1秒以上时距判断的ERP研究

以视觉呈现时距信号,采用时间泛化范式要求被试判断5种探测时距(1～4秒)与标准时距(2秒)之间的长度关系,并记录11名大学生在时距判断过程中的事件相关电位(ERP),继而探讨不同探测时距条件下CNV波幅特征变化以及左、右侧额叶在时距判断中的功能。结果发现:1秒、1.42秒以及2秒条件下,CNV波幅峰出现在探测时距结束点,2.84秒、4秒条件下,CNV波幅峰出现在大约2秒处(标准时距);CNV负性翻转至基线位置在1秒、1.42秒、2秒条件下随探测时距的增长而延后,而在2.84秒、4秒两种条件下无显著差异;左、右侧额叶处诱发的CNV波幅峰潜时在2.84秒、4秒探测时距条件下无显著差异,且均在2秒附近。这说明在1秒以上视时距判断中CNV波幅峰反映了基于记忆中标准时距的时距判断的决策过程;CNV负性翻转至基线位置与时距判断的决策阶段存在共变关系,CNV负性翻转至基线位置相当于负荷解脱过程中的一个由负翻正的转折点;左、右侧额叶均参与了时距脉冲累加过程。     

恐惧情绪面孔影响不同年龄个体时距知觉的研究

为证实相对中性面孔,恐惧面孔时距知觉会出现延长效应且不受年龄因素调节,本研究采用时距两分任务(400ms短标准时距和1600ms长标准时距)考察5岁组、8岁组及成年组被试的恐惧面孔和中性面孔时距知觉的表现。结果发现,对于所有被试,相比中性面孔,恐惧面孔时距两分任务心理物理函数偏左,两分点显著下降,且不受年龄因素调节。这意味着相对中性面孔,恐惧面孔时距知觉存在延长效应,且这种效应不受年龄因素调节。     

新颖性图像加工的时间进程

采用ERPs技术,考察了个体新颖性图像加工的时间进程。行为结果表明: 新颖性图像的判断时间更长。ERPs结果显示:新颖与非新颖图像在刺激呈现后190–340ms诱发出明显的前额区N190–340,但在波幅上无显著差异;在400–600ms以及600–1000ms,新颖性图像在顶区与额–中央区, 特别在右侧半球诱发出更大的正性偏移(P400–600和LPC)。研究表明: 图像新颖性属性的识别主要发生在涉及图像特征融合、图像记忆编码等多项认知活动参与的晚期加工阶段,并存在半球右侧化效应。     

聋生1秒以下与以上的视时距知觉研究

采用时距二分任务,探讨聋生在视觉通道的1s以下和1s以上时距知觉的特点。结果发现,在1s以下条件下,聋生时距判断准确性低于普通学生;聋生CNV峰值与LPCt波幅低于普通学生,CNV潜伏期短于普通学生,LPCt峰值潜伏期长于普通学生。在1s以上条件下,聋生时距判断准确性高于普通学生;聋生N1、P2、CNV与LPCt成分各项指标与普通学生均没有显著差异。这说明,听觉丧失损伤了聋生1s以下的时距记忆与决策过程,支持了普遍缺陷假设;但听觉丧失未对聋生1s以上时距加工产生显著影响,支持了感觉补偿机制。因此,时距长度在听觉丧失对视觉时距知觉的影响中具有调节作用,为时间认知的分段综合模型提供了新的支持证据。     

听觉经验缺失对时距估计影响的实验研究

采用复制法,通过聋人与听力正常人时距估计的对比实验研究,结果发现听觉经验缺失对时距估计有一定的影响：（1）两类被试在2000ms和10000ms的时距估计中,再现时距的平均数表现出了显著性差异。听力正常被试倾向于低估时距,聋人被试倾向于高估时距。（2）聋人被试不同时距再现相对误差率之间不存在显著性差异;听力正常被试时距再现相对错误率在2000ms与10000ms、30000ms存在显著差异,10000ms和30000ms之间差异不显著。     

时间知觉和关联负变化

关联负变化（contingent negative variation, CNV）被认为是与时间知觉过程有关的ERP成份。有关研究发现,CNV波幅会随着时间知觉到的长度和时间知觉的准确性而发生变化;CNV波幅的潜伏期与时间比较的判断决策过程有关;时间知觉中所诱发的CNV的脑内源存在历时性激活的特点且存在半球效应。为了进一步揭示时间知觉的神经机制,还需要结合具有高空间分辨率的脑成像技术和神经心理学的研究     

1s范围视听时距认知的分段性研究

时距认知分段性指不同长度时距加工机制和表征方式不同。以往研究对1s范围时距认知分段性仍存在分歧,为此在规避以往研究局限基础上设计实验1和实验2。实验1和实验2分别采用双任务范式探讨心算任务对100ms和1000ms听、视时距比较的选择性干扰,结果表明,心算任务影响了1000ms听、视时距比较的75%差别阈限,心算加工负荷越大,75%差别阈限越大,但对100ms听、视时距比较的75%差别阈限没有影响。两项实验支持了1s范围视、听时距认知均具有分段性。     

数字加工任务影响时距知觉的数字效应

本研究采用复制时距和数字加工双任务,探讨数字大小影响时距知觉的机制。实验首先呈现不同时距的圆点,然后让被试按键复制圆点呈现的时距,与此同时,对屏幕上出现的数字进行命名(实验1)、奇偶数判断(实验2)、大小判断(实验3)。实验结果发现对数字进行奇偶数判断时,数字大小对时距知觉没有影响;进行数字命名和大小判断任务时,数字大小对时距知觉都产生了影响,并且时距不同,数字大小对时距知觉的影响也不同。该结果表明时距知觉的数字效应与数字加工任务和时距长短有关,呈现出动态变化的过程。     

时距估计任务中的间断期望效应

使用单任务研究程序,采用引入提示线索的方法,以产生时距作为反应指标对存在间断的时距估计任务中的间断期望效应和提示线索效应（注意效应）进行系统考察,并对间断时距的效应、产生时距与等待时距的关系问题作出进一步探讨。结果表明,间断位置（等待时距）因素是被试时间判断的主要线索,被试的产生时距随着等待时距的增加而延长。间断实验中表现出极其显著的提示线索效应,此效应既增加了时距估计的变异,又延长了被试的时距估计。无间断实验条件下,被试表现出显著的间断期望效应,被试对间断的期望有损于时间估计。     

汉字识别中字形畸变和语境的ERP效应

以事件相关电位（ERP）技术和语义启动范式,采用同一字判断（靶字延迟反应）作业,考察字形畸变和语境对低频汉字识别的影响。结果发现,无语义启动时,畸变靶字正确率低于清晰靶字;启动效应只体现在畸变时的正确率上。150–300ms窗口,畸变字比清晰字诱发峰值更负的N170;300–500ms时间窗口,不启动条件诱发平均波幅更负的N400,畸变字诱发更大N400。结论是,畸变字诱发的N170成分,在一定程度上反映了字形加工;N400的语义启动效应和畸变效应,扩展Holcomb的研究,并支持语义提取理论。     

海洛因戒断者的时间知觉特征

本研究采用时间二分任务来探讨海洛因戒断者的时间知觉特征。结果发现: (1)戒断组的长反应比例在中间时距上显著高于对照组; (2)戒断组的主观相等点低于对照组且差异显著, 韦伯比例与对照组相比差异不显著。结论: 海洛因戒断者更容易高估时间, 并且对时间的高估更多体现在中间时距上。     

右侧背外侧前额叶皮质在时间知觉中的作用:基于经颅磁刺激的研究

将10 Hz的重复经颅磁刺激(r TMS)施加于右背外侧前额叶皮质(r DLPFC),探讨该区域在时间加工模型中的作用。实验一采用时间复制任务,通过比较基线和后测条件下时间估计行为的差异,探究高频r TMS离线施加于r DLPFC之后对时间知觉的影响。实验二采用毫秒和秒两种范围的时距,探究r DLPFC在不同范围的时间知觉中的作用。结果发现r TMS施加于r DLPFC导致对1.5 s高估,对600 ms的估计无显著影响,提示r DLPFC在涉及工作记忆加工过程的秒范围的时间知觉中有重要作用。     

Actively Controlling Anticipation of Irregular Events

There have been no investigations as to how people respond to sequences of events which occur at brief, unpredictable intervals as in everyday life. Eleven young adults were practised at a two-choice, continuous, serial choice-response task in which intervals between each response and the onset of the next signal (RSIs) varied randomly from trial to trial. On half the trials in each of four conditions the RSI was 20 ms, and on the other trials 200, 400, 800 and 1600 ms respectively. Reaction times fell as RSIs increased from 20-200 ms but thereafter appeared to be unaffected by RSI duration. In the 20/200 and 20/400 ms RSI conditions RT was not affected by transitions between different RSIs but in the 20/800 and 20/1600 ms conditions RTs were faster when the longer RSI recurred on immediately successive trials than if the long RSI followed the short (20 ms) RSI. These results are discussed in terms of a control system model for the way in which subjects actively trade off between their internal performance limitations to optimally meet task demands.     

Speeding up an internal clock in children? Effects of visual flicker on subjective duration

Children of 3, 5, and 8 years of age were trained on a temporal bisection task where visual stimuli in the form of blue circles of 200 and 800 ms or 400 and 1600 ms duration, preceded by a 5-s white circle, served as the short and long standards. Following discrimination training between the standards, stimuli in the ranges 200-800 ms or 400-1600 ms were presented with the white circle either constant or flickering. Relative to the constant white circle, the flicker (1) increased the proportion of "long" responses (responses appropriate to the long standard), (2) shifted the psychophysical functions to the left, (3) decreased bisection point values, at all ages, and (4) did not systematically affect measures of temporal sensitivity, such as difference limen and Weber ratio. The results were consistent with the idea that the repetitive flicker had increased the speed of the pacemaker of an internal clock in children as young as 3 years. The "pacemaker speed" interpretation of the results was further strengthened by a greater effect of flicker in the 400/1600-ms condition than in the 200/800-ms condition.     

The contingent negative variation laterality and dynamics in antisaccade task in normal and unmedicated schizophrenic subjects

Contingent negative variation (CNV) topography, hemispheric asymmetry and time-course were investigated in healthy subjects and non-medicated paranoid schizophrenic patients in two antisaccade paradigms with the short (800-1000 ms) and long (1200-1400 ms) durations of the fixation period. EEG and electrooculogram (EOG) were recorded. Saccade characteristics and mean amplitudes of slow cortical potentials time-locked to peripheral target were analyzed in 23 healthy volunteers and 19 schizophrenic patients. Compared to healthy control subjects, schizophrenic patients had significantly slower antisaccades and committed significantly more erroneous saccades in the both antisaccade tasks. The prolongation of the fixation period resulted in noticeable decrease of error percent in patients group. The analysis of CNV time-course has revealed two distinct stages in both groups. The early CNV stage was represented by a negative wave with the maximal amplitude over midline fronto-central area, and the late stage was characterized by increased CNV amplitude at the midline and left parietal electrode sites. In healthy subjects the simultaneous activation of frontal and parietal areas was observed in the paradigm with the shorter fixation interval; the increase of the fixation period produced consecutive activation of these areas. Schizophrenic patients' CNV amplitude was generally smaller than that of healthy subjects. The most pronounced between-group differences of the negative shift amplitude were revealed at frontal electrode sites during the early CNV stage in both modifications of the antisaccade task. The deficit of frontal activation revealed in patients at the early stage of antisaccade preparatory set in both antisaccadic paradigms may be related to pathogenesis of paranoid schizophrenia.     

BRIEF REPORT Perception of the duration of emotional events

Participants were trained on a temporal bisection task in which visual stimuli (a pink oval) of 400 ms and 1600 ms served as short and long standards, respectively. They were then presented comparison durations between 400 ms and 1600 ms, represented by faces expressing three emotions (anger, happiness, and sadness) and a neutral‐baseline facial expression. Relative to the neutral face, the proportion of long responses was higher, the psychophysical functions shifted to the left, and the bisection point values were lower for faces expressing any of the three emotions. These findings indicate that the duration of emotional faces was systematically overestimated compared to neural ones. Furthermore, consistent with arousal‐based models of time perception, temporal overestimation for the emotional faces increased with the duration values. It appears, therefore, that emotional faces increased the speed of the pacemaker of the internal clock.     

The relationship between variability of intertap intervals and interval duration

Summary Subjects tracked intervals in a synchronization paradigm at interval durations of 180, 210, 240, 270, 300, 400, 500, 600, 700, 800, 900, and 1,000 ms. The variability of intertap intervals (ITIs) shows a sudden increase near 300 ms. This increase is interpreted as indicating the transition from automatic to controlled movement. It is suggested that the sudden change in the variability of ITIs does not reflect the operation of different timing mechanisms at short and long intervals, but differences in the way in which attentional processes come to bear on movement initiation for different interval durations. In contrast to previous findings reported in the literature, a U-shaped function between interval duration and variability in the 300-to-1,000-ms range was not observed.     

The differential effects of brief exposures and surrounding contours on direct and indirect tilt illusions

Four experiments in which logarithmic intervals between 25 and 1600 ms were used for stimulus duration in tests for the tilt illusion are reported. It is demonstrated that the direct and the indirect tilt illusions both increase in magnitude inversely with length of stimulus presentation. The data suggest that whereas the direct effect peaks with a value of about +7 degrees at the shortest flash duration used (25 ms), peak indirect effects (of about +2 degrees) do not occur at this duration. In addition, whereas direct effects level out after 100 ms stimulus exposure times, to the usual magnitude obtained with long presentations (about +2 degrees), indirect effects reach their standard magnitude (-0.5 degrees to -1.0 degrees) later, at exposures of about 400 ms. Even at very short flash durations, a luminance square frame surrounding the illusion display reduces the indirect effect by two thirds of its magnitude but has no effect at all on the direct effect. It is suggested that direct effects arise early in visual processing, in area V1, where there are transient mechanisms and where corruption of orientation analysis by the inducing grating would occur prior to later, extrastriate, global analysis of the surrounding peripheral frame. Indirect effects, on the other hand, may arise later, along the sustained parvocellular colour-form pathway, where more global processing occurs and susceptibility to surrounding fields might be expected.     

Does time-shrinking take place in visual temporal patterns?

The duration of a short empty time interval (typically shorter than 300 ms) is often underestimated when it is immediately preceded by a shorter time interval. This illusory underestimation--time-shrinking--had been studied only with auditory temporal patterns. In the present study, we examined whether similar underestimation would take place with visual temporal patterns. It turned out that underestimation of the same kind takes place also in the visual modality. However, a considerable difference between the auditory and the visual modalities appeared. In the auditory modality, it had been shown that the amount of underestimation decreased for preceding time intervals longer than 200 ms. In the present study, the underestimation increased when the preceding time interval varied from 160 to 400 ms. Furthermore, the differences between the two neighbouring intervals which could cause this underestimation had always been in a fixed range in the auditory modality. In the visual modality, the range was broader when the intervals were longer. These results were interpreted in terms of an assimilation process in light of the processing-time hypothesis proposed by Nakajima (1987 Perception 16 485-520) in order to explain an aspect of empty-duration perception.