title: Contingency learning and causal detection in Hermissenda: II. Cellular mechanisms.
abstract: Neural correlates of contingency-sensitive behavioral changes in the nudibranch Hermissenda were studied by in vitro conditioning of the isolated nervous system. The additions of unpaired light-alone or hair cell-alone stimulation presentations to sequences of light-hair cell stimulation pairings were found to attenuate the cumulative depolarization of Type B photoreceptors that normally result from pairings. Unpaired light presentations produced a transitory depression of the light-induced depolarizing generator potential of the B cell. Unpaired hair cell stimulation synaptically hyperpolarized the B photoreceptor and thus acted in a retroactive manner to partially reverse the cumulative depolarization owing to prior pairings. Behavioral experiments revealed a striking temporal specificity for the decremental effects of added light and rotational stimulation. The present experiments indicate that contiguity and contingency relations are both encoded and stored in the Type B photoreceptors, and to a first approximation reflect similar biophysical mechanisms.
mesh_terms: D000818:Animals; D001245:Association Learning / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D003214:Conditioning, Classical / Q000502:physiology*; D005071:Evoked Potentials; D007473:Ion Channels / Q000502:physiology; D007858:Learning / Q000502:physiology*; D008027:Light; D008465:Mechanoreceptors / Q000502:physiology; D008974:Mollusca / Q000502:physiology*; D009949:Orientation / Q000502:physiology; D010153:Paired-Associate Learning / Q000502:physiology; D011188:Potassium / Q000378:metabolism
chemical_list: D007473:Ion Channels; D011188:Potassium; D002118:Calcium