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Electrical coupling provided by connexins (Cx) in gap junctions (GJ) plays important roles in both the developing and the mature retina. In mammalian nocturnal species, Cx36 is an essential component in the rod pathway, the retinal circuit specialized for night, scotopic vision. Here, we report the expression of Cx36 in a species (Gallus gallus) that phylogenetic development endows with an essentially rodless retina. Cx36 gene is very highly expressed in comparison with other Cxs previously described in the adult retina, such as Cx43, Cx45, and Cx50. Moreover, real-time PCR, Western blot, and immunofluorescence all revealed that Cx36 expression massively increased over time during development. We thoroughly examined Cx36 in the inner and outer plexiform layers, where this protein was particularly abundant. Cx36 was observed mainly in the off sublamina of the inner plexiform layer rather than in the on sublamina previously described in the mammalian retina. In addition, Cx36 colocalized with specific cell markers, revealing the expression of this protein in distinct amacrine cells. To investigate further the involvement of Cx36 in visual processing, we examined its functional regulation in retinas from dark-adapted animals. Light deprivation markedly up-regulates Cx36 gene expression in the retina, resulting in an increased accumulation of the protein within and between cone synaptic terminals. In summary, the developmental regulation of Cx36 expression results in particular circuitry-related roles in the chick retina. Moreover, this study demonstrated that Cx36 onto- and phylogenesis in the vertebrate retina simultaneously exhibit similarities and particularities.

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Although the impact of education and age on executive functions (EF) has been widely studied, the influence of daily cognitive stimulation on EF has not been sufficiently investigated. Therefore, the aim of the present study was to evaluate whether the age, education, and frequency of reading and writing habits (FRWH) of healthy adults could predict their performance on measures of inhibition and cognitive flexibility. Inhibition speed, inhibitory control, and set shifting were assessed using speed, accuracy, and discrepancy scores on the Trail-Making Test (TMT) and Hayling Test. Demographic characteristics and the FRWH were assessed using specialized questionnaires. Regression analyses showed that age and the FRWH predicted speed and accuracy on the TMT. The FRWH predicted both speed and accuracy on the Hayling Test, for which speed and accuracy scores were also partly explained by age and education, respectively. Surprisingly, only the FRWH was associated with Hayling Test discrepancy scores, considered one of the purest EF measures. This highlights the importance of regular cognitive stimulation over the number of years of formal education on EF tasks. Further studies are required to investigate the role of the FRWH so as to better comprehend its relationship with EF and general cognition.

The present study compared decision-making processing between patients with traumatic brain injury (TBI) and healthy controls. The study also sought to identify dissociations in the frequency of deficits in executive functions (EF) tasks that mainly assess decision making (DM; hot component) and inhibition (cold component) following TBI. The sample was composed of 16 post-TBI adults aged between 18 and 68 years and 16 healthy controls matched by age and education. Decision-making was assessed with the Iowa Gambling Task (IGT), and inhibitory control was assessed with the Trail Making Task (TMT) and Hayling Test. No differences were found between groups in total scores and block scores on the IGT. However, TBI patients preferred the disadvantageous decks, with no evidence of learning during the task. Seven patients presented dissociations between deficient DM on the IGT and accurate inhibition on the Hayling Test and TMT. Conversely, five patients presented partial dissociations between deficits in the IGT and TMT and opposite performance in the Hayling Test. Only three patients exhibited deficits on all of the instruments. These results indicate that patients can maintain comparable performance on the IGT after TBI. Therefore we found dissociations in hot and cold executive components.

Results indicate poor DM on the IGT in patients with TBI, regardless of lesion location and severity. The instrument proved to be equally sensitive to both frontal and extrafrontal lesions and did not differentiate between patients with mild and severe TBI.

In this article we discuss the effect of verb type on subject/verb agreement in Brazilian Portuguese and compare its effect with subject position and animacy. We analyze a sample of 4601 tokens (64 speakers) with verbs categorized along traditional lines (main, linking, and auxiliary) as well with verbs categorized along other traditional and generative lines (transitive, intransitive, linking, auxiliary/modal, and existential). None of the verb-type variables were selected as statistically significant. Subject position and animacy are the variables that reveal significant influence on subject/verb agreement; the only characteristic of the verb chosen is phonetic salience of the singular/plural opposition. KEY-WORDS: subject/verb agreement; type of verb; subject position and animacy; phonetic salience.RESUMO: Discutimos neste texto o efeito do tipo de verbo na concordância verbal no português brasileiro em confronto com o efeito da posição e da animacidade do sujeito. Analisamos 4601 dados (64 falantes) com os verbos categorizados numa perspectiva tradicional (nocional, de ligação e auxiliar) e também dados com os verbos categorizados D.E.L. T.A., 23:esp., 2007 (283-317)

Apoptosis is genetically programmed cell death, an irreversible process of cell senescence with characteristic features different from other cellular mechanisms of death such as necrosis. In the last years, apoptosis has been extensively studied in the scientific literature, because it has been established that apoptosis plays a crucial role following the time course of chronic degenerative diseases, such as cancer. Thus, several researchers have strugged to detect what chemical agents are able to inter fere with the apoptotic process. Thus, the purpose of this literature review is to assess if fluoride induces apoptosis in mammalian cells using in vivo and in vitro test systems. Certain mammalian cell types such as oral cells, blood and brain were exetensively investigated; the results showed that fluoride is able to induce apoptosis in both intrinsinc and extrinsic pathways. Moreover, other cells types have been poorly investigated such as bone, kidney and reproductive cells with conflicting results so far. Therefore, this area needs further investigation for the safety of human populations exposed to fluoride in a chronic way, as for example in developing countries.