Genetics and delusional disorder

This article gives an overview of genetic research approaches and their application to delusional disorder. Most studies have been based on small samples and have had other methodological limitations, so it is not clear whether there is a genetic contribution to the aetiology of delusional disorder. It is unlikely that delusional disorder is strongly related genetically to affective disorder or schizophrenia, but more subtle relationships cannot be ruled out. The rarity of multiply affected families prohibits linkage studies and, to date, molecular genetic investigations have been mainly limited to small association studies of dopamine receptor polymorphisms. A range of considerably larger, epidemiologically rigorous studies is required, but the uncommonness and other features of the disorder put strong limitations on the prospects for ascertaining adequate samples.     

New reflections on visual search: Interitem symmetry matters!

A 90 degrees rotation of a display can turn a relatively easy visual search into a more difficult one. A series of experiments examined the possible causes of this effect, including differences in overall item shape and response mapping (Experiment 1), the interpretation of scene lighting (Experiment 2), the axis of internal symmetry of the search items (Experiment 3), and the axes of interitem symmetry between target and distractor items (Experiment 4). Only the elimination of differences in interitem mirror symmetry resulted in equal search efficiency in the upright and rotated displays. This finding is strong support for the view that visual search is guided by an analysis that considers interitem relations.     

Statistical manifold as an affine space: A functional equation approach

A statistical manifold M_μ consists of positive functions f such that defines a probability measure. In order to define an atlas on the manifold, it is viewed as an affine space associated with a subspace of the Orlicz space L^Φ. This leads to a functional equation whose solution, after imposing the linearity constrain in line with the vector space assumption, gives rise to a general form of mappings between the affine probability manifold and the vector (Orlicz) space. These results generalize the exponential statistical manifold and clarify some foundational issues in non-parametric information geometry.     

Saccadic latency as a function of target duration in a spatial localization task

This study examined a potential confound in the inverse relationship between target duration and saccadic latency reported by Adam, Ketelaars, Kingma, and Hoek in 1993. Eight participants located a briefly flashed target by moving the eyes and the cursor toward its position in a (backward) mask condition and in a no-mask condition. Analysis showed similar saccadic latencies in both conditions, thereby refuting the potentially confounding role of the backward masking procedure. It is tenatively suggested that the longer saccadic latencies noted for shorter target durations may be associated with delayed accumulation of evidence for the detection of the target.     

Relation of attention control and school performance in normal children

This study examined the relation of attention control and school performance in a sample of 113 school children (51 boys, 62 girls), ages 9 to 12 years (M = 10.86, SD = 0.91). Children and parents completed the Attention Control Scale for Children, which measures children's ability to focus and shift attention, and also a scale for assessing symptoms of Attention-Deficit Hyperactivity Disorder. Teachers provided a global rating of children's school performance. Analysis indicated that attention control correlated positively with school performance.     

The Moral Judgment of Juvenile Delinquents: A Meta-Analysis

A meta-analysis of 50 studies was conducted to investigate whether juvenile delinquents use lower levels of moral judgment than their nondelinquent age-mates and, if so, what factors may influence or moderate the developmental delay. The results show a lower stage of moral judgment for juvenile delinquents (d=.76). Effect sizes were large for comparisons involving male offenders, late adolescents, delinquents with low intelligence, and incarcerated delinquents. The largest effect sizes were found for period of incarceration and comparisons involving juvenile delinquents with psychopathic disorder. Production instead of recognition measures, dilemma-free assessment methods, and non-blind scoring procedures yielded relatively large effect sizes, whereas effect sizes were medium for comparisons involving delinquents with average intelligence, non-incarcerated delinquents, female offenders, as well as early and middle adolescents. Psychopathic disorder and institutionalization were identified as unique moderators of the link between moral judgment and juvenile delinquency. It is concluded that developmentally delayed moral judgment is strongly associated with juvenile delinquency, even after controlling for socioeconomic status, gender, age and intelligence.This article stems from a paper presented at the meeting of the Association for Moral Education, July 2006, Fribourg, Switzerland.     

The relationship of neuronal activity within the sensori-motor region of the subthalamic nucleus to speech

Microelectrode recordings of human sensori-motor subthalamic neuronal activity during spoken sentence and syllable-repetition tasks provided an opportunity to evaluate the relationship between changes in neuronal activities and specific aspects of these vocal behaviors. Observed patterns of neuronal activity included a build up of activity in anticipation of the start of the utterance, a marked reduction in activity associated with the start of the utterance, and a burst of activity during the course of the sentence between the noun phrase and the verb phrase. Overall, changes of neuronal activity were more robust for the sentence repetition task. These data suggest that the basal ganglia play a role in generating meaningful speech utterances, which may parallel its role in complex sequential limb movements. It is possible that the basal ganglia play a role in generating the syntactical structure of language.     

The generalized optic acceleration cancellation theory of catching

The generalized optic acceleration cancellation (GOAC) theory of catching proposes that the path of a fielder running to catch a ball is determined by the attempt to satisfy 2 independent constraints. The 1st is to keep the angle of elevation of gaze to the ball increasing at a decreasing rate. The 2nd is to control the rate of horizontal rotation necessary to maintain fixation on the ball. Depending on the lateral velocity of the ball relative to the fielder, this rate may be zero or constant at a negative or positive value. The authors show that a simulated fielder implementing the GOAC strategy follows a path indistinguishable from that of real fielders running to catch balls thrown on the same trajectories.     

Sequential modulations of correspondence effects across spatial dimensions and tasks

In two experiments, we explored sequential modulations of correspondence effects in a prime-target paradigm. In Experiment 1, the participants responded to the direction of target arrows that were preceded by prime arrows with a corresponding or noncorresponding direction. This produced a prime-target correspondence effect that was reduced when the preceding trial contained a noncorresponding prime-target event. This sequential modulation of the correspondence effect was observed even when neither stimuli nor responses were repeated from one trial to the next, ruling out explanations of sequential modulations in terms of stimulus or response repetitions. Experiment 2 combined the prime-target correspondence effect with a Simon-type correspondence effect. Both effects were reduced following noncorrespondence of the same type and, to a lesser extent, following noncorrespondence of the other type. Altogether, these results suggest that part of the sequential modulation of correspondence effects reflects an adaptation to a preceding response conflict independently of the peripheral stimulus events that produced this conflict.     

Cerebrovascular risk factors, activity limitations, and depressed mood in African American older adults

This study investigated the association between cerebrovascular risk factors (CVRFs), physical activity limitations, and depressed mood. The 12-item Short-Form Health Survey (SF-12) was administered to 1,034 urban African American older adults. A chi-square analysis demonstrated that the prevalence of depressed mood among those with high CVRF burden (13.4%) was significantly higher than among those with low vascular burden (7.6%). Physical activity limitations also predicted depressed mood, but this relationship did not mediate the relationship between cerebrovascular burden and depression. These findings highlight the relationships among cerebrovascular burden, physical activity limitations, and depressed mood among African American older adults.