Dynamic characteristics of visual evoked potentials in the dog. I. Cortical and subcortical potentials evoked by sine wave modulated light.

Brain Research Group, Institute of Medical Physics TNO, 45, Da Costakade, Utrecht The Netherlands
Electroencephalography and Clinical Neurophysiology 10/1970; 29(3):246-59. DOI: 10.1016/0013-4694(70)90137-9
Source: PubMed

ABSTRACT 1.1. Potentials evoked by sinusoidally modulated light (SML) were recorded from the lateral geniculate nucleus and occipital cortex of unanaesthetized dogs. The evoked potentials were analysed by discrete Fourier analysis.2.2. The harmonic components of SML evoked potentials were described by frequency response functions. The range of linear and non-linear behaviour was determined.3.3. A linear description was only possible regarding the SML evoked potentials recorded from the posterior marginal gyrus.4.4. Three types of non-linearities were characterized: saturation, non-linear oscillations responsible for the generation of subharmonics and essential non-linearities.5.5. The essential non-linearities correspond to rectification occurring in “on” and “off” neuronal populations; they were the dominant features of SML evoked potentials in the lateral geniculate nucleus and the calcarine region of occipital cortex, but not in the posterior marginal gyrus.6.6. The phase functions were shown to be determined in part by a delay time.7.7. The relations between SML evoked potential parameters and data obtained at the unit level are discussed.Résumé1.1. Les potentiels évoqués par une lumière modulée sinusoïdalement (LMS) ont été enregistrés au niveau du noyau géniculé latéral et du cortex occipital chez des chiens non-anesthésiés. Les potentiels évoqués ont été analysés par l'analyse de Fourier discrète.2.2. Les composantes harmoniques des potentiels évoqués par la LMS sont décrits par des fonctions amplitude/fréquence. La marge de comportement linéaire et non-linéaire est déterminée.3.3. Une description linéaire n'est possible que pour les potentiels évoqués par LMS enregistrés au niveau du gyrus marginal postérieur.4.4. Trois types de non-linéarité ont été définis: saturation, oscillation non-linéaire responsable de la production de sousharmoniques et non-linéarité essentielle.5.5. Les non-linéarités essentielles correspondent à une rectification survenant dans les populations neuroniques “on” et “off” ;elles constituent les données dominantes des potentiels évoqués par LMS dans le noyau géniculé latéral et la région calcarine du cortex occipital mais non dans le gyrus marginal postérieur.6.6. Les fonctions de phase se montrent déterminées partiellement par un temps de délai.7.7. Les relations entre les paramètres des potentiels évoqués par LMS et les données obtenues au niveau unitaire sont discutées.

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