年老化视觉空间注意等级效应脑机制的研究

目的：应用“提示-目标”的视觉实验范式，以汉字提示不同等级的搜索范围并设置干扰，通过事件相关电位技术研究视觉注意年老化脑机制。方法：用青年和老年人各16名为受试对象，背景由三个同心圆组成，提示为汉字“大”、“中”、“小”，刺激材料是随机选取的大写英文字母，组成3个同心圆圈。“T”为靶刺激，“T”不是唯一的，受试对象按照提示搜索提示范围上的靶刺激，忽略其它范围里的“T”。结果：随着提示等级的减小，两组反应时均加快，而早期ERP成分P1与N1波幅均增大，与青年组相比，老年组反应时更长，且后部P1显著增强和N1明显抑制，老年组前部P2成分亦受到显著抑制，这种抑制不仅表现在波幅上，还表现在波形的不规则和不稳定。结论：老年受试对象随任务的复杂度增加需要消耗更多的资源，与年老化的“复杂度效应”一致。老年组P2成分的显著抑制为首次发现，表明老年组受试对象对靶刺激的评估识别能力降低，提示年老化可能导致视觉空问注意的前脑区功能缺陷。     

θ节律串刺激对视觉空间注意的行为学及事件相关电位研究

目的:研究持续性θ节律串刺激(cTBS)对视觉空间注意障碍的作用机制.方法:将30例正常受试者随机分为实验组(刺激组)和对照组(假刺激组),两组经过TBS刺激后进行事件相关电位(ERP)实验,实验范式为“提示一靶”,包括范围提示和汉字提示,范围提示为“大”圈和“小”圈,汉字提示为“大”字和“小”字.TBS刺激参数频率为30Hz,刺激强度为刺激器输出的50％,刺激部位为受试者右侧大脑的顶叶后部(P4),刺激脉冲801串,刺激间隔100ms.结果:实验组和对照组在汉字提示和范围提示时,反应时表现出提示等级效应(P＜0.05).实验组与对照组比较,在汉字提示下P1、P2波幅明显低于对照组(P＜0.05),在范围提示下PO4部位的P1、N1、N2波幅明显低于对照组(P＜0.05).实验组汉字提示与范围提示比较,范围提示时P1、P2、N2波幅更大(P＜0.05);对照组汉字提示与范围提示比较,范围提示时P1、N1、P2波幅更大(P＜0.05).结论:对右侧顶后叶皮质(PPC)进行抑制性cTBS刺激,能够影响大脑皮质神经元兴奋性活动,尤其会影响对左侧靶目标的识别及加工.     

不同意识水平下视觉注意范围提示的事件相关电位研究

目的:采用“提示―目标”的视觉实验范式,通过事件相关电位(ERP)研究在不同意识水平下,视觉空间注意范围的作用,以进一步了解提示引起视觉注意的脑机制。方法:被试者为18名在校大学生,以大、小2种不同直径的圆圈作为注意范围的区域性提示,让被试者完成视觉搜索任务,并记录反应时与ERP数据。结果:在短提示(40ms)条件下,随着提示等级的增大,反应时延长,早期成分的P1波幅增大,而N1波幅在小提示时最大,N2波幅也在小提示时最大;在长提示(150ms)条件下,结果相同。同时在大、小范围条件下,比较小提示与长提示两种提示条件,P1、N1成分均无显著性差异(P>0.05)。结论:40ms作为感觉阈限时,其提示信息的加工达到了注意范围信息的层次,其加工机制与长提示信息的加工机制相同,只是处于不同意识水平下的自动加工程度不同。     

应用Neuroscan脑电记录系统评价概念相似汉字与图片加工的事件相关电位差异

背景：已经证明大脑对具体的词和抽象的词处理方式是不一样的,许多事件相关电位实验证明脑对图片和文字的信息处理也是不同的。目的：以事件相关电位验证概念相似的汉字和图片在大脑中的处理模式是否相同。设计、时间及地点：2007-09/2008-01在蓝天学院信息技术研究所完成多刺激物的Oddball实验模式。受试者：被试为12名健康大学生,男生8名,女生4名,平均年龄22岁。刺激材料包括5个物体图片和5个概念相关的中文词,出现概率均为10%。方法：一次实验全过程包含2个子实验,在实验1中,以图片为靶刺激,相关的中文词作为相关非靶刺激,其他的为非靶刺激;而在实验2中将中文词作为靶刺激,相关的图片作为相关非靶刺激。采用心理数数的方式计算靶刺激,通过Neuroscan脑电记录系统进行诱发电位的采集、放大和处理。主要观察指标：受试者对靶刺激和非靶刺激是否会产生P300,以及P300的波幅。结果：实验1中靶刺激诱发出明显的P300,相关非靶刺激和其他非靶刺激未能诱发明显的P300。实验2靶刺激和相关非靶刺激都诱发出明显的P300,尽管相关非靶刺激诱发的波幅比较小,其他非靶刺激未能诱发P300。结论：2个实验出现不同的效果表明有概念联系的图片和中文词在大脑中存在不同的处理模式。     

经颅直流电刺激对脑卒中视觉空间忽略患者视运动探查功能的影响

摘要 目的：观察阳极经颅直流电刺激作用于右侧后顶叶皮质对右侧脑卒中后左侧视觉空间忽略患者视运动探查功能表现的影响。 方法：研究纳入20例右侧脑卒中后左侧视觉空间忽略患者,分为治疗组和对照组：治疗组（n=10）行经颅直流电刺激联合常规康复治疗;对照组（n=10）行常规康复治疗。治疗前、治疗后予以不同注意需求的视运动探查任务评估：单纯搜索目标（线段删除）、对不同搜索目标进行不同标记（缺口探查）、从干扰刺激中搜索目标（星星删除）。 结果：治疗组线段删除得分较治疗前有改善,左侧缺口圆判断错误率、星星删除遗漏率有所减低,且差异均有显著性意义（P＜0.05）;而对照组较基线水平相比差异无显著性意义（P＞0.05）;治疗后两组间线段删除、缺口探查未标记目标百分比及左侧缺口率差异有显著性意义（P＜0.05）,但星星删除差异无显著性意义（P＞0.05）。 结论：阳极经颅直流电刺激作用于右侧后顶叶皮质对不同注意加工需求的视运动探查任务影响不同,经颅直流电刺激对单纯目标搜索功能的改善和以目标物自身为参考框架成分加工的改善有促进作用。     

多目标注意追踪的干扰效应

背景：由于在研究技术、实验方法和实验条件控制等方面的困难,视觉动态信息加工的研究相对较少.而在实际生活中,视觉接受的大部分信息是动态变化的,所以,对动态视觉信息加工的研究不仅有助于对视觉信息加工机制有更全面的了解,而且对实际工作与生活中自然、高效的人机界面的设计以及特殊专业领域的人员选拔都有重要的理论和应用价值.目的：通过注意追踪的研究范式考察了分心刺激的数量、颜色和形状特征变化对多目标注意追踪的影响.设计：采用2&;#215;3&;#215;2的被试内设计,被试为在读本科生.单位：北京师范大学心理学院.对象：实验于2003-04在北京师范大学心理学院实验室完成.选择北京师范大学24名大学生,其中男生11名,女生13名,年龄17～25岁,视力或矫正视力正常,颜色知觉正常.方法：①实验仪器为PIV2.0计算机,显示器为Founder17英寸平面显示器.实验采用多目标追踪实验程序,被试通过键盘进行反应实验材料为“日”字形的字符.“日”字的数量分别是5和9及13个.不同数量的“日”字经过3 s的随机运动,最后变成字母H和P及.实验采用的3个自变量分别是：分心物的数量（2,6和10个3个水平）,分心物与目标的颜色（一致和不一致两个水平）,分心物和目标的形状变化（变化一致P/P或q/q,变化不一致H/P或H/q）.②对测试结果的统计分析采用三因素重复测量的方差分析和多重比较分析及配对T检验.主要观察指标：被试者按键反应时和正确率.结果：被试24名均进入结果分析.①三因素重复测量的方差分析显示,分心物数量变化的主效应达到了显著水平[F1（1,22）=6.040,P＜0.05],当目标与分心物形状不一致/颜色一致时,分心物数量变化对目标识别速度的主效应达到了显著水平[F（1,23）=9.965,P＜0.01].多重比较结果表明,分心物从2个增加到10个时的结果差异显著（RT10-RT2=109 m,P＜0.01;RT10-RT6=69 m,P＜0.05,单侧检验）,这也表明分心物数量增加对目标识别产生了一定的干扰效应.②当分心物为2和10个时,无论颜色一致与否,被试对目标识别的反应速度均未达到显著水平,这说明分心物数量很少和很多时对目标注意追踪与识别的影响不明显;而当分心物数量为6个时,无论目标与分心物颜色是否一致,被试对与分心物形状不一致的目标的反应速度均显著快于形状一致的情况（T颜色一致=1.926;T颜色不一致=2.044,＜0.05,单侧检验）,这说明在分心物为6个时,分心物形状特征对目标识别造成了显著的干扰效应.颜色一致性主效应不显著.这说明在分心物颜色变化对目标识别没有显著干扰效应.结论：①分心物数量增加及其形状与目标的一致性对被试追踪和识别目标产生了一定影响.当目标与分心物形状和颜色均不一致时,分心物没有表现出干扰效应.②当目标与分心物空间特征（形状）一致时,无论颜色一致与否,分心物没有对目标追踪和识别造成干扰效应.③目标与分心物形状不一致时表现出了明显的干扰效应;但颜色一致时对目标识别没有显著的影响.     

老年期精神病性抑郁患者听觉诱发电位P300特征

背景：听觉诱发电位P300是评价个体认知功能客观的电生理指标。应用听觉诱发电位P300探讨老年期精神病性抑郁患者认知功能损害的特征具有可靠性。目的：探讨老年期精神病性抑郁患者听觉诱发电位P300的特征。设计：以病例为观察对象的配对设计探索性观察。对象：于2002-01／2003-10选择河南省精神病医院抑郁症患者60例为观察对象。具有精神病症状患者21例为实验组1，无精神病症状患者39例为实验组2。对照组选择与实验组在年龄、性别上相匹配且无精神疾病阳性家族史的健康者60例。对照组样本来自河南省精神病医院退休人员及患者家属。与实验组1相匹配的21人为对照组1；与实验组2相匹配的39人为对照组2。方法：应用配对设计，对60例老年期抑郁症患者采用诱发电位系统完成听觉诱发电位P300检测。应用丹麦ECI公司针状电极。电极位置参照国际脑电图学会10／20标准，记录电极置于中央中线Cz点，参考电极置于右耳M2点，前额FPz点接地，电极间阻抗小于5K，分析时间为1000ms。被检者接受双耳的短音刺激，刺激频率为1次／s，刺激持续时间10ms，灵敏度为5μV，带通低频滤波0．1Hz，高频滤波50Hz，叠加200次。采用两套触发和刺激系统、两个完全独立的时间窗口来进行听觉诱发电位P300检测。非靶刺激（NT）强度为85dB，频率为1000Hz，占80％。靶刺激（T）频率为2OOHDHz，强度为95dB，随机出现，串插在非靶刺激中，占20％。两者次序关系的范例如下：NT NT NT T NT NT NT NT T T NT NT NT NT NT T NT NT NT。受试者对靶刺激作按键反应，每例重复两次，取平均值。主要观察指标：①靶刺激N1，P2，N2，P3潜伏期及波幅。②反应时间：结果：实验组1及实验组2听觉诱发电位P300，P2，N2，P3潜伏期、反应时间分别比对照组明显延长，P2，N2，P3波幅分别比对照组明显降低（P〈0.02及P〈0.01）。实验组1P3潜伏期及反应时间比实验组2明显延长（P〈0.01）。结论：听觉诱发电位P300对老年期抑郁症认知功能损害评定有一定意义。具有精神病性症状与无精神病性症状的老年期抑郁症P300改变的特征不十分一致，提示精神病性症状加重老年期抑郁症患者认知功能的损害。     

抑郁患者自我注意的功能性MRI初步探讨

目的：研究抑郁患者自我注意的大脑皮层功能变化,探讨自我注意是否与抑郁情绪相关。方法：选取8名抑郁患者和9名健康志愿者进行fMRI。采用BOLD组块设计,受试者接受与自我注意相关的3种任务刺激,原始数据经SPM8脑功能MR软件包处理,获得受试者的脑激活图,并进行对照研究,分析抑郁患者和健康志愿者脑激活空间分布的差异。结果：三种靶刺激条件下,抑郁患者比正常志愿者均存在较多激活脑区。抑郁患者在“我”靶刺激条件下脑区激活显著多于“*”和“他”靶刺激条件。结论：抑郁患者可能存在自我注意偏向,抑郁情绪可能与自我注意相关。     

左侧空间忽略患者关联性注意捕捉效应的研究

目的:探讨脑损伤后致左侧空间忽略患者的注意捕捉效应。方法:本研究对右侧大脑半球损伤伴左侧忽略的患者及健康被试各20例,分别进行神经心理学背景测试及关联性注意捕捉效应测试,观察左侧空间忽略患者与健康被试之间注意捕捉效应的差异,分析影响关联性注意捕捉效应强度的因素。结果:①与健康对照组相比,左侧空间忽略组的数字捕捉正确率明显降低(P<0.01)。②健康对照组:无论干扰刺激颜色与目标刺激颜色是否一致,左侧视野出现干扰刺激时的数字捕捉正确率均明显低于右侧视野出现干扰刺激时(P<0.01);无论干扰刺激在目标刺激的左侧或右侧,当干扰刺激颜色与目标刺激颜色一致时,数字捕捉正确率低于干扰刺激颜色与目标刺激颜色不一致时(P<0.01,0.05)。③左侧空间忽略组:无论干扰刺激颜色与目标刺激颜色是否一致,右侧视野出现干扰刺激时的数字捕捉正确率均低于左侧视野出现干扰刺激时(P<0.05);左侧视野出现的干扰刺激颜色与目标刺激颜色一致或不一致时,对数字捕捉正确率的影响差异无统计学意义,而右侧视野出现的干扰刺激颜色与目标刺激颜色一致时,数字捕捉正确率低于颜色不一致时(P<0.05)。结论:左侧空间忽略患者的注意功能下降,但无论对于健康受试者或者左侧空间忽略患者,符合目标刺激颜色特征的干扰刺激均能够增强非随意性地注意捕捉效应。     

执行37分钟听觉Odd-ball任务中事件相关电位变化与注意的关系

背景:许多报道只是分别观察了执行Oddball任务完成过程中事件相关电位各成分的变化,没有结合实验任务模式全面分析各成分的变化及其可能存在的内在联系.目的:通过测定健康人在执行连续37 min听觉辨别Odd-ball任务过程中的事件相关电位,分析事件相关电位各成分的变化特征与注意的关系.设计、时间及地点:经典的37 min持续Oddball听觉辨别任务及盲法评估试验,于2003-04/2007-07在日本北九州产业医科大学康复科完成.对象:20名健康在读大学生,全部为右利手,试验前所有学生均签署知情同意书.方法:在执行任务过程中,学生观察以10%的概率出现的2 kHz短音靶刺激,靶刺激是随机分布于以90%的概率出现的1 kHz短音非靶刺激之间,全部实验过程为37 min,包括1 214个声音刺激.前4 min为练习阶段,让学生熟悉任务,之后开始真正的实验过程,将其划分为阶段1,阶段2,阶段3,每阶段为10.9分.主要观察指标:在额叶、顶叶和额顶中点采集靶刺激和非靶刺激的事件相关电位,非靶刺激包括靶刺激之前第1个和之后第1个非靶刺激的事件相关电位.除了用传统的平均加权法进行研究外,同时进行了单次P3成分分析.实验结束后,所有学生填写问卷,要求填写在各个实验阶段中的主观感受包括他们的清醒度、注意程度和对实验的兴趣程度等.结果:①各反应电位在不同实验阶段的变化:靶刺激之前第1个非靶刺激的事件相关电位的N1波幅、靶刺激N2的波幅及靶刺激P3的波幅在实验的不同阶段发生显著变化.②不同反应电位之间的比较:靶刺激之前第1个非靶刺激的事件相关电位的N1波幅显著小于靶刺激之后第1个非靶刺激的事件相关电何和靶刺激的N1(实验阶段2、3的额叶、额顶中点和顶叶):靶刺激之前第1个非靶刺激的事件相关电位的P2潜伏期显著小于靶刺激之后第1个非靶刺激的事件相关电位的P2潜伏期(实验阶段2的额叶、额顶中点和顶叶位置七和实验阶段3的额叶);靶刺激之前第1个非靶刺激的事件相关电位的P2的波幅显著小于靶刺激之后第1个非靶刺激的事件相关电位的P2波幅(实验阶段2的额顶中点、在实验阶段3的额叶、额顶中点和项叶);认知电位变化最敏感区在额叶.③总的平均加权的靶刺激之前第1个非靶刺激的事件相关电位波形.有正负(N1-P2)波峰复合波形,而且在刺激启动后300 ms回到摹线水平,而总平均加权的靶刺激之后第1个非靶刺激的事件相关电位波形的正负(N1-P2)复合波峰的连续负波在刺激启动后450 ms之后回到基线水平(额叶和额顶中点).④事件相关电位的单次分析显示类型2(非 P3成分)出现的百分率在额叶位置上显著大于在顶叶位置(实验阶段1,2和3);类型2出现的百分率在实验阶段3的显著大于在实验阶段1(额叶和额顶中点).⑤在各个实验阶段中,反应时间差异无显著性意义.⑥根据问卷调查,所有的被测试者均认为试验任务非常简单.测试早期处于紧张、全神贯注的状态,随着试验的进展感到轻松、单调和机械化的完成任务,注意力时有分散,但未在测试过程中入睡.结论:在执行37 min听觉辨别任务过程中,事件相关电位各成分的变化是认知调整的结果,各成分的变化存在内在的联系,推测这种变化与被检者适应过程有关,并直接反映注意不同因素的影响.     

Critical care cardiovascular nurse expert and novice diagnostic cue utilization

AIM: Critical care cardiovascular (CCCV) nursing diagnostic expertise was the focus of this research. The purpose of the study was to compare diagnostic cue utilization between expert and novice CCCV nurses. BACKGROUND: Knowledge related to objective measures of clinical nursing diagnostic expertise would enhance effective and efficient recognition, utilization, and reward of clinical expertise. METHODS: Five CCCV written simulations served as instruments in the study. Diagnostic content areas included left ventricular dysfunction, cardiac tamponade, sepsis, right ventricular failure, and hypovolemia related to internal abdominal haemorrhage. The sample was composed of 23 expert and 23 novice nurses. After reading each simulation, subjects were asked to verbally recall the simulation, give an impression of the predominant problem or diagnosis, and give a diagnostic explanation. Verbal recalls were audio-taped for protocol analysis. Diagnostic accuracy and cue utilization were determined through comparisons of subjects' recalled diagnoses and cues with results from an expert panel review consensus. The major variable was the mean recalled proportion of highly relevant cues to total cues (HRC/TC) on accurately diagnosed simulations. Chi-square analysis revealed that diagnostic accuracy was greater with experts than with novices. Differences between and among simulations, expertise, accuracy and the mean proportion of highly relevant cues to total cues were examined with a 4 x 2 x 2 factorial analysis of variance. RESULTS: When considering all accurately diagnosed simulations, experts had a higher HRC/TC than novices. The major limitations were the use of low fidelity written simulations and virgin verbal protocol methods. CONCLUSION: The findings generally support the idea that the development of diagnostic expertise is associated with the ability to focus on highly relevant cues.     

Left and right occipital cortices differ in their response to spatial cueing

We investigated cue and target-related laterality effects with event-related fMRI. Both left and right occipital areas responded maximally when both cue and target were presented in the contralateral visual hemifield (VF), and minimally when cue and target were presented in the ipsilateral VF. However, whereas signal increases in right ventromedial and lateral occipital cortex were intermediate in those trials in which the cue appeared in the VF contralateral to the target (invalid cue trials), signal strength in left occipital cortex was almost identical for valid and invalid cues, i.e., high for RVF cues, and low for LVF cues, independent of the VF of the target. These data support theories which postulate a greater ability of the right hemisphere for bilateral processing. However, these laterality effects were observed earlier in the visual pathway than previously thought, leading to the question whether the hemispheric differences observed in occipital cortex are generated in the activated areas or are the effect of reentrant processes from more anterior areas, potentially in parietal cortex.     

From cue to meaning: Brain mechanisms supporting the construction of expectations of pain

The brain mechanisms by which sensory cues become transformed into expectations of impending events are a critical component of cognitive tuning of sensory processing. However, distinctions among the afferent processing of cue-related activity itself versus those mechanisms supporting the contextual meaning imparted to the cue remain limited. Do sensory cues with equal meaning engage similar patterns of brain activations even if they are delivered in separate modalities? To address this question, we used functional magnetic resonance imaging of an expectation paradigm in which cues were delivered with visual or innocuous thermal stimuli. Cues were designed to be highly meaningful because they predicted the delivery of high and low painful stimuli. As expected, the cues themselves activated unimodal sensory cortices. This cue modality-specific activation was transformed into a pattern of activity reflecting cue meaning. Cues signaling high pain produced greater activity in the left dorsolateral prefrontal cortex and anterior cingulate cortex. Such activity is consistent with the graded encoding of the magnitude of expected pain. In contrast, cues signaling low pain produced greater activity in the right intraparietal sulcus. This activation may reflect processes directing spatial attention to the stimulated body region in order to more accurately evaluate the relatively weak, low pain stimulus. Taken together, these findings indicate that cues arising from different sensory modalities ultimately engage common brain mechanisms that reflect the meaning of the cue. This meaning-related activity is presumably critical for preparing sensory systems to optimally process afferent information.     

Facilitating Effect of Grapheme and Syllable Cues on the Writing Performance of Children with Chinese Dictation Difficulties

Spelling difficulties is referred to as dictation difficulties in China. The visual-auditory binding deficit hypothesis suggested that Chinese dictation difficulties can be correlated with deficits in binding visual and auditory information. However, how Chinese characters are mentally represented in children with dictation difficulties remained unexplored. In this study, 20 children with dictation difficulties and 18 chronically age-matched controls completed dictation tasks using grapheme cues, syllable cues, and grapheme-syllable cues. Dictation accuracy was recorded. Findings showed that under the grapheme cue condition, dictation accuracy between the two groups did not differ significantly; under the grapheme-syllable and the syllable condition, dictation accuracy in children with dictation difficulties was significantly lower compared to controls. These findings supported that the graphemic and phonological representations of Chinese characters might loosely associated in the mental lexicon of children with dictation difficulties. Intervention strategies should take into account improving their ability to associate graphemes and syllables of Chinese characters.

     

The influence of stimulus cue on the initiation of stepping in young and older adults

OBJECTIVES: To investigate the influence of different reaction stimulus cues on the characteristics of ground reaction forces during the initiation of rapid forward stepping, and to determine whether age-related differences in step initiation are influenced by the type of stimulus cue used to trigger stepping. DESIGN: Case-control study. SETTING: University-based research laboratory. PARTICIPANTS: Fifteen healthy younger adults and 35 community-dwelling older adult volunteers. MAIN OUTCOME MEASURES: Subjects performed forward step initiation in response to 3 different reaction stimulus cues (light, sound, electrocutaneous) during simple reaction-time conditions. Ground reaction force data were collected and used to characterize the timing and magnitude features of the postural (weight-transfer) and step components. RESULTS: In comparison with the light and sound stimuli, the nonnoxious electrocutaneous trigger cue was associated with an increase in the magnitude of the initial displacement of the center of pressure (COP) in the mediolateral direction. Overall, older subjects were slower to initiate the postural and step components, and displayed a reduction in the initial posterior displacement of the COP. CONCLUSIONS: The postural component for lateral weight transfer was augmented by the electrocutaneous trigger cue, suggesting its potential to enhance step initiation among clinical populations. Age-related changes in stepping were unaffected by the type of stimulus cue, but the older group had a slower response initiation time and less forward propulsion. The abilities of many older persons may be compromised in situations where rapid adjustments in the base of support through stepping are triggered by environmental stimuli.     

Implicit learning in children with and without developmental coordination disorder.

OBJECTIVE: The ability to use perceptual cues within the environment to guide movement accurately can be acquired implicitly in that skill may increase while the learner is not consciously aware of what cues are being used. In this study, the implicit learning capabilities of children with and without developmental coordination disorder were compared. METHOD: Twenty-two children (11 with developmental coordination disorder, 11 without the disorder) played a computer game where they "caught" a descending ball image with a paddle on the screen. The dependent variable was accuracy of catch, as measured by the score on the computer game. On training trials, a visual cue appeared 50% of the time that signaled the direction of the ball. On probe trials, the visual cue was false. After completing the task, the children were interviewed about their conscious awareness of the cue. A mixed factorial analysis of variance (ANOVA) was used to analyze the data for group comparisons. RESULTS: Of the 22 children, only 6 indicated that they were aware of the cue. A mixed factorial ANOVA was significant for greater error when the visual cue was false, F(11.12, 22.49) = 27.27, p = .000, indicating that the children responded to the cue. No difference was found between groups in game performance. CONCLUSION: Children with developmental coordination disorder in this study were able to implicitly recognize and use a perceptual cue to enhance their performance on a computer game. Strategies that foster implicit learning may be relevant to occupational therapy intervention.     

Cortical competition during language discrimination

How do human listeners differentiate one language from another? In this study we examine the contributions of acoustic and linguistic cues to successful language discrimination. In particular, we report findings that reveal patterns of cortical competition as a function of the competition between prosodic, phonological, and lexical semantic information during language discrimination. We manipulated four types of stimuli in the listening environment: synthesized speech with rhythmic information, synthesized speech with rhythmic plus intonational information, natural speech from Japanese and Italian, and natural speech from Chinese and English. Our study shows that, depending on the amount and the kind of cues available, the listener recruits different areas of the brain for the same language task. Furthermore, brain activations do not monotonically multiply as a function of the complexity of the cues available, but are the outcomes of cue competition as a function of cue validity for the discrimination task. These findings show how acoustic and linguistic cues lead to cortical competition and how cortical activities adapt to the task demand for successful information processing.     

Different time courses of Stroop and Garner effects in perception — An Event-Related Potentials Study

Visual integration between target and irrelevant features leads to effects of irrelevant feature congruency (Stroop) or variation (Garner) on target classification performance. Presenting closed geometrical shapes as stimuli, we obtained Stroop and Garner effects of one part of their contour on another, in response times and error rates. The correlates of these effects in brain activity were observed in event-related potentials (ERP). Stroop effects occurred in ERP amplitude of the N1 and N2 components, starting about 170 ms after stimulus onset; Garner effects occurred in amplitude of the rising part of the P3 component, starting about 330 ms after stimulus onset. A subsequent point-wise analysis of Stroop and Garner effects in ERP showed that they belong to different, cascaded processing stages. The difference in time course between Stroop and Garner effects in ERP is in accordance with the view that both are produced by different mechanisms, the former sensitive to interference within presentations and the latter sensitive to interference between presentations. The brief interval of 330–370 ms after stimulus onset when these two mechanisms overlap may correspond to the central processing bottleneck, responsible for the combinations of Stroop and Garner effects generally found in response times.     

Contributions of the hippocampus and the striatum to simple association and frequency-based learning

Using fMRI and a learning paradigm, this study examined the independent contributions of the hippocampus and striatum to simple association and frequency-based learning. We scanned 10 right-handed young adult subjects using a spiral in/out sequence on a GE 3.0 T scanner during performance of the learning paradigm. The paradigm consisted of 2 cues that predicted each of 3 targets with varying probabilities. Simultaneously, we varied the frequency with which each target was presented throughout the task, independent of cue associations. Subjects had shorter response latencies to frequently occurring and highly associated target stimuli and longer response latencies to infrequent target stimuli, indicating learning. Imaging results showed increased caudate activity to infrequent relative to frequent targets and increased hippocampal activity to infrequent relative to frequent cue-target associations. This work provides evidence of different neural mechanisms underlying learning based on simple frequencies versus associations within a single paradigm.