hypothesis" seems to account for the results: significantly less time was spent in the markets during the loud session, although there was no significant difference in sales, nor in the customers' reported satisfaction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential effects of environmental enrichment on the open-field behavior of wild and domestic Norway rats.

Early postweaning experience in an enriched environment had a greater influence on the open-field behavior and body weight of 32 wild Norway rats than of their 32 counterparts. Genetic changes accompanying the domestication process may have reduced the relative impact of postweaning experience on the development of the domestic S's response to changes in its environment. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Androgens and imprinting: Differential effects of testosterone on filial preference in the domestic chick.

After hatching, chicks received either a subcutaneous injection of testosterone enanthate (0.5–5 mg) in oil or oil alone (controls). Ss were then trained by exposing them to a rotating imprinting stimulus, either a red box or a stuffed jungle fowl. A preference score was then determined, providing a measure of the strength of imprinting. Plasma testosterone concentration after testing did not differ significantly between males and females and was unaffected by the type of training stimulus. In fowl-trained Ss, preference score was positively correlated with plasma testosterone concentration. The mean preference score of the fowl-trained Ss that had received exogenous testosterone was significantly higher than that of controls; no such effect was found in box-trained Ss. A previous study by D. C. Davies et al (1985) showed that imprinting with the box, but not the fowl, was profoundly impaired by a noradrenergic neurotoxin. Results suggest that some of the neural systems supporting the preference for a simple artificial object are different from some of those supporting the preference for the stuffed jungle fowl. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Teratogenic effects of trichlorfon (Metrifonate) on the guinea-pig brain. Determination of the effective dose and the sensitive period

The conditions (sensitive period and doses) for producing hypoplasia in guinea-pig offspring after treatment of pregnant guinea-pigs with the organophosphorous agent trichlorfon (metrifonate, 0,0-dimethyl 2,2,2-trichloro-1-hydroxyethylphosphonate) were examined. The results showed that the minimal dose required was 100 mg/kg on three consecutive days. For the cerebellum the most sensitive period was 42-44 day of gestation, for cortex the most vulnerable period was gestational days 48-50. The doses could be given either per os or subcutaneously. Almost all regions of the brain were reduced in weight. Cerebellum was the most vulnerable region, but also the medulla and hypothalamus were greatly reduced in weight. The mechanism behind the teratogenic effect is not known, but alkylation of DNA or an effect on its repair mechanism are possible effects.     

The effects of donor stage on the survival and function of embryonic striatal grafts in the adult rat brain. I. Morphological characteristics

The effects of the stage of donor embryos on the survival of grafts from different neuronal cell types have been well documented. Indeed, this parameter has been shown to be highly important in the survival and function of transplants of various tissues of the CNS. However this question has not been addressed in grafts of embryonic striatal tissue transplanted into animal models of Huntington's disease. In this study, rats which had received a unilateral ibotenic acid lesion in the dorsal striatum received grafts from a standard dissection of embryonic striatal primordium taken from donors of embryonic stage either E14, E16, E17 or E19 days. Three months after transplantation six rats from each group were killed for analysis of graft survival and morphology. The remaining animals in each group were killed between 10 and 14 months after grafting. Graft morphology was detected using a range of markers including: acetylcholinesterase and Cresyl Violet, the 32,000 mol. wt dopamine- and cyclic AMP-regulated phosphoprotein (DARPP-32), tyrosine hydroxylase and striatally-enriched phosphatase. All the grafts from different donor stages survived well at both time-points and Cresyl Violet staining indicated neuronal cell types spread throughout the grafts. The transplants were seen to have a characteristic "patchy" appearance with areas of dense AChE activity and DARPP-32 immunopositivity interspersed with areas of much lighter expression. These areas also co-localized consistently with striatally-enriched phosphatase and tyrosine hydroxylase expression, indicating that they comprised the striatal-like compartment of the graft (the so called P zones, containing cells of the mature striatum), and receiving specific afferent input from the host dopaminergic system. There was no significant difference in total graft volume, when comparing individual groups at both time-points from grafting. However, when comparing the volume of the P zones, the striatal primordium from the youngest donor stages (E14 and E16) produced grafts with a significantly higher proportion of striatal-like tissue. Therefore, in order to increase the proportion of striatal tissue within these grafts, tissue from younger embryonic donors should be used. This has important implications in the application of this model towards clinical trials in Huntington's disease.     

Preliminary study on the chemical constituents and #microbiologic activity of Asphodelus microcarpus (Salzm. et Viv.)

Pharmacotherapy of various neurologic and psychiatric disorders is based on amplification of the effects of the inhibitory neurotransmitter GABA in the CNS. Of particular importance is the modulation of GABAA receptors by benzodiazepines. Their effects are activity-dependent and self limiting. With the development of new ligands for the benzodiazepine receptorsite selective activity-profiles with minimal side-effects are sought. Progress is to be expected from partial agonists and in particular from ligands with selectivity for receptor subtypes.     

Enhancing brain adenosine signaling with the nucleoside transport blocker NBTI (S-(4-nitrobenzyl)-6-theoinosine) mimics the effects of inescapable shock on later shuttle-escape performance in rats.

Experience with unsignaled, inescapable shock represents a profound challenge to brain metabolic function and physiology. The authors have argued that behavioral impairment following this traumatic stress is a consequence of enhanced brain adenosine signaling, which promotes metabolic recovery by profoundly inhibiting neural activation. The authors tested this hypothesis by artificially increasing extracellular brain adenosine concentration by blocking uptake transport with NBTI in rats given only restraint stress in five experiments. NBTI impaired shuttle-escape performance in the manner of inescapable shock in a dose-dependent manner and acted synergistically with an ineffective number of inescapable shocks to maximally impair test performance. These deficits produced by inescapable shock and NBTI were reversed by the nonselective adenosine receptor antagonist caffeine, and the highly selective A2A receptor antagonist CSC (8-(3-chloro-styrl)caffeine). The highly selective A? receptor antagonist DPCPX (8-Cyclopentyl-1,3-Dipropylxanthine) failed to improve performance in rats preexposed to inescapable shock or pretreated with NBTI. These data suggest that enhanced adenosine signaling at a brain A2A receptor impairs escape performance following inescapable shock in the learned helplessness paradigm. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Androgen receptors in the anterior pituitary and central nervous system of the androgen "insensitive" (Tfm) rat: correlation between receptor binding and effects of androgens on gonadotropin secretion

The cytosol fractions of the anterior pituitary, hypothalamus, preoptic area and brain cortex of androgen "insensitive" (Tfm) rats possess androgen receptors. However, in the Tfm rats the androgen binding per mg protein was only 10-15% of that in the corresponding normal littermates (Nl). The physicochemical properties of the androgen receptors in the anterior pituitary of the Tfm rat were indistinguishable from those of the normal rat. Thus, no distinctive differences were observed with regard to electrophoretic mobility in 3.25% polyacrylamide gels, isoelectric point (pI=5.8), binding affinity (KD=1.5 X 10(-9)M), temperature stability, sulfhydryl dependence and steroid specificity. It is, therefore, likely that the very low androgen binding capacity by the anterior pituitary and the central nervous system is due to an extreme reduction in the receptor number rather than to the presence of abnormal receptors. Since in the Tfm animals the androgen receptor number is reduced by 85-90%, it is to be expected that very high doses of androgens would be required to achieve hormonal effects. In fact, low doses of 5alpha-dihydrotestosterone propionate (50 mug/100 g body weight) given sc daily for 12 days had no effect on serum levels of LH and FSH. However, very high doses (2 mg/100 g body weight) of testosterone propionate and 5alpha-dihydrotestosterone propionate, which maintained circulating androgen levels above 20 ng/ml, significantly reduced serum gonadotropin levels in castrated Tfm rats. In normal littermates both low and high doses of the androgens suppressed gonadotropin secretion to low levels. These findings strongly indicate that androgen receptors are essential to androgen action on the anterior pituitary and central nervous system in the rat. The serum levels of testosterone (7.7+/-0.15 (SE) ng/ml) and 5alpha-dihydrotestosterone (0.37+/-0.06 ng/ml) were significantly higher in intact Tfm rats than in normal littermates (2.6+/-0.03 and less than 0.1 ng/ml, respectively). The failure of the elevated concentrations of serum androgens to reduce the high serum levels of LH and FSH in intact Tfm rats is most likely due to the extreme reduction of the androgen receptor number and the consequent insufficient hypothalamic and/or pituitary response to androgens.     

Trial distribution effects on postasymptotic performance and retention of the rabbit's (Oryctolagus cuniculus) classically conditioned nictitating membrane response.

Conditioned the nictitating membrane response to asymptote under identical experimental parameters in 3 groups of albino rabbits (N = 36). Subsequently, the 1st group was shifted to a longer modal intertrial interval (ITI) for further training, the 2nd group was switched to a shorter modal ITI, and the 3rd group was continued with intermediate ITI values. Results reveal (a) immediate incremental and decremental performance adjustments following the shift to longer and shorter modal ITIs, respectively, which were maintained over 10 postasymptotic sessions; (b) evidence of within-session performance decrements during postasymptotic conditioning; and (c) no evidence of retention losses in a retention test conducted 72 hr following the final conditioning session. (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of duration on the equal loudness contours of short and brief tones: 40 phones equal loudness contours. Preliminary experiments (author's transl)

Loudness balances have been obtained between 10-, 20-, 100- and 1,000-ms tones of different frequencies (62.5, 125, 250, 500, 1,000, 2,000, 4,000, 8,000 and 12,000 Hz), and a constant reference tone of 1,000 Hz and 1,000 ms duration at 40 dB SPL. The absolute thresholds were also measured on the same observers at each duration. Progressive shifts of the equal loudness contours appear when the durations become shorter, in the same direction as the corresponding shifts of the threshold curves; the shifts of the equal loudness contours and the corresponding shifts of the threshold curves do not however appear completely similar; some differences may also exist between tones of differing frequencies. These experiments were preliminary ones; some problems arise, in relation with the technique used; improvements appear necessary.