RESUMO
The parabigeminal nucleus (PBG) is the mammalian homologue to the isthmic complex of other vertebrates. Optogenetic stimulation of the PBG induces freezing and escape in mice, a result thought to be caused by a PBG projection to the central nucleus of the amygdala. However, the isthmic complex, including the PBG, has been classically considered satellite nuclei of the Superior Colliculus (SC), which upon stimulation of its medial part also triggers fear and avoidance reactions. As the PBG-SC connectivity is not well characterized, we investigated whether the topology of the PBG projection to the SC could be related to the behavioral consequences of PBG stimulation. To that end, we performed immunohistochemistry, in situ hybridization and neural tracer injections in the SC and PBG in a diurnal rodent, the Octodon degus. We found that all PBG neurons expressed both glutamatergic and cholinergic markers and were distributed in clearly defined anterior (aPBG) and posterior (pPBG) subdivisions. The pPBG is connected reciprocally and topographically to the ipsilateral SC, whereas the aPBG receives afferent axons from the ipsilateral SC and projected exclusively to the contralateral SC. This contralateral projection forms a dense field of terminals that is restricted to the medial SC, in correspondence with the SC representation of the aerial binocular field which, we also found, in O. degus prompted escape reactions upon looming stimulation. Therefore, this specialized topography allows binocular interactions in the SC region controlling responses to aerial predators, suggesting a link between the mechanisms by which the SC and PBG produce defensive behaviors.
Assuntos
Comportamento Animal/fisiologia , Reação de Fuga/fisiologia , Medo/fisiologia , Vias Neurais/fisiologia , Octodon/fisiologia , Colículos Superiores/fisiologia , Teto do Mesencéfalo/fisiologia , Animais , Mapeamento Encefálico , Feminino , Masculino , OptogenéticaRESUMO
We evaluated the extent to which manipulation of early olfactory environment can influence social behaviours in the South American Hystricognath rodent Octodon degus. The early olfactory environment of newborn degus was manipulated by scenting all litter members with eucalyptol during the first month of life. The social behaviour of sexually mature animals (5-7 months old) towards conspecifics was then assessed using a y-maze to compare the response of control (naïve) and treated animals to two different olfactory configurations (experiment 1): (i) a non-familiarized conspecific impregnated with eucalyptol (eucalyptol arm) presented against (ii) a non-familiarized unscented conspecific (control arm). In addition, in dyadic encounters, we assessed the behaviour of control and eucalyptol treated animals towards a non-familiarized conspecific scented with eucalyptol (experiment 2). We found that control subjects explored and spent significantly less time in the eucalyptol arm, indicating neophobic behaviours towards the artificially scented conspecific. Treated subjects explored and spent similar time in both arms of the maze, showing the same interest for both olfactory stimuli presented. During dyadic encounters in experiment 2, an interaction effect between early experience and sex was observed. Control males escaped and avoided their scented partner more frequently than eucalyptol treated male subjects and than females. Both groups did not differ in the exploration of their scented partners, suggesting that avoidance within agonistic context does not relate to neophobic behaviours. Our results suggest that the exposure to eucalyptol during early ontogeny decreases evasive behaviours within an agonistic context as a result of olfactory learning. Altogether, these results indicate that olfactory cues learned in early ontogeny can influence olfactory-guided behaviours in adult degus.
Assuntos
Comportamento Animal , Meio Ambiente , Octodon/fisiologia , Percepção Olfatória , Comportamento Social , Animais , Animais Recém-Nascidos , Sinais (Psicologia) , Feminino , Relações Interpessoais , Masculino , Aprendizagem em Labirinto , Fatores de TempoRESUMO
El objetivo de esta investigación fue determinar la adherencia a las sesiones de hemodiálisis de 71 pacientes con insuficiencia renal crónica (IRC), que asistieron a las sesiones programadas por el Hospital Militar Central, entre los meses de abril, mayo yjunio de 2007. Para recolectar la información se utilizaron dos cuestionarios: el primero, para caracterizar la población de estudio, y el segundo, para registrar la asistencia. En los resultados se halló un porcentaje de cumplimiento del 98.6 por ciento (1939 sesiones cumplidas de 1967 programadas); por tanto, sólo se incumplió el 1.4 por ciento (28) de las sesiones. Entre los factores que permitieron mantener la adherencia a las sesiones de hemodiálisis se identificaron: la concientización de estos pacientes sobre las consecuencias de la inasistencia a las sesiones de hemodiálisis, que los expone al descontrol de la enfermedad y a que el tratamiento sea ineficaz; la conformidad con el horario de las sesiones; la satisfacción con el personal de salud que los atiende y la aceptación de la enfermedad.