Bryant Kathleen G, Barker Jacqueline M
Department of Pharmacology and Physiology, Drexel University, Philadelphia, PA, United States.
Front Neurosci. 2020 Dec 17;14:615337. doi: 10.3389/fnins.2020.615337. eCollection 2020.
When environmental cues or stimuli that represent both rewarding and aversive outcomes are presented, complex computations must be made in order to determine whether approach or avoidance is the better behavioral strategy. In many neuropsychiatric illnesses these computations can be skewed. In some instances, circumstances that may normally warrant avoidance instead promote approach, thus producing compulsive-like behavioral strategies that are inflexible in response to new or conflicting information. Alternatively, high sensitivity to aversion or low sensitivity to reward can result in the failure to achieve goals and loss of resilience that characterizes depressive disorders. Increases in compulsive-like behavior have been found to be associated with disrupted signaling in regions that regulate response to conflicting stimuli, including the hippocampus. Classic behavioral inhibition theories of hippocampus function in anxiety suggest that the hippocampus blocks aberrant behavior in response to anxiety related cues or stimuli. The hippocampus may act to block approach in the face of conflicting stimuli. Dysregulations of hippocampal function, as may be present in neuropsychiatric disorders, may therefore promote aberrant approach behavior. The ventral hippocampus (vHPC) subregion is key for coordinating this approach/avoidance conflict resolution, likely through its participation with cortico-striatal and mesolimbic circuits. We revisit Gray's behavioral inhibition theory of HPC function, first posited in the 1980s, and interpret in the context of new knowledge on vHPC function gained through modern technology. Taken together with the extant, classical literature on hippocampal function, we propose that these new findings suggest that vHPC circuits balance behavioral response to conflicting stimuli in a manner that is both state- and context-dependent and, further, that disruption of specific vHPC circuits tips the balance in favor of biased approach or avoidance behavioral strategies.
当呈现代表奖励和厌恶结果的环境线索或刺激时，必须进行复杂的计算，以确定接近还是回避是更好的行为策略。在许多神经精神疾病中，这些计算可能会出现偏差。在某些情况下，通常需要回避的情况反而会促使接近，从而产生类似强迫的行为策略，这种策略对新的或相互矛盾的信息缺乏灵活性。或者，对厌恶的高敏感性或对奖励的低敏感性可能导致无法实现目标以及丧失韧性，这是抑郁症的特征。已发现类似强迫行为的增加与调节对冲突刺激反应的区域（包括海马体）中的信号传导中断有关。海马体在焦虑中功能的经典行为抑制理论表明，海马体在面对与焦虑相关的线索或刺激时会阻止异常行为。面对冲突刺激时，海马体可能会阻止接近行为。神经精神疾病中可能存在的海马体功能失调，因此可能会促进异常的接近行为。腹侧海马体（vHPC）子区域对于协调这种接近/回避冲突解决至关重要，可能是通过其参与皮质-纹状体和中脑边缘回路来实现的。我们重新审视了格雷在20世纪80年代首次提出的海马体功能行为抑制理论，并在通过现代技术获得的关于vHPC功能的新知识背景下进行解释。结合现有的关于海马体功能的经典文献，我们提出这些新发现表明，vHPC回路以一种既依赖状态又依赖情境的方式平衡对冲突刺激的行为反应，而且，特定vHPC回路的破坏会使平衡倾向于有偏差的接近或回避行为策略。
