Kennerley Steven W, Wallis Jonathan D
Department of Psychology and Helen Wills Neuroscience Institute, University of California at Berkeley, California 94720-3190, USA.
J Neurosci. 2009 Mar 11;29(10):3259-70. doi: 10.1523/JNEUROSCI.5353-08.2009.
Although research implicates lateral prefrontal cortex (PFC) in executive control and goal-directed behavior, it remains unclear how goals influence executive processes. One possibility is that goal-relevant information, such as expected rewards, could modulate the representation of information relating to executive control, thereby ensuring the efficient allocation of cognitive resources. To investigate this, we examined how reward modulated spatial working memory. Past studies investigating spatial working memory have focused on dorsolateral PFC, but this area only weakly connects with areas processing reward. Ventrolateral PFC has better connections in this regard. Thus, we contrasted the functional properties of single neurons in ventrolateral and dorsolateral PFC as two subjects performed a task that required them to hold spatial information in working memory under different expectancies of reward for correct performance. We balanced the order of presentation of spatial and reward information so we could assess the neuronal encoding of the two pieces of information independently and conjointly. Neurons in ventrolateral PFC encoded both spatial and reward information earlier, stronger and in a more sustained manner than neurons in dorsolateral PFC. Within ventrolateral PFC, spatial selectivity was more prevalent on the inferior convexity than within the principal sulcus. Finally, when reward increased spatial selectivity, behavioral performance improved, whereas when reward decreased spatial selectivity, behavioral performance deteriorated. These results suggest that ventrolateral PFC may be a locus whereby information about expected rewards can modulate information in working memory. The pattern of results is consistent with a role for ventrolateral PFC in attentional control.
尽管研究表明外侧前额叶皮层（PFC）参与执行控制和目标导向行为，但目标如何影响执行过程仍不清楚。一种可能性是，与目标相关的信息，如预期奖励，可能会调节与执行控制相关的信息表征，从而确保认知资源的有效分配。为了研究这一点，我们研究了奖励如何调节空间工作记忆。过去研究空间工作记忆的实验主要集中在背外侧PFC，但该区域与处理奖励的区域连接较弱。在这方面，腹外侧PFC的连接更好。因此，当两名受试者执行一项要求他们在不同的正确表现奖励预期下将空间信息保持在工作记忆中的任务时，我们对比了腹外侧和背外侧PFC中单个神经元的功能特性。我们平衡了空间和奖励信息的呈现顺序，以便能够独立和联合评估这两种信息的神经元编码。与背外侧PFC中的神经元相比，腹外侧PFC中的神经元更早、更强且更持续地编码空间和奖励信息。在腹外侧PFC内，空间选择性在下凸面比在主沟内更普遍。最后，当奖励增加空间选择性时，行为表现改善，而当奖励降低空间选择性时，行为表现恶化。这些结果表明，腹外侧PFC可能是预期奖励信息调节工作记忆中信息的位点。结果模式与腹外侧PFC在注意力控制中的作用一致。
