Structural and functional roles of KCC2 in developing cortex

Cation chloride cotransporters (CCCs) are critical for controlling intracellular chloride homeostasis. The CCC family is composed of four isoforms of K-Cl cotransporters (KCC1-4), two isoforms of Na-K-2Cl cotransporters (NKCC1-2), one Na-Cl cotransporter (NCC) and two the structurally related proteins with unknown function, CCC8 also known as cation-chloride cotransporter interaction protein, CIP, and CCC9. KCC2 is a neuron-specific isoform, which plays a prominent role in controlling the intracellular Cl- concentration in neurons and is responsible for producing the negative shift of GABAA responses from depolarizing to hyperpolarizing during neuronal maturation. In the present studies we first used in situ hybridization to examine the developmental expression patterns of the cation-chloride cotransporters KCC1-4 and NKCC1. We found that they display complementary expression patterns during embryonic brain development. Most interestingly, KCC2 expression in the embryonic central nervous system strictly follows neuronal maturation. In vitro data obtained from primary and organotypic neuronal cultures support this finding and revealed a temporal correlation between the expression of KCC2 and synaptogenesis. We found that KCC2 is highly expressed in filopodia and mature spines as well as dendritic shaft and investigated the role of KCC2 in spine formation by analyzing KCC2-/- neurons in vitro. Our studies revealed that KCC2 is a key factor in the maturation of dendritic spines. Interestingly, the effect of KCC2 in spine formation is not due to Cl- transport activity, but mediated through the interaction between KCC2 C-terminal and intracellular protein associated with cytoskeleton. The interacting protein we found is protein 4.1N by immunoprecipitation. Our results indicate a structural role for KCC2 in the development of functional glutamatergic synapses and suggest KCC2 as a synchronizer for the functional development of glutamatergic and GABAergic synapses in neuronal network. Studies on the regulatory mechanisms of KCC2 expression during development and plasticity revealed that synaptic activity of both the glutamatergic and GABAergic system is not required for up-regulation of KCC2 during development, whereas in acute mature hippocampal slices which undergo continuous synchronous activity induced by the absence of Mg2+ solution, KCC2 mRNA and protein expression were down-regulated in CA1 pyramidal neurons subsequently leading to a reduced capacity for neuronal Cl- extrusion. This effect is mediated by endogenous BDNF-TrkB down-stream cascades involving both Shc/FRS-2 and PLCγ-CREB signaling. BDNF mediated changes in KCC2 expression indicate that KCC2 is significantly involved in the complex mechanisms of neuronal plasticity during development and pathophysiological conditions.

Generation and Characterization of the Cation-Chloride Cotransporter KCC2 Hypomorphic Mouse

The cation-Cl- cotransporter (CCC) family comprises of Na+-Cl- cotransporter (NCC), Na+-K+-2Cl- cotransporters (NKCC1-2), and four K+-Cl- cotransporters (KCC1-4). These proteins are involved in several physiological activities, such as cell volume regulation. In neuronal tissues, NKCC1 and KCC2 are important in determining the intracellular Cl- levels and hence the neuronal responses to inhibitory neurotransmitters GABA and glycine. One aim of the work was to elucidate the roles for CCC isoforms in the control of nervous system development. KCC2 mRNA was shown to be developmentally up-regulated and follow neuronal maturation, whereas NKCC1 and KCC4 transcripts were highly expressed in the proliferative zones of subcortical regions. KCC1 and KCC3 mRNA displayed low expression throughout the embryogenesis. These expression profiles suggest a role for CCC isoforms in maturation of synaptic responses and in the regulation of neuronal proliferation during embryogenesis. The major aim of this work was to study the biological consequences of KCC2-deficiency in the adult CNS, by generating transgenic mice retaining 15-20% of normal KCC2 levels. In addition, by using these mice as a tool for in vivo pharmacological analysis, we investigated the requirements for KCC2 in tonic versus phasic GABAA receptor-mediated inhibition. KCC2-deficient mice displayed normal reproduction and life span, but showed several behavioral abnormalities, including increased anxiety-like behavior, impaired performance in water maze, alterations in nociceptive processing, and increased seizure susceptibility. In contrast, the mice displayed apparently normal spontaneous locomotor activity and motor coordination. Pharmacological analysis of KCC2-deficient mice revealed reduced sensititivity to diazepam, but normal gaboxadol-induced sedation, neurosteroid hypnosis and alcohol-induced motor impairment. Electrophysiological recordings from CA1-CA3 subregions of the hippocampus showed that KCC2 deficiency affected the reversal potentials of both the phasic and tonic GABA currents, and that the tonic conductance was not affected. The results suggest that requirement for KCC2 in GABAergic neurotransmission may differ among several functional systems in the CNS, which is possibly due to the more critical role of KCC2 activity in phasic compared to tonic GABAergic inhibition.

Ion-regulatory proreins in neuronal development and communication

Brain function is critically dependent on the ionic homeostasis in both the extra- and intracellular compartment. The regulation of brain extracellular ionic composition mainly relies on active transport at blood brain and at blood cerebrospinal fluid interfaces whereas intracellular ion regulation is based on plasmalemmal transporters of neurons and glia. In addition, the latter mechanisms can generate physiologically as well as pathophysiologically significant extracellular ion transients. In this work I have studied molecular mechanisms and development of ion regulation and how these factors alter neuronal excitability and affect synaptic and non-synaptic transmission with a particular emphasis on intracellular pH and chloride (Cl-) regulation. Why is the regulation of acid-base equivalents (H+ and HCO3-) and Cl- of such interest and importance? First of all, GABAA-receptors are permeable to both HCO3- and Cl-. In the adult mammalian central nervous system (CNS) fast postsynaptic inhibition relies on GABAA-receptor mediated transmission. Today, excitatory effects of GABAA-receptors, both in mature neurons and during the early development, have been recognized and the significance of the dual actions of GABA on neuronal communication has become an interesting field of research. The transmembrane gradients of Cl- and HCO3- determine the reversal potential of GABAA-receptor mediated postsynaptic potentials and hence, the function of pH and Cl- regulatory proteins have profound consequences on GABAergic signaling and neuronal excitability. Secondly, perturbations in pH can cause a variety of changes in cellular function, many of them resulting from the interaction of protons with ionizable side chains of proteins. pH-mediated alterations of protein conformation in e.g. ion channels, transporters, and enzymes can powerfully modulate neurotransmission. In the context of pH homeostasis, the enzyme carbonic anhydrase (CA) needs to be taken into account in parallel with ion transporters: for CO2/HCO3- buffering to act in a fast manner, CO2 (de)hydration must be catalyzed by this enzyme. The acid-base equivalents that serve as substrates in the CO2 dehydration-hydration reaction are also engaged in many carrier and channel mediated ion movements. In such processes, CA activity is in key position to modulate transmembrane solute fluxes and their consequences. The bicarbonate transporters (BTs; SLC4) and the electroneutral cation-chloride cotransporters (CCCs; SLC12) belong the to large gene family of solute carriers (SLCs). In my work I have studied the physiological roles of the K+-Cl- cotransporter KCC2 (Slc12a5) and the Na+-driven Cl--HCO3- exchanger NCBE (Slc4a10) and the roles of these two ion transporters in the modualtion of neuronal communication and excitability in the rodent hippocampus. I have also examined the cellular localization and molecular basis of intracellular CA that has been shown to be essential for the generation of prolonged GABAergic excitation in the mature hippocampus. The results in my Thesis provide direct evidence for the view that the postnatal up-regulation of KCC2 accounts for the developmental shift from depolarizing to hyperpolarizing postsynaptic EGABA-A responses in rat hippocampal pyramidal neurons. The results also indicate that after KCC2 expression the developmental onset of excitatory GABAergic transmission upon intense GABAA-receptor stimulation depend on the expression of intrapyramidal CA, identified as the CA isoform VII. Studies on mice with targeted Slc4a10 gene disruption revealed an important role for NCBE in neuronal pH regulation and in pH-dependent modulation of neuronal excitability. Furthermore, this ion transporter is involved in the basolateral Na+ and HCO3- uptake in choroid plexus epithelial cells, and is thus likely to contribute to cerebrospinal fluid production.

Developmental-like responses in injured mature central neurons

Traumatic insults to the central nervous system are frequently followed by profound and irreversible neuronal loss as well as the inability of the damaged neurons to regenerate. One of the major therapeutic challenges is to increase the amount of surviving neurons after trauma. Thus it is crucial to understand how injury affects neuronal responses and which conditions are optimal for survival to prevent neuronal loss. During development neuronal survival is thought to be dependent on the competition for the availability of survival-promoting molecules called neurotrophic factors. Much less is known on the survival mechanisms of mature neurons under traumatic conditions. Increasing amount of evidence points towards the possibility that after injury neuronal responses might aquire some developmental characteristics. One of the important examples is the change in the responses to the neurotransmitter GABA: it is inhibitory in the intact mature neurons, but can induce excitation during development and after trauma. An important step in the maturation of GABAergic transmission in the CNS is the developmental shift in the action of GABAA receptor from depolarization in immature neurons to hyperpolarization in mature neurons. GABAA-mediated responses are tightly linked to the homeostasis of the chloride anion (Cl-), which in neurons is mainly regulated by Na+-K+-2Cl- cotransporter NKCC1 and K+-Cl- cotransporter KCC2. Trauma-induced functional downregulation of KCC2 promotes a shift from hyperpolarizing GABAA-mediated responses to depolarizing. Other important consequences of neuronal trauma are the emergence of dependency of central neurons on brain-derived neuro¬trophic factor (BDNF) for survival, as well as the upregulation of neurotrophin receptor p75NTR. Our aim was to answer the question whether these post-traumatic events are interrelated, and whether the regulation of BDNF and KCC2 expression is different under traumatic conditions and in intact neurons. To study responses of injured mature central neurons, we used an in vitro and in vivo axotomy models. For in vitro studies, we lesioned organotypic hippocampal slices between CA3 and CA1 regions, which resulted in selective axotomy of the CA3 neurons and denervation of the CA1 neurons. Some experiments were repeated in vivo by lesioning the neurons of the corticospinal tract at the internal capsule level, or by lesioning spinal motoneurons at the ventral root. We show that intact mature neurons do not require BDNF for survival, whereas in axotomized neurons apoptosis is induced upon BDNF deprivation. We further show that post-traumatic dependency on BDNF is mediated by injury-induced upregulation of p75NTR. Post-traumatic increase in p75NTR is induced by GABAA-mediated depolarization, consequent opening of voltage-gated Ca2+ channels, and the activation of Rho kinase ROCK. Thus, post-traumatic KCC2 downregulation leads to the dependency on BDNF through the induction of p75NTR upregulation. Neurons that survive after axotomy over longer period of time lose BDNF dependency and regain normal KCC2 levels. This phenomenon is promoted by BDNF itself, since after axotomy contrary to normal conditions KCC2 is upregulated by BDNF. The developmentally important thyroid hormone thyroxin regulates BDNF expression during development. We show that in mature intact neurons thyroxin downregulates BDNF, whereas after axotomy thyroxin upregulates BDNF. The elevation of BDNF expression by thyroxin promoted survival of injured neurons. In addition, thyroxin also enhanced axonal regeneration and promoted the regaining of normal levels of KCC2. Thus we show that this hormone acts at several levels on the axotomy-initiated chain of events described in the present work, and could be a potential therapeutic agent for the injured neurons. We have also characterized a previously unknown downregulatory interaction between thyroxin and KCC2 in intact neurons. In conclusion, we identified several important interactions at the neurotrophin-protein and hormone-neurotrophin level that acquire immature-like characteristics after axotomy and elucidated an important part of the mechanism by which axotomy leads to the requirement of BDNF trophic support. Based on these findings, we propose a new potential therapeutic strategy where developmentally crucial agents could be used to enhance survival and regeneration of axotomized mature central neurons.

Functional expression and subcellular localization of the Cl- cotransporters KCC2 and NKCC1 in rodent hippocampal and neocortical neurons

The work presented here has focused on the role of cation-chloride cotransporters (CCCs) in (1) the regulation of intracellular chloride concentration within postsynaptic neurons and (2) on the consequent effects on the actions of the neurotransmitter gamma-aminobutyric acid (GABA) mediated by GABAA receptors (GABAARs) during development and in pathophysiological conditions such as epilepsy. In addition, (3) we found that a member of the CCC family, the K-Cl cotransporter isoform 2 (KCC2), has a structural role in the development of dendritic spines during the differentiation of pyramidal neurons. Despite the large number of publications dedicated to regulation of intracellular Cl-, our understanding of the underlying mechanisms is not complete. Experiments on GABA actions under resting steady-state have shown that the effect of GABA shifts from depolarizing to hyperpolarizing during maturation of cortical neurons. However, it remains unclear, whether conclusions from these steady-state measurements can be extrapolated to the highly dynamic situation within an intact and active neuronal network. Indeed, GABAergic signaling in active neuronal networks results in a continuous Cl- load, which must be constantly removed by efficient Cl- extrusion mechanisms. Therefore, it seems plausible to suggest that key parameters are the efficacy and subcellular distribution of Cl- transporters rather than the polarity of steady-state GABA actions. A further related question is: what are the mechanisms of Cl- regulation and homeostasis during pathophysiological conditions such as epilepsy in adults and neonates? Here I present results that were obtained by means of a newly developed method of measurements of the efficacy of a K-Cl cotransport. In Study I, the developmental profile of KCC2 functionality during development was analyzed both in dissociated neuronal cultures and in acute hippocampal slices. A novel method of photolysis of caged GABA in combination with Cl- loading to the somata was used in this study to assess the extrusion efficacy of KCC2. We demonstrated that these two preparations exhibit a different temporal profile of functional KCC2 upregulation. In Study II, we reported an observation of highly distorted dendritic spines in neurons cultured from KCC2-/- embryos. During their development in the culture dish, KCC2-lacking neurons failed to develop mature, mushroom-shaped dendritic spines but instead maintained an immature phenotype of long, branching and extremely motile protrusions. It was shown that the role of KCC2 in spine maturation is not based on its transport activity, but is mediated by interactions with cytoskeletal proteins. Another important player in Cl- regulation, NKCC1 and its role in the induction and maintenance of native Cl- gradients between the axon initial segment (AIS) and soma was the subject of Study III. There we demonstrated that this transporter mediates accumulation of Cl- in the axon initial segment of neocortical and hippocampal principal neurons. The results suggest that the reversal potential of the GABAA response triggered by distinct populations of interneurons show large subcellular variations. Finally, a novel mechanism of fast post-translational upregulation of the membrane-inserted, functionally active KCC2 pool during in-vivo neonatal seizures and epileptiform-like activity in vitro was identified and characterized in Study IV. The seizure-induced KCC2 upregulation may act as an intrinsic antiepileptogenic mechanism.

Manejo del ganado cunícola

El conejo es un animal herbivoro que se conoce de la antigüedad. Las civilizaciones mas antiguas como la china griega, egipcia e hindu, criaban conejos desde épocas muy remotas. De Grecia el conejo paso a España, en donde ya existia una buena cantidad de estos animales, razón por la que muchos autores han llegado a considerarla como " La tierra del conejo", significado en hebreo· del vocablo hispanja, de donde se deriva como tal el nombre de España. Es aceptado· que de España, el conejo paso al resto de Europa, en tanto en América, el conejo se conocia desde antes de la llegada de los colonizadores españoles, es asi como los indios Azteca de México, tenían . en gran consideración estos pequeños mamiferos, que entre otras cosas representaban la fecundidad y el nexo de lo conocido con lo inexplicable La utilidad que el hombre ha dado al conejo inicialmente ha sido como fuente de alimento, posteriormente utilizó sus pieles para confeccion ar vestimentas. En la actualidad el conejo tiene diversas utilidades en las diferentes ramas de la ciencia podemos encontrarlo como animal experimental a nivel de laboratorios, como vientres receptores temporales de embriones de ganado vacuno (En el caso de la coneja) para su posterior trasplante a las vacas, En la extraccion de suero sanguineo, para fabricar medio de cultivo y fabricar vacunas etc. No cabe duda que este anima, ha sido y sigue siendo de gran utilidad para el hombre por lo que se necesita de sus habitos y su conducta, para llevar a cabo una buena explotación y obtener así el mayor provecho y beneficio posible.

Fantasmas da televisão : o debate sobre a TV digital no Congresso Nacional

Analisa o debate político relativo à implantação da TV digital no Brasil, tendo como referência a audiência pública da Comissão de Ciência, Tecnologia, Comunicação e Informática da Câmara dos Deputados, realizada em 31 de janeiro de 2006, com a participação do ministro das Comunicações, Hélio Costa. Parte-se do pressuposto de que o Congresso Nacional exerceu relevante papel no debate relativo ao tema, mas não exerceu nenhuma influência na escolha do modelo de TV digital, rendendo-se à proposta do Executivo que, por sua vez, acatou o projeto de interesse dos empresários do setor. Constata-se que existem pelo menos três fantasmas que perseguem as empresas brasileiras de televisão: 1) a possibilidade de um novo marco regulatório para o setor de radiodifusão; 2) o aumento da concorrência; e 3) e a ameaça do fim do broadcast, o sistema de difusão de informações utilizado pelo rádio e pela televisão, em que há apenas um emissor e diversos receptores simultaneamente.

Transmissão vertical do hiv e transplante de fígado

"Aborda dois Projetos de Lei na área de saúde pública em tramitação no Congresso Nacional. As proposições referidas são: o Projeto de Lei n° 5522, de 2005, que dispõe sobre a obrigatoriedade da implementação de protocolo terapêutico para a prevenção da transmissão vertical do HIV, e o Projeto de Lei n.º 2.745, de 2003, que dispõe sobre as regras para elaboração da lista nacional de receptores de fígado do Sistema Nacional de Transplante."

Programa Fale Conosco da Câmara dos Deputados : é possível participar e interagir?

Procura conhecer o trabalho de atendimento das mensagens enviadas para o "Fale Conosco", canal de comunicação e interação com a sociedade da Câmara dos Deputados. Busca verificar, mais especificamente, como os provedores de informação, identificados nos órgãos considerados estatisticamente como os maiores receptores de mensagens, concebem o diálogo e a interação com o público externo à Casa. Examina, também, no processo dialógico gerado pela troca de mensagens, a percepção desses provedores quanto ao uso do canal como recurso facilitador de participação política. Para a consecução desse propósito, optou-se pela realização de pesquisa de cunho qualitativo por meio de entrevistas em cada órgão selecionado. São apresentadas questões de cunho teórico metodológico sobre a pesquisa qualitativa e a lógica interpretativa, e de cunho teórico sobre a Internet e os conceitos de governo eletrônico, democracia eletrônica, interação, interatividade e participação. A análise do material empírico parte de uma perspectiva hermenêutica em que se busca correlacionar concepções presentes nas entrevistas dos respondentes do Fale Conosco com algumas das perspectivas teóricas apresentadas. Espera-se com os resultados do estudo, poder contribuir para o enriquecimento dos debates que se fizerem futuramente sobre o serviço de atendimento das mensagens do Fale Conosco, principalmente, no que diz respeito aos seus aspectos valorativos.

[R_Clavijo_SanPrudencio] Intensive Program ERASMUS: TOPCART. Geometric Documentation of the Heritage (report of activities 2010-2011)

[EN] Data contained in this record come from the following accademic activity (from which it is possible to locate additional records related with the Monastery):

Regulación alfa1-adrenérgica de la corriente IKr cardiaca

149 p. : il., graf.

A técnica retórica da refutação no discurso da oposição e do governo : o caso da Contribuição Social para a Saúde (CSS)

Os discursos dos deputados federais Henrique Fontana (PT-RS) e Antônio Carlos Magalhães Neto (DEM-BA) sobre a criação da Contribuição Social para a Saúde (CSS) constituem o tema deste trabalho, cujos focos são o aspecto político-retórico e a utilização das técnicas do discurso clássico, especialmente a refutação, nas intervenções desses líderes. Conclui-se que os discursos políticos ainda consideram determinadas referências clássicas, embora com menos ênfase do que na antiguidade, e que novas mídias e auditórios externos são elementos recentes na relação entre o político e os receptores de suas peças oratórias.

Intensive Program ERASMUS: TOPCART. Geometric Documentation of the Heritage (administrative and academic documentation)

[EN] This academic activity has been the origin of other work that are also located in this repository. The first one is the dataset of information about the geometry of the Monastery recorded during the two years of fieldwork, then some bachelor thesis and papers are listed:

La dispersión urbana en el País Vasco. Los patrones de la redistribución espacial de la población y nuevas realidades residenciales y urbanísticas, 1991-2010

La investigación parte de la hipótesis de que la dispersión urbana que ha afectado a las sociedades avanzadas durante las últimas décadas, también ha cobrado fuerza y se ha impuesto en el País Vasco, transformando en pocos años el panorama urbanístico. La población vasca se ha desconcentrado espacialmente y al mismo tiempo la actividad inmobiliaria se ha intensificado y propagado por todo el territorio, afectando tanto a las periferias urbanas como a entornos más excéntricos con escaso dinamismo anterior. De este modo, en un contexto caracterizado por la globalización y los avances tecnológicos, se han generalizado realidades urbanas más dispersas, laxas y discontinuas que han ido desdibujando el anterior modelo urbano de mayor centralidad. Estos procesos territoriales se han afianzado durante las dos últimas décadas en el País Vasco, impulsados por el ciclo económico expansivo. Pero también han estado respaldados por los instrumentos de ordenación territorial, que en su propósito de reequilibrar la red de asentamientos han favorecido la reclasificación de abundante suelo en entornos alternativos a los tradicionales. Como consecuencia, ha tenido lugar un importante desarrollo residencial de asentamientos más periféricos, lo que ha propiciado la dispersión urbana. El emplazamiento y las características de los diferentes ámbitos receptores han canalizado la llegada de distintas clases sociales y se ha traducido en entornos residenciales diferentes. Mientras los espacios aledaños a los grandes centros y ejes urbanos se han desarrollado bajo formas más estandarizadas, en los ámbitos excéntricos pero dotados de amenidades ambientales y residenciales, los nuevos residentes presentan un nivel socioeconómico más elevado y la colonización ha sido más selecta.

Comportamento de bugios (Alouatta clamitans Cabrera, 1940) na Ilha Grande, RJ

Alouatta clamitans é uma espécie endêmica da Mata Atlântica, bioma que vem sendo continuamente reduzido, o que torna de extrema urgência o conhecimento sobre a espécie. No Estado do Rio de Janeiro, sua área de ocorrência abrange a região da Ilha Grande, município de Angra dos Reis. A Ilha Grande possui uma extensa área de preservação, o Parque Estadual da Ilha Grande, que atua na conservação de cerca de 62,5% da sua extensão. O isolamento das espécies em ilhas pode provocar o desenvolvimento de características morfológicas e comportamentais diferentes das espécies do continente. No entanto, não existem trabalhos sistematizados sobre a ecologia e o comportamento da espécie no local. Este estudo objetivou analisar aspectos do comportamento de Alouatta clamitans na Ilha Grande, contribuindo para uma melhor compreensão sobre a biologia da espécie. Durante nove meses foram registrados dados de composição social e comportamento de grupos da espécie através da amostragem por varredura instantânea e todas as ocorrências. Observou-se que o tamanho médio dos grupos foi de cinco indivíduos e a composição social por grupo foi representada por um a dois machos adultos, uma a três fêmeas adultas e imaturos de diferentes classes etárias, com predominância de grupos unimacho. Em média, os grupos eram compostos por 22% de machos adultos, 38% de fêmeas adultas, 4% de machos subadultos, 27% de juvenis e 9% de infantes. O comportamento mais observado foi o repouso (45,2%), seguido da alimentação (28%), movimentação (21,7%) e comportamento social (5,1%), e dentre os comportamentos sociais, o mais exibido foi a vocalização (45,8%), seguido dos comportamentos de catação (33,7%), agonístico (7,9%), brincadeira (5,8%), marcação (4,2%) e comportamento sexual (2,6%). Não foram encontradas diferenças estatisticamente significativas nestas atividades entre os períodos seco e chuvoso. As vocalizações foram predominantemente emitidas por machos e adultos e estiveram relacionadas ao encontro de grupos. O comportamento de catação teve as fêmeas adultas como principais iniciadoras e os machos adultos, principais receptores, sendo realizado durante o comportamento de repouso, após a cópula, após e durante encontro de grupos e após perseguições. Os comportamentos agonísticos tiveram relação com o encontro de grupos em 40% dos registros e em 33,3% destes ocorreu entre fêmeas e pareceu estar associado à disputa por alimento e espaço, mas não houve registros de agressão física. O comportamento de marcação envolveu a utilização da garganta e das costas e esteve relacionado com encontros inter-grupais e com a ocorrência de chuvas. Cinco cópulas foram registradas no período de estudo nos meses de setembro, outubro e fevereiro e tiveram duração menor que um minuto. Nos encontros com primatas de outras espécies, os bugios pareceram neutros em relação aos estímulos. Os dados obtidos sobre a composição dos grupos, padrão de atividades e comportamentos sociais observados na Ilha Grande, de maneira geral, mostraram-se semelhantes aos resultados obtidos em outros trabalhos sobre a espécie e o gênero, de maneira que podemos concluir que os grupos, mesmo residentes em ilha, não demonstraram modificações comportamentais significativas que possam diferenciar-lhes de populações estudadas no continente.