A case of partial biotinidase deficiency associated with autism.

We report the case of a child with partial biotinidase deficiency and autistic developmental disorder. We arrived at the diagnosis of biotinidase deficiency when the child was almost 4 years of age. Consequently, he began cofactor biotin treatment (10 mg daily) which did not resolve his autistic behavior. His younger brother was affected by partial biotinidase deficiency diagnosed at birth through our neonatal screening program. He was precociously treated with cofactor biotin therapy (10 mg daily) and did not show any behavioral abnormality or developmental delay. Since the brain is quite vulnerable to biotin deficiency, delayed biotin therapy could result in neurological damage. Our patient is the first case of partial biotinidase deficiency associated with autism. We hypothesize that the low biotinidase activity could have caused biotin deficiency in his brain and cerebrospinal fluids and consequently serious neurological problems, such as stereotyped and autistic behaviors, which were irreversible in spite of biotin supplementation.     

Testing the abstractness of children's linguistic representations: lexical and structural priming of syntactic constructions in young children

The current studies used a priming methodology to assess the abstractness of children's early syntactic constructions. In the main study, 3-, 4- and 6-year-old children were asked to describe a prime picture by repeating either an active or a passive sentence, and then they were left to their own devices to describe a target picture. For half the children at each age, the prime sentences they repeated had high lexical overlap with the sentence they were likely to produce for the target, whereas for the other half there was very low lexical overlap between prime and target. The main result was that 6-year-old children showed both lexical and structural priming for both the active transitive and passive constructions, whereas 3- and 4-year-old children showed lexical priming only. This pattern of results would seem to indicate that 6-year-old children have relatively abstract representations of these constructions, whereas 3- and 4-year-old children have as an integral part of their representations certain specific lexical items, especially pronouns and some grammatical morphemes. In a second study it was found that children did not need to repeat the prime out loud in order to be primed - suggesting that the priming effect observed concerns not just peripheral production mechanisms but underlying linguistic representations common to comprehension and production. These results support the view that young children develop abstract linguistic representations gradually during the preschool years.     

Co-occurrence of sequential and practice effects in the Simon task: Evidence for two independent mechanisms affecting response selection

The Simon effect refers to the observation that responses to a relevant stimulus dimension are faster and more accurate when the stimulus and response spatially correspond than when they do not, even though stimulus position is irrelevant. Recent findings have suggested that the Simon effect can be strongly modulated by prior practice with a spatially incompatible mapping and by correspondence sequence. Although practice is thought to influence conditional stimulus —response (S-R) processing, leaving response priming through the unconditional route unaffected, sequential effects are thought to represent trial-by-trial adaptations that selectively involve unconditional S —R processing. In the present study, we tested this assumption by assessing the effects of correspondence sequence both when the Simon task alone was performed and when it was preceded by a spatial compatibility task with either incompatible (Experiments 1-2) or compatible (Experiment 2) instructions. The observation that practice and correspondence sequence co-occur and exert additive effects strongly demonstrates that the two factors affect different processing routes.     

Under Reporting of Suicide Ideation in US Army Population Screening: An Ongoing Challenge

Previous research in US Army Soldiers shows rates of mental health concerns as two to four times higher on anonymous surveys than on postdeployment health assessments. In this study, Soldiers presenting for health reassessment completed two questionnaires on suicide risk factors: one linked to the health assessment and one anonymous. About 5.1% of respondents reported suicide ideation on the anonymous questionnaire, 3.0% on the linked questionnaire, and 0.9% on the health reassessment. About 56.4% who reported suicide ideation anonymously told nobody of their thoughts. Current screening procedures identify only one in seven Soldiers experiencing suicide ideation and highlight the need for alternative risk‐detection strategies.     

Current Trends in Education in Russia: Preliminary Outcomes Indicative of Students' Cognitive Development

Using a sample school population (N = 333) in Voronezh, Russia, this study investigated the comparative effect of two different types of Russian public schooling—traditional and innovative—on students' analytical, creative, and practical abilities. These abilities were assessed through (1) ratings by parents and teachers and (2) student performances on tests and other evaluative exercises, as well as student self-reports. The study found that innovative schools appear to do a better job of developing students' cognitive abilities (analytical, creative, and practical) than do more traditional institutions; in particular, the innovative schools significantly enhanced students' creative abilities. This study begins to illuminate the impact of massive societal change, and accompanying educational responses, on the cognitive development of Russian youth.     

Probability effects in choice reaction time tasks

This paper contains a short review of the main results that were obtained by the author in a series of experiments that constituted a study of the effects of signal probability on choice reaction time. The effects of stimulus probability are shown to be influenced by the following variables: (1) differences in the method of varying stimulus probability, (2) differences in task complexity, (3) differences in S-R code, and (4) differences in Ss’ motivation. The data that are considered here are the overall mean RT for particular signals and the mean RT for sequential repetitions. Two questions, related to the psychological “nature” of the probability effects in choice RT are discussed: (1) The question of the relationship between the relative frequency and the number of alternatives as two different ways of determining the probability effect in choice RT; and (2) the question of identifying the main determinants of the trial-to-trial variability of RT in such experiments.

     

The Small Worlds and Floyd's algorithms: a way to study scientific collaboration

Many proposals from the analysis of social networks focused on the study of scientific collaboration have been made recently. The Small Worlds theory seems to be the most efficient to study the inner features of the scientific community. Those researches have demonstrated that small communities are based on some key individuals who connect some groups which, on the contrary, would be disconnected. One of the disadvantages from the perspective of the analysis of networks is the lack of researches of particular nodes. With the implementation of a pseudocode algorithm of Floyd, we try to avoid this. To study how a small community is formed and, as a research of one case, we observe the invisible college which is formed when connecting the fifteen most productive authors of the Journal of Personality and Social Psychology .     

Hypnotic suggestion modulates cognitive conflict: the case of the flanker compatibility effect

The present work was aimed at investigating whether the flanker compatibility effect can be eliminated by means of a posthypnotic suggestion influencing attentional focusing. In Experiment 1, participants who scored high and low on hypnotic susceptibility performed the flanker compatibility task when naturally awake and when under a posthypnotic suggestion aimed at increasing the target's discriminability from the flankers. Results showed that the posthypnotic suggestion effectively eliminated the flanker compatibility effect in highly susceptible participants, whereas low-susceptibility participants did not show any reduction in the effect. In Experiment 2, highly susceptible participants performed the task after receiving a suggestion but without the induction of hypnosis. Results showed that the suggestion alone was not sufficient to reduce the flanker compatibility effect. These results support the view that in highly susceptible participants, hypnotic suggestion can influence the ability to focus on relevant information.     

Generation of hypotheses in Wason's 2-4-6 task: an information theory approach.

We explored the "context of discovery" in Wason's 2-4-6 task, focusing on how the first hypothesis is generated. According to Oaksford and Chater (1994a) people generate hypotheses extracting "common features", or regularities, from the available triples, but their model does not explain why some regularities contribute to the hypothesis more than do other regularities. Our conjecture is that some regularities contribute to the hypothesis more than do other regularities because people estimate the amount of information in the perceived regularities and try to preserve as much information as possible in their initial hypotheses. Experiment 1, which used two initial triples, showed that the presence of high-information relational regularities in the initial triples affected the information in the initial hypotheses more than did the presence of low-information object regularities. Experiment 2 extended the results to the classic situation in which only one initial triple is given. It also suggested that amount of information is the only aspect of the structure of the triple that affects hypotheses generation. Experiment 3 confirmed the latter finding: Although relations are commonly distinguished between first-order and higher order relations, the latter being most important for generating hypotheses (Gentner, 1983), higher order relations do have an effect on Wason's 2-4-6 task only if their presence incre ases information. In the conclusion we discuss the statistical soundness of human hypotheses generation processes, and we ask an unanswered question: Amount of information explains why some regularities are preferred to others, but only within a set of "nonarbitrary" regularities; there are object regularities that are rich in information content, but are considered "arbitrary", and are not used in generating hypotheses. Which formal property can distinguish between these two sets of regularities?     

Endocrinology of menopausal transition and its brain implications

The central nervous system is one of the main target tissues for sex steroid hormones, which act on both through genomic mechanisms, modulating synthesis, release, and metabolism of many neuropeptides and neurotransmitters, and through non-genomic mechanisms, influencing electrical excitability, synaptic function, morphological features, and neuron-glia interactions. During the climacteric period, sex steroid deficiency causes many neuroendocrine changes. At the hypothalamic level, estrogen withdrawal gives rise to vasomotor symptoms, to eating behavior disorders, and altered blood pressure control. On the other hand, at the limbic level, the changes in serotoninergic, noradrenergic, and opioidergic tones contribute to the modifications in mood, behavior, and nociception. Hormone replacement therapy (HRT) positively affects climateric depression throughout a direct effect on neural activity and on the modulation of adrenergic and serotoninergic tones and may modulate the decrease in cognitive efficiency observed in climaterium. The identification of the brain as a de novo source of neurosteroids, suggests that the modifications in mood and cognitive performances occurring in postmenopausal women may also be related to a change in the levels of neurosteroids. These findings open new perspectives in the study of the effects of sex steroids on the central nervous system and on the possible use of alternative and/or auxiliary HRT.