Browsing by Author "Lopez, J"

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    Effect of psychostimulants on distinct attentional parameters in attentional deficit/hyperactivity disorder
    (SOC BIOLGIA CHILE, 2004) Lopez, J; Lopez, V; Rojas, D; Carrasco, X; Rothhammer, P; Garcia, R; Rothhammer, F; Aboitiz, F
    Although there is extensive literature about the effects of stimulants on sustained attention tasks in attentional deficit/hyperactivity disorder (ADHD), little is known about the effect of these drugs on other attentional tasks involving different neural systems. In this study we measured the effect of stimulants on ADHD children, both in the electroencephalographic (EEG) activity during sustained attentional tasks and in psychometric performance during selective attentional tasks. These tasks are known to rely on different cortical networks. Our results in children medicated with 10 mg of d-amphetamine administered 60 min before the study indicate (i) a significant increase in amplitude but not latency of the P300 component of the event-related potential (ERP) during the sustained attentional task and (ii) a significant improvement in the reaction times and correct responses in the selective attentional task. In addition to supporting the use of stimulants in children with attentional deficit/hyperactivity disorder, these results show a multifocal activity improvement of cortical structures linked to dopamine, and interestingly, to attention. All these analyses are framed in a wider study of diverse attentional functions in this syndrome.
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    Long distance communication in the human brain: timing constraints for inter-hemispheric synchrony and the origin of brain lateralization
    (SOCIEDAD BIOLGIA CHILE, 2003) Aboitiz, F; Lopez, J; Montiel, J
    Analysis of corpus callosum fiber composition reveals that inter-hemispheric transmission time may put constraints on the development of inter-hemispheric synchronic ensembles, especially in species with large brains like humans. In order to overcome this limitation, a subset of large-diameter callosal fibers are specialized for fast interhemispheric transmission, particularly in large-brained species. Nevertheless, the constraints on fast interhemispheric communication in large-brained species can somehow contribute to the development of ipsilateral, intrahemispheric networks, which might promote the development of brain lateralization.
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    Partial synthesis of (-)-11,12-dinordriman-8-one and the (-)-enantiomer of polywood
    (SCIENCE REVIEWS 2000 LTD, 1998) Cortes, M; Moreno, L; Lopez, J
    A chiral sequiterpene diol 6, readily available from the natural product polygodial (4), has been used for the first partial synthesis of the title compounds.