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The present study was designed to examine the effects of prenatal stress on the morphological development of sexually dimorphic structures in the anterior hypothalamus in male rats and to determine if there is a relationship between morphologic development of the brain and copulatory behavior in individual animals. Dams in the stress group were subjected to treatments of heat-light restraint during the third trimester of gestation (day 14 to parturition) three times daily for 45-min periods. At 90 days of age, prenatally stressed and control male offspring were tested during the dark cycle for spontaneous male sexual behavior. Volumes of the sexually dimorphic nucleus of the preoptic area (SDN-POA) and the anteroventral periventricular nucleus (AVPV) were measured. Comparisons were made between copulatory behavior and hypothalamic nuclear volumes. SDN-POA volumes were significantly reduced (feminized; males have a larger SDN-POA than females) in prenatally stressed males that did not copulate, whereas, SDN-POA volumes in prenatally stressed males that copulated were not altered. The few control males that did not copulate (sexually non-active) also had significantly reduced SDN-POA volumes compared to the control males that did copulate (sexually active). The volume of the AVPV was significantly increased (feminized; males have a smaller AVPV than females) in prenatally stressed males that were sexually non-active compared to AVPV volumes in sexually active males. The results obtained in this study provide a strong positive relationship between sexual behavior and the morphology of the two sexually dimorphic structures measured.

The purpose of the present study was to determine the effects of sexual behaviorial manipulation on brain plasticity in adult male rats. Adult male Sprague-Dawley rats that copulated during male sexual behavior testing were divided into four groups: control male; gonadectomized (Gdx) male; sexually active male; and sexually nonactive male. Female animals were used as an additional control group. At the end of a 12-week experimental period, the animals were again tested for male sexual behavior and tested for sexual motivation. Sexual behavior manipulations over the 12-week period resulted in significant differences in mount latency, mount frequency, intromission latency, intromission frequency, ejaculation latency, and the postejaculation interval. In the motivation test, significant differences in the number of approaches, contacts, and crossings of an electrified grid separating the test animal from a receptive female were also observed. Sexually dimorphic nucleus of the preoptic area (SDN-POA) volumes in sexually nonactive males were significantly smaller than in control males or sexually active males. Anteroventral periventricular nucleus (AVPV) volumes in the male groups were not significantly altered by sexual behavioral manipulations, however, the nonactive AVPV vol. was the only vol. not significantly different from the control female vol. These data demonstrate that in the adult rat, sexual behavioral manipulations resulted in significant alterations in behavior and in the vol. of the SDN-POA and that the effect of sexual behavior on the AVPV needs to be further investigated.

The South African private health care sector has been looking to managed health care (MHC) to control the unsustainable cost escalations of the last decade. This paper draws on experience of MHC in other countries, particularly the USA, to assess its potential for solving the private sector's difficulties. In addition, it looks at problems which may be associated with MHC in a South African setting. The conclusion reached is that MHC alone cannot be seen as a panacea for the private sector's financial problems, although it may produce a degree of saving and be part of a solution. It is argued that MHC per se seems unlikely to compromise equity, quality of care or the public health care sector, and that it may potentially promote national health policy objectives. However, if MHC's benefits are to be maximised and potential negative effects controlled, ongoing monitoring of MHC, coupled with an appropriate regulatory and incentive environment, will be required.

Sexual activity values, volume measures of the sexually dimorphic nucleus of the preoptic area (SDN-POA), and testosterone levels of a sample of 30 male offspring selected from litters born to control and prenatally stressed mothers were intercorrelated. The resulting correlations were then submitted to partial correlational analyses in order to determine the relative contributions of anatomical structure and testosterone levels in mediating sexual behavior. It was observed that SDN-POA volume was a better predictor of sexual activity than were testosterone levels.

Photically evoked after-discharge (PhAD) bursting was examined in albino rats following either bilateral or unilateral dorsal frontal lesions. The initial effect of either type of frontal lesion was to significantly suppress PhAD occurrence. However, after repeated exposure to the PhAD recording environment no difference could be seen between the lesioned and control animals. In addition, no difference in PhAD could be detected between the two visual cortices in any of the groups. Spontaneous alternation and open-field activity were also tested. Both frontally lesioned groups of animals were significantly more active than control animals in the initial stages of testing. These findings indicate that the frontal cortex can inhibit brain stem mechanisms which are responsible for behavioral arousal and the modulation of hypersynchronous bursting in the cortex. However, because no difference was seen between the two visual cortices in any of the groups, it is suggested that this mechanism is not a strictly unilateral mechanism.

Photically evoked after-discharge (PhAD) bursting was examined in lightly restrained albino rats following frontal and mid-cortical lesions. The initial effect of dorsal frontal lesions was to significantly suppress PhAD occurrence. Spontaneous activity as measured on an open-field arena was examined as a second variable. Frontally lesioned animals were significantly more active than mid-cortically lesioned and non-lesioned control animals in the initial stages of behavioral testing. These results indicate that the frontal cortex has an inhibitory influence on reticular formation (rf) arousal mechanisms which are responsible for behavioral arousal and the modulation of hypersynchronous burst-like phenomena occurring at the level of the cortex.

In 1978, the original learned helplessness model was critiqued and reformulated by Abramson, Seligman, and Teasdale. Using attributional theory, the reformulation postulated that causal attributions mediate the effects of helplessness according to three dimensions: internal-external, global-specific, and stable-unstable. The present study was a multidimensional test of the reformulation. Ninety-six subjects were administered identical pretreatments of unsolvable puzzles, and given different reasons for their failure. A later test of solvable anagrams measured cognitive and motivational deficits of helplessness from the pretreatment. Global subjects solved fewer problems than specific subjects. Subjects who were both global and stable solved fewer problems in the test phase than other subjects. The results supported the global-specific dimension and the two-way interaction between the global-specific and the stable-unstable dimensions. The authors conclude that further investigation should elucidate the stable-unstable dimension (perseveration of helplessness deficits over time).

Diamond and collaborators have reported sexual dimorphic right greater than left thickness asymmetries in the cerebral cortices of male Long-Evans rats. In the present work we report that normal Sprague-Dawley males show a similar cortical asymmetry. On the other hand, Sprague-Dawley males whose mothers were subjected to treatments of prenatal stress three times daily during the third trimester of gestation showed a nonsignificant left greater than right pattern in the same cortical areas--a pattern characteristic of the female cortex. These results are consistent with other findings from our laboratory wherein we have recently shown that prenatal stress during the third trimester of gestation demasculinizes sexually dimorphic regions of the preoptic hypothalamus in male rats. It is concluded that stress mediated changes in the prenatal environment can have a profound effect on the developmental processes which shape the morphology of sexually dimorphic regions of the brain in male offspring. Normal male anatomy is biased in the direction of a feminine structure. Such an anatomical picture is consistent with demasculinized and feminized behavior patterns exhibited by male offspring of prenatally stressed dams.

The sexually dimorphic nucleus of the preoptic area (SDN-POA) has recently been shown to be reduced in cross-sectional area in prenatally stressed male rats. As masculine copulatory behavior is also reduced in prenatally stressed animals, the present study was designed to test a possible relationship between the entire volume of the SDN-POA and masculine sexual activity in both prenatally stressed and control adult male rats. We report here that prenatally stressed adult males have significantly reduced SDN-POA volumes, reduced levels of sexual activity and lower plasma testosterone levels as compared to control animals. Additionally, however, a strong positive relationship was demonstrated between SDN-POA volume and sexual activity in both stressed and control animals. SDN-POA volumes of sexually active animals from stressed and control groups are approximately equal. SDN-POA volumes of sexually non-active animals are also equal and are about two times smaller than those of sexually active animals, either stressed or control. Similar correlations are reported between SDN-POA volume and testosterone level, and between testosterone level and sexual activity. It is concluded that (1) SDN-POA volume is predictive of sexual activity in both stressed and control male rats, (2) there is a relationship between SDN-POA volume and plasma testosterone level, and (3) the SDN-POA likely has multiple roles in the circuitry underlying masculine reproductive processes and hormone regulation.