How do constraints on leaving a marriage affect behavior within the marriage?

Like relationship satisfaction, constraints on leaving a relationship have been described as a component of global commitment. But do constraints increase or decrease efforts to maintain the relationship? To address this question, the authors of the current article describe 3 independent studies of spouses and married couples. Across all studies, wives who perceived more constraints on leaving the marriage exhibited lower levels of negative behavior only when their husbands were relatively unconstrained. In Study 3, this association was especially pronounced among less satisfied wives. In Study 2, spouses' perceived constraint also interacted to predict husbands' behavior, but in the opposite direction: Husbands who perceived more constraints behaved less negatively when their wives were similarly constrained but more negatively when their wives were less constrained. These results highlight differences in behavior between couples who persist in marriage because they desire to and those who endure because they have to, raising questions about measures of global commitment that obscure these distinctions. They also highlight the need for a dyadic perspective on the forces that keep relationships together.     

Progesterone to ovariectomized mice enhances cognitive performance in the spontaneous alternation, object recognition, but not placement, water maze, and contextual and cued conditioned fear tasks

Research on how steroid hormones mediate mnemonic processes have focused on effects of 17β-estradiol (E₂); yet, progesterone (P₄) co-varies with E₂ across endogenous hormonal milieu, and itself may influence cognitive processes. We investigated the hypothesis that acute P₄ treatment enhances cognitive performance compared to vehicle. Ovariectomized (OVX) c57/BL6J mice were randomly assigned to be subcutaneously injected with oil vehicle or P₄ (10 mg/kg). Mice were trained in the spontaneous alternation, object recognition, object placement, water maze, or fear conditioning tasks, and injected with vehicle or P₄ before training or immediately post-training, and then were tested 1, 4, or 24 h later. The data obtained from these experiments supported our hypothesis. P₄ increased the percentage of spontaneous alterations made in a T-maze more so than did vehicle. P₄, compared to vehicle, increased the percentage of time spent exploring the novel object in the object recognition task, but did not alter performance in the object placement task. P₄, compared to vehicle, decreased latencies to reach the location in the water maze where the platform had been during training in a probe trial, but did not alter performance in the control, cued trial. Compared to vehicle, P₄ treatment increased freezing in contextual and cued fear testing. Thus, acute P₄ treatment to OVX mice can improve cognitive performance across a variety of tasks.     

Rapid Word Recognition as a Measure of Word-Level Automaticity and its Relation to Other Measures of Reading

The present study investigated the relationship between rapid recognition of individual words (Word Recognition Test) and two measures of contextual reading: (1) grade-level Passage Reading Test (IRI passage) and (2) performance on standardized STAR Reading Test. To estabilish if time of presentation on the word recognition test was a factor in predicting contextual reading performance, four computerized presentation times were used: 300 msec, 650 msec, 1000 msec, adn 2000 msec. Regression analyses revealed that, for both third- and fourth-grade students, there was evidence that presentation times of less than 1 second better approximated performance on the two contextual reading measures.     

Effects of progesterone administration and APPswe+PSEN1Deltae9 mutation for cognitive performance of mid-aged mice

Progesterone (P(4)) and its metabolite, 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP) have trophic effects and may improve cognitive function. We investigated the role of progestins in a murine model of Alzheimer's Disease (AD) in which transgenic mice co-overexpress a mutant form of amyloid precursor protein (APPswe) and a deletion in presenilin 1 Delta exon 9 (APPswe+PSEN1Deltae9). We hypothesized that: (1) mice with the APPswe+PSEN1Deltae9 mutation would have performance deficits compared to wildtype mice and (2) long-term administration of P(4) would enhance cognitive performance and increase brain progestin levels over placebo. Mice were ovariectomized at 6 months of age and administered placebo or P(4) via subcutaneously implanted pellets. Mice were tested between 9 and 12 months of age for cognitive performance in the object placement, water maze, object recognition, and T-maze tasks and for motor behavior in an activity monitor and then tissues were collected for steroid measurement. P(4) administration increased progestin levels in cortex, diencephalon, midbrain, and cerebellum of wildtype and mutant mice, but increases in 3alpha,5alpha-THP levels in the hippocampus of APPswe+PSEN1Deltae9 mutant mice were attenuated compared to that observed in wildtype mice. APPswe+PSEN1Deltae9 mice showed poorer performance in hippocampus measures (object placement and water maze tasks). In the object recognition and T-maze task, which are mediated by the cortex and hippocampus, P(4) administration improved performance in both wildtype and APPswe+PSEN1Deltae9 mutant mice compared to placebo administration. Thus, APPswe+PSEN1Delta9 mice have deficits in hippocampal performance and capacity to form 3alpha,5alpha-THP in the hippocampus and both wildtype and APPswe+PSEN1Delta9 mice show beneficial effects of P(4) in cortical function and similar capacity to form 3alpha,5alpha-THP in the cortex.     

Neurosteroids for a successful pregnancy

Steroid hormones play a critical role in the initiation and maintenance of pregnancy. In particular, the important role that the progesterone metabolite, and neurosteroid, allopregnanolone, may play in fetal and adolescent development is becoming increasingly evident. Unlike steroid hormones, neurosteroids act at nontraditional targets in the central and peripheral nervous systems, including GABA(A) receptor complexes. This commentary discusses the three works in this issue that elucidate the important role of allopregnanolone in the mechanisms that regulate stress hypo-sensitivity of rodents in late pregnancy, neuroprotective effects in fetal sheep exposed to a hypoxic insult, and the continuing role that prefrontal cortex formation of allopregnanolone may play on the cognitive development of gestationally stressed rat offspring, grown to adolescence. The narrative that these works comprise was facilitated by the 5(th) International Meeting on Steroids and the Nervous System (Torino, Italy), which is organized to update our knowledge on the relationships between steroid hormones synthesized in different organs and the nervous system. Topics covered in this most recent meeting included sex differences in, and hormonal influences on, cannabinoid-regulated biology; steroids and pain; the importance of co-regulatory factors for steroid receptor action in the brain; mechanism and role of estrogen-induced nonclassical signaling in the brain; vitamin D as the forgotten neurosteroid; neurosteroids and GABA(A) receptors; and pathogenic mechanisms mediated by glucocorticoid receptors in psychiatric disorders. The 6(th) International Meeting on Steroids and the Nervous System will be held in Torino, Italy in February 2011.     

Juvenile offspring of rats exposed to restraint stress in late gestation have impaired cognitive performance and dysregulated progestogen formation

Gestational stress may have lasting effects on the physical and neurocognitive development of offspring. The mechanisms that may underlie these effects are of interest. Progesterone and its 5α-reduced metabolites, dihydroprogesterone and 5α-pregnan-3α-ol-20-one (3α,5α-THP), maintain pregnancy, have neurotrophic effects, and can enhance cognitive performance. We hypothesized that some of the deleterious effects of gestational stress on the cognitive performance of offspring may be related to progestogen formation. Pregnant rat dams were exposed to restraint under a bright light (thrice daily for 45 min) on gestational days 17-21 or were minimally handled controls. Dams that were exposed to restraint had lower circulating levels of 3α,5α-THP and significantly greater concentrations of corticosterone at the time of birth than did control dams. Male and female offspring, that were gestationally stressed or not, were cross-fostered to non-manipulated dams. Between postnatal days 28-30, offspring were assessed for object recognition, a prefrontal cortex (PFC)-dependent cognitive task. Restraint-exposed offspring performed more poorly in the object recognition task than did control offspring, irrespective of sex. As well, progesterone turnover to its 5α-reduced metabolites in the medial PFC (but not the diencephalon) was significantly reduced among restraint-exposed, compared to control, offspring. Progesterone turnover, and levels of 3α,5α-THP, positively correlated with performance in the object recognition task. Thus, restraint stress in late pregnancy impaired cognitive development and dysregulated progestogen formation in brain.     

Posttraining androgens' enhancement of cognitive performance is temporally distinct from androgens' increases in affective behavior

Steroid hormone-induced variations in spatial learning and memory tasks have been reported. In this study, androgens’ effects in various cognitive and affective tasks were investigated in order to determine whether any observed differences in cognitive performance could be due to affective changes produced by the hormones. Ovariectomized rats (N = 72) received 0.0, 3.0, or 7.5 mg/kg subcutaneously, of testosterone (T), dihydrotestosterone (DHT), or 5α-androstane-3α, 17β-diol (3a-Diol) suspended in 10% ethanol/sesame oil v/v. For the cognitive tasks (Y maze, inhibitory avoidance, and object recognition), subjects were injected after training trials. For the affective tasks (open field, elevated plus maze, and tailflick), subjects were injected 1 or 24 h before testing. Posttraining injections that produced physiological concentrations of androgens - T, DHT, and 3α-Diol - 1 h later increased the percentage of correct choices in the Y maze, the latencies to cross to the shock-associated side of the inhibitory avoidance chamber, and percentage of time exploring novel objects 24 h later, when androgen levels were no longer increased. Administration of T, DHT, and 3α-Diol also increased the number of entries into the center squares of a brightly lit open field, open-arm time in the elevated plus maze, and tailflick latencies 1 but not 24 h following administration. These findings suggest that these androgens, when administered following training, can enhance cognitive performance in the tasks investigated 24 h later when androgen levels nadir, but overt changes in the affective behaviors examined occurred at the time of physiological concentrations 1 h but not 24 h following androgen administration. These findings suggest posttraining androgens can enhance consolidation and cognitive performance, independent of their anxiolytic actions.     

Estradiol decreases anxiety behavior and enhances inhibitory avoidance and gestational stress produces opposite effects

Although there is evidence that estradiol has effects in women and in animal models to reduce anxiety and depressive behavior and enhance performance in some cognitive tasks, this is not seen among all individuals. Given the interaction between estradiol and hypothalamic-pituitary-adrenal function, we hypothesized that an individual's prior exposure to stress may mitigate some of the subsequent effects of estradiol. To address this, rats were exposed to gestational stress, or not, to determine if stress exposure during development alters behavioral responses to estradiol in adulthood. If estradiol's effects on anxiety and cognitive behavior are modulated by prior stress experience, then gestationally-stressed rats administered estradiol should have decreased anti-anxiety (open field, elevated plus maze) behavior and cognitive performance in the inhibitory avoidance task. Offspring of dams that were exposed to restraint stress daily on gestational days 14-20, or no such manipulation, were used as adults either intact in behavioral estrus (high estradiol) or diestrus (low estradiol), or ovariectomized (OVX) with empty or estradiol-containing silastic implants. Rats were used for blood collection to determine plasma corticosterone and estradiol concentrations, or were used for behavioral testing. Compared with rats in diestrus or OVX and vehicle-replaced, rats in behavioral estrus and OVX rats with estradiol implants had higher estradiol concentrations, entered more central squares in an open field, spent more time on the open arms of the plus maze, and had a longer latency to crossover to the dark, shock-associated side of the inhibitory avoidance chamber. Gestational stress increased plasma corticosterone but not estradiol levels, decreased plus maze open arm time in cycling rats, and decreased inhibitory avoidance performance. Thus, estradiol and gestational stress can have opposite effects on anxiety and inhibitory avoidance performance.     

Estrogens and progestins enhance spatial learning of intact and ovariectomized rats in the object placement task

Steroid modulation of cognitive function has focused on estrogen (E(2)), but progestins naturally co-vary with E(2) and may also influence cognitive performance. Spatial performance in the object placement task over endogenous hormonal states in which E(2) and progestins vary, and when E(2) and/or progestins were administered, was examined. Experiment 1: Rats in proestrus or estrus had significantly better performance in the object placement task than did diestrus rats. Experiment 2: Rats in the third trimester, post-partum, or lactation exhibited significantly better performance in the object placement task than did rats in the first trimester. Experiment 3: Ovariectomized (ovx) rats administered 17beta-estradiol (0.9 mg/kg), subcutaneously (sc), progesterone (P; 4 mg/kg, sc), or E(2) and P, immediately after training in the object placement task, performed significantly better when tested 4h later, than did control rats administered vehicle (sesame oil 0.2 cc). Experiment 4: ovx rats administered E(2) or P with a 1.5h delay after training in the object placement task, did not perform differently than vehicle-administered controls. Experiment 5: ovx rats administered post-training E(2), which has a high affinity for both E(2) receptor (ER)alpha and beta isoforms, or propyl pyrazole triol (PPT; 0.9 mg/kg, sc), which is more selective for ERalpha than ERbeta, had significantly better performance in the object placement task than did rats administered vehicle or diarylpropionitrile (DPN; 0.9 mg/kg, sc), an ERbeta selective ligand. Experiment 6: ovx rats administered P, or its metabolite, 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP; 4 mg/kg, sc), immediately post-training performed significantly better in the object placement task than did vehicle control rats. Thus, performance in the object placement task is better when E(2) and/or P are naturally elevated or when E(2), the ERalpha selective ER modulator PPT, P, or its metabolite, 3alpha,5alpha-THP, are administered post-training.     

Androgens' performance-enhancing effects in the inhibitory avoidance and water maze tasks may involve actions at intracellular androgen receptors in the dorsal hippocampus

Androgens can have performance-enhancing effects in some cognitive tasks, but the mechanism of these effects has not been established. Experiments examined whether androgens' actions to bind to intracellular androgen receptors (ARs) in the hippocampus are necessary to enhance cognitive performance in the inhibitory avoidance and water maze tasks. If androgens' binding at ARs are essential, then blocking them through intrahippocampal administration of flutamide, an AR receptor antagonist, should attenuate androgens' performance-enhancing effects in the inhibitory avoidance and water maze tasks. In Experiments 1 and 2, flutamide was administered through intrahippocampal inserts to intact male rats immediately pre- and post-training in the inhibitory avoidance and water maze tasks. Both pre- and post-training administration of flutamide to the dorsal hippocampus, but not missed sites, produced significantly poorer performance in the inhibitory avoidance and water maze tasks, without influencing control measures such as flinch/jump threshold or swim speed. In Experiment 3, flutamide administration to the hippocampus was delayed two hours following training in the inhibitory avoidance and water maze tasks. There was no significant effect of delayed administration of flutamide on performance in either of these tasks. Together, these findings suggest that blocking ARs in the dorsal hippocampus with flutamide administration immediately pre- or post-training can produce decrements in cognitive performance, which implies that androgens' performance-enhancing effects may occur, in part, through binding at intracellular androgen receptors in the dorsal hippocampus.