左右半球在语篇理解中的协同作用

通过2例一侧颞叶损伤患者研究了一侧颞叶损伤及两侧半球的协同作用对语篇理解的影响,并探讨了发生此种影响的可能机制。结果表明一侧颞叶的损伤将导致患者语篇水平的理解障碍及语言推理能力的下降;提示语篇理解需双侧半球的协同作用,而推理能力下降可能是引发语篇理解障碍的原因之一。     

中等强度情绪性图片的神经机制——一项fMRI研究

采用修订后的中等唤起度的国际情绪图片为刺激材料,以12名女性大学生为被试,考察情绪性图片引起的脑激活模式。结果发现,与中性条件相比,消极情绪图片激活了枕叶、杏仁核、海马旁回和壳核。积极情绪图片引起枕叶、内侧眶额、额中回等脑区的激活,研究结果再次验证了杏仁核与消极情绪的密切关系,同时推测,内侧眶额可能是中等唤起度的趋近性积极情绪的一个脑功能区。     

Re-emergence of extinguished auditory-cued conditioned fear following a sub-conditioning procedure: effects of hippocampal and prefrontal tetanic stimulations

Post-extinction exposure of rats to a sub-conditioning procedure can evoke conditioned fear, which may correspond to fear return and/or fear learning potentiation. The aim of the present study was to clarify this issue and examine the effects of tetanic stimulation of the hippocampus (HPC) and medial prefrontal cortex (mPFC), two brain regions implicated in post-extinction modulation of conditioned fear. Rats were initially submitted to five tone-shock pairings with either a 0.7-mA or 0.1-mA shock. Tone-evoked freezing was observed only with the higher shock intensity, indicating that the 0.1-mA shock corresponded to a sub-conditioning procedure. All conditioned rats underwent fear extinction with 20 tone-alone trials. When retrained with the sub-conditioning procedure, they displayed again tone-evoked freezing, except when the initial tone was unpaired or a new tone was paired with the 0.1-mA shock, demonstrating fear return rather than fear learning potentiation. We also found that HPC and mPFC tetanic stimulations, applied 24h after the sub-conditioning procedure, similarly reduced this fear return. However, mPFC inactivation abolished temporary HPC tetanus effect, whereas HPC inactivation did not interfere with mPFC tetanus effect. These data confirm our previous findings and reveal the nature of HPC-mPFC interactions in post-extinction modulation of conditioned fear.     

粤语-普通话双言者和普通话单言者周期性时间推理比较

通过4个实验,考察粤-普双言者与普通话单言者周期性时间推理的差异。实验1和2表明,无论时间以5为单位、不以5为单位还是以“字”为单位,双言者反应时均显著长。实验3和4表明,当时间为以5为单位时,双言者与单言者均采用数字加工方式;当材料以“字”为单位时,双言者采用空间表象加工方式。     

Social brain development and the affective consequences of ostracism in adolescence

Recent structural and functional imaging studies have provided evidence for continued development of brain regions involved in social cognition during adolescence. In this paper, we review this rapidly expanding area of neuroscience and describe models of neurocognitive development that have emerged recently. One implication of these models is that neural development underlies commonly observed adolescent phenomena such as susceptibility to peer influence and sensitivity to peer rejection. Experimental behavioural evidence of rejection sensitivity in adolescence is currently sparse. Here, we describe a study that directly compared the affective consequences of an experimental ostracism manipulation (Cyberball) in female adolescents and adults. The ostracism condition led to significantly greater affective consequences in the adolescents compared with adults. This suggests that the ability to regulate distress resulting from ostracism continues to develop between adolescence and adulthood. The results are discussed in the context of models of neurocognitive development.     

The effect of attending to motor overflow on its voluntary inhibition in young and older adults

Motor overflow refers to involuntary movement or muscle activity coinciding with voluntary movement. We examined whether 16 young adults (18-30 years) and 16 older adults (50-80 years) could voluntarily inhibit overflow. Participants performed a finger pressing task, exerting 50% of their maximal force. Overflow was concurrently recorded in the non-task hand. In the first condition, participants were not made aware of their motor overflow. Then participants, though informed of it, were asked to ignore their overflow. Finally, participants were requested to inhibit overflow with, and then without visual feedback, or vice versa. Overflow was exacerbated when older adults were unaware of it, and was reduced once they were informed. For young adults there was no significant difference between these conditions. Both Age Groups could significantly reduce overflow when so requested, independent of visual feedback. Thus motor overflow can be modulated by higher order cognitive control with directed attention.     

时间距离、自我差异的自动激活与价值偏好

本研究对时间距离对自我差异的自动激活假说进行了检验。研究首先启动个体不同的时间自我知觉,然后利用评价性条件反射使先前激活的自我知觉中止,以检验对价值偏好的影响。结果证实了本研究的假设,当消极情绪词语和自我词语同时启动时,先前激活的自我知觉回落到未激活前的基线水平,并使得远期时间距离所引发的可能自我差异或近期时间距离所引发的当前自我差异减弱,从而导致价值偏好不再随时间线索发生系统改变。研究最后讨论了这一发现对自我调节研究的意义。     

一种对动物学习记忆能力突变筛查的新途

本文详细描述了一种全自动化的行为检测方案。在自然饲养环境/检测环境(24/7)中, 我们测量了小鼠针对两个给食器中获得食物的比例与它们在相应给食器停留时长的比例进行匹配的精确性与准确性。该方案是对传统条件性习得 (trials-to-acquisition) 行为测验设备的改进, 可以检测动物时间间隔能力的精确性与准确性, 对定时目标选择的相关概率的效果, 以及记忆一天中从不同给食器中获得食物次数的精确性与准确性。该压缩系统避免了在整个实验过程中对小鼠的持握操作, 可忽略实验者/技术员的实验操作时间, 而且可以递送小鼠置入实验环境后, 7~9个实验日中全部3组实验流程产生的大量结果。其中, 第一个实验流程为单个24小时周期内完成的时间匹配能力的筛查, 它对动物的时间、空间估计能力的记忆机制进行精确检测。因此, 该系统允许在有限的实验空间、较短的实验周期内, 对大量的实验小鼠进行有可能存在的学习记忆能力缺陷进行大规模筛查。此外, 该系统运行所依赖的软件可以在公共开放平台获得。