SHIMOJO Implicit Brain Function Project, Exploratory Research for Advanced Technology, Japan Science and Technology Agency, NTT Atsugi Research and Development Center 3-1 Morinosatowakamiya, Atsugi-shi, Kanagawa 243-0198, Japan.
Brain Res. 2010 Jun 25;1342:94-103. doi: 10.1016/j.brainres.2010.04.050. Epub 2010 Apr 25.
Drug cravings are elicited by environmental stimuli associated with the rewarding effects of drugs. As an animal model of such associative learning, conditioned place preference (CPP) is widely used. Since the hippocampus is closely related to reward memory and the hippocampal local field potential (LFP), and in particular the theta rhythm is known to be associated with bodily movements, the theta rhythm might be one of the key neural substrates. On the basis of this assumption, we recorded the behaviors and hippocampal LFP of eight rats during cocaine-induced acquisition and expression of CPP. The earliest appearance of phase-locked theta activity was observed before the rats entered the cocaine-paired environment after conditioning; after entrance, the theta disappeared. This phase-locked theta was stronger when the rats stayed for a long time in the cocaine-paired environment. Our observation suggested that the phase-locked hippocampal theta rhythm is related to the approaching behavior of the rat caused by reward memory. Thus, the role of the hippocampus in drug craving should be emphasized further.
药物渴望是由与药物奖赏效应相关的环境刺激引起的。条件位置偏爱（CPP）作为这种联想学习的动物模型被广泛应用。由于海马体与奖赏记忆密切相关，海马体局部场电位（LFP），特别是θ节律与身体运动有关，因此θ节律可能是关键的神经基质之一。基于这一假设，我们记录了 8 只大鼠在可卡因诱导的 CPP 获得和表达过程中的行为和海马 LFP。在训练后大鼠进入可卡因配对环境之前，我们观察到了最早出现的锁相θ活动；进入环境后，θ消失了。当大鼠在可卡因配对环境中停留较长时间时，这种锁相θ活动更强。我们的观察表明，锁相海马θ节律与由奖赏记忆引起的大鼠接近行为有关。因此，应进一步强调海马在药物渴望中的作用。
