Neural substrates of cognitive skill learning in Parkinson's disease

While cognitive skill learning is normally acquired implicitly through frontostriatal circuitry in healthy individuals, neuroimaging studies suggest that patients with Parkinson's disease (PD) do so by activating alternate, intact brain areas associated with explicit memory processing. To further test this hypothesis, 10 patients with PD and 12 healthy controls were tested on a modified, learning version of the Tower of London task while undergoing positron emission tomography at four different time points over the course of learning. Despite having less accurate problem solving abilities than controls, PD patients were able to acquire the skill learning task. However, as compared to controls, they maintained higher levels of cerebral blood flow activity in the dorsolateral prefrontal cortex and hippocampus and showed an increase in activity in the frontopolar cortex and posterior cingulate over the course of learning. These findings reflect a shift to the explicit memory system in PD patients, enabling them to learn this cognitive skill, which is normally acquired by control subjects using implicit learning strategies and frontostriatal circuitry.     

Neural substrates for processing task-irrelevant sad images in adolescents

Neural systems related to cognitive and emotional processing were examined in adolescents using event-related functional magnetic resonance imaging (fMRI). Ten healthy adolescents performed an emotional oddball task. Subjects detected infrequent circles (targets) within a continual stream of phase-scrambled images (standards). Sad and neutral images were intermittently presented as task-irrelevant distracters (novels). As previously shown for adults, when the adolescents responded to the task-relevant targets, activation increased in the dorsal attention-executive system including the anterior middle frontal gyrus (aMFG), dorsal anterior cingulate (ACG), posterior cingulate (PCG), insula, and supramarginal gyrus (SMG). Unlike adults, however, the adolescents exhibited strong activation to the emotional distracter images not only in the ventromedial prefrontal cortex (VmPFC), but also in the posterior middle frontal gyrus (pMFG) and in the parietal cortex. Those subjects who had stronger VmPFC activation to emotional distraction also had reduced activation in the aMFG during target detection, suggesting that emotional information may interfere with executive processing in these adolescents. In contrast, pMFG and PCG activation to emotional distracters was positively correlated with aMFG activation to targets, indicating a different role of these regions from the VmPFC. The pattern of activation to task-irrelevant emotional distraction suggests a possible immaturity of brain function in cognitive control over emotional distraction in adolescents.     

The relationship between speed of information processing and cognitive ability

Speed of information processing as measured by various reaction time and inspection tasks has been shown to correlate with psychometric intelligence, and it has been suggested that general intelligence (g) is determined to some degree by the speed that information is processed. If this is so, then various measures of speed of information processing should correlate substantially with each other, and each should also correlate with a wide range of psychometric tests that load on g. Alternatively, intelligence may be considered to be a multi-faceted complex of partially related abilities with specific abilities being dependent upon specific cognitive processes. If this is the case, it should be possible to discover independent cognitive processes, some of which correlate with one facet or broad ability and some with another. This paper presents three experiments in which the relationship between intellectual ability and four speed of information processing measures was examined. These were rate of memory scanning, rate of retrieval of information from long term memory, speed of stimulus-response mapping and inspection time (IT). Results showed that correlations between IT and most reaction time measures of speed of information processing were low, and that correlations between different versions of IT were negligible. In addition, some cognitive tasks with verbal material (memory scanning rate for digits and Posner letter matching IT) correlated most substantially with Verbal Reasoning whereas non-verbal (two-line) IT consistently correlated with tests loading on g. It was thus suggested that while non-verbal IT may be a measure of a perceptual speed attribute that contributes to mental functioning, other “speed of information processing” parameters may be more specific to a subset of abilities.     

On relations among perceptual and cognitive measures of information processing

Tests of visual information processing and verbal information processing were administered to 178 Ss. Intercorrelations showed low positive relationships between two sets of two cognitive measures each, the Sentence Completion Test (Schroder, Driver, & Streufert, 1967) and the Interpersonal Topical Inventory (Tuckman, 1965), and the Interpersonal Topical Inventory and the Polarity Scale (1965), and a high negative correlation between preference for highly complex and for moderately complex visual stimuli. Factor analysis showed three reliable major factors. There was little evidence for a relationship between perceptual and cognitive processing characteristics, which indicates some danger for general theorists.     

Culture-fair cognitive ability assessment: information processing and psychophysiological approaches

Valid assessment with diverse populations requires tools that are not influenced by cultural elements. This study investigated the relationships between culture, information processing efficiency, and general cognitive capacities in samples of Caucasian and Mexican American college students. Consistent with the neural efficiency hypothesis, pupillary responses (indexing mental effort) and detection accuracy scores on a visual backward-masking task were both significantly related to the Wechsler Adult Intelligence Scale-Revised (WAIS-R) Full Scale scores. These measures of information processing efficiency were similar in the two groups. However, they were related only to Caucasian American, but not to a comparable sample of Mexican American, students' WAIS-R scores. Therefore, the differential validity in prediction suggests that the WAIS-R test may contain cultural influences that reduce the validity of the WAIS-R as a measure of cognitive ability for Mexican American students. Information processing and psychophysiological approaches may be helpful in developing culture-fair cognitive ability measures.     

Neural dynamics of autistic behaviors: cognitive, emotional, and timing substrates

What brain mechanisms underlie autism, and how do they give rise to autistic behavioral symptoms? This article describes a neural model, called the Imbalanced Spectrally Timed Adaptive Resonance Theory (iSTART) model, that proposes how cognitive, emotional, timing, and motor processes that involve brain regions such as the prefrontal and temporal cortex, amygdala, hippocampus, and cerebellum may interact to create and perpetuate autistic symptoms. These model processes were originally developed to explain data concerning how the brain controls normal behaviors. The iSTART model shows how autistic behavioral symptoms may arise from prescribed breakdowns in these brain processes, notably a combination of underaroused emotional depression in the amygdala and related affective brain regions, learning of hyperspecific recognition categories in the temporal and prefrontal cortices, and breakdowns of adaptively timed attentional and motor circuits in the hippocampal system and cerebellum. The model clarifies how malfunctions in a subset of these mechanisms can, through a systemwide vicious circle of environmentally mediated feedback, cause and maintain problems with them all.     

Response to an abnormal ovarian cancer-screening test result: Test of the social cognitive processing and cognitive social health information processing models

All cancer screening tests produce a proportion of abnormal results requiring follow up. Consequently, the cancer-screening setting is a natural laboratory for examining psychological and behavioural response to a threatening health-related event. This study tested hypotheses derived from the social cognitive processing and cognitive–social health information processing models in trying to understand response to an abnormal ovarian cancer (OC) screening test result. Women (n = 278) receiving an abnormal screening test result a mean of 7 weeks earlier were assessed prior to a repeat screening test intended to clarify their previous abnormal result. Measures of disposition (optimism, informational coping style), social environment (social support and constraint), emotional processing, distress, and benefit finding were obtained. Regression analyses indicated greater distress was associated with greater social constraint and emotional processing and a monitoring coping style in women with a family history of OC. Distress was unrelated to social support. Greater benefit finding was associated with both greater social constraint and support and greater distress. The primacy of social constraint in accounting for both benefit finding and distress was noteworthy and warrants further research on the role of social constraint in adaptation to stressful events.     

Neural correlates of three cognitive processes involved in theory of mind and discourse comprehension

Neuroimaging studies have found that theory of mind (ToM) and discourse comprehension involve similar brain regions. These brain regions may be associated with three cognitive components that are necessarily or frequently involved in ToM and discourse comprehension, including social concept representation and retrieval, domain-general semantic integration, and domain-specific integration of social semantic contents. Using fMRI, we investigated the neural correlates of these three cognitive components by exploring how discourse topic (social/nonsocial) and discourse processing period (ending/beginning) modulate brain activation in a discourse comprehension (and also ToM) task. Different sets of brain areas showed sensitivity to discourse topic, discourse processing period, and the interaction between them, respectively. The most novel finding was that the right temporoparietal junction and middle temporal gyrus showed sensitivity to discourse processing period only during social discourse comprehension, indicating that they selectively contribute to domain-specific semantic integration. Our finding indicates how different domains of semantic information are processed and integrated in the brain and provides new insights into the neural correlates of ToM and discourse comprehension.     

Neural mechanisms of the automatic processing of emotional information from faces and voices

Theoretical accounts suggest an increased and automatic neural processing of emotional, especially threat-related, facial expressions and emotional prosody. In line with this assumption, several functional imaging studies showed activation to threat-related faces and voices in subcortical and cortical brain areas during attentional distraction or unconscious stimulus processing. Furthermore, electrophysiological studies provided evidence for automatic early brain responses to emotional facial expressions and emotional prosody. However, there is increasing evidence that available cognitive resources modulate brain responses to emotional signals from faces and voices, even though conflicting findings may occur depending on contextual factors, specific emotions, sensory modality, and neuroscientific methods used. The current review summarizes these findings and suggests that further studies should combine information from different sensory modalities and neuroscientific methods such as functional neuroimaging and electrophysiology. Furthermore, it is concluded that the variable saliency and relevance of emotional social signals on the one hand and available cognitive resources on the other hand interact in a dynamic manner, making absolute boundaries of the automatic processing of emotional information from faces and voices unlikely.     

错误记忆产生的认知与神经机制：信息加工视角

采用信息加工视角, 在划分不同信息来源的基础上分析编码、存储(巩固)、再激活/再巩固和提取的一系列加工过程如何导致错误记忆形成, 由此总结出错误记忆产生的三个可能原因：(1)因缺乏针对目标事物特异性细节的记忆表征而侧重于编码和提取目标和非目标事物共享的抽象记忆表征, 使被试更倾向于依赖抽象表征对缺失的目标细节进行重构, 引发错误记忆; (2)目标事物启动了对应图式, 导致与图式相关的非目标事物记忆表征得到增强, 引发错误记忆; (3)误导信息干扰了再度激活状态下目标事物的记忆表征, 妨碍其进行准确的记忆再巩固, 从而引发错误记忆。未来研究可进一步探讨目标事物特异性细节的表征区域、不同类型的图式表征促进非目标事物记忆表征的具体机制以及提取阶段的图式复现对错误记忆形成的影响等问题。     

Refractoriness in information processing

Two experiments on refractoriness were carried out in which the warning, first and second signals, S₀, S₁ and S₂ respectively, were all single-valued, and the distributions of random intervals between S₀ and S₁, and S₁ and S ₂ were the same. In the first experiment the intervals in a trial were statistically independent: the null hypothesis, that the latencies of the two responses would be similar, was rejected, but the results were also found to agree with no existing alternative hypothesis. In the second experiment the intervals in a trial were conditionally related and the second response was found to be faster than in the first experiment. This is discussed in the context of the issue of serial or parallel processing of information.     

Moral chronicity and social information processing: Tests of a social cognitive approach to the moral personality

Following Higgins, King, and Mavin (1982) chronicity paradigm, we examined the effects of chronically accessed moral constructs for prototypic moral character using two different research paradigms, spontaneous trait inferencing and lexical decision. Study 1 presented target sentences in a deliberate or spontaneous processing condition. Recall was cued with either a dispositional or semantic cue. Moral chronics made more spontaneous trait inferences with dispositional cues than semantic cues. In Study 2, participants read stories about characters who did or did not help. Moral chronics were faster responding to probes reflecting negative evaluations of story characters who did not help when requested (e.g., “disloyal”). Findings support claims that the moral personality is usefully conceptualized in terms of the chronic accessibility of moral knowledge structures.     

Sex differences in information processing

Sex differences in cognitive activity were investigated. Using a list containing words with masculine, feminine, and neutral connotations, Experiment 1 revealed that masculine words were better recalled by male college students (n=16) while feminine words were better recalled by female college students (n=16). This difference was reduced on a recognition test. Experiment 2 demonstrated that the phenomenon was not due to a difference in the way males (n=20) and females (n=20) interpreted the meaning of the words. Finally, in Experiment 3, the memorial selectivity was shown to exist in the same manner for White middle-class elementary school (n=32) and high school (n=32) students. Learning and repression interpretations of the effect were proposed. Some practical implications of the data were suggested.These investigations were supported by a seed grant to the first author. This grant was jointly funded by Southern Methodist University and the National Science Foundation's Institutional Grants for Science Program (GU-3752). The authors would like to express their appreciation to the pupils and teachers on Fain Elementary School and Rider High School, both in Wichita Falls, Texas.