Cognitive and Neuroscience Research Center (CNRC), Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran.
Department of Psychology, Faculty of Education, Islamic Azad University, Garmsar Branch, Tehran, Iran.
Psychopharmacology (Berl). 2017 Nov;234(22):3407-3416. doi: 10.1007/s00213-017-4722-6. Epub 2017 Sep 8.
The effects of pharmacological interventions on fear memory have widely been studied, but there are very few studies about the effects of brain electrical stimulation on fear memory function.
Therefore, our aim was to determine whether anodal/cathodal transcranial direct current stimulation (tDCS) over the right frontal cortex would modify propranolol-induced contextual and auditory fear memory deficits, before or after training.
The adult NMRI male mice were randomly assigned into three groups: the sham group, the anodal tDCS group, and the cathodal tDCS group. Fear memories were evaluated using a classical fear conditioning apparatus.
While the anodal stimulation did not affect fear retrieval, post-training cathodal stimulation improved fear memory retrieval. Regardless of when propranolol (0.1 mg/kg) was administered, it impaired fear memory retrieval. However, when anodal stimulation and propranolol were applied prior to the training, contextual fear memory retrieval was increased and auditory fear memory was reversed. An enhanced contextual retrieval was also observed when propranolol was administered prior to the training and stimulation occurred after the training. Only when the stimulation occurred prior to the training and propranolol was administered after the training was there a selective improvement in contextual fear memory retrieval, leaving the auditory fear memory retrieval impaired. Interestingly, cathodal stimulation improved the effects of propranolol on auditory fear memory only when it occurred prior to the training.
The results highlight possible improving effects for anodal/cathodal tDCS on propranolol-induced deficits on fear memories. The timing of the interventions related to the specific phases of memory formation is important in modulating fear behaviors.
药物干预对恐惧记忆的影响已得到广泛研究，但关于脑电刺激对恐惧记忆功能的影响的研究却很少。
因此，我们的目的是确定在训练前后，右额皮质的阳极/阴极经颅直流电刺激（tDCS）是否会改变普萘洛尔引起的情境和听觉恐惧记忆缺陷。
成年 NMRI 雄性小鼠被随机分为三组：假刺激组、阳极 tDCS 组和阴极 tDCS 组。使用经典的恐惧条件反射装置评估恐惧记忆。
虽然阳极刺激不会影响恐惧记忆的检索，但训练后的阴极刺激可改善恐惧记忆的检索。无论何时给予普萘洛尔（0.1mg/kg），都会损害恐惧记忆的检索。然而，当在训练前给予阳极刺激和普萘洛尔时，情境恐惧记忆检索增加，听觉恐惧记忆反转。当在训练前给予普萘洛尔，而刺激发生在训练后时，也观察到情境检索的增强。只有当刺激发生在训练前，而普萘洛尔在训练后给予时，才会选择性地改善情境恐惧记忆检索，而听觉恐惧记忆检索仍然受损。有趣的是，只有在训练前进行阴极刺激时，阴极刺激才会改善普萘洛尔对听觉恐惧记忆的影响。
结果强调了阳极/阴极 tDCS 对普萘洛尔引起的恐惧记忆缺陷的可能改善作用。干预的时间与记忆形成的特定阶段有关，对于调节恐惧行为很重要。
