Cognitive functioning after medial frontal lobe damage including the anterior cingulate cortex: a preliminary investigation

Two patients with medial frontal lobe damage involving the anterior cingulate cortex (ACC) performed a range of cognitive tasks, including tests of executive function and anterior attention. Both patients lesions extended beyond the ACC, therefore caution needs to be exerted in ascribing observed deficits to the ACC alone. Patient performance was compared with age and education matched healthy controls. Both patients showed intact intellectual, memory, and language abilities. No clear-cut abnormalities were noted in visuoperceptual functions. Speed of information processing was mildly reduced only in Patient 2 (bilateral ACC lesion). The patients demonstrated weak or impaired performance only on selective executive function tests. Performance on anterior attention tasks was satisfactory. We tentatively suggest that our findings are inconsistent with anterior attention theories of ACC function based on neuroimaging findings. We propose that the data may imply that the ACC does not have a central role in cognition. We speculate that our findings may be compatible with the view that the ACC integrates cognitive processing with autonomic functioning to guide behaviour.     

Temporal associations and prior-list intrusions in free recall

When asked to recall the words from a just-presented target list, subjects occasionally recall words that were not on the list. These intrusions either appeared on earlier lists (prior-list intrusions, or PLIs) or had not appeared over the course of the experiment (extra-list intrusions). The authors examined the factors that elicit PLIs in free recall. A reanalysis of earlier studies revealed that PLIs tend to come from semantic associates as well as from recently studied lists, with the rate of PLIs decreasing sharply with list recency. The authors report 3 new experiments in which some items in a given list also appeared on earlier lists. Although repetition enhanced recall of list items, subjects were significantly more likely to make PLIs following the recall of repeated items, suggesting that temporal associations formed in earlier lists can induce recall errors. The authors interpret this finding as evidence for the interacting roles of associative and contextual retrieval processes in recall. Although contextual information helps to focus recall on words in the target list, it does not form an impermeable boundary between current- and prior-list experiences.     

On the likelihood ratio test in structural equation modeling when parameters are subject to boundary constraints

The authors show how the use of inequality constraints on parameters in structural equation models may affect the distribution of the likelihood ratio test. Inequality constraints are implicitly used in the testing of commonly applied structural equation models, such as the common factor model, the autoregressive model, and the latent growth curve model, although this is not commonly acknowledged. Such constraints are the result of the null hypothesis in which the parameter value or values are placed on the boundary of the parameter space. For instance, this occurs in testing whether the variance of a growth parameter is significantly different from 0. It is shown that in these cases, the asymptotic distribution of the chi-square difference cannot be treated as that of a central chi-square-distributed random variable with degrees of freedom equal to the number of constraints. The correct distribution for testing 1 or a few parameters at a time is inferred for the 3 structural equation models mentioned above. Subsequently, the authors describe and illustrate the steps that one should take to obtain this distribution. An important message is that using the correct distribution may lead to appreciably greater statistical power.     

Development of the Critical Elements of Genetic Evaluation and Genetic Counseling for Genetic Professionals and Perinatologists in Washington State

We present a method for the development of consensus documents describing the components of genetic evaluation and genetic counseling for various diagnoses. These documents were developed to encourage consistency among genetic professionals in Washington State. Other possible uses of these documents are to provide information regarding genetic evaluations for health care practitioners and payers, and to assist in quality assurance and genetic training programs. A working group of six genetic professionals developed two templates for the critical elements of genetic evaluation and genetic counseling, for clinical (nonprenatal) and prenatal patients. The working group then completed prototype templates for several specific genetic disorders. The templates and prototypes were sent to interested genetic professionals and perinatologists who submitted a total of 76 draft critical elements (CE's) to the working group. At two statewide meetings, participating practitioners modified and unanimously approved the CE templates, then unanimously approved the 21 draft CEs that had been finalized in small group discussions. Approved CE's were distributed to genetic professionals and perinatologists within the state.     

Two effects of repetition: Support for a dual-process model of know judgments and exclusion errors

In three experiments, aremember/know recognition test (Experiments 1–2) and an exclusion test (Experiments 2–3) were used to examine effects of repeated study presentations. An effect of study repetition was obtained for remember but not know judgments, similar to results reported by Gardiner, Kaminska, Dixon, and Java (1996). Experiment 2 demonstrated the similarity between know responses and exclusion errors; neither was affected by repeated study presentations. In Experiment 3, a response deadline procedure was used to show that exclusion errors are the product of two opposing processes—recollection and familiarity—both of which are influenced by repetition. The interpretation of exclusion errors and know responses is shown to require a dual-process model that includes an assumption about the relationship between processes.     

Sex-role identity and separation-individuation pathology

The Mahlerian theory of childhood psychological development suggests that the same sex parenting of girls in the mother-child dyad predisposes women to experience specific difficulties in the separation-individuation (S-I) process (Mahler, Pine & Bergman, 1975). Pathological states in adulthood have been attributed to these S-I disturbances (Pine 1979; Kernberg 1980). However, this theory has never been empirically tested. In this study 53 subjects were assessed for adult manifestation of disturbance in the separation-individuation process using a self-report questionnaire (Separation-Individuation Inventory: Christenson & Wilson, 1985), In contrast to previous theoretical work, women showed significantly lower levels of disturbance in the separation-individuation process than did men. Assessment of sex-role identity (Bem Sex Role Inventory: Bem, 1981) showed no significant difference between overall sex-role identity of the male and female subjects. Individuals lacking any clear sex-role identity showed significantly higher levels of disturbance in the separation-individuation process than those with feminine, masculine or androgynous identity. These findings demonstrate the importance of considering sex-role identity as well as biological sex when describing some psychological characteristics and also demonstrate the importance of any sex-role acquisition, whether male or female, for psychological well-being.     

Test-induced priming of false memories

Of interest was whether prior testing of related words primes false memories in the Deese/Roediger-McDermott (DRM) paradigm. After studying lists of related words, subjects made old-new judgments about zero, three, or six related items before being tested on critical nonpresented lures. When the recognition test was self-paced, prior testing of list items led to faster false recognition judgments, but did not increase the rate of false alarms to lures from studied lists. Critically, this pattern changed when decision making at test was speeded. When forced to respond quickly—presumably precluding the use of monitoring processes—clear test-induced priming effects were observed in the rate of false memories. The results are consistent with an activation-monitoring explanation of false memories and support that retrieving veridical memories can be a source of memory error.     

Executive dysfunction as a risk marker for substance abuse: The role of impulsive personality traits

The relationships between family history of substance use, executive functions, impaired decision making, and current substance dependence are the focus of this study. Thirty-eight substance-dependent inpatients were compared with 30 community controls on performance on the Wisconsin Card Sorting Test, Trail-Making Test-B, the Stroop Color Word Test, the Wais-II Digit Span, and the Iowa Gambling Task. Recent alcohol use, depressive symptoms, and impulsivity were also assessed. As hypothesized, individuals with substance dependence exhibited poorer executive functioning. Family history status was modestly related to impaired performance on tests designed to measure the integrity of the dorsolateral prefrontal cortex. In particular, substance-dependent, family history positive individuals performed less well on the Wisconsin Card Sorting Test than substance-dependent individuals without a family history. Digit Span performances were worse among family history positive controls when compared with family history negative controls. Impulsive personality traits—specifically, difficulty thinking before acting (Urgency)—were related, as hypothesized, to executive functioning. Results indicate that family history status confers an increased risk of impairment beyond that conferred by recent substance abuse, and that impulsive personality traits are related to performance on tests of executive functions. Implications for criminality are discussed. Copyright © 2008 John Wiley & Sons, Ltd.     

The development of metacognitive ability in adolescence

Introspection, or metacognition, is the capacity to reflect on our own thoughts and behaviours. Here, we investigated how one specific metacognitive ability (the relationship between task performance and confidence) develops in adolescence, a period of life associated with the emergence of self-concept and enhanced self-awareness. We employed a task that dissociates objective performance on a visual task from metacognitive ability in a group of 56 participants aged between 11 and 41 years. Metacognitive ability improved significantly with age during adolescence, was highest in late adolescence and plateaued going into adulthood. Our results suggest that awareness of one’s own perceptual decisions shows a prolonged developmental trajectory during adolescence.