The Artificial Grammar Learning task has been used extensively to assess individuals' implicit learning capabilities. Previous work suggests that participants implicitly acquire rule-based knowledge as well as exemplar-specific knowledge in this task. This study investigated whether exemplar-specific knowledge acquired in this task is based on the visual features of the exemplars. When a change in the font and case occurred between study and test, there was no effect on sensitivity to grammatical rules in classification judgments. However, such a change did virtually eliminate sensitivity to training frequencies of letter bigrams and trigrams (chunk strength) in classification judgments. Performance of a secondary task during study eliminated this font sensitivity and generally reduced the contribution of chunk strength knowledge. The results are consistent with the idea that perceptual fluency makes a contribution to artificial grammar judgments. 相似文献
Several lines of evidence indicate that gamma-aminobutyric acid (GABA) type A (GABA(A)) receptors regulate memory consolidation. Here we studied the effect on consolidation of the selective antagonist of GABA(A) receptors, bicuculline, given into several regions of the cortex at different times after one-trial step-down inhibitory avoidance (0.5 mA, 2-s footshock). Rats were bilaterally implanted with cannulae aimed at the CA1 region of the dorsal hippocampus, entorhinal cortex or posterior parietal cortex, three areas known to be involved in the memory consolidation of this task. At different times after training, bicuculline (0.5 microg/side) was infused into the above mentioned structures. Bicuculline increased memory retention when administered either immediately or 1.5h after training into CA1, and both immediately and 3h after training in the entorhinal or parietal cortex. Thus, in agreement with previous findings using other drugs, the response was biphasic in these latter structures. This suggests that GABAergic mechanisms normally downregulate, memory processing by inhibiting on-going activities necessary for consolidation at the times in which bicuculline was effective in each structure. Based on previous findings, in the hippocampus, such activity involves a number of receptors and signaling pathways in the first 1.5h after training. In the entorhinal and parietal cortex memory-related activities include the participation of protein kinase A and extracellularly regulated kinase (ERK) twice, right after training and then again 3h later. 相似文献
Anxiety disorders are the most common type of psychiatric conditions in children. Early identification and intervention during preschool years is critical for minimizing their detrimental long-term effects. The Preschool Anxiety Scale (PAS) is a developmentally-sensitive and symptom-specific instrument that has been commonly used and widely validated in the west. The current study tested the psychometric properties of its Traditional Chinese version (PAS-TC) in Hong Kong. The study sample consisted of a total of 1317 Hong Kong parents, recruited from 12 local preschools, with preschool children aged from three to six years old. Results showed that a correlated five-factor model demonstrated a good fit for the data. PAS-TC also demonstrated acceptable reliability and satisfactory validity. Furthermore, gender but not age effects were found in Hong Kong. Additionally, similar to previous studies, items from physical injury fears were the most reported in the top-ten frequently endorsed items. Finally, the anxiety level of our Hong Kong sample was found to be between the Mainland China and western countries. Clinical implications of the above findings concerning PAS-TC are discussed.
Eight pigeons were trained on multiple schedules of reinforcement where pairs of components alternated in blocks on different keys to define 2 local contexts. On 1 key, components arranged 160 and 40 reinforcers/hr; on the other, components arranged 40 and 10 reinforcers/hr. Response rates in the 40/hr component were higher in the latter pair. Within pairs, resistance to prefeeding and resistance to extinction were generally greater in the richer component. The two 40/hr components did not differ in resistance to prefeeding, but the 40/hr component that alternated with 10/hr was more resistant to extinction. This discrepancy was interpreted by an algebraic model relating response strength to component reinforcer rate, including generalization decrement. According to this model, strength is independent of context, consistent with research on schedule preference. 相似文献
ABSTRACT— Here we show that demands associated with brood parasitism have favored sophisticated cognitive abilities in female brown-headed cowbirds. We discovered that cowbirds can use the rate at which eggs are added to a nest across days to assess the readiness of the nest for incubation, which would allow them to synchronize laying with the host and avoid nests where incubation has most likely commenced. In three experiments, cowbirds investigated and laid eggs in artificial nests that differed in the number of eggs they contained. Across days, we added eggs to nests at different rates to simulate differences in the timing of reproduction of the hosts. Cowbirds avoided a nest if the number of eggs that had been added was less than the number of days that had elapsed. The ability of females to remember egg number and compare changes in egg number across days allows them to select nests most suitable for parasitism. 相似文献
Previous work done by our laboratory has demonstrated a reduction of the post-burst afterhyperpolarization (AHP) and accommodation following trace eyeblink conditioning in rabbit CA1 pyramidal neurons. Our laboratory has also demonstrated a reduction in the AHP in rat CA1 pyramidal neurons following spatial learning. In the current study we have extended our findings in rabbits by showing a reduction in both the AHP and accommodation in F344 X BN rat CA1 pyramidal neurons following acquisition of trace eyeblink conditioning. A component current of the AHP, I(M), was evaluated with a specific blocker of this current, and showed no apparent contribution to the learning-related increase in neuronal excitability. Rather, a reduction in an isoproterenol-sensitive component of the AHP, presumably sI(AHP), was observed to underlie the learning-specific change. 相似文献
Vietnam veterans (N = 232) recruited from three sources were assessed for suicidal thinking and behaviors, and symptoms of posttraumatic stress disorder (PTSD) and depression. Findings support the notion that suicidal thoughts are prevalent in this group, with veterans in psychotherapy reporting a greater likelihood of such symptoms (82.6%) than veterans in the community (35.7%) or those seeking assistance through a veteran's outreach center (66.7%). Thoughts of ending one's life and a previous suicide attempt were significantly correlated with a diagnosis of PTSD (r = .53, p < .001; and r = .33, p < .001, respectively). Veterans with a diagnosis of PTSD and depression or dysthymia were also more likely to report suicidal thinking and behaviors than veterans with only one of the diagnoses. 相似文献
The efficacy of home-delivered cognitive-behavioral therapy (CBT) in improving quality of life and reducing psychological symptoms in older adults was examined in this study. One hundred thirty-four participants, predominately African American and characterized as primarily rural, low resource, and physically frail, were randomly assigned to either CBT or a minimal support control condition. Results indicate that CBT participants evidenced significantly greater improvements in quality of life and reductions in psychological symptoms. Mediation of treatment through cognitive and behavioral variables was not found despite the acceptable delivery of CBT by research therapists. These data suggest that treatment can be effective with a disadvantaged sample of older adults and extend efficacy findings to quality of life domains. Creating access to evidence-based treatments through nontraditional delivery is an important continuing goal for geriatric health care. 相似文献
This paper examines the quality of employed women's experience in the homemaking-role and its relationship to their psychological well-being and distress. The subjects (N=403) were drawn from a random stratified sample of women, ages 25 to 55, who were employed as social workers or licensed practical nurses. Positive homemaking-role experience was associated with increased psychological well-being and lowered psychological distress. These associations were affected by the quality of the subjects' experiences in the paid work-role. Thus the favorable association of positive homemaking-role quality with psychological well-being and distress was enhanced by positive paid work-role quality, suggesting that the relationship of homemaking-role quality to the psychological outcomes is influenced by the effects of paid work-role quality on psychological well-being and distress.Data for this paper were collected as part of a larger project funded by the National Institute on Occupational Safety and Health (1 RO1-OHO-1968). The initial analyses and writing of this paper took place at the Center for Research on Women, Wellesley College, and was supported by NIMH postdoctoral training grant no. MH-17058-053. We would like to express special thanks to the late Grace K. Baruch for her enthusiastic support and encouragement of this paper. 相似文献