Dougherty J, Pickens R
J Exp Anal Behav. 1973 Jul;20(1):111-8. doi: 10.1901/jeab.1973.20-111.
Fixed-interval schedules of intravenous cocaine presentation were examined as a function of injection dose (0.32 to 0.64 mg/kg) and interval duration (200 to 400 sec) in two rats. Cocaine was found to exert a dose-related temporal control over the initiation of responding that was unaffected by the fixed-interval contingency. Fixed-interval pause duration was linearly related to injection dose and was the same duration as the interresponse time found on continuous reinforcement schedules of cocaine presentation. The fixed-interval pause remained constant with changes in interval duration. Characteristic fixed-interval patterns of responding were observed. However, overall response rates were inversely related to injection dose and directly related to interval duration. Running response rates varied unsystematically with both variables. These findings are at variance with results typically found in studies of fixed-interval food and electric shock presentation.
在两只大鼠中，研究了静脉注射可卡因的固定间隔时间表与注射剂量（0.32至0.64毫克/千克）和间隔持续时间（200至400秒）之间的关系。发现可卡因对反应起始具有剂量相关的时间控制，且不受固定间隔条件的影响。固定间隔暂停持续时间与注射剂量呈线性相关，且与可卡因连续强化给药时间表上的反应间隔时间相同。随着间隔持续时间的变化，固定间隔暂停保持不变。观察到了典型的固定间隔反应模式。然而，总体反应率与注射剂量呈负相关，与间隔持续时间呈正相关。奔跑反应率随这两个变量无规律地变化。这些发现与固定间隔食物和电击给药研究中通常发现的结果不同。
