Acute stress persistently enhances estrogen levels in the female rat

Here we tested whether exposure to either tailshock or swim stress alters ovarian hormone levels, estrogen and progesterone, in females and whether the effects are persistent. Adrenal hormone levels were also measured in males and females. Estradiol levels were elevated in unstressed females during proestrus relative to females in other stages of estrous, and exposure to the stressors enhanced estradiol beyond basal levels. For females stressed during diestrus 2, estradiol levels were elevated immediately after stressor cessation and up to 24 hrs. Exposure to tailshock, but not swim-stress, transiently enhanced progesterone in females stressed during the stage of proestrus and estrus. Glucocorticoid levels were elevated in response to both stressors and were supraelevated in females under both basal and stress conditions relative to males, particularly in blood from females exposed to acute swim stress. These results indicate that exposure to a relatively acute stressful event immediately and persistently enhances serum estradiol and are discussed in the context of reports that exposure to the same stressors immediately and persistently impairs associative learning in the female rat.     

THERE ARE TWO WORD-LENGTH EFFECTS IN VERBAL SHORT-TERM MEMORY:

Abstract— In the word-length effect (WLE), lists of shorter words are better recalled than lists of longer words This effect a fundamental to decay-based theories of verbal short-term memory, such as the phonological loop theory (Baddeley, 1986) The WLE has been attributed to the time taken to articulate words, not their structure, a critical point in the debate between decay and interference theories However, this article, we show that the traditional WLE comprises two opposed effects an advantage for words spoken more quickly (short words in terms of duration) and an advantage for words with more elements (long words in terms of complexity) We also report two interactions a disadvantage for a midlist change in duration and an advantage for a midlist change in complexity These results contradict simple decay- based theories and establish the importance of interference in short- term memory We discuss whether decay is also required     

Why Dexamethasone Poorly Penetrates in Brain

Dexamethasone poorly penetrates in brain. A tracer amount of [3H]-dexamethasone administered to adrenalectomized rats or mice is poorly retained by glucocorticoid receptors in brain, while pituitary corticotrophs containing equivalent amounts of these receptors accumulate and retain large amounts of this synthetic steroid. However, adrenalectomized mice with a genetic disruption of the multiple drug resistance (mrd1a) gene have a tenfold increase of [3H]-dexamethasone uptake in brain glucocorticoid target sites reaching levels observed in the pituitary. These data demonstrate that dexamethasone is extruded from brain by the mrd1a-encoded P-glycoproteins. The data support the concept of a pituitary site of action of dexamethasone in blockade of stress-induced ACTH release, which implies that chronic dexamethasone treatment does not replace the endogenous corticosteroids depleted from brain mineralocorticoid (MRs) and glucocorticoid receptors (GRs). Dexamethasone, therefore, causes a profound disturbance in the balance of these two receptor types in hippocampus, which is an unfavourable condition threatening the neuronal integrity of this brain structure through the expression of noxious genes.     

Do people with low self-esteem really want to feel better? Self-esteem differences in motivation to repair negative moods.

This research examined the hypothesis that people with low self-esteem (LSE) are less motivated than people with high self-esteem (HSE) to repair their negative moods. In Study 1, participants completed diaries in response to either a success or a failure in their everyday lives. Participants described what they intended to do next and the reasons behind those plans. After failure, fewer LSE than HSE participants expressed a goal to improve their mood. A follow-up investigation (Study 2) suggested that this difference was not due to a self-esteem difference in knowledge of mood repair strategies. In Study 3, after undergoing a negative mood induction, fewer LSE than HSE participants chose to watch a comedy video, even though both groups believed the comedy video would make them happy. Studies 4 and 5 explored possible reasons why LSE people are less motivated than HSE people to repair their negative moods.     

Evidence for a non-linguistic distinction between singular and plural sets in rhesus monkeys

Set representations are explicitly expressed in natural language. For example, many languages distinguish between sets and subsets (all vs. some), as well as between singular and plural sets (a cat vs. some cats). Three experiments explored the hypothesis that these representations are language specific, and thus absent from the conceptual resources of non-linguistic animals. We found that rhesus monkeys spontaneously discriminate sets based on a conceptual singular-plural distinction. Under conditions that do not elicit comparisons based on approximate magnitudes or one-to-one correspondence, rhesus monkeys distinguished between singular and plural sets (1 vs. 2 and 1 vs. 5), but not between two plural sets (2 vs. 3, 2 vs. 4, and 2 vs. 5). These results suggest that set-relational distinctions are not a privileged part of natural language, and may have evolved in non-linguistic species to support domain general quantitative computations.