Interval timing, the ability to encode and retrieve the memory of intervals from seconds to minutes, guides fundamental animal behaviors across the phylogenetic tree. In Pavlovian fear conditioning, an initially neutral stimulus (conditioned stimulus, CS) predicts the arrival of an aversive unconditioned stimulus (US, generally a mild foot-shock) at a fixed time interval. Although some studies showed that temporal relations between CS and US events are learned from the outset of conditioning, the question of the memory of time and its underlying neural network in fear conditioning is still poorly understood. The aim of the present study was to investigate the role of the dorsal striatum in timing intervals in odor fear conditioning in male rats. To assess the animal’s interval timing ability in this paradigm, we used the respiratory frequency. This enabled us to detect the emergence of temporal patterns related to the odor-shock time interval from the early stage of learning, confirming that rats are able to encode the odor-shock time interval after few training trials. We carried out reversible inactivation of the dorsal striatum before the acquisition session and before a shift in the learned time interval, and measured the effects of this treatment on the temporal pattern of the respiratory rate. In addition, using intracerebral microdialysis, we monitored extracellular dopamine level in the dorsal striatum throughout odor-shock conditioning and in response to a shift of the odor-shock time interval. Contrary to our initial predictions based on the existing literature on interval timing, we found evidence suggesting that transient inactivation of the dorsal striatum may favor a more precocious buildup of the respiratory frequency’s temporal pattern during the odor-shock interval in a manner that reflected the duration of the interval. Our data further suggest that the conditioning and the learning of a novel time interval were associated with a decrease in dopamine level in the dorsal striatum, but not in the nucleus accumbens. These findings prompt a reassessment of the role of the striatum and striatal dopamine in interval timing, at least when considering Pavlovian aversive conditioning.

间隔时间，编码和检索从几秒到几分钟的间隔记忆的能力，指导整个系统发育树的基本动物行为。在巴甫洛夫恐惧条件反射中，最初的中性刺激（条件刺激，CS）预测厌恶的无条件刺激（美国，通常是轻微的足部电击）以固定的时间间隔到达。尽管一些研究表明，CS 和 US 事件之间的时间关系是从条件反射开始就学习的，但在恐惧条件反射中时间记忆及其潜在神经网络的问题仍然知之甚少。本研究的目的是调查背侧纹状体在雄性大鼠气味恐惧调节时间间隔中的作用。为了评估该范例中动物的间隔计时能力，我们使用了呼吸频率。这使我们能够从学习的早期阶段检测到与气味休克时间间隔相关的时间模式的出现，确认大鼠在几次训练试验后能够编码气味休克时间间隔。我们在采集会话之前和学习时间间隔的变化之前对背侧纹状体进行了可逆的灭活，并测量了这种治疗对呼吸频率时间模式的影响。此外，使用脑内微透析，我们在整个气味休克调节过程中监测背侧纹状体中的细胞外多巴胺水平，并响应气味休克时间间隔的变化。与我们基于现有关于间隔时间的文献的初步预测相反，我们发现有证据表明背侧纹状体的短暂失活可能有利于在气味休克间隔期间以反映间隔持续时间的方式更早熟地积累呼吸频率的时间模式。我们的数据进一步表明，新时间间隔的调节和学习与背侧纹状体中多巴胺水平的降低有关，但与伏隔核无关。这些发现促使人们重新评估纹状体和纹状体多巴胺在间隔时间中的作用，至少在考虑巴甫洛夫厌恶条件反射时是这样。我们的数据进一步表明，新时间间隔的调节和学习与背侧纹状体多巴胺水平的降低有关，但与伏隔核无关。这些发现促使人们重新评估纹状体和纹状体多巴胺在间隔时间中的作用，至少在考虑巴甫洛夫厌恶条件反射时是这样。我们的数据进一步表明，新时间间隔的调节和学习与背侧纹状体中多巴胺水平的降低有关，但与伏隔核无关。这些发现促使人们重新评估纹状体和纹状体多巴胺在间隔时间中的作用，至少在考虑巴甫洛夫厌恶条件反射时是这样。