Department of Psychology and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, B.C., Canada V6T 1Z3.
Department of Psychology and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, B.C., Canada V6T 1Z3
J Neurosci. 2020 Jun 10;40(24):4773-4787. doi: 10.1523/JNEUROSCI.0414-20.2020. Epub 2020 May 11.
Flexible initiation or suppression of actions to avoid aversive events is crucial for survival. The prelimbic (PL) and infralimbic (IL) regions of the medial prefrontal cortex (mPFC) have been implicated in different aspects of avoidance and reward-seeking, but their respective contribution in instigating versus suppressing actions in aversive contexts remains to be clarified. We examined mPFC involvement in different forms of avoidance in rats well trained on different cued lever-press avoidance tasks. Active/inhibitory avoidance required flexible discrimination between auditory cues signaling foot-shock could be avoided by making or withholding instrumental responses. On a simpler active avoidance task, a single cue signaled when a lever press would avoid shock. PL inactivation disrupted active but not inhibitory avoidance on the discriminative task while having no effect on single-cued avoidance. In comparison, IL inactivation broadly impaired active and inhibitory avoidance. Conversely, on a cued appetitive go/no-go task, both IL and PL inactivation impaired inhibitory but not active reward-seeking, the latter effect being diametrically opposite to that observed on the avoidance task. These findings highlight the complex manner in which different mPFC regions aid in initiating or inhibiting actions in the service of avoiding aversive outcomes or obtaining rewarding ones. IL facilitates active avoidance but suppress inappropriate actions in appetitive and aversive contexts. In contrast, contextual valence plays a critical role in how the PL is recruited in initiating or suppressing actions, which may relate to the degree of cognitive control required to flexibly negotiate response or motivational conflicts and override prepotent behaviors. Choosing to make or withhold actions in a context-appropriate manner to avoid aversive events or obtain other goals is a critical survival skill. Different medial prefrontal cortex (mPFC) regions have been implicated in certain aspects of avoidance, but their contributions to instigating or suppressing actions remains to be clarified. Here, we show that the dorsal, prelimbic (PL) region of the medial PFC aids active avoidance in situations requiring flexible mitigation of response conflicts, but also aids in withholding responses to obtain rewards. In comparison the ventral infralimbic (IL) cortex plays a broader role in active and inhibitory avoidance as well as suppressing actions to obtain rewards. These findings provide insight into mechanisms underlying normal and maladaptive avoidance behaviors and response inhibition.
灵活地启动或抑制行动以避免厌恶事件对于生存至关重要。内侧前额叶皮层（mPFC）的额前皮质（PL）和下边缘皮质（IL）区域已被牵涉到回避和寻求奖励的不同方面，但它们在回避和厌恶环境中启动和抑制行动方面的各自贡献仍有待阐明。我们在经过不同的线索按压回避任务训练的大鼠中检查了 mPFC 在不同形式回避中的作用。主动/抑制性回避需要灵活区分听觉线索，通过进行或不进行工具性反应来避免足底电击。在更简单的主动回避任务中，单一线索表示按压杠杆可以避免电击。PL 失活破坏了区分任务中的主动回避但不影响抑制性回避，而对单一线索回避没有影响。相比之下，IL 失活广泛损害了主动和抑制性回避。相反，在线索性奖赏 Go/No-Go 任务中，IL 和 PL 失活均损害了抑制性但不损害主动性奖赏寻求，后者的效果与在回避任务中观察到的效果截然相反。这些发现强调了不同 mPFC 区域在启动或抑制行动以避免厌恶结果或获得奖励方面的复杂方式。IL 促进了主动回避，但在奖赏和厌恶环境中抑制了不适当的行为。相比之下，上下文效价在 PL 被招募以启动或抑制行动的方式中起着关键作用，这可能与灵活解决反应或动机冲突并克服优势行为所需的认知控制程度有关。以适当的方式选择进行或不进行行动以避免厌恶事件或获得其他目标是一项关键的生存技能。不同的内侧前额叶皮层（mPFC）区域已被牵涉到某些回避方面，但它们对启动或抑制行动的贡献仍有待阐明。在这里，我们表明，内侧 PFC 的背侧、额前皮质（PL）区域有助于在需要灵活缓解反应冲突的情况下进行主动回避，但也有助于抑制反应以获得奖励。相比之下，腹侧下边缘皮质（IL）在主动和抑制性回避以及抑制获得奖励的行动方面发挥了更广泛的作用。这些发现为正常和适应不良的回避行为和反应抑制的机制提供了深入的了解。
