对听感觉运动门控自上而下调节的动物模型和神经机制

对惊反射的前脉冲抑制是减少干扰影响、保护脑内信息加工的重要机制。它既是研究感觉运动门控的模型, 也是探究精神分裂症机制的模型。前脉冲抑制可被选择性注意和情绪等高级认知活动所调节。本论文工作围绕着恐惧条件化和知觉空间分离去掩蔽(空间选择性注意)对听觉前脉冲抑制多层次化的自上而下调节, 在大鼠行为模型、神经通路、神经电生理机制等几个层次上开展了系统性研究, 并引入了精神分裂症的神经发育模型, 证实早期社会隔离饲养对前脉冲抑制注意调节的破坏影响。本论文研究成果不仅对认识正常情况下脑在复杂刺激场景中的信息加工机制有重要意义, 以感觉运动门控认知调节功能缺失为基础的动物模型也将推动精神分裂症心理学和神经生物学机制的研究。     

Studies on time: a proposal on how to get out of circularity

The analysis of time is vitiated very often by circularity: several disciplines, such as psychology, linguistics, and neurosciences, analyze time by using concepts or terms which already contain in themselves, or are based, on the experience and notion of time (as when, for example, time is defined as “duration”, or when our ability to estimate durations is explained by resorting to the notion of an internal clock). Some detailed examples of circularity in the analysis of time are given here and examined. A way out of circularity is then given: it is represented by the proposal of attentional semantics (AS) of considering words and their meanings in terms of the aim they serve, and the means and processes developed and implemented in order to achieve that aim. According to AS, the main aim of words is that of indicating to, and eliciting in, the listener or reader a specific conscious experience: namely, the conscious experience referred to by their meanings. Words achieve their main aim by conveying the condensed instructions on the attentional operations one has to perform if one wants to consciously experience what is expressed through and by them. By describing the conscious experiences elicited by words in terms of the attentional operations that are responsible for the production of such conscious experiences, AS offers an a-linguistic counterpart to language, and therefore an effective way out of circularity. Following in footsteps of Mach (Contributions to the analysis of the sensations, 1890), but slightly revising his hypothesis, AS defines time-sensation as the perception of the effort made, or alternatively the nervous energy expended, by the organ of attention when performing a “temporal activity” (for instance, estimating duration), that is, when one’s own attention is focused in a continuous and incremental way on the conscious product of the (“non-temporal”) activity performed by means of another portion of one’s attention.

Processing efficiency in preschoolers’ memory span: Individual differences related to age and anxiety

In self-paced auditory memory span tasks, the microanalysis of response timing measures represents a developmentally sensitive measure, providing insights into the development of distinct processing rates during recall performance. The current study first examined the effects of age and trait anxiety on span accuracy (effectiveness) and response timing (efficiency) measures from word and digit span performance in a preschool sample (N = 76, mean age = 57 months, SD = 11). Children were reassessed 8 months later using the same two tasks plus a test of nonword memory span and a measure of articulation rate. The results at the second time point (T2) confirmed the effects of age on both processing effectiveness and efficiency. Trait anxiety was an additional negative predictor of span effectiveness (especially for digit span) and efficiency (in the case of word and nonword span). The findings are discussed in the context of factors contributing to early short-term memory development and attentional control theory.     

Dream rebound of suppressed emotional thoughts: the influence of cognitive load

Initial evidence suggests that suppressing a thought prior to sleep results in subsequent dreaming of that thought. The present research examined the influence of cognitive load on dreaming following suppression. In Experiment 1, 100 participants received either a suppression instruction or no instruction for an intrusive thought prior to sleep, and subsequently completed a dream diary. Participants instructed to suppress reported dreaming about the target thought more than controls; dream rebound was predicted by poorer performance on a working memory task. In Experiment 2, 126 participants received either a suppression instruction or no instruction for an intrusive thought prior to sleep, and half of participants also had cognitive load of learning a 9-digit number. Participants receiving the suppression instruction under cognitive load reported greater dream rebound than other participants. These findings indicate that thought suppression prior to sleep leads to dream rebound, and this effect is enhanced by cognitive load.     

Individuals differ in the attentional blink: Mental speed and intra-subject stability matter

The failure to correctly report two targets (“T₁”, “T₂”) that follow each other in close temporal proximity has been called the “attentional blink” (AB). The AB has, so far, mainly been studied using experimental approaches. The present studies investigated individual differences in AB performance, revealing (among further findings) a high positive correlation between the accuracies of detecting the two targets correctly (r = 0.69); and between T₂∣T₁ accuracy and psychometric intelligence (0.41 ≤ r ≤ 0.43) and RT variability in short-term and working memory (− 0.38 ≤ r ≤ − 0.45). Together, these results support important aspects of major theoretical accounts of the AB from an individual differences perspective and introduce intelligence and intra-subject stability as contributing factors in AB performance.     

Processing spatial relations with different apertures of attention

Neuropsychological studies suggest the existence of lateralized networks that represent categorical and coordinate types of spatial information. In addition, studies with neural networks have shown that they encode more effectively categorical spatial judgments or coordinate spatial judgments, if their input is based, respectively, on units with relatively small, nonoverlapping receptive fields, as opposed to units with relatively large, overlapping receptive fields. These findings leave open the question of whether interactive processes between spatial detectors and types of spatial relations can be modulated by spatial attention. We hypothesized that spreading the attention window to encompass an area that includes two objects promotes coordinate spatial relations, based on coarse coding by large, overlapping, receptive fields. In contrast, narrowing attention to encompass an area that includes only one of the objects benefits categorical spatial relations, by effectively parsing space. By use of a cueing procedure, the spatial attention window was manipulated to select regions of differing areas. As predicted, when the attention window was large, coordinate spatial transformations were noticed faster than categorical transformations; in contrast, when the attention window was relatively smaller, categorical spatial transformations were noticed faster than coordinate transformations. Another novel finding was that coordinate changes were noticed faster when cueing an area that included both objects as well as the empty space between them than when simultaneously cueing both areas including the objects while leaving the gap between them uncued.     

The effect of attention modification with explicit vs. minimal instructions on worry

In this experiment we investigated the effect of different instructions on the modification of attentional biases, and subsequently on worry persistence. Participants without excessive worry completed a modified dot-probe task, designed to train attention either to threat or neutral words. Half of each group was given explicit instructions regarding the relationship between word valence and target location, and half were given the more usual minimal instructions. Impact on worry persistence was assessed by categorizing the valence of thought intrusions before and after a period of instructed worry. Response latencies to test items on the dot-probe task showed that attention had been successfully manipulated in the expected direction, and explicit instructions led to more effective attention modification. Moreover, participants in the attend-threat group who received explicit instructions reported significantly more negative thought intrusions following instructed worry, as rated by an assessor, whereas participants in the attend-neutral group did not. These findings suggest that an attentional bias towards threatening information plays a role in worry persistence, and that explicit instructions may be helpful in modifying this bias.     

超文本阅读绩效研究述评——认知的视角

网络不同于传统媒介的最大特点是以灵活的超文本形式呈现信息,超文本将关联的信息以网络状形式加以组织,读者可以通过链接从一个节点跳转到其他任何一个节点。本文回顾了超文本阅读的研究历程,指出目前这一领域研究存在的困境并试图寻找原因,在此基础上提出了今后研究的建议。     

Bimanual reaching across the hemispace: Which hand is yoked to which?

When both hands perform concurrent goal-directed reaches, they become yoked to one another. To investigate the direction of this coupling (i.e., which hand is yoked to which), the temporal dynamics of bimanual reaches were compared with equivalent-amplitude unimanual reaches. These reaches were to target pairs located on either the left or right sides of space; meaning that in the bimanual condition, one hand's contralateral (more difficult) reach accompanied by the other hand's ipsilateral (easier) reach. By comparing which hand's difficult reach was improved more by the presence of the other hand's easier ipsilateral reach, we were able to demonstrate asymmetries in the coupling. When the cost of bimanual reaching was controlled for the contralateral reaching left hand's performance was improved, suggesting that the left hand is yoked to the right during motor output. In contrast, the right hand showed the greatest improvements for contralateral reaching in terms of reaction time, pointing toward a dominant role for the left hand in the processes prior to movement onset. The results may point toward a mechanism for integrating the unitary system of attention with bimanual coordination.     

The effects of a concurrent task on human optimization and self control

Memory deficits have been shown to hamper decision making in a number of populations. In two experiments, participants were required to select one of three alternatives that varied in reinforcer amount and delay, and the effect of a concurrent task on a behavioral choice task that involved making either an impulsive, self-controlled, or optimal response was studied. The studies aimed to see whether or not individuals were capable of optimizing when confronted with a three-alternative choice paradigm, and if a concurrent task could induce over-selectivity toward a self-controlled, or impulsive, choice, rather than an optimal choice. Various factors which could possibly influence optimization were also explored. The results suggest that some, but not all, individuals are capable of optimizing in a three-alternative choice paradigm, especially when there is a great differential between reinforcement rates of optimal versus non-optimal behaviors. Participants with a concurrent task (continuously subtracting seven from a large number) displayed over-selectivity, evidenced by the high proportion of self-controlled responses.