研究表明了动机如何帮助大脑记住特定的目标，从而让饥饿或口渴的大鼠可以使用记忆在迷宫中找到食物或水。
Matthew Shapiro 和Pamela Kennedy追踪了大脑中支持记忆的海马区的特定神经元的活动，结果发现了当这些大鼠饥饿而寻找食物时与当它们口渴而在同一地点找水时，这些神经元以不同的方式触发。海马区的神经元有“位置区”，而且在当大鼠经过它的环境中的一个特定区域时触发。然而，通过剥夺大鼠的食物或水，这组科学家建立了大鼠不同的内部动机，大鼠用这些动机在迷宫中走向含有食物或水的奖赏的特定已知目标。当不同的动机状态（饥饿或口渴）控制行为的时候，它们激活了大鼠海马区神经冲动的不同模式，这既反映了大鼠的内部刺激，又反映了外部刺激。
这组作者说，这些结果可能证明了动机如何影响记忆处理以及根据过去的经验帮助选择不同的行为。（生物谷Bioon.com）
生物谷推荐原始出处：
PNAS June 15, 2009, doi: 10.1073/pnas.0903259106
Motivational states activate distinct hippocampal representations to guide goal-directed behaviors
Pamela J. Kennedy and Matthew L. Shapiro,1
Adaptive behaviors are guided by motivation and memory. Motivational states specify goals, and memory can inform motivated behavior by providing detailed records of past experiences when goals were obtained. These 2 fundamental processes interact to guide animals to biologically relevant targets, but the neuronal mechanisms that integrate them remain unknown. To investigate these mechanisms, we recorded unit activity from the same population of hippocampal neurons as rats performed identical tasks while either food or water deprived. We compared the influence of motivational state (hunger and thirst), memory demand, and spatial behavior in 2 tasks: hippocampus-dependent contextual memory retrieval and hippocampus-independent random foraging. We found that: (i) hippocampal coding was most strongly influenced by motivational state during contextual memory retrieval, when motivational cues were required to select among remembered, goal-directed actions in the same places; (ii) the same neuronal populations were relatively unaffected by motivational state during random foraging, when hunger and thirst were incidental to behavior, and signals derived from deprivation states thus informed, but did not determine, hippocampal coding; and (iii) “prospective coding” in the contextual retrieval task was not influenced by allocentric spatial trajectory, but rather by the animal's deprivation state and the associated, non-spatial target, suggesting that hippocampal coding includes a wide range of predictive associations. The results show that beyond coding spatiotemporal context, hippocampal representations encode the relationships between internal states, the external environment, and action to provide a mechanism by which motivation and memory are coordinated to guide behavior.
