ACOUSTICALLY EVOKED POTENTIALS IN THE RAT DURING CONDITIONING.
MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS
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Acoustically evoked potentials were recorded from unanesthetized rats in a series of experiments designed to study changes in evoked potentials during conditioning. It is shown that when clicks are established as conditional stimuli CS in conditioned emotional response CER situations, click-evoked potentials recorded from central auditory structures and from mesencephalic reticular formation exhibit amplitude increases. Similar increases were found with Sidman avoidance conditioning. These changes during aversive conditioning were not related to acquired discriminative properties of the acoustic stimulus, since similar changes in click-evoked potentials were found when a CER was elicited by a photic CS. The changes were shown to be independent of movement-related variables. Potentials evoked in central auditory structures by electrical stimulation of the cochlear nucleus or cochlea increased in amplitude during acquisition of a CER. In one CER situation nearly all movement was eliminated through methods of behavioral control, and data-sampling techniques provided a control for residual differences in amount of movement during CS and control periods. These procedures did not eliminate increases in click-evoked potentials during conditioning. In general, whenever behavioral measures indicated that rats were frightened, acoustically evoked potentials exhibited increased amplitudes, whether or not a CS was present, but only changes in late components of click-evoked potentials were consistently related to observed behavioral changes. Author
- Anatomy and Physiology