Gibson Evelyn, Reed Phil
St George's Hospital London, UK.
J Autism Dev Disord. 2005 Dec;35(6):851-9. doi: 10.1007/s10803-005-0030-9.
The present study explored whether a similar phenomenon to stimulus over-selectivity occurred in rats, in the hope of establishing a non-human model for the autism. Rats were serially presented with two-15 seconds, two-element compound stimuli prior to the delivery of food, in an appetitive classical conditioning procedure. Each compound stimulus consisted of two lights. Once the rats had acquired a conditioned response (CR) to the stimuli, they were presented with each of the component elements separately in extinction. The rats demonstrated greater conditioning to components of the compound presented just prior to reinforcement than to the components of the temporally distant compound. However, there was a smaller difference between CRs to the components of the compound presented just prior to reinforcement (i.e. less overshadowing) than between the components of the temporally distant compound. It is suggested that rats demonstrated a form of stimulus over-selectivity, resulting in greater overshadowing of one cue by another. Such results may form the basis of a viable non-human model of this symptom of autistic spectrum disorder.
本研究探讨了大鼠是否会出现与刺激过度选择性类似的现象，以期建立一种自闭症的非人类模型。在食欲性经典条件反射程序中，在给予食物之前，依次向大鼠呈现两个15秒的双元素复合刺激。每个复合刺激由两盏灯组成。一旦大鼠对刺激获得了条件反应（CR），就在消退过程中分别向它们呈现每个组成元素。与时间上较远的复合刺激的组成部分相比，大鼠对紧接强化之前呈现的复合刺激的组成部分表现出更强的条件作用。然而，紧接强化之前呈现的复合刺激的组成部分的条件反应之间的差异较小（即遮蔽较少），比时间上较远的复合刺激的组成部分之间的差异小。研究表明，大鼠表现出一种刺激过度选择性的形式，导致一个线索对另一个线索的遮蔽作用更强。这些结果可能构成自闭症谱系障碍这一症状可行的非人类模型的基础。
