Aprendizagem de discriminação operante em pombos (Columba livia) destelencefalados : implicações para o estudo da plasticidade neural
Operant discriminative behavior provides a useful baseline for analyzing the effects of lesions both for mammal and avian brains. The neural substrates of thediscriminative behavior include integrative functions by telencephalic and subtelencephalic systems. The present work was conducted to analyze behavior under discrimination contingencies and morphological characteristics of visual pathway components in detelencephated pigeons. Adult pigeons divide into different groups according to lesion and learning conditions were used: pigeons submitted to telencephalic lesions and learning (LA), sham-Iesion-Iearning (SA), non-syrgery-Iearning (NA) or non-lesion-non learning (NN).Behavioral analysis was carried out through key pecking conditioning, operant discrimination and reversal discrimination learning training. After experimental procedure pigeons were perfused and their brains were used stained according to Klüver-Barrera techique. Pigeons LA and NN were submitted to morphometric analysis. Brains of nontrained lesioned pigeosn (LNA) and sham-Iesionedtrained pigeons (LSA) were submitted to immunohistochemical analysis of neurofilament (NF) and glial fibrillary acidic protein (GFAP). The morphometric and immunohistochemicalanalyses were realized in the Optic Tectum (OT) and nucleus Rotundus (Rt). LL and control group comparisons showed that lesioned birds had more sessions for key peck acquisition and steady-state behavior (p< 0.05). Rt increases were observed in perimeter, neuronal soma and vascularity (p< 0.05), contrasting with a decreased number ofneurons (p< 0.05). The OT analysis showed a major disorganization in celllayers and was associated to increased thickness of layers 1,2 e 3. The GFAP immunohistochemistry showed an astrocytic reaction in the Rt and OT (p<0,02). The NF immunohistochemistry demonstrated a decreased NF immunoreativity (IR) in the Rt in layers ofthe OT in lesioned pigeons The number ofNF immunoreactive (ir) nerve terminais was decreaesd in the analised regions. The overall data demonstrated that telencephalic systems are not essentiai for discrimination learning but have a function in the acquisition of key pecking and reversal learning. The long-term analysis of detelencephalated pigeons demonstrated a degeneration of the visual neuronal pathway and long lasting activation of astrocytes. These evidences of plastic changes of subtelencephalic systems after long-term detelencephalated suggest functional mechanisms correlated with learning and neural plasticity in pigeons.
Advisor:Elenice A. de Moraes Ferrari; Gerson Chadi; Elenice A. de Moraes Ferrari [Orientador]; Carlos Alexandre Netto; Luis Roberto Giorgetti Britto; Francesco Langone; Luiz Marcellino de Oliveira
School:Universidade Estadual de Campinas
Source Type:Master's Thesis
Keywords:pombo aprendizagem discriminatoria lesão cerebral neurologia
Date of Publication:05/26/1997