RESUMO
Single-unit recordings of the nucleus of the optic tract (NOT) under visual stimulation were performed in 5 opossums. Most of the units were directionally selective. Receptive fields for the contralateral eye lie mainly in the contralateral field while those for the ipsilateral eye were mainly in the ipsilateral field. As the nasal retina does not project ipsilaterally, recrossing must occur in the pathway from the retina to the ipsilateral NOT. Possible sites for this recrossing are discussed.
Assuntos
Quiasma Óptico/fisiologia , Campos Visuais/fisiologia , Vias Visuais/fisiologia , Animais , Eletrofisiologia , Movimentos Oculares , GambásRESUMO
The chick retina in vitro preparation was used to quantify the effect of Na+ and Cl- on the velocity of propagation of spreading depression (SD). The progressive reduction of chloride concentration in the superfusing Ringer solution, either by partial removal of NaCl or by its partial substitution with isethionate, caused a logarithmic increase in the velocity of propagation of SD. Substituting Tris for Na+ had no appreciable effect on propagation velocity, suggesting that the propagation of the reaction is not necessarily dependent on Na+. However, choline did not substitute for Na+ because it decreased propagation velocity and, at higher concentrations, even blocked the spread of the reaction.
Assuntos
Cloro/farmacologia , Depressão Alastrante da Atividade Elétrica Cortical/efeitos dos fármacos , Retina/efeitos dos fármacos , Sódio/farmacologia , Animais , Galinhas , Soluções Isotônicas , Solução de Ringer , Cloreto de Sódio/metabolismoRESUMO
Single-unit recordings of the nucleous of the optic tract (NOT) under visual stimulation were performed in 5 opossums. Most of the units were directionally selective. Receptive fields for the contralateral eye lie mainly in the contralateral field while those for the ipsilateral eye were mainly in the ipsilateral field. As the nasal does not project ipsilaterally, recrossing must occur in the pathway from the retina to the ipsilateral NOT. Possible sites for this recrossing are discussed
Assuntos
Animais , Quiasma Óptico/fisiologia , Campos Visuais/fisiologia , Vias Visuais/fisiologia , Eletrofisiologia , Movimentos Oculares , GambásRESUMO
The chick retina in vitro preparation was used to quantify the effect of Na+ and Cl- on the velocity of propagation of spreading depression (SD). The progressive reduction of chloride concentration in the superfusing Ringer solution, solution, either by partial removal of NaCl or by its partial substitution with isethionate, caused a logarithmic increase in the velocity of propagation of SD. Substituting Tris for Na+ had no appreciable effect on propagation velocity, suggesting that the propagation of the reaction is not necessarily dependent con Na+. Howeverm choline did not substitute for Na+ because it decreased propagation velocity and, at higher concentration, even blocked the spread of the reaction