盲人的跨感觉通道重组

失去视觉的盲人往往伴随着行为代偿,如听觉和触觉能力的提高。脑成像等认知神经科学研究发现,盲人行为代偿的神经机制之一是大脑皮层的跨感觉通道重组,即盲人的视皮层并没有因为视觉剥夺而失去作用,而是广泛地参与了其他感知觉任务。原本暂时的神经联结由于受到新的感觉信息传入方式的持续激活而固化,从而形成新的神经回路,可能是此类跨通道重组的神经基础。     

猜谜作业中顿悟的ERP效应

采用事件相关电位(ERP)探索问题解决过程中顿悟的神经机制。以猜谜作业为实验程序,对“有顿悟”和“无顿悟”答案引发的脑电分别进行叠加和平均,并将二者相减（有顿悟-无顿悟）得到差异波。在250~500 ms “有顿悟”比“无顿悟”的ERP波形有一个更加负性的偏移,在差异波中,这个负成分的潜伏期约为380 ms（N380）。地形图和电流密度图显示,N380在额中央区活动最强。偶极子源定位分析结果显示,N380可能起源于扣带前回。因此,N380可能反映顿悟问题解决过程中思维定势的突破。     

大脑前扣带回皮层与执行功能

回顾了近期有关大脑前扣带回皮层（ACC）参与执行功能的研究资料。结果显示,ACC可以对正在进行的目标定向行为实施在线监控,在出现反应冲突或错误时提供信号,以便能及时调整与分配注意资源,因此可能是一个行为规划与执行的高级调控结构。这两年来的新发现提示,ACC的执行监控作用可能是基于动机与奖赏期待做出的对“意志行动”的整合性控制,并可能具有对行动结果的情绪评价意义。     

儿童执行功能与情绪调节

大脑执行功能是一种调节、控制、综合、分析个体心理过程和外显行为的认知神经机制。儿童的高级认知活动、社会性行为（同伴交往、攻击性行为）都受到执行功能发展水平的制约。研究者希望通过儿童执行功能的发展,了解整个执行系统的发展成熟过程,揭示执行控制机能的内在机制。同时,有研究者把执行控制这种认知神经机制和儿童的社会性行为包括自我控制、情绪调控等方面的发展结合起来研究,从中发现二者的联系。该文就这方面的核心问题以及研究成果进行了综述。     

On the emergence of modern humans

The emergence of modern humans with their extraordinary cognitive capacities is ascribed to a novel type of cognitive computational process (sustained non-routine multi-level operations) required for abstract projectuality, held to be the common denominator of the cognitive capacities specific to modern humans. A brain operation (latching) that allows this novel computational process is proposed as well as a physics-inspired mechanism that could explain its rather recent emergence without invoking unlikely genetic or structural changes.     

Ignition’s glow: Ultra-fast spread of global cortical activity accompanying local “ignitions” in visual cortex during conscious visual perception

Despite extensive research, the spatiotemporal span of neuronal activations associated with the emergence of a conscious percept is still debated. The debate can be formulated in the context of local vs. global models, emphasizing local activity in visual cortex vs. a global fronto-parietal “workspace” as the key mechanisms of conscious visual perception. These alternative models lead to differential predictions with regard to the precise magnitude, timing and anatomical spread of neuronal activity during conscious perception. Here we aimed to test a specific aspect of these predictions in which local and global models appear to differ – namely the extent to which fronto-parietal regions modulate their activity during task performance under similar perceptual states. So far the main experimental results relevant to this debate have been obtained from non-invasive methods and led to conflicting interpretations. Here we examined these alternative predictions through large-scale intracranial measurements (Electrocorticogram – ECoG) in 43 patients and 4445 recording sites. Both ERP and broadband high frequency (50–150 Hz – BHF) responses were examined through the entire cortex during a simple 1-back visual recognition memory task. Our results reveal short latency intense visual responses, localized first in early visual cortex followed (at ∼200 ms) by higher order visual areas, but failed to show significant delayed (300 ms) visual activations. By contrast, oddball image repeat events, linked to overt motor responses, were associated with a significant increase in a delayed (300 ms) peak of BHF power in fronto-parietal cortex. Comparing BHF responses with ERP revealed an additional peak in the ERP response – having a similar latency to the well-studied P3 scalp EEG response. Posterior and temporal regions demonstrated robust visual category selectivity. An unexpected observation was that high-order visual cortex responses were essentially concurrent (at ∼200 ms) with an ultra-fast spread of signals of lower magnitude that invaded selected sites throughout fronto-parietal cortical areas. Our results are compatible with local models in demonstrating a clear task-dependence of the 300 ms fronto-parietal activation. However, they also reveal a more global component of low-magnitude and poor content selectivity that rapidly spreads into fronto-parietal sites. The precise functional role of this global “glow” remains to be elucidated.     

Efficacy of neurostimulation to treat symptoms of Mal de Debarquement Syndrome. A preliminary study using repetitive transcranial magnetic stimulation

Mal de debarquement syndrome (MdDS) is a rare and poorly understood condition of perceived continual motion. Using a multiple‐case design (n = 13; 8 f; 63.5 ± 12.6 years), this study investigated the efficacy of eight 20‐min sessions, over 4 weeks, of repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral pre‐frontal cortex. Compared to sham, rTMS demonstrated improvement in balance and confidence in daily living activities. rTMS shows promise for the treatment of MdDS. However, larger trials with longer intervention periods are required.