THE EPIC OF PERSONAL DEVELOPMENT AND THE MYSTERY OF SMALL WORKING MEMORY

Abstract. A partial analogy exists between the lifespan neuropsychological development of individuals and the biological evolution of species: In both of these major categories of growth, progressive emergence of wholes transcends inherently limited part‐processes. The remarkably small purview of each moment of consciousness experienced by an individual may be a crucial aspect of maintaining organization in that individual's cognitive development, protecting it from combinatorial chaos. In this essay I summarize experimental psychology research showing that working memory capacity comprises the so‐called magical number 7±2 items, not only for words and digits but for spatial items and other sorts of cognitive materials, and not only in humans but also in other species. This is so to such an extent that 7±2 may be a “constant of nature.” The small quantity range 7±2 independent items, which builds upon a more elementary, instantaneous working memory capacity of three or four items, is surprisingly independent of the time duration of a cognitive task. Moreover, it is largely independent of ontogeny. Explanations of these powerful facts about working memory are offered here within both a functionalistic framework and a framework of hypothetical neural processes. At the neural level, working memory dynamics may comprise certain brain wave harmonics or topological relationships in the sheetlike cortex. Within the functionalistic framework, I suggest an additional analogy, pertaining to cultural evolution, with Tom Gilbert's work on risk analysis and “the global problematic” that follows from unforeseen consequences of the expansiveness of human ambition. Several connections are drawn with ideas presented by participants in the Chicago Religion and Science Group about how theologies and sciences try to understand the possibility of adaptive exercises of human freedom in the face of the extreme finiteness of each human individual.     

计时和计数的相似与差异

计时指判断时距的长短, 计数指辨别刺激呈现数目的多少。研究者发现计时和计数具有相似性, 表现在类似的基本原理, 对时间和数目的记忆都受到时间延迟的影响, 跨通道效应类似, 而且药物对它们的影响一致。模式控制模型认为计时和计数共享同一机制, 量值理论的观点是时间和数目等不同维度具有部分重叠的同一表征形式。计时和计数都激活了前额、顶叶、小脑等区域, 但两者在行为结果和激活的脑区上也有部分差异。计时和计数具有同一表征还是两者独立加工, 只在对比反应阶段存在共同机制仍需要进一步研究。     

Pre‐frontal‐insular‐cerebellar modifications correlate with disgust feeling blunting after subthalamic stimulation: A positron emission tomography study in Parkinson's disease

Subthalamic nucleus (STN) deep brain stimulation (DBS) has recently advanced our understanding of the major role played by this basal ganglion in human emotion. Research indicates that STN DBS can induce modifications in all components of emotion, and neuroimaging studies have shown that the metabolic modifications correlated with these emotional disturbances following surgery are both task‐ and sensory input‐dependent. Nevertheless, to date, these modifications have not been confirmed for all emotional components, notably subjective emotional experience, or feelings. To identify the neural network underlying the modification of feelings following STN DBS, we assessed 16 patients with Parkinson's disease before and after surgery, using both subjective assessments of emotional experience and ¹⁸[F]fluorodeoxyglucose positron emission tomography (¹⁸FDG‐PET). The patients viewed six film excerpts intended to elicit happy, angry, fearful, sad, disgusted, and neutral feelings, and they self‐rated the intensity of these feelings. After DBS, there was a significant reduction in the intensity of the disgust feeling. Correlations were observed between decreased disgust experience and cerebral glucose metabolism (FDG uptake) in the bilateral pre‐frontal cortices (orbitofrontal, dorsolateral, and inferior frontal gyri), bilateral insula, and right cerebellum. We suggest that the STN contributes to the synchronization process underlying the emergence of feelings.     

Contribution of the parafascicular nucleus in the spontaneous object recognition task

The parafascicular (PF) nucleus, a posterior component of the intralaminar nuclei of the thalamus, is considered to be an essential structure in the feedback systems of basal ganglia–thalamo-cortical circuits critically involved in cognitive processes. The specific role played by multimodal information encoded in PF neurons in learning and memory processes is still unclear. We conducted two experiments to investigate the role of the PF in the spontaneous object recognition (SOR) task. The behavioral effects of pretraining rats with bilateral lesions of PF with N-methyl-D-aspartate (NMDA) were compared to vehicle controls. In the first experiment, rats were tested on their ability to remember the association immediately after training trials and in the second experiment after a 24 h delay. Our findings provide evidence that PF lesions critically affect both SOR tests and support its role in that non-spatial form of relational memory.     

Septal area lesions impair spatial working memory in homing pigeons (Columba livia)

The septo-hippocampal system in birds resembles that of mammals, motivating research into the function of the avian hippocampus while surprisingly little attention has been given to the septum. To investigate a possible role of the avian septum in memory, the effects of septal area lesions on a spatial working memory (SpWM) task was tested in homing pigeons. After preoperative training on an analogue eight-arm (feeders) radial maze, now sham-operated control and septal lesioned pigeons were then trained again on the same task of locating the four feeders on the test phase of a trial that were not baited during the sample phase of a trial. During the test phase of a working memory trial, septal lesioned pigeons, compared to both their own preoperative performance and the performance of the controls, required significantly more choices to locate the four baited feeders not baited during the sample phase of a trial, and they made significantly fewer correct responses to the now baited feeders on their first four choices. The results demonstrate that, like its mammalian counterpart, the avian septum plays an important role in SpWM, suggesting that at least some functional properties of the septum are evolutionarily conserved in birds and mammals.     

大脑皮层-背侧纹状体通路在吗啡强迫性觅药和用药行为中的作用

药物成瘾是以强迫性觅药和用药行为为核心特征的慢性脑疾病。从初始用药到强迫性用药是成瘾者的觅药行为从目标导向性向习惯化发展的过程。强迫性觅药和用药行为是依赖于背外侧纹状体的习惯化行为, 同时前额叶皮层-背内侧纹状体通路对行为的控制减弱, 导致感觉运动皮层-背外侧纹状体通路对行为的控制持续占主导地位, 是成瘾行为具有强迫性特征的重要神经基础。本项目围绕这一重要问题展开研究, 在建立具有成瘾特征的动物模型的基础上, 采用行为学、行为药理学和组织形态学等方法揭示皮层-纹状体通路在强迫性觅药和用药行为中的作用。研究结果有望为进一步寻找该神经网络参与成瘾行为的分子机制提供重要线索。     

Primate prefrontal neurons encode the association of paired visual stimuli during the pair-association task

The prefrontal cortex (PFC) is known to contribute to memory processes such as encoding representations into long-term-memory (LTM) and retrieving these representations from LTM. However, the details of the PFC's contribution to LTM processes are not well known. To examine the characteristics of the PFC's contribution to LTM processes, we analyzed single-neuron activity while monkeys performed a pair-association (PA) task using 12 pairs of complex visual images. Among 60 neurons with sample-period activity, 32% showed the strongest and second-strongest sample-period activities when a particular pair of stimuli was presented (pair selectivity). In addition, the mean latency of sample-period activity was 138 ms in the PFC, which was longer than that observed in ITC neurons under bottom-up conditions, but shorter than that under top-down conditions. These results indicate that the PFC participates in encoding and retrieving information in LTM processes and that pair-selective sample-period activity might be a candidate for the top-down signal that the PFC provides to the ITC during the retrieval of information from LTM.     

Cognitive control of a simple mental image in patients with obsessive--compulsive disorder

The nature of obsessions has led researchers to try to determine if the main problem in obsessive-compulsive disorder (OCD) is impaired inhibitory control. Previous studies report that the effort to suppress is one of the factors that increase the frequency of obsessive thoughts. Based on these results and those of the present study that suggest inferior parietal lobe (IPL) abnormality in OCD and findings of a recent study that reported the importance of the right posterior parietal cortex in cognitive control of a simple mental image, the present cognitive control paradigm study aimed to determine whether there is a difference in brain dynamics between OCD patients and non-obsessive controls while performing tasks that necessitate cognitive control of a simple mental image, and whether the right posterior parietal region is one of the regions in which a difference in activity between the OCD patients and controls would be observed. Functional brain imaging was performed while the participants attempted to suppress, imagine, or manipulate a mental image. The general linear model showed that there was a main effect of group and main effect of task. Accordingly, in all contrasts (suppression minus free-imagination, erasing minus free-imagination, and imagination minus free-imagination), the right IPL, right posterior cingulate cortex, and right superior frontal gyrus activity were lower in the OCD patients than in the healthy controls. These results and the observed correlations between activity levels, and symptom and subjective performance scores are discussed. In conclusion, the results of the present study and those of previous studies suggest that the main problem in OCD might be difficulty activating the right frontoparietal networks during tasks that require cognitive control, which might result in the intrusiveness of obsessive thoughts.     

Parent-Child Engagement in Decision Making and the Development of Adolescent Affective Decision Capacity and Binge Drinking

The goal of this study was to investigate how parents’ engagement of their child in everyday decision-making influenced their adolescent’s development on two neuropsychological functions, namely, affective decision-making and working memory, and its effect on adolescent binge-drinking behavior.We conducted a longitudinal study of 192 Chinese adolescents. In 10th grade, the adolescents were tested for their affective decision-making ability using the Iowa Gambling Task (IGT) and working memory capacity using the Self-ordered Pointing Test (SOPT). Questionnaires were used to assess perceived parent-child engagement in decision-making, academic performance and drinking behavior. At one-year follow-up, the same neuropsychological tasks and questionnaires were repeated.Results indicate that working memory and academic performance were uninfluenced by parent-child engagement in decision-making. However, compared to adolescents whose parents made solitary decisions for them, adolescents engaged in everyday decision-making showed significant improvement on affective decision capacity and significantly less binge-drinking one year later.These findings suggest that parental engagement of children in everyday decision-making might foster the development of neurocognitive functioning relative to affective decision-making and reduce adolescent substance use behaviors.     

右腹外侧前额叶对高抑郁水平成年人社会情绪调节的作用：一项tDCS研究

已有的经颅直流电刺激(transcranial direct current stimulation, tDCS)研究证明, 右腹外侧前额叶(right ventrolateral prefrontal cortex, RVLPFC)是社会情绪调节的重要脑区, 激活RVLPFC可显著降低人们对社会性负性情绪体验的强度。社会功能受损是抑郁症患者或抑郁倾向人群的重要特征之一。该群体对社会排斥的敏感性高, 且对负性社会情绪体验的情绪调节能力降低。在本研究中, 我们采用外显的情绪调节任务, 研究了高、低抑郁水平的两组成年人被试在RVLPFC接受阳性tDCS后其情绪调节能力的改变。结果表明, 虽然采用tDCS激活RVLPFC可帮助被试通过情绪调节(认知重评)减弱负性情绪体验, 但高抑郁水平被试的负性情绪强度下降程度明显小于低抑郁水平被试。另外本文还发现, 与源于个人的负性情绪相比, tDCS效应对源于社会的负性情绪(即社会排斥)更强。本研究是采用电或磁刺激提高抑郁人群社会情绪调节能力的首次尝试。实验结果表明, 高抑郁水平成年人的RVLPFC仅通过单次、短时间(34 min)的tDCS激活, 其情绪调节能力并未得到显著提升。这提示对抑郁倾向群体或抑郁症患者的干预或治疗需要多次施加tDCS。