[The behavioral reactions of fresh-water crayfish to sensory exposures: the autonomic components]. / Povedencheskie reaktsii presnovodnykh rakov na sensornye vozdeistviia: vegetativnye komponenty.

Sudden changes of the environment such as a short-lasting shadowing of an animal, placing of some small objects into the tank, light vibrations of the bottom etc. Caused vegetative responses in the freely moving native crayfish Astacus astacus and the American crayfish Procambarus cubensis adapted for many generations to aquarium habitat. We observed mainly a sudden decrease of ECG-frequency correlated with similar changes in the electrical activity of the muscles moving the specific ventilatory appendages, scaphognathites (scaphognathite-gram, SGG). Rise of the ECG and SGG rate was shown during and after the illumination of dark-adapted animals. The rate changes could be coincided with different changes of the amplitude of both ECG- and SGG-waves. It should be noticed that these vegetative responses took place mostly without any body movements of the animal. We suggest that the crayfish responses to sudden environmental changes are similar to mammalian orienting response; probably they also include an emotional component.

[Effect of preliminary presentation of a future conditioned stimulus on the rate of elaboration of an instrumental defensive reflex in the rat]. / Vliianie predvaritel'nogo pred"iavleniia budushchego uslovnogo razdrazhitelia na skorost' vyrabotki instrumental'nogo oboronitel'nogo refleksa u krys.

Preliminary presentation of future conditioned stimulus without reinforcement delayed and then accelerated subsequent elaboration of defensive conditioned reflex to this stimulus in rats. Preliminary presentation of resembling stimuli influenced the speed of conditioning in a lesser degree. It is suggested that such changes are due to formation of a local conditioned reflex to the future conditioned stimulus.