Hippocampal and lateral entorhinal cortex physiological activity during trace conditioning under urethane anesthesia
Hippocampal and lateral entorhinal cortex physiological activity during trace conditioning under urethane anesthesia
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DOI：
10.1152/jn.00293.2020
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发表时间：
2020-09-01
影响因子：
2.5
通讯作者：
Reyes, Marcelo Bussotti
中科院分区：
文献类型：
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作者：
de Oliveira, Eliezyer Fermino;Dickson, Clayton Thomas;Reyes, Marcelo Bussotti
大量证据表明，延迟条件反射的获得可以发生在无意识状态下，如麻醉状态。然而，目前还不清楚在非清醒状态下，动物可以达到什么程度和什么类型的条件反射。痕迹条件反射是一个有吸引力的协议，在麻醉下研究，考虑到长期的空白间隙分离的条件和非条件刺激，这必须桥接收购发生。在这里，我们显示的证据表明，大鼠在麻醉下的跟踪条件反射范式的生理反应。本研究记录了麻醉大鼠海马（HPC）和外侧内嗅皮层（LEC）的活动，并进行了沿着肌电图和心电图检查。该方案包括随机呈现两种不同的声音刺激（CS-和CS+），其中只有一种刺激（CS+）被分配为与足电击配对。试验平均值分析显示，动物在CS发作时开始出现显著的爬升心率活动，并在跟踪期间持续存在。CS-和CS+都出现了这种爬升，斜率相似，但截距不同，表明CS+心率通常高于CS-。HPC和LEC高频带（>100 Hz）的功率和相干性在CS呈现和跟踪期间显著增加，类似于CS-和CS+，并且对激活或失活状态不敏感。据我们所知。这是第一次尝试在麻醉状态下执行痕量调节协议。确认这一过程的获得可以为探索大脑机制提供新的准备，这些机制将时间不连续的事件联系在一起。新&值得注意的是，某些形式的学习，如某些类型的条件反射，可以在麻醉状态下发生。然而，在这些状态下记忆能在多大程度上形成仍然是一个悬而未决的问题。在这里，我们研究了乌拉坦麻醉下的痕迹条件反射，发现心率，海马和外侧内嗅皮层的生理变化，以刺激的介绍。这种新的准备可能允许探索非清醒大脑中时间不连续事件的记忆获取。
Significant evidence shows that the acquisition of delay conditioning can occur in out-of-awareness states, such as under anesthesia. However, it is unclear to what extent and what type of conditioning animals may achieve during nonawake states. Trace conditioning is an appealing protocol to study under anesthesia, given the long empty gap separating the conditioned and unconditioned stimuli, which must be bridged for acquisition to happen. Here, we show evidence that rats develop physiological responses during the trace conditioning paradigm under anesthesia. We recorded the activity of the hippocampus (HPC) and lateral entorhinal cortex (LEC) in urethane-anesthetized rats, along with an electromyogram and an electrocardiogram. The protocol consisted of randomly presenting two distinct sound stimuli (CS- and CS+), where only one stimulus (CS+) was assigned to be trace-paired with a footshock. A trial-average analysis revealed that animals developed significant climbing heart rate activity initiating at the CS onset and persisting during the trace period. Such climbing arose for both CS- and CS+ with similar slopes but different intercepts, suggesting CS+ heart rates were typically above CS-. The power and coherence of HPC and LEC high-frequency bands (>100 Hz) significantly increased during CS presentation and trace, similarly to CS- and CS+ and insensitive to either activated or deactivated states. To the best of our knowledge. this is the first attempt to perform a trace conditioning protocol under anesthesia. Confirmation of this procedure acquisition can allow a new preparation for the exploration of brain mechanisms that bind time-discontinuous events.NEW & NOTEWORTHY Some forms of learning, such as some types of conditioning, can occur in anesthetized states. However, the extent to which memories can be formed in these states is still an open question. Here, we investigated the trace conditioning under urethane anesthesia and found heart rate, hippocampus, and lateral entorhinal cortex physiological changes to stimuli presentation. This new preparation may allow for exploration of memory acquisition of time-discontinuous events in the nonawake brain.