Do fast retinal oscillations play a role in vision? A study in the anesthetized and awake cat
Early physiologists were dazzled by the occurrence of high-amplitude, periodic oscillations, easily discernible in recording traces from the eye, optic tract and optic ganglia. Numerous studies thereafter pointed to retinal ganglion cell as the elements responsible for the generation of these fas...
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Retina Geniculado Oscilação Coerência Halotano Acordado CNPQ::OUTROS::CIENCIAS: NEUROCIÊNCIAS |
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Retina Geniculado Oscilação Coerência Halotano Acordado CNPQ::OUTROS::CIENCIAS: NEUROCIÊNCIAS Manços, Giovanne de Rosso Do fast retinal oscillations play a role in vision? A study in the anesthetized and awake cat |
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Early physiologists were dazzled by the occurrence of high-amplitude, periodic
oscillations, easily discernible in recording traces from the eye, optic tract and optic
ganglia. Numerous studies thereafter pointed to retinal ganglion cell as the
elements responsible for the generation of these fast rhythms, which were known to
propagate to the lateral geniculate and to the cortex. Only recently, however, these early
observations gained renewed interest, mainly in the light of recent theories linking
neuronal oscillations to various cognitive processes, such as perceptual binding, attention
and memory. In this context, fast retinal oscillations have been associated to the binding
of contiguous contours or surfaces, which in principle could support a fast feedforward
segmentation process. In addition, a series of experiments in the cat have shown that fast
oscillations in the retina may convey global stimulus properties, such as size. A limitation in these previous studies, however, was that most of them where were made in the anesthetized and paralyzed cat. Only a few early studies have been performed in the non-anesthetized but still paralyzed cat. Another concern was that, in these latter experiments, visual stimuli were often limited to ganzfeld flashes, far from
natural vision conditions. Moreover, very recently we made the surprising observation
that fast retinal oscillations depend strongly on halothane (and isoflurane) anesthesia. It
was therefore imperative to verify whether oscillatory activity is also present in the
awake cat, under naturalistic conditions, such as during free-viewing of a visual scene.
This is the main goal of the present study. Simultaneous multiple-electrode recordings were made from the lateral geniculate nucleus (LGN) and the retina of anesthetized cats (N= 3) and from the LGN
of an awake cat (N= 1). Comparisons were made for responses to natural movies and
flashed stationary light stimuli. To test specifically the role of retinal oscillations in
encoding stimulus size we designed a protocol made of a light circle of varying size along
the trial. Spike sorting techniques allowed us to study separately the ON- and OFFcomponents
of the responses. Analysis consisted in measuring synchronous oscillations
for single cell spiking activity in the time (sliding correlation analysis) and spectral
domains (multitaper spectral analysis, multitaper coherence). Our present results based
on single-cells extend our previous findings in the anesthetized cat, which were
restricted to an autocorrelation analysis of LGN mutiunitary responses. Both ON- and
OFF-responses to varying size stimuli show that coherent oscillations appear only after
the stimulus attained a minimum size of about 5° (depending on the contrast level),
suggesting that oscillations in the retina are rather limited in encoding subtle changes in
stimulus size. Recordings obtained directly from eye showed that oscillations in the
retina, as in the LGN, are highly correlated with the concentrations level of halothane.
Notably, in a series of sessions we were able to record LGN responses in an awake cat,
which was subsequently anesthetized with halothane, keeping the same recording site.
Oscillations were completely absent in the awake condition and appeared strong as usual
during the halothane anesthesia. Overall these results weaken substantially the notion that fast retinal oscillations are meaningful for vision. Nevertheless, as shown from our single cell analysis, retinal
oscillations share many of the properties of cortical gamma oscillations. In this respect,
oscillations in the retina induced by halothane serve as a valuable preparation, even
though artificial, for studying oscillatory neuronal dynamics. |
author2 |
Maciel, Sergio Tulio Neuenschwander |
author_facet |
Maciel, Sergio Tulio Neuenschwander Manços, Giovanne de Rosso |
format |
masterThesis |
author |
Manços, Giovanne de Rosso |
author_sort |
Manços, Giovanne de Rosso |
title |
Do fast retinal oscillations play a role in vision? A study in the anesthetized and awake cat |
title_short |
Do fast retinal oscillations play a role in vision? A study in the anesthetized and awake cat |
title_full |
Do fast retinal oscillations play a role in vision? A study in the anesthetized and awake cat |
title_fullStr |
Do fast retinal oscillations play a role in vision? A study in the anesthetized and awake cat |
title_full_unstemmed |
Do fast retinal oscillations play a role in vision? A study in the anesthetized and awake cat |
title_sort |
do fast retinal oscillations play a role in vision? a study in the anesthetized and awake cat |
publisher |
Brasil |
publishDate |
2017 |
url |
https://repositorio.ufrn.br/jspui/handle/123456789/22633 |
work_keys_str_mv |
AT mancosgiovannederosso dofastretinaloscillationsplayaroleinvisionastudyintheanesthetizedandawakecat |
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1773960773316378624 |
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ri-123456789-226332017-11-04T12:31:18Z Do fast retinal oscillations play a role in vision? A study in the anesthetized and awake cat Manços, Giovanne de Rosso Maciel, Sergio Tulio Neuenschwander http://lattes.cnpq.br/5090331396282908 Queiroz, Cláudio Marcos Teixeira de http://lattes.cnpq.br/3384801391828521 Baron, Jerome Paul Armand Laurent Retina Geniculado Oscilação Coerência Halotano Acordado CNPQ::OUTROS::CIENCIAS: NEUROCIÊNCIAS Early physiologists were dazzled by the occurrence of high-amplitude, periodic oscillations, easily discernible in recording traces from the eye, optic tract and optic ganglia. Numerous studies thereafter pointed to retinal ganglion cell as the elements responsible for the generation of these fast rhythms, which were known to propagate to the lateral geniculate and to the cortex. Only recently, however, these early observations gained renewed interest, mainly in the light of recent theories linking neuronal oscillations to various cognitive processes, such as perceptual binding, attention and memory. In this context, fast retinal oscillations have been associated to the binding of contiguous contours or surfaces, which in principle could support a fast feedforward segmentation process. In addition, a series of experiments in the cat have shown that fast oscillations in the retina may convey global stimulus properties, such as size. A limitation in these previous studies, however, was that most of them where were made in the anesthetized and paralyzed cat. Only a few early studies have been performed in the non-anesthetized but still paralyzed cat. Another concern was that, in these latter experiments, visual stimuli were often limited to ganzfeld flashes, far from natural vision conditions. Moreover, very recently we made the surprising observation that fast retinal oscillations depend strongly on halothane (and isoflurane) anesthesia. It was therefore imperative to verify whether oscillatory activity is also present in the awake cat, under naturalistic conditions, such as during free-viewing of a visual scene. This is the main goal of the present study. Simultaneous multiple-electrode recordings were made from the lateral geniculate nucleus (LGN) and the retina of anesthetized cats (N= 3) and from the LGN of an awake cat (N= 1). Comparisons were made for responses to natural movies and flashed stationary light stimuli. To test specifically the role of retinal oscillations in encoding stimulus size we designed a protocol made of a light circle of varying size along the trial. Spike sorting techniques allowed us to study separately the ON- and OFFcomponents of the responses. Analysis consisted in measuring synchronous oscillations for single cell spiking activity in the time (sliding correlation analysis) and spectral domains (multitaper spectral analysis, multitaper coherence). Our present results based on single-cells extend our previous findings in the anesthetized cat, which were restricted to an autocorrelation analysis of LGN mutiunitary responses. Both ON- and OFF-responses to varying size stimuli show that coherent oscillations appear only after the stimulus attained a minimum size of about 5° (depending on the contrast level), suggesting that oscillations in the retina are rather limited in encoding subtle changes in stimulus size. Recordings obtained directly from eye showed that oscillations in the retina, as in the LGN, are highly correlated with the concentrations level of halothane. Notably, in a series of sessions we were able to record LGN responses in an awake cat, which was subsequently anesthetized with halothane, keeping the same recording site. Oscillations were completely absent in the awake condition and appeared strong as usual during the halothane anesthesia. Overall these results weaken substantially the notion that fast retinal oscillations are meaningful for vision. Nevertheless, as shown from our single cell analysis, retinal oscillations share many of the properties of cortical gamma oscillations. In this respect, oscillations in the retina induced by halothane serve as a valuable preparation, even though artificial, for studying oscillatory neuronal dynamics. Os primeiros fisiologistas ficaram certamente impressionados com a existência de oscilações periódicas de alta amplitude, claramente visíveis nos traçados obtidos da retina, trato óptico e gânglios ópticos. Posteriormente vários estudos mostraram ser a células ganglionares os elementos responsáveis pela geração destes ritmos rápidos, que sabia-se podem propagar da retina ao geniculado lateral e ao córtex. Apenas recentemente, no entanto, estas observações ganharam novo interesse, principalmente a luz de teorias e conjecturas que atribuem às oscilações neuronais vários processos cognitivos, como a ligação perceptual, a atenção e a memória. Segundo esta hipótese, oscilações rápidas da retina seriam importantes para a ligação de contornos contíguos ou superfícies, podendo assim constituir um mecanismo feedforward importante na segmentação visual. Em acordo com estas noções, uma série de experimentos no gato mostraram que oscilações rápidas da retina podem ser informativas sobre propriedades globais do estímulo como o seu tamanho. Uma grande limitação nestes estudos, no entanto, foi o fato de terem sido feitos sob anestesia e paralisia. Apenas alguns experimentos foram realizados em gatos nãoanestesiados, mesmo assim, paralisados. Uma outra limitação foi o uso de estímulos visuais limitados a breves exposições, que ocupavam todo o campo visual, muito longe de condições naturais da visão. Por outro lado, muito recentemente, fizemos uma observação inesperada no nosso laboratório: oscilações rápidas da retina dependem fortemente da anestesia por halotano (e isoflurano). Tornou-se assim imperativo investigar se as oscilações rápidas da retina estão presentes ou não no gato não anestesiado, em condições naturais, como por exemplo durante a observação-livre de uma cena visual. Este é o principal objetivo deste estudo. Para isto, registros simultâneos através de eletródios-múltiplos foram feitos no geniculado lateral e na retina de gatos anestesiados (N= 3) e acordado (N= 1). Comparações foram feitas para respostas a filmes de cenas naturais e estímulos estacionários, como círculos luminosos. Para testar especificamente o papel das oscilações rápidas da retina na codificação do tamanho do estímulo visual aplicamos um protocolo que consiste em apresentar sobre os campos receptores um círculo luminoso de tamanho variável ao longo do tempo. Técnicas de separação de potenciaisde- ação nos permitiu estudar individualmente os componentes ON e OFF das respostas multi-unitárias. Nossa análise consistiu em obter medidas das oscilações sincrônicas para células isoladas ao longo do tempo no domínio temporal (análise de correlação por janela deslizante) e no domínio espectral (análise espectral por afunilamento múltiplo, coerência por afunilamento múltiplo). Estes resultados estendem os nossos achados prévios no gato anestesiado, que foram restritos à análise de auto-correlação de repostas multi-unitárias do geniculado lateral. Tanto as repostas ON como as respostas OFF a estímulos visuais de tamanho variável mostram que oscilações coerentes, que aparecem apenas para estímulos que atingem um tamanho mínimo de cerca de 5° (dependendo do nível de contraste do estímulo). Estes resultados sugerem que oscilações rápidas da retina codificam mal mudanças sutis no tamanho do estímulo visual. Como nos estudos anteriores no geniculado lateral, registros obtidos diretamente da retina mostraram que oscilações rápidas da retina são altamente dependentes dos níveis de anestesia por halotano. E mais importante, em uma série de experimentos pode-se registrar respostas do geniculado lateral em um gato acordado, que foi subsequentemente anestesiado por halotano, mantendo-se o mesmo sítio de registro. Oscilações rápidas da retina, ausentes durante a condição acordado, apareceram fortes como usualmente na condição de anestesia por halotano. Estes resultados como um todo enfraquecem substancialmente a noção de serem as oscilações rápidas da retina importantes para o processamento visual. Por outro lado, demonstram que oscilações rápidas da retina podem apresentar propriedades semelhantes a oscilações gama no cortex. Desta forma, oscilações da retina induzidas por halotano podem servir como uma preparação interessante, mesmo se artificial, para o estudo da dinâmica de oscilações neuronais. 2017-04-11T23:30:45Z 2017-04-11T23:30:45Z 2015-08-28 masterThesis MANÇOS, Giovanne de Rosso. Do fast retinal oscillations play a role in vision? A study in the anesthetized and awake cat. 2015. 58f. Dissertação (Mestrado em Neurociências) - Instituto do Cérebro, Universidade Federal do Rio Grande do Norte, Natal, 2015. https://repositorio.ufrn.br/jspui/handle/123456789/22633 por Acesso Aberto application/pdf Brasil UFRN PROGRAMA DE PÓS-GRADUAÇÃO EM NEUROCIÊNCIAS |