Fogel S M, Smith C T, Beninger R J
Centre for Neuroscience Studies, Queen's University.
Department of Psychology, Trent University.
Behav Neurosci. 2010 Feb;124(1):79-86. doi: 10.1037/a0018244.
Newly formed memories are initially fragile and require consolidation to be transformed into an enduring state. Memory consolidation may occur during increased postlearning REM sleep. REM deprivation during these periods (termed REM sleep windows [RSWs]) impairs subsequent performance. The pedunculopontine nucleus (PPT) and adjacent deep mesencephalic reticular nuclei (DpMe) have been implicated in the generation of REM sleep. Following 24-hr baseline recording, rats were trained on the 2-way avoidance task for 50 trials/day over 2 days and retested on Day 3. EEG was recorded 22 hr after training on training Days 1 and 2. Rats were injected with the GABAB agonist baclofen or saline into the PPT/DpMe region at 0300 to coincide with the start of a known RSW. Based on shuttle performance, saline rats were assigned post hoc to a learning group (LG) that avoided the footshock at least 60% at retest or nonlearning group (NLG) that performed below this criterion. Baclofen-injected rats were not assigned post hoc into separate groups as all rats performed below the learning criterion. PPN/DpMe infusions of the inhibitory GABAB agonist baclofen decreased REM and impaired subsequent memory performance. Normal GABAergic transmission in the PPN/DpMe may be necessary for REM to occur and for the consolidation of incentive learning.
新形成的记忆最初是脆弱的，需要巩固才能转化为持久状态。记忆巩固可能发生在学习后快速眼动睡眠增加期间。在这些时期（称为快速眼动睡眠窗口[RSW]）剥夺快速眼动睡眠会损害随后的表现。脚桥核（PPT）和相邻的中脑深部网状核（DpMe）与快速眼动睡眠的产生有关。在进行24小时基线记录后，大鼠在双向回避任务上进行训练，每天训练50次，持续2天，并在第3天进行重新测试。在训练的第1天和第2天训练后22小时记录脑电图。在03:00将GABAB激动剂巴氯芬或生理盐水注入大鼠的PPT/DpMe区域，以与已知的快速眼动睡眠窗口开始时间一致。根据穿梭箱表现，事后将生理盐水处理的大鼠分为学习组（LG），即在重新测试时至少60%能避免足部电击，或非学习组（NLG），其表现低于该标准。注射巴氯芬的大鼠未事后分为单独的组，因为所有大鼠的表现均低于学习标准。在PPT/DpMe中注入抑制性GABAB激动剂巴氯芬会减少快速眼动睡眠并损害随后记忆表现。PPT/DpMe中正常的GABA能传递对于快速眼动睡眠的发生和奖励学习的巩固可能是必要的。
