McNaughton Neil, Wickens Jeff
Department of Psychology, Neuroscience Centre, University of Otago, Dunedin, New Zealand.
Cortex. 2003 Sep-Dec;39(4-5):1139-63. doi: 10.1016/s0010-9452(08)70882-7.
The hippocampus has been proposed as a key component of a "behavioural inhibition system". We explore the implications of this idea for the nature of associative memory--i.e. learning that is distinct from the moulding of response sequences by error correction and reinforcement. It leads to the view that all associative memory depends on purely Hebbian mechanisms. Memories involve acquisition of new goals not the strengthening of new stimulus-response links. Critically, memories will consist of affectively positive and affectively negative associations as well "purely cognitive" information. The hippocampus is seen as a supervisor that is normally "just checking" information about current available goals. When one available goal is pre-eminent there is no hippocampal output and the goal controls the response system. When two or more goals are similarly and highly primed there is conflict. This is detected by the hippocampus which sends output that increases the valence of affectively negative perceptions and so resolves the conflict by suppressing more aversive goals. Such conflict resolution occurs with innate as well as acquired goals and is fundamentally non-memorial. But, in memory paradigms, it can often act to suppress interference on the current trial and, through Hebbian association of the increase in negative affect, decrease the probability of interference on later trials and during consolidation. Both memory-driven and innate behaviour is made hippocampal-dependent by innate and acquired conflicting tendencies and not the class of stimulus presented.
海马体被认为是“行为抑制系统”的关键组成部分。我们探讨了这一观点对联想记忆本质的影响——即这种学习不同于通过错误纠正和强化来塑造反应序列。这导致了一种观点，即所有联想记忆都依赖于纯粹的赫布机制。记忆涉及获取新目标，而不是强化新的刺激-反应联系。至关重要的是，记忆将由情感上积极和消极的联想以及“纯粹认知”信息组成。海马体被视为一个监督者，通常只是“检查”有关当前可用目标的信息。当一个可用目标占主导地位时，海马体没有输出，该目标控制反应系统。当两个或更多目标被同样高度激活时，就会产生冲突。海马体检测到这种冲突，并发送输出，增加情感上消极感知的效价，从而通过抑制更厌恶的目标来解决冲突。这种冲突解决既发生在先天目标上，也发生在后天目标上，从根本上来说与记忆无关。但是，在记忆范式中，它通常可以起到抑制当前试验干扰的作用，并通过消极情感增加的赫布式关联，降低后续试验和巩固过程中干扰的可能性。无论是记忆驱动的行为还是先天行为，都是由先天和后天的冲突倾向而非所呈现的刺激类别导致依赖海马体的。
