奖赏对海洛因成瘾者执行功能的影响机制

一些研究发现海洛因成瘾者奖赏失调表现为:对海洛因相关线索的注意偏向、渴求感增加,对金钱奖赏表现出"即时收益优先"的高风险决策模式和对长时收益的敏感性降低。另一些研究发现海洛因成瘾者的执行功能存在障碍。奖赏失调和执行功能障碍在成瘾物质使用的维持和复吸中起着重要作用。双重竞争模型认为奖赏和执行功能的交互作用决定着行为的结果,但是奖赏对海洛因成瘾者执行功能的影响机制还不清楚。因此,拟使用事件相关电位技术来考察海洛因相关线索和金钱奖赏对不同戒断期成瘾者执行功能的影响机制,短期(1~3个月)、长期(18个月以上)海洛因戒断者和健康对照组被比较。这不仅有助于构建完善的成瘾理论体系,还有助于确定临床戒断后复吸的风险因素和不同戒断期的治疗目标。     

Adolescent risk-taking is predicted by individual differences in cognitive control over emotional,but not non-emotional,response conflict

While much research on adolescent risk behaviour has focused on the development of prefrontal self-regulatory mechanisms, prior studies have elicited mixed evidence of a relationship between individual differences in the capacity for self-regulation and individual differences in risk taking. To explain these inconsistent findings, it has been suggested that the capacity for self-regulation may be, for most adolescents, adequately mature to produce adaptive behaviour in non-affective, “cold” circumstances, but that adolescents have a more difficult time exerting control in affective, “hot” contexts. To further explore this claim, the present study examined individual differences in self-control in the face of affective and non-affective response conflict, and examined whether differences in the functioning of cognitive control processes under these different conditions was related to risk taking. Participants completed a cognitive Stroop task, an emotional Stroop task, and a risky driving task known as the Stoplight game. Regression analyses showed that performance on the emotional Stroop task predicted laboratory risk-taking in the driving task, whereas performance on the cognitive Stroop task did not exhibit the same trend. This pattern of results is consistent with theories of adolescent risk-taking that emphasise the impacts of affective contextual influences on the ability to enact effective cognitive control.     

Neuropsychological deficits in preschool as predictors of ADHD symptoms and academic achievement in late adolescence

High levels of ADHD symptoms are related to severe negative outcomes, which underscore the importance of identifying early markers of these behavior problems. The main aim of the present study was therefore to investigate whether neuropsychological deficits in preschool are related to later ADHD symptoms and academic achievement, over and above the influence of early ADHD symptom levels. The present study is unique because it includes a broader range of predictors compared to previous studies and the participants are followed over time for as long as 13 years (i.e., ages 5–18 years). Preschool data included measures of executive functioning and reaction time variability as well as emotional reactivity and emotion regulation of both positive and negative emotions. When controlling for early ADHD symptom levels, working memory, reaction time variability, and regulation of happiness/exuberance were significantly related to inattention whereas regulation of happiness/exuberance and anger reactivity were significantly related to hyperactivity/impulsivity. Furthermore, working memory and reaction time variability in preschool were significantly related to academic achievement in late adolescence beyond the influence of early ADHD symptoms. These findings could suggest that it is possible to screen for early neuropsychological deficits and thereby identify children who are at risk of negative outcomes. Furthermore, our results suggest that interventions need to look beyond executive functioning deficits in ADHD and also target the role of emotional functioning and reaction time variability. The importance of including both the positive and negative aspects of emotional functioning and distinguishing between emotion regulation and emotional reactivity was also demonstrated.     

Cognitive and behavioral rating measures of executive function as predictors of academic outcomes in children

Interrelations of two measurement methods (cognitive versus behavioral ratings) for executive function (EF) were examined and related to reading comprehension and math calculations in fourth and fifth grade students (n = 93) in the context of a diverse urban student population. Relations among measures within four EF processes (working memory, planning, inhibition and shifting) were modest; relations to academics were stronger. EF measures contributed to both academic outcomes even in the context of relevant covariates (age, language and educational program). Working memory was particularly important for reading comprehension across measurement type. Cognitive measures from all EF processes, particularly inhibition and planning, and behavioral ratings of working memory were important for math.     

Contextual control of equivalence-based transformation of functions

The transformation of functions refers to the untrained acquisition of stimulus functions among members of stimulus equivalence classes or relational frames. Although it is widely assumed that contextual control over the transformation of fuctions must exist, this has not yet been conclusively demonstrated in laboratory studies. Four experiments are reported in which (a) stimulus equivalence classes were established, (b) a conditional stimulus function was trained for one member of each of the classes, and (c) multiple-exemplar procedures were used to train and test for contextual control over the transformation of the stimulus function within the classes and to assess whether it generalized to new equivalence classes. Although a significant amount of training was required, the procedures ultimately resulted in the contextual control of function transformation for 9 of 10 participants and generalized contextual control for 4 of 5 participants.     

Effects of right and left hemisphere damage on performance of the "Right Hemisphere Communication Battery"

A Hebrew adaptation of Gardner and Brownell's (1986) "Right Hemisphere Communication Battery" (HRHCB) was administered to 27 right brain-damaged (RBD) patients, 31 left brain-damaged (LBD) patients, and 21 age-matched normal controls. Both patient groups showed deficits relative to controls and overall there was no difference between the two patient groups. A factor analysis of patients' scores on the HRHCB yielded two interpretable factors, a verbal and a nonverbal one. These factors were not lateralized. Performance of patients on the HRHCB correlated significantly and positively with performance on most tests of basic language functions, measured with a Hebrew adaptation of the "Western Aphasia Battery" (HWAB) and with other cognitive functions measured with standardized neuropsychological tests. There were stronger correlations of HRHCB with subtests of the HWAB in LBD patients and with nonlanguage cognitive tests in RBD patients. In the LBD group, HRHCB subtests' scores correlated negatively with lesion extent in frontal and temporal perisylvian regions. Such localization was not observed in RBD patients. The results argue against selective right hemisphere (RH) involvement in the RHCB, alleged to measure pragmatic aspects of language use, and show, instead, bilateral involvement. The results also argue against a modular organization of these functions of language use, especially in the RH.     

Semantic similarity and grammatical class in naming actions

Italian speakers were asked to name pictures of actions (e.g. "bere", to drink). Pictures were presented at the same time as distracter words that were semantically related or unrelated to the picture names, and were of the same or different grammatical class (verbs or nouns). Half of the participants named the actions as verbs in citation form, the other half as verbs inflected for third person singular or plural. We found a reliable semantic interference effect. Crucially, we also observed a significant interaction between naming context and grammatical class: naming latencies were slower for verb distracters in the inflected form condition, but not in the citation form condition. The results are taken to provide evidence for the separability of semantics and grammatical class.     

Age changes in the missing-letter effect revisited

When participants search for a target letter while reading, they make more omissions if the target letter is embedded in frequent function words than in less frequent content words. Reflecting developmental changes in component language and literacy skills, the size of this effect increases with age. With adults, the missing-letter effect is due to both word function and word frequency. With children, it is unclear whether the growing size of the missing-letter effect across development is due to a larger effect of word function, word frequency, or both because previous studies with children seeking to isolate the influence of word frequency and word function suffer from important methodological limitations. With these methodological limitations eliminated (Experiments 1 and 2), performance in a letter detection task was assessed for children in Grades 1, 2, 3, 4, and 7 as well as for undergraduate students. The results revealed that the influence of word function increases with age, whereas the effect of frequency is fairly stable across ages. Furthermore, normative predictability data collected in Experiment 3 revealed that third graders and undergraduate students were equally good at predicting function slots in a sentence.     

Psychometric Modeling of response speed and accuracy with mixed and conditional regression

Human performance in cognitive testing and experimental psychology is expressed in terms of response speed and accuracy. Data analysis is often limited to either speed or accuracy, and/or to crude summary measures like mean response time (RT) or the percentage correct responses. This paper proposes the use of mixed regression for the psychometric modeling of response speed and accuracy in testing and experiments. Mixed logistic regression of response accuracy extends logistic item response theory modeling to multidimensional models with covariates and interactions. Mixed linear regression of response time extends mixed ANOVA to unbalanced designs with covariates and heterogeneity of variance. Related to mixed regression is conditional regression, which requires no normality assumption, but is limited to unidimensional models. Mixed and conditional methods are both applied to an experimental study of mental rotation. Univariate and bivariate analyzes show how within-subject correlation between response and RT can be distinguished from between-subject correlation, and how latent traits can be detected, given careful item design or content analysis. It is concluded that both response and RT must be recorded in cognitive testing, and that mixed regression is a versatile method for analyzing test data.I am grateful to Rogier Donders for putting his data at my disposal.     

On the function of weak phantasmata in perception: Phenomenological,psychological and neurological clues for the transcendental function of imagination in perception

Weak phantasmata have a decisive and specifically transcendental function in our everyday perception. This paper provides several different arguments for this claim based on evidence from both empirical psychology and phenomenology.I would like to express my gratitude to Bill McKenna for his help with the English text and his critical remarks. This paper was presented in the Cork Roundtable for Philosophy in March 2003, at University College, Cork, and I would like to thank Julia Jansen, Tony O’Connor and the other participants for their constructive critique.