title: [Early positive component of the evoked potential of the midbrain tectum of the dogfish shark during electric stimulation of the optic nerve].
abstract: Midbrain tectal evoked responses to electric stimulation of the optic nerve were investigated in shark (Squalus acanthias). An early positive component was found as a part of negative phase of "classic" negative-positive evoked potential. Similar component was recorded from the ipsilateral tectal hemisphere as well. An increase of the positive component along with penetration of the electrode, its resistance to functional blockade by KCl application to the tectum surface and recording of a similar potential from the ventricular floor surface after extirpation of the tectum suggested the localization of the source of this component outside the tectum. Existence of a focus of maximal activity located in the rostral part of undertectal brain structures and disappearance of early positive component after functional blockade and extirpation of this brain area indicate the leading role of thalamic nuclei in generation of this component.
mesh_terms: D000818:Animals; D001931:Brain Mapping; D004284:Dogfish / Q000502:physiology*; D005074:Evoked Potentials, Visual; D009900:Optic Nerve / Q000502:physiology*; D012754:Sharks / Q000502:physiology*; D003336:Tectum Mesencephali / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology
vernacular_title: Ranniĭ pozitivnyĭ komponent vyzvannogo potentsiala kryshi srednego mozga koliucheĭ akuly pri élektrostimuliatsii zritel'nogo nerva.