Encefalizacion y procesos humanos

Chapter · January 2011with10 Reads

In book: Darwin y las ciencias del comportamiento, Edition: 1, Publisher: Universidad Nacional de Colombia, pp.415-427
  • [Show abstract] [Hide abstract] ABSTRACT: Early life experience can induce long-lasting changes in brain and behaviour that are opposite in direction, such as enhancement or impairment in regulation of stress response, structural and functional integrity of the hippocampus, and learning and memory. To explore how multiple early life events jointly determine developmental outcome, we investigated the combined effects of neonatal trauma (anoxia on postnatal day 1, P1) and neonatal novelty exposure (P2-21) on adult social recognition memory (3 months of age) and synaptic plasticity in the CA1 of the rat hippocampus (4.5-8 months of age). While neonatal anoxia selectively reduced post-tetanic potentiation (PTP), neonatal novel exposure selectively increased long-term potentiation (LTP). No interaction between anoxia and novelty exposure was found on either PTP or LTP. These findings suggest that the two contrasting neonatal events have selective and distinct effects on two different forms of synaptic plasticity. At the level of behaviour, the effect of novelty exposure on LTP was associated with increased social memory, and the effect of anoxia on PTP was not accompanied by changes in social memory. Such a finding suggests a bias toward the involvement of LTP over PTP in social memory. Finally, we report a surprising finding that an early behavioural measure of emotional response to a novel environment obtained at 25 days of age can predict adult LTP measured several months later. Therefore, individual differences in emotional responses present during the juvenile stage may contribute to adult individual differences in cellular mechanisms that underlie learning and memory.
    Article · Aug 2006
  • [Show abstract] [Hide abstract] ABSTRACT: We evaluated the long-term speech intelligibility of young deaf children after cochlear implantation (CI). A prospective study on 47 consecutively implanted deaf children with up to 5 years cochlear implant use was performed. The study was conducted at a pediatric tertiary referral center for CI. All children in the study were deaf prelingually. They each receive implant before the program of auditory verbal therapy. A speech intelligibility rating scale evaluated the spontaneous speech of each child before and at frequent interval for 5 years after implantation. After cochlear implantation, the difference between the speech intelligibility, rating increased significantly each year for 3 years (P < 0.05). For the first year, the average rating remained "prerecognizable words" or "unintelligible speech". After 2 year of implantation the children had intelligible speech if someone concentrates and lip-reads (category 3). At the 4- and 5-year interval, 71.5 and 78% of children had intelligible speech to all listeners (category 5), respectively. So, 5 years after rehabilitation mode and median of speech intelligibility rating was five. Congenital and prelingually deaf children gradually develop intelligible speech that does not plateau 5 years after implantation.
    Full-text · Article · Dec 2007
  • [Show abstract] [Hide abstract] ABSTRACT: The somatic marker hypothesis provides a systems-level neuroanatomical and cognitive framework for decision making and the influence on it by emotion. The key idea of this hypothesis is that decision making is a process that is influenced by marker signals that arise in bioregulatory processes, including those that express themselves in emotions and feelings. This influence can occur at multiple levels of operation, some of which occur consciously and some of which occur non-consciously. Here we review studies that confirm various predictions from the hypothesis. The orbitofrontal cortex represents one critical structure in a neural system subserving decision making. Decision making is not mediated by the orbitofrontal cortex alone, but arises from large-scale systems that include other cortical and subcortical components. Such structures include the amygdala, the somatosensory/insular cortices and the peripheral nervous system. Here we focus only on the role of the orbitofrontal cortex in decision making and emotional processing, and the relationship between emotion, decision making and other cognitive functions of the frontal lobe, namely working memory.
    Article · Apr 2000
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