Walasek G, Zieliński K
Acta Neurobiol Exp (Wars). 1987;47(1):1-18.
Stable conditioned enhancement of barpressing in rats was elicited by darkness stimulus signaling continuous food reinforcement (CRF) component of a multiple schedule in which 2.5 min variable interval reinforcement (VI) constituted the second component. Conditioned enhancement was rapidly acquired and resistant to extinction. In some groups concurrent alimentary and defensive training was conducted in which darkness signaled food CRF and acoustic white noise signaled inescapable foot shock, both presented against the 2.5 min VI food reinforcement schedule. The continuous reinforcement schedule and/or conditioned enhancement showed a decremental effect on conditioned suppression, but only when defensive trials were less frequent than trials with continuous reinforcement of barpresses. Residual enhancement of barpressing after termination of the stimulus eliciting conditioned enhancement, observed at early stages of training, was then changed to a slight decrease of the barpressing rate. Opposite changes were observed after the offset of the stimulus eliciting conditioned suppression. Changes in intertrial response rates are considered as reflecting the summation of stimuli possesing oposite motivational values.
在大鼠中，通过黑暗刺激引发稳定的条件性压杆增强，黑暗刺激标志着多重时间表中的连续食物强化（CRF）成分，其中2.5分钟可变间隔强化（VI）构成第二个成分。条件性增强迅速获得且抗消退。在一些组中进行了同时的进食和防御训练，其中黑暗标志着食物CRF，声学白噪声标志着不可逃避的足部电击，两者都与2.5分钟VI食物强化时间表相对。连续强化时间表和/或条件性增强对条件性抑制有递减作用，但仅当防御性试验比连续强化压杆试验频率低时才会出现。在训练早期观察到，引发条件性增强的刺激终止后，压杆的残余增强随后变为压杆率略有下降。在引发条件性抑制的刺激消失后观察到相反的变化。试验间反应率的变化被认为反映了具有相反动机值的刺激的总和。
