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| Natura: | Artículo científico |
| Lingua: | en |
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Academia Brasileira de Ciências
2001
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| Accesso online: | https://www.redalyc.org/articulo.oa?id=32773306 |
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| _version_ | 1866556805358813184 |
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| author | Vera M. Fernandes-de-Lima |
| author_facet | Vera M. Fernandes-de-Lima |
| contents | Wave onset in central gray matter its intrinsic optical signal and phase transitions in extracellular polymers Vera M. Fernandes-de-Lima João E. Kogler Jocelyn Bennaton Wolfgang Hanke Multidisciplinaria (Ciencias Naturales y Exactas) polymers INTRODUCTION spreading depression extracellular matrix central gray matter The brain is an excitable media in which excitationwaves propagate at several scales of time and space. Onedimensionalaction potentials (millisecond scale) along the axon membrane, and spreading depressionwaves(seconds to minutes) at the three dimensions of the gray matter neuropil (complex of interacting membranes)are examples of excitation waves. In the retina, excitation waves have a prominent intrinsic optical signal(IOS). This optical signal is created by light scatter and has different components at the red and blue end ofthe spectrum. We could observe the wave onset in the retina, and measure the optical changes at the criticaltransition from quiescence to propagating wave. The results demonstrated the presence of fluctuationspreceding propagation and suggested a phase transition. We have interpreted these results based on anextrapolation from Tasakis experiments with action potentials and volume phase transitions of polymers.Thus, the scatter of red light appeared to be a volume phase transition in the extracellular matrix that wascaused by the interactions between the cellular membrane cell coat and the extracellular sugar and proteincomplexes. If this hypothesis were correct, then forcing extracellular current flow should create a similarsignal in another tissue, provided that this tissue was also transparent to light and with a similarly narrowextracellular space. This control tissue exists and it is the crystalline lens. We performed the experimentsand confirmed the optical changes. Phase transitions in the extracellular polymers could be an important partof the long-range correlations found during wave propagation in central nervous tissue. 2001 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32773306 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.3 Vol.73 |
| format | Artículo científico |
| id | redalyc_32773306 |
| language | en |
| publishDate | 2001 |
| publisher | Academia Brasileira de Ciências |
| spellingShingle | Wave onset in central gray matter its intrinsic optical signal and phase transitions in extracellular polymers Vera M. Fernandes-de-Lima Multidisciplinaria (Ciencias Naturales y Exactas) polymers INTRODUCTION spreading depression extracellular matrix central gray matter Wave onset in central gray matter its intrinsic optical signal and phase transitions in extracellular polymers Vera M. Fernandes-de-Lima João E. Kogler Jocelyn Bennaton Wolfgang Hanke Multidisciplinaria (Ciencias Naturales y Exactas) polymers INTRODUCTION spreading depression extracellular matrix central gray matter The brain is an excitable media in which excitationwaves propagate at several scales of time and space. Onedimensionalaction potentials (millisecond scale) along the axon membrane, and spreading depressionwaves(seconds to minutes) at the three dimensions of the gray matter neuropil (complex of interacting membranes)are examples of excitation waves. In the retina, excitation waves have a prominent intrinsic optical signal(IOS). This optical signal is created by light scatter and has different components at the red and blue end ofthe spectrum. We could observe the wave onset in the retina, and measure the optical changes at the criticaltransition from quiescence to propagating wave. The results demonstrated the presence of fluctuationspreceding propagation and suggested a phase transition. We have interpreted these results based on anextrapolation from Tasakis experiments with action potentials and volume phase transitions of polymers.Thus, the scatter of red light appeared to be a volume phase transition in the extracellular matrix that wascaused by the interactions between the cellular membrane cell coat and the extracellular sugar and proteincomplexes. If this hypothesis were correct, then forcing extracellular current flow should create a similarsignal in another tissue, provided that this tissue was also transparent to light and with a similarly narrowextracellular space. This control tissue exists and it is the crystalline lens. We performed the experimentsand confirmed the optical changes. Phase transitions in the extracellular polymers could be an important partof the long-range correlations found during wave propagation in central nervous tissue. 2001 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32773306 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.3 Vol.73 |
| title | Wave onset in central gray matter its intrinsic optical signal and phase transitions in extracellular polymers |
| topic | Multidisciplinaria (Ciencias Naturales y Exactas) polymers INTRODUCTION spreading depression extracellular matrix central gray matter |
| url | https://www.redalyc.org/articulo.oa?id=32773306 |