Navegando por Autor "DIAS, Ivanira Amaral"

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Acesso aberto (Open Access)
Morphometric analysis of feedforward pathways from the primary somatosensory area (S1) of rats
(Universidade Federal do Pará, 2016-05) SÁ, Andrea Lima de; BAHIA, Carlomagno Pacheco; DIAS, Ivanira Amaral; BATISTA, C.; LEAL, Walace Gomes; PINHO, André Luís Santos de; HOUZEL, Jean Christophe; DINIZ, Cristovam Wanderley Picanço; PEREIRA JÚNIOR, Antônio; CORREA, Vânia Castro
We used biotinylated dextran amine (BDA) to anterogradely label individual axons projecting from primary somatosensory cortex (S1) to four different cortical areas in rats. A major goal was to determine whether axon terminals in these target areas shared morphometric similarities based on the shape of individual terminal arbors and the density of two bouton types: en passant (Bp) and terminaux (Bt). Evidence from tridimensional reconstructions of isolated axon terminal fragments (n=111) did support a degree of morphological heterogeneity establishing two broad groups of axon terminals. Morphological parameters associated with the complexity of terminal arbors and the proportion of beaded Bp vs stalked Bt were found to differ significantly in these two groups following a discriminant function statistical analysis across axon fragments. Interestingly, both groups occurred in all four target areas, possibly consistent with a commonality of presynaptic processing of tactile information. These findings lay the ground for additional work aiming to investigate synaptic function at the single bouton level and see how this might be associated with emerging properties in postsynaptic targets.
Acesso aberto (Open Access)
Plasticidade de modalidade cruzada em córtices sensoriais adulto
(Universidade Federal do Pará, 2018-12-21) DIAS, Ivanira Amaral; BOTELHO, Eliã Pinheiro; http://lattes.cnpq.br/6276864906384922; PEREIRA JÚNIOR, Antônio; http://lattes.cnpq.br/1402289786010170; BAHIA, Carlomagno Pacheco; http://lattes.cnpq.br/0910507988777644
The central nervous system (CNS) neural circuitry is highly dynamic and is continuously modified by sensory experience, in a process we call neuroplasticity, which gives the CNS the ability to adapt to changes in the sensory periphery and / or in response to environmental stimuli . This ability of the CNS remains lifelong, although it is more intense during early stages of development, especially during the critical plasticity period. The main goal of the present work was to evaluate the effects of bilateral sensory deprivation on cross modal neuroplasticity in the visual, somatosensory, and auditory primary cortices od adult rats. Animals (Rattus novergicus) (authorization CEUA/UFPA: 141-13) were divided into three experimental groups: a control group (CTL), an unimodal deprivation group (DEP), in which the animals were subjected to visual deprivation by bilateral enucleation, and a bimodal deprivation group (DDEP), whose animals were submitted to both visual and whisker deprivation bilaterallly. After 60 days of sensory deprivation, the rats were perfused and the brains were sectioned in the coronal plane for immunohistochemistry procedures aimed at revealing the activation of immediate early genes (c-Fos). The results showed that after bilateral visual deprivation the number of c-Fos+ neurons decreased in the visual cortex (** p < 0.0056), increased in the auditory cortex (** p <0.0099), and had no effect in the somatosensory cortex. Bilateral visual and whisker deprivation decreased the number of c-Fos+ neurons in the visual cortex (* p <0.0268) but did not have any effect in the somatosensory and auditory cortices.