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11.
Interactions between acute stress and systemic insulin and epinephrine on GABAA receptor density in the forebrain were studied. Here, 10 day-old chicks were intraperitoneally injected with insulin, epinephrine or vehicle and then immediately stressed by partial water immersion for 15 min and killed by decapitation. Non-stressed controls were similarly injected, then returned to their rearing boxes for 15 min and then killed. Forebrains were dissected and GABAA receptor density was measured ex vivo in synaptosomes by 3[H]-flunitrazepam binding assay. In non-stressed chicks, insulin at 1.25, 2.50 and 5.00 IU/kg of body weight (non-hypoglycemic doses) increased Bmax by 33, 53 and 44% compared to saline, respectively. A similar increase of 41% was observed in receptor density after stress. However, the insulin effect was not additive to the stress-induced increase suggesting that both effects occur through similar mechanisms. In contrast, epinephrine, at 0.25 and 0.5 mg/kg did not induce any changes in Bmax in non-stressed chicks. Nevertheless, after stress these doses increased the receptor density by about 13 and 27%, respectively. Similarly, the same epinephrine doses co-administered with insulin (2.50 IU/kg), increased the receptor density by about 20% compared to insulin alone. These results suggest that systemic epinephrine, perhaps by evoking central norepinephrine release, modulates the increase in forebrain GABAA receptor binding induced by both insulin and stress. 相似文献
12.
The effect of unimanual practice of the non-preferred hand on manual asymmetry and manual preference for sequential finger movements was evaluated in right-handers before, immediately after, and 30 days following practice. The results demonstrate that unimanual practice induced a persistent shift of manual preference for the experimental task in most participants, but no significant correlation between manual asymmetry and manual preference was detected. These findings are explained by proposing that manual preference is influenced by a task-specific confidence developed from the recent history of differential use of the limbs, in interaction with a generalized confidence on a single hand for performance of motor skills. 相似文献
13.
This study evaluated the serial position curve based on free recall of spatial position sequences. To evaluate the memory processes underlying spatial recall, some manipulations were introduced by varying the length of spatial sequences (Exp. 1) and modifying the presentation rate of individual positions (Exp. 2). A primacy effect emerged for all sequence lengths, while a recency effect was evident only in the longer sequences. Moreover, slowing the presentation rate increased the magnitude of the primacy effect and abolished the recency effect. The main novelty of the present results is represented by the finding that better recall of early items in a sequence of spatial positions does not depend on the task requirement of an ordered recall but it can also be observed in a free recall paradigm. 相似文献
14.
Little direct evidence has emerged regarding the influence of switching between tasks on the performance of skills studied in the motor domain. The present study reported the results of two experiments that examined the effects of task switching on a simple object projection task, which presumably emphasized processes related to response planning and execution. The experimental task required participants to gently tap a knob to make it travel along two parallel rods until it reached a specified target distance. In both experiments, participants in the repeated conditions performed a single target distance while participants in the switched conditions alternated between two target distances. Results indicated that switching between targets degraded accuracy for the two short targets (30cm, Exp. 1; 20cm, Exp. 2). Results were consistent with the preservation of parameter values [Rosenbaum, D. A., Weber, R. J., Hazelett, W. M., & Hindorff, V. (1986). The parameter remapping effect in human performance. Evidence form tongue twisters and finger fumblers. Journal of Memory and Language, 25, 710-725; Sherwood, D. E. (2007). Separate movement planning and spatial assimilation effects in sequential bimanual aiming movements. Perceptual and Motor Skills, 105, 501-513] and suggested an additional role for persisting activation in accounting for spatial assimilation and magnitude effects. 相似文献
15.
When sequences of discrete events, or other units, are independently coded by two coders using a set of mutually exclusive
and exhaustive codes, but the onset times for the codes are not preserved, it is often unclear how pairs of protocols should
be aligned. Yet such alignment is required before Cohen’s kappa, a common agreement statistic, can be computed. Here we describe
a method—based on the Needleman and Wunsch (1970) algorithm originally devised for aligning nucleotide sequences—for optimally
aligning such sequences; we also offer the results of a simulation study of the behavior of alignment kappa with a number
of variables, including number of codes, varying degrees of observer accuracy, sequence length, code variability, and parameters
governing the alignment algorithm. We conclude that (1) under most reasonable circumstances, observer accuracies of 90% or
better result in alignment kappas of .60 or better; (2) generally, alignment kappas are not strongly affected by sequence
length, the number of codes, or the variability in the codes’ probability; (3) alignment kappas are adversely affected when
missed events and false alarms are possible; and (4) cost matrices and priority orders used in the algorithm should favor
substitutions (i.e., disagreements) over insertions and deletions (i.e., missed events and false alarms). Two computer programs
were developed: Global Sequence Alignment, or GSA, for carrying out the simulation study, and Event Alignment, or ELign, a
user-oriented program that computes alignment kappa and provides the optimal alignment given a pair of event sequences. 相似文献
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17.
Mild cognitive impairment (MCI) is a heterogeneous condition characterized by the presence in an otherwise healthy elderly
individual of cognitive deficits involving specific domains in the absence of significant functional impairments. Reports
indicate that prospective memory (PM), that is, the ability to remember to execute delayed intentions, is impaired in individuals
with MCI. The present review discusses the current debate in the literature on PM functioning in MCI by focusing on the relationship
between prospective retrieval and retrospective memory functioning. Analysis of the reported evidence revealed that both the
prospective component and the retrospective component of PM can be impaired in MCI. Declarative memory dysfunction may account
for the retrospective memory impairment, while either reduced executive abilities or a deficit of reflexive mechanisms could
explain the prospective component impairment. 相似文献
18.
Diego Augusto Santos Silva Markus Vinicius Nahas Thiago Ferreira de Sousa Giovâni Firpo Del Duca Karen Glazer Peres 《Body image》2011,8(4):427-431
We investigated the prevalence of body image dissatisfaction (BID) and associated factors in Florianopolis, Brazil. BID was analyzed in a sample (N = 1720) of adults through the Figure Rating Scale. The independent variables were sociodemographic factors, health behaviors, and morbidities. A multinomial logistic regression analysis was used. More men (14.2%) than women (6.1%) presented BID by being lighter than ideal (LI). Conversely, more women (66.6%) than men (46.3%) showed BID by being heavier than ideal (HI). BID by being HI was higher among older women, those with high BMI and those with a partner. In men, lower BMI and the presence of common mental disorders were associated with BID due to being LI. Advanced ages, alcohol abuse, physical inactivity, and obesity were associated with BID due to being HI. We must consider different public health interventions for men and women to reduce BID in Brazilian adults. 相似文献
19.
Neuropsychological investigation of the development of the mnesic function in mental retardation has primarily focused on evaluating short-term memory (STM). Studies have often documented a reduced verbal short-term memory span in individuals with mental retardation and with Down syndrome in particular, compared to groups of mental age-matched controls. However, recent evidence suggests that verbal short-term memory is not equally impaired in all individuals with mental retardation. Findings in children with Williams syndrome are particularly relevant in this regard. Also, data concerning STM for visual information suggest that visual-object and visual-spatial working memory may be differently compromised in people with mental retardation. In particular, individuals with Williams syndrome exhibit specific difficulties in visual-spatial but not in visual-object working memory tasks compared to typically-developing children matched for mental age. Instead, people with Down syndrome show reduced performance in both visual-spatial and visual-object tests. Taken together, these results reinforce the view that intellectual disability is not a unitary condition characterized by homogeneous slowness of cognitive development but a variety of conditions in which some cognitive functions may be more disrupted than others. The finding that the working memory deficit in individuals with Williams and Down syndrome may be qualitatively differentiated also supports the hypothesis that it is not simply a manifestation of general cognitive impairment but, rather, the expression of a specific deficit of a discrete cognitive ability. 相似文献