Muscarinic cholinergic receptor blockade in the rat prelimbic cortex impairs the social transmission of food preference

Previous findings demonstrate the involvement of the cholinergic NBM in the acquisition of the social transmission of food preference (STFP), a relational associative odor-guided learning task. There is also evidence that muscarinic receptors in the medial prefrontal cortex, an important NBM target area, may modulate olfactory associative memory. The present experiment determined the consequences of blocking muscarinic cholinergic receptors in a component of the medial prefrontal region (the prelimbic cortex) on the STFP task. Adult male Wistar rats were bilaterally infused with scopolamine (20 microg/site) prior to training and showed a severe impairment in the expression of the task measured in two retention sessions, both immediately and 24h after training. Local scopolamine injections in the prelimbic cortex did not affect other behavioral measures such as olfactory perception, social interaction, motivation to eat, neophobia, or exploration. Results suggest that muscarinic transmission in the prelimbic cortex is essential for the STFP, supporting the hypothesis that ACh in a specific prefrontal area is important for this naturalistic form of olfactory relational memory. Current data are discussed in the context of disruption of learning as a result of interferences in PLC functions such as behavioral flexibility, attention, and strategic planning.     

中国高中学生中的反应风格及其效应

通过测试正反向陈述的NEO-FFI和EPQ,探讨了中国高中生中默认、极端化、折中化、弹性反应风格的特点,及题目陈述方向的改变对其人格测验信效度的影响。结果发现反应风格在中国高中生中确实存在,折中化和弹性风格对测验的影响最为严重,其次为极端化风格,默认风格则可能不算一种偏差。NEO-FFI量表在使用反向陈述题目时信效度下降,说明由于教育水平低而使高中生理解反向题时存在困难     

一种自上而下加工的注意选择新机制:视觉标记

视觉标记是国外新近提出的有关注意选择机制的一种假设。该假设认为,在任务目标预先设定的条件下视觉系统是通过抑制旧刺激所处的位置来实现对新刺激的优先选择。本文主要介绍了视觉标记研究的经典实验范式、视觉标记理论的行为实验依据和脑成像实验依据,还概述了三种质疑视觉标记理论的观点。最后对视觉标记的未来研究做了展望。     

靶子的潜在位置数对辨别任务中返回抑制的影响

摘要在严格控制的条件下,以大学生为被试．采用线索一靶子模式的返回抑制范式．考察了靶子在注视点周边可能出现的位置数与辨别任务中返回抑制的关系。实验结果表明．在辨别任务中靶子的潜在位置数对返回抑制量有影响,随着位置数的增加,返回抑制量减小。该结论为返回抑制的注意性观点提供了新的证据。     

Flexible conceptual projection of time onto spatial frames of reference

Flexibility in conceptual projection constitutes one of the most challenging issues in the embodiment and conceptual metaphor literatures. We sketch a theoretical proposal that places the burden of the explanation on attentional dynamics in interaction with mental models in working memory that are constrained to be maximally coherent. A test of this theory is provided in the context of the conceptual projection of time onto the domain of space. Participants categorized words presented at different spatial locations (back–front, left–right) as referring to the past or to the future. Responses were faster when the irrelevant word location was congruent with the back–past, front–future metaphoric mapping. Moreover, when a new highly task-relevant spatial frame of reference was introduced, it changed the projection of past and future onto space in a way that was congruent with the new frame (past was now projected to left space and future to right space), as predicted by the theory. This study shows that there is substantial flexibility in conceptual projection and opens a venue to study metaphoric variation across tasks, individuals, and cultures as the result of attentional dynamics.     

Sequential effects on speeded information processing: a developmental study

Two experiments were performed to assess age-related changes in sequential effects on choice reaction time (RT). Sequential effects portray the influence of previous trials on the RT to the current stimulus. In Experiment 1, three age groups (7-9, 10-12, and 18-25 years) performed a spatially compatible choice task, with response-to-stimulus intervals (RSIs) of 50 and 500 ms varied between trial blocks. In Experiment 2, three age groups (7-9, 15-16, and 18-25 years) performed the task with spatial stimulus-response (S-R) mappings (compatible versus incompatible) varied between participants. For adults, the experiments yielded a pattern of sequential effects suggestive of "automatic facilitation" (i.e., a first-order repetition effect and a higher order benefit-only pattern for short RSIs) and "subjective expectancy" (i.e., a first-order alternation effect and a higher order cost-benefit pattern for long RSIs). Automatic facilitation was more pronounced for incompatible responses than for compatible responses. Both experiments showed the anticipated decrease in automatic facilitation with advancing age. Finally, the first-order alternation effect showed the predicted age-related increase, but the cost-benefit pattern revealed an opposite trend, suggesting that the first-order and higher order indexes of subjective expectancy may relate to dissociable mechanisms.     

Attentional control in the aging brain: insights from an fMRI study of the stroop task

Several recent studies of aging and cognition have attributed decreases in the efficiency of working memory processes to possible declines in attentional control, the mechanism(s) by which the brain attempts to limit its processing to that of task-relevant information. Here we used fMRI measures of neural activity during performance of the color-word Stroop task to compare the neural substrates of attentional control in younger (ages: 21-27 years old) and older participants (ages: 60-75 years old) during conditions of both increased competition (incongruent and congruent neutral) and increased conflict (incongruent and congruent neutral). We found evidence of age-related decreases in the responsiveness of structures thought to support attentional control (e.g., dorsolateral prefrontal and parietal cortices), suggesting possible impairments in the implementation of attentional control in older participants. Consistent with this notion, older participants exhibited more extensive activation of ventral visual processing regions (i.e., temporal cortex) and anterior inferior prefrontal cortices, reflecting a decreased ability to inhibit the processing of task-irrelevant information. Also, the anterior cingulate cortex, a region involved in evaluatory processes at the level of response (e.g., detecting potential for error), showed age-related increases in its sensitivity to the presence of competing color information. These findings are discussed in terms of newly emerging models of attentional control in the human brain.     

Positive emotions enhance recall of peripheral details

Emotional arousal and negative affect enhance recall of central aspects of an event. However, the role of discrete emotions in selective memory processing is understudied. Undergraduates were asked to recall and rate autobiographical memories of eight emotional events. Details of each memory were rated as central or peripheral to the event. Significance of the event, vividness, reliving and other aspects of remembering were also rated for each memory. Positive affect enhanced recall of peripheral details. Furthermore, the impairment of peripheral recall was greatest in memories of anger, not of fear. Reliving the experience at retrieval was negatively correlated with recall of peripheral details for some emotions (e.g., anger) but not others (e.g., fear), irrespective of similarities in affect and intensity. Within individuals, recall of peripheral details was correlated with less belief in the memory's accuracy and more likelihood to recall the memory from one's own eyes (i.e., a field perspective).     

Effect of negative emotional content on attentional maintenance in working memory

ABSTRACT

Previous research has shown that emotional stimuli may interfere with working memory (WM) processes, but little is known about the process affected. Using a complex span task, the present study investigated the influence of processing negative emotional content on attentional maintenance in WM. In two experiments conducted under articulatory suppression, participants were asked to remember a series of five letters, each of which was followed by an image to be categorised. In half of the trials, the images were negative and in the other half, they were neutral. In both experiments, our results showed longer processing times for emotional stimuli than neutral stimuli, and lower memory performance when participants processed negative stimuli. We propose that emotional stimuli direct more attentional resources towards the processing component of the WM task, thereby reducing the storage capacity available for the items that are to be remembered.