The cognitive significance of resonating neurons in the cerebral cortex

Most neural fibers of the cerebral cortex engage in electric signaling, but one particular fiber, the apical dendrite of the pyramidal neuron, specializes in electric resonating. This dendrite extends upward from somas of pyramidal neurons, the most numerous neurons of the cortex. The apical dendrite is embedded in a recurrent corticothalamic circuit that induces surges of electric current to move repeatedly down the dendrite. Narrow bandwidths of surge frequency (resonating) enable cortical circuits to use specific carrier frequencies, which isolate the processing of those circuits from other circuits. Resonating greatly enhances the intensity and duration of electrical activity of a neuron over a narrow frequency range, which underlies attention in its various modes. Within the minicolumn, separation of the central resonating circuit from the surrounding signal processing network separates “having” subjective impressions from “thinking about” them. Resonating neurons in the insular cortex apparently underlie cognitive impressions of feelings.     

创造性的生理研究新进展

创造性的生理基础很复杂。关于创造性生理基础的研究集中在大脑皮质激活与脑半球不对称两个方面。研究发现,大脑皮质激活状态对创造性有影响,低水平的皮质激活,特别是低水平的前额叶激活,较有利于创造性．研究还发现,创造性和左右半球不对称活动有关,处于创造状态时,右半球相对要比左半球激活程度更高。     

Differential effects of assisted cycling therapy on short-term and working memory of adolescents with Down syndrome

Persons with Down syndrome (DS) suffer from prefrontal cortex dysfunction and deficits in executive functions. The current study examined the effects assisted cycling therapy (ACT) on short-term (STM) and working memory (WM) in adolescents with DS. During ACT, the cadence of participants on a stationary bicycle was augmented with an electrical motor to 180% of the voluntary cadence. Participants completed eight weeks of ACT (n?=?17), eight weeks of voluntary cycling (VC) at their own preferred cadence (n?=?16), or eight weeks of no cycling (np?≥?.149) and working memory improved only in the ACT group (Hedge’s g?=?1.66; p?=?.003). The results indicate that assisted high-cadence cycling (i.e. ACT) produces superior neural benefits in the dorsolateral prefrontal cortex compared to VC.     

MRI对儿童难治性、局灶性癫痫的临床诊断及预后判断

癫痫外科的临床病理研究表明,儿童局灶性皮质发育不良(FCD)及海马硬化是儿童难治性局灶性癫痫常见的致病因素。但在术前的常规的MRI检查中,这些结构上的异常经常被忽视,从而造成延误诊断。临床医生在阅片判断上的失误可能是一个原因,但癫痫的影像专业知识的不全面是重要因素。本文结合MRI技术在癫痫临床诊断领域的应用进展,阐述了儿童难治性、局灶性癫痫患者MRI影像中可能出现的结构性病变;重点阐述了临床易于忽视的局灶性皮质发育不良(FCD)及海马硬化的MRI研究、应用进展。     

趋近和回避动机的区分及其对心理病理学的影响

趋近和回避是动机的两种最基本形式, 反映着个体与环境的相互作用方式, 是个体适应环境的核心机能。回避动机保证了个体的生存, 趋近动机则促进个体的成长。两类动机系统在前额叶皮层呈不对称偏侧化分布, 趋近动机与左侧额叶皮层激活相连, 回避动机与右侧额叶皮层激活相连。Youngstorm 和Izard等认为两类动机系统失调可能与一系列的情绪和行为问题有关, 如躁狂、抑郁、焦虑和儿童多动症等。这一观点已得到一些相关研究和临床研究证实。建议未来研究关注趋近-回避动机区分与情绪和认知功能研究的融合, 进一步检验趋近-回避动机系统失调模型, 并加强趋近和回避动机系统的可塑性研究。     

客体工作记忆任务中大脑皮层活动的记忆负荷效应

利用128导事件相关电位技术,采用延迟匹配任务的实验范式,测查了20名正常被试完成不同负荷客体任务时的皮层慢电位（slow cortical potentials,简称sp成分）,实验发现：背侧前额叶在刺激呈现后的700ms到1400ms出现记忆负荷效应,高负荷任务诱发的sp成分显著负于低负荷任务;低负荷任务诱发的sp成分在左前额区（500~1800ms）、左前额-中央区（700~1800ms）、左中央-顶叶区（1000~1400s和1800~4800ms）、右前额区（1800~4800ms）和右前额-中央区（1400~4800ms）显著负于高负荷任务,出现记忆负荷效应,但这种负荷效应在左右大脑半球所反映的心理意义可能不同     

An experimental analysis of social traps

Social traps, such as the overgrazing of pasturelands, overpopulation, and the extinction of species, are situations where individuals in a group respond for their own advantage in a manner damaging to the group. A laboratory analog was devised to simulate conditions that produce social traps. The traps were constructed by superimposing schedules of reinforcement. Single responses were followed by multiple consequences which were opposite in valence, with the negative consequence delayed. Subjects in groups of three could respond individually for points that applied toward class credit. Each ten presses of a button added one point to the subject's total and subtracted one point from a common pool. The pool was replenished with points at fixed rates. If subjects responded for points faster than the replenishment rates, the pool would empty and the experiment would terminate before subjects could accumulate maximum credit. In addition, the maximum pool size and the ability to communicate were varied. Main effects were found for both, which indicated the least effective resource management occurred when the pool was small and no communication allowed. An analysis of cumulative records showed differing response patterns across conditions.     

The temporal evolution of pre-stimulus slow cortical potentials is associated with an upcoming stimulus’ access to visual consciousness

Slow cortical potentials (SCPs) have been proposed to be essential for the formation of conscious experience. To examine their temporal characteristics, we recorded electroencephalography during a visual backward-masking task, which required participants to localize the missing part of a target stimulus. A subsequent confidence rating was used as a proxy for the target’s access to consciousness. Event-related potentials (ERPs) of all correct trials were determined relative to a brief period immediately before the target and then compared among consciousness levels. In an interval ranging from 2 s prior to target presentation up to this period, a negative relationship between slowly fluctuating ERP values and the level of consciousness became evident. After target presentation, high conscious awareness was characterized by an enhanced visual awareness negativity, an increased P3 component, and associated positive SCPs. Together, these findings add new evidence to the proposed role of SCPs in the emergence of visual consciousness.     

空间频率影响恐惧面孔表情加工的神经通路

恐惧情绪由于其具有威胁性而优先得到有效的加工。其中空间频率作为处理面孔信息的基础成分, 通过不同的神经通路影响恐惧面孔表情的加工。双通路观点认为在皮层下通路上, 低空间频率的恐惧面孔表情存在优先传递性, 高空间频率则主要通过皮层通路对恐惧面孔表情进行精细化加工; 而多通路则能够更加灵活地处理空间频率对情绪加工的影响。未来研究应明确脑区及其子区域在多条通路上的作用, 从而进一步验证视觉信息是如何影响情绪加工的。     

客体与空间工作记忆的分离：来自皮层慢电位的证据

利用128导事件相关电位技术,采用延迟匹配任务的实验范式,测查了16名正常被试在完成客体任务和空间任务时的皮层慢电位（slow cortical potentials,简称sp成分）,实验发现：在后部脑区,客体工作记忆与空间工作记忆在慢波活动的时间上存在分离,空间任务更早的诱发出负sp成分,并且空间任务激活更多的后部脑区;左下前额叶在客体工作记忆任务与空间工作记忆任务中都有激活,并且激活强度不存在显著差异;背侧前额叶主要负责客体信息的保持与复述,但左右背侧前额叶的激活强度存在不对称性。