NK(3) receptor agonism promotes episodic-like memory in mice

The mammalian tachykinins are a family of closely related peptides including substance P, neurokinin A, neurokinin B and, recently, also hemokinin-1. They are present in the peripheral and central nervous systems, and bind to three known neurokinin (NK) receptors, the NK(1)-, NK(2)- and NK(3) receptors. In both rodents and humans, NK(3) receptors are expressed in brain structures which have been associated with learning and memory. Evidence for a role of NK(3) receptors in learning and memory has been found in NK(3) receptor knockout mice. Here, we investigated the influence of the NK(3) receptor agonist, senktide (0.1, 0.2 and 0.4 mg/kg), on the performance of C57BL/6 mice in a recently developed episodic-like memory task. Since a promnestic effect of senktide was expected, we employed an experimental protocol that provided sub-optimal learning conditions for episodic-like memory. The results indicate that senktide promotes episodic-like memory in mice in a dose-dependent manner, providing, for the first time, evidence for an involvement of NK(3) receptors in episodic-like memory.     

Perceived behavioral changes in early multiple sclerosis

Acquired behavioral changes have essentially been described in advanced multiple sclerosis (MS). The present study was designed to determine whether behavioral modifications specifically related to the MS pathological process could be identified in the initial phase of the disease, as compared to control patients with chronic, relapsing and progressive inflammatory disorders not involving the central nervous system (CNS). Eighty-eight early MS patients (Expanded Disability Status Scale score 相似文献   

Is optimal vision required for the successful execution of an interceptive task?

The importance of optimal visual function in demanding interceptive tasks is far from established. The aim of the study was to determine whether induced myopic blur and hence sub-optimal visual function would give rise to a detrimental effect on performance in the execution of an interceptive task. The batting performance of grade level cricket players was assessed facing a bowling machine whilst wearing contact lenses of four different refractive conditions (plano (nil), +1.00, +2.00 and +3.00D over-refraction), inducing increasing amounts of myopic blur. Performance for each condition was assessed based both on the shot quality against each delivery judged by a qualified cricket coach blind to each condition, along with an evaluation of the quality of ball-bat contact for each delivery. No significant change was found in batting performance with the introduction of +1.00 and +2.00D of induced myopic blur. A +3.00D over-correction was required before any significant decrease in batting performance was detected, demonstrating that batters needed to be essentially legally blind (as simulated through the use of the +3.00D over-refraction) before there was any significant measurable decrement in batting performance. We concluded that optimal visual correction is not necessarily required for optimal performance in a demanding interceptive task, and that the human perceptual-motor system is capable of compensating for marked alterations in input.     

Association among items from the self-report version of the Hamilton Depression Scale (Carroll Rating Scale) and respondents' sex

The association among items of the self-reported version of the Hamilton Depression Scale (Carroll Rating Scale), answered according to a memory of a maximally disturbing event experienced, and respondents' sex was examined in a nonclinical sample of 320 college students, 164 women (M age=21.7 yr., SD=3.6) and 156 men (M age=23.5 yr., SD=5.8). An assessment of sex bias was also evaluated. Multiple regression analysis showed that statements regarding unhappiness, urge to cry, dizziness and faintness, and waking in the middle of the night were significantly associated with women. Removal of these items from the Carroll Rating Scale Total scores eliminated the sex differences in depression rates. Items that displayed significant sex bias were those regarding behavior and emotions commonly attributed to women within the general population.     

The contributions of visual and central attention to visual working memory

We investigated the role of two kinds of attention—visual and central attention—for the maintenance of visual representations in working memory (WM). In Experiment 1 we directed attention to individual items in WM by presenting cues during the retention interval of a continuous delayed-estimation task, and instructing participants to think of the cued items. Attending to items improved recall commensurate with the frequency with which items were attended (0, 1, or 2 times). Experiments 1 and 3 further tested which kind of attention—visual or central—was involved in WM maintenance. We assessed the dual-task costs of two types of distractor tasks, one tapping sustained visual attention and one tapping central attention. Only the central attention task yielded substantial dual-task costs, implying that central attention substantially contributes to maintenance of visual information in WM. Experiment 2 confirmed that the visual-attention distractor task was demanding enough to disrupt performance in a task relying on visual attention. We combined the visual-attention and the central-attention distractor tasks with a multiple object tracking (MOT) task. Distracting visual attention, but not central attention, impaired MOT performance. Jointly, the three experiments provide a double dissociation between visual and central attention, and between visual WM and visual object tracking: Whereas tracking multiple targets across the visual filed depends on visual attention, visual WM depends mostly on central attention.     

Effects of delayed constructed-response identity matching on spelling of dictated words

We studied the effects of delayed constructed-response identity matching on spelling with 6 first graders with histories of school failure. After training, the children learned to spell words to dictation and their cursive writing improved. These results replicate studies showing that delayed constructed-response matching establishes spelling. For 2 children, spelling of generalization words--words formed by recombining the syllables of training words--also improved. These results extend studies that have shown recombinative generalization in reading and spelling.     

Emotional and sexual jealousy as a function of sex and sexual orientation in a Brazilian sample

The goal of the present study was to compare the relative distress of homosexual and heterosexual Brazilian men and women on scenarios in which they imagined their partners sexually or emotionally involved with another person, using a forced-choice paradigm and continuous measures. Participants were 68 heterosexual men, 72 heterosexual women, 42 homosexual men, and 35 homosexual women. On the forced-choice questions heterosexual men (39 on one question and 37 on the other) were more upset than their female counterparts (21 on one question and 15 on the other) by scenarios of sexual infidelity than those of emotional infidelity. On questions using continuous measures no significant difference was found between pleasurable sex and attachment scenarios for heterosexual women or heterosexual men. On the highly upsetting scenarios heterosexual men discriminated between flirting and both pleasurable sex and attachment scenarios, being less disturbed by the former. In contrast, heterosexual women were equally distressed by the three scenarios. Scores for the homosexual men and homosexual women fell in between those of the heterosexual men and heterosexual women and did not show a clear cut preference for the sexual infidelity or the emotional alternative on the forced-choice paradigm. However, on the continuous measures of jealousy homosexuals resembled heterosexuals of the opposite sex. There was no evidence that jealousy would be less intense among homosexuals although reproductive outcomes were not at risk.     

Amnesic effect of GMP depends on its conversion to guanosine

Extracellular guanine-based purines, namely the nucleotides GTP, GDP, GMP and the nucleoside guanosine, exert important neuroprotective and neuromodulator roles in the central nervous system, which may be related to inhibition of the glutamatergic neurotransmission activity. In this study, we investigated GMP effects on mice inhibitory avoidance performance and the dependence on its conversion to guanosine for such effect, by using the ecto-5'-nucleotidase specific inhibitor AOPCP. We also investigated if this conversion occurs in the central nervous system or peripherally, and if guanosine and GMP affect nociception by the tail-flick test. I.p. GMP or guanosine (7.5 mg/kg) or i.c.v. GMP (480 nmol) pretraining administration was amnesic for the inhibitory avoidance task. I.c.v. AOPCP (1 nmol) administration completely reversed the amnesic effect of i.c.v. GMP, but not of i.p. GMP, indicating that peripheral conversion of GMP to guanosine is probably relevant to this effect. AOPCP alone did not interfere with the performance. Furthermore, tail-flick measurement was unaffected by i.p. GMP and guanosine, suggesting that the amnesic effect of both purines was not due to some antinociceptive effect against the footshock used in the task. All these data together, in accordance to those previously observed in studies involving glutamate uptake and seizures reinforce the idea that guanosine is the specific extracellular guanine-based purines effector and indicate that its conversion occurs not only in the central nervous system but also peripherally.     

Sustained and transient modulation of performance induced by emotional picture viewing

We investigated how viewing task-irrelevant emotional pictures affects the performance of a subsequent nonemotional visual detection task. Subjects performed target-detection trials following the offset of individual unpleasant, pleasant, and neutral pictures. Sustained interference occurred when subjects viewed unpleasant pictures (mutilated bodies) in a sequential, "blocked" fashion. Such slowing down of reaction time appeared to build up with time, consistent with the instatement of a defensive emotional state. With a randomized picture presentation, only a transient interference effect was observed, consistent with increased attentional demands during the processing of unpleasant pictures. During blocked presentation of affiliative pleasant pictures, reaction times were faster, suggesting the activation of appetitive motivational systems. Ultimately, both attentional and motivational systems are intricately tied in the brain and, together, determine behavior.     

The Impact of Coping Strategies on the Operations in the Jungle Course of the Brazilian Army

The aim of this study is to investigate which coping strategies can predict success or failure in the Brazilian Army’s Jungle Operations Course. To achieve this, the sample included 36 military volunteers (18 who quit and 18 who completed the course) from a total of 63 candidates (57.14%), all male career officers and sergeants of the Brazilian Army. Results indicate that completers (n = 18) show significantly higher scores in 2 of the 8 different coping strategy factors—self-control and positive reappraisal—than those in the quitters group (n = 18). In general, emotion-focused strategies were prominent in relation to problem-focused ones. The findings of this study suggest that coping strategies focused on emotion, especially self-control and positive reappraisal, can influence individuals’ performance in situations of intensive military training, which possibly makes them more resilient, preparing them for a more successful training.