The extent of active processing of a long-duration stimulus modulates the scalp-recorded sustained potential

A long-duration stimulus will elicit a negative sustained potential (SP) that is maximum in amplitude over fronto-central areas of the scalp. This study examines how the duration of active attentional processing of the stimulus might also elicit a nonsensory contingent negative variation (CNV) that overlaps and summates to the SP. Subjects were presented with either a low- or high-pitched 1.4s duration stimulus. In different conditions, a 20 ms gap occurred either 300 or 1300 ms after stimulus onset in half the stimuli. The subject's task was to button press upon detection of the gap in the low-pitched stimulus. The subject was not required to respond to the gap occurring in the high-pitched tone. In a separate Ignore condition, subjects ignored all stimuli and read a book. In the Ignore condition, a SP was apparent to the long-duration stimuli. In the Attend condition, a large amplitude slow wave, probably the CNV, overlapped and summated with the SP. The extent of the overlapping CNV was dependent on whether the gap occurred early or late. The CNV was not apparent following presentation of the high-pitched tone, when the gap did not need to be detected. Consistent with previous studies, a SP was thus elicited even when active processing of the stimulus was not required. The morphology of the scalp-recorded SP was, nevertheless, much modified by an overlapping and summating CNV, depending on the extent to which active processing of the long-duration stimulus was required.     

Timing dysfunctions in schizophrenia as measured by a repetitive finger tapping task

Schizophrenia may be associated with a fundamental disturbance in the temporal coordination of information processing in the brain, leading to classic symptoms of schizophrenia such as thought disorder and disorganized and contextually inappropriate behavior. Although a variety of behavioral studies have provided strong evidence for perceptual timing deficits in schizophrenia, no study to date has directly examined overt temporal performance in schizophrenia using a task that differentially engages perceptual and motor-based timing processes. The present study aimed to isolate perceptual and motor-based temporal performance in individuals diagnosed with schizophrenia using a repetitive finger-tapping task that has previously been shown to differentially engage brain regions associated with perceptual and motor-related timing behavior. Thirty-two individuals with schizophrenia and 31 non-psychiatric control participants completed the repetitive finger-tapping task, which required participants to first tap in time with computer-generated tones separated by a fixed intertone interval (tone-paced tapping), after which the tones were discontinued and participants were required to continue tapping at the established pace (self-paced tapping). Participants with schizophrenia displayed significantly faster tapping rates for both tone- and self-paced portions of the task compared to the non-psychiatric group. Individuals diagnosed with schizophrenia also displayed greater tapping variability during both tone- and self-paced portions of the task. The application of a mathematical timing model further indicated that group differences were primarily attributable to increased timing – as opposed to task implementation – difficulties in the schizophrenia group, which is noteworthy given the broad range of impairments typically associated with the disorder. These findings support the contention that schizophrenia is associated with a broad range of timing difficulties, including those associated with time perception as well as time production.     

Lateralized effects of categorical and coordinate spatial processing of component parts on the recognition of 3D non-nameable objects

Participants performed two object-matching tasks for novel, non-nameable objects consisting of geons. For each original stimulus, two transformations were applied to create comparison stimuli. In the categorical transformation, a geon connected to geon A was moved to geon B. In the coordinate transformation, a geon connected to geon A was moved to a different position on geon A. The Categorical task consisted of the original and the categorically transformed objects. The Coordinate task consisted of the original and the coordinately transformed objects. The original object was presented to the central visual field, followed by a comparison object presented to the right or left visual half-fields (RVF and LVF). The results showed an RVF advantage for the Categorical task and an LVF advantage for the Coordinate task. The possibility that categorical and coordinate spatial processing subsystems would be basic computational elements for between- and within-category object recognition was discussed.     

Empathy and emotion recognition in semantic dementia: A case report

Recent studies have demonstrated that patients suffering from frontotemporal lobar degeneration (FTLD) show impairments in empathy and emotional processing. In this study, we examined two different aspects of these abilities in a patient with semantic dementia (SD), a variant of FTLD. The first aspect was the assessment of the cognitive and emotional components of empathy through the Interpersonal Reactivity Index. The second was the naming and comprehension of emotions using the Ekman 60 Faces Test. The patient’s emotion word knowledge was spared and the emotional aspects of empathy preserved. Conversely, the patient performed below average for all of the basic emotions when an emotion word had to be matched with a picture. When picture-to-picture matching was tested, however, the patient was able to recognize happiness. This case is a good example of a dissociation of covert and overt emotional functioning in SD. Results are discussed in terms of the impaired empathic behavior and emotional functioning in FTLD.     

工作记忆中汉语反词长效应机制

工作记忆中的反词长效应(reverse word-length effect)指在对长词和短词混合的词表进行即时序列回忆时, 独立长词回忆成绩优于独立短词的现象。以汉字词语为材料通过3个实验探讨反词长效应的机制。实验1采用纯粹词表和长短词混合词表, 既得到纯粹词词长效应, 也得到独立词反词长效应。实验2削弱了长短词之间的词长差异, 结果独立词反词长效应消失, 且独立词回忆成绩优于纯粹词。实验3设计了视觉延迟条件, 得到与实验1类似的结果, 只是独立词反词长效应有所削弱。三个实验的结果并不一致, 无法用现有的语音回路理论或SIMPLE理论进行很好地解释, 理论的整合与创新显得非常重要。因此, 提出多重编码以既相互竞争又相互补充方式进行平行加工的观点进行更完整地解释。     

中文阅读的副中央凹-中央凹效应：词n的语义透明度对词n-1的影响

研究探讨中文阅读中的副中央凹-中央凹效应。副中央凹-中央凹效应是指副中央凹处词的特性对中央凹处词汇加工的影响。实验以27名大学生为被试,采用句子阅读材料,考察词n的语义透明度特性对词n-1（高频、低频）加工的影响。结果表明,词n的语义透明度的高低对词n-1（高频、低频）的加工没有影响,没有出现副中央凹-中央凹效应。实验结果支持E-Z读者模型的假设。     

工作记忆负载对位置干扰子激活加工和抑制加工的影响

针对工作记忆（WM）负载对干扰子加工的影响存在认知控制机制和负载特异机制两种分歧观点的争议及Park等人的负载特异机制研究中存在的不足,文章尝试采用干扰效应和负启动效应双指标考察了三种不同类型的WM负载对位置干扰子加工的影响。结果表明,WM负载对位置干扰子加工的影响存在双重作用机制（认知控制机制和负载特异机制）;目标刺激与干扰子刺激的属性一致时,亦可得出负载特异机制观点,且可将WM任务与选择性注意任务之间竞争的资源锁定为知觉处理资源;导致上述两种观点争议的原因是以往研究未将干扰子加工过程分离为激活加工阶段和抑制加工阶段来考察;用双指标分离干扰子加工阶段的研究思路和方法不但可解决这两种观点的争议且可为两者的统合奠定基础。     

语音在维——汉双语者汉字识别中的作用

采用语音启动技术,以第二语言为汉语的46名维吾尔族大学生为研究对象,考查了语音在维-汉双语者汉字识别中的作用.结果发现,维吾尔族被试在命名任务和词汇判断任务中都获得了语音启动效应,语义启动效应只出现在词汇判断任务中.结论:语音在维吾尔族大学生汉字识别中是自动激活的,而且语音的自动激活参与了语义通达.     

风险决策任务中时间距离对框架效应的影响

通过考察中国大学生时间距离的认知相关性,并进而探讨时间距离对风险决策任务加工方式及框架效应的影响.实验一通过问卷调查发现,与发生时间相对较远的事件相比,相对较近的事件,其认知相关性更大,验证了时间距离的认知相关性假设.在此基础上,以时间距离为自变量,设计小同的风险决策任务,考察框架效应发生的可能性(实验二、实验三).结果显示,时间距离近时,框架效应不明显;时间距离远时,框架效应明显.其原因是,发生在相对不远的将来事件引起分析加工模式,导致框架效应的减弱;发生在相对远的将来事件引起整体加工模式,导致框架效应的增强.