The role of monoamines in reward processing in the prefrontal cortex

为了阐明奖励处理的神经元底物，我们记录了猴子执行各种认知任务时背外侧前额叶皮层（DLPFC）的神经元活动。使用一个变体的oculardial延迟反应任务与两个奖励条件（奖励/非奖励），我们发现，DLPFC包含不同的神经元组，代码的结果后，差分空间响应，这应该发挥作用，在关联不同的响应与其结果。这种编码对于根据规则灵活控制行为可能是至关重要的，这被认为是DLPFC的关键作用。为了解决这个问题，我们检查了神经元活动，而猴子进行了一项眼动规则转换任务，要求他们改变基于响应结果的行为规则。DLPFC神经元的一个子集显示出不同的活动，在当前的试验中使用的规则（回顾性代码），这将用于下一个试验（前瞻性代码）。活动 ...更多信息 当猴子不得不改变规则时，这些神经元的活性增加得尤其明显。规则的回顾性和前瞻性编码可能分别是基于反应-结果的规则转换和对转换规则的保留的关键神经元基质。接下来，为了研究奖励期望如何影响感觉记忆和运动准备的神经元过程，我们记录了猴子DLPFC的神经元活动，这些猴子执行延迟反眼跳任务的变体，该任务可以在奖励和无奖励条件下将感觉记忆的神经元活动与运动准备的神经元活动分离。我们发现，奖励期望增强了感觉记忆的神经元过程，但在DLPFC的运动准备。此外，根据先前的结果，为了检查单胺在改变行为中的参与，我们将多巴胺能和去甲肾上腺素能拮抗剂注射到DLPFC中，而猴子正在执行眼部规则转换任务。结果发现，D1-多巴胺拮抗剂诱导的缺陷，其特征在于持续错误的增加。DLPFC中的D1-多巴胺受体可能参与执行控制的功能;即，基于结果和规则的交替行为。少

To clarify neuronal substrates for reward processing, we recorded neuronal activity in the dorsolateral prefrontal cortex (DLPFC) while the monkey performed various cognitive tasks. Using a variant of the oculomotor delayd-response task with two reward conditions (reward/non-reward), we found that the DLPFC contains distinct neuronal groups that code outcome following the differential spatial response, which should play a role in associating different response with its outcome. Such coding may be critical for flexible control of behavior according to a rule, which has been considered a critical role of the DLPFC. To address this issue, we examined neuronal activity while monkeys performed an oculomotor rule-shifting task that required them to shift behavioral rules based on response-outcome. A subset of DLPFC neurons showed differential activity by the rule that was used in the current trial (a retrospective code), and that would be used in the next trial (a prospective code). The acti … More vity of these neurons increased particularly when the monkey had to alter the rule. The retrospective and prospective coding of rules may be critical neuronal substrates for rule-shifting based on response-outcome and retention of the shifted rule, respectively. Next, to examine how the reward expectation affects neuronal processes of the sensory memory and that of motor preparation, we recorded neuronal activities from the DLPFC of monkeys that performed a variant of delayd anti-saccade task that can dissociate neuronal activity for sensory memory from that for motor preparation under reward and no-reward conditions. We found that the reward expectation enhances the neuronal process for sensory memory but not for motor preparation in the DLPFC. Further, to examine the involvement of monoamines in changing behavior based on the previous outcome, we injected dopaminergic and noradrenergic antagonists into the DLPFC, while the monkeys were performing an oculomotor rule-shifting task. It was found that D1-dopamine antagonist induced a deficit characterized by the increase in perseveration-errors. D1-dopamine receptors in the DLPFC are likely to be involved in a function of executive control ; i.e., alternating behavior based on outcome and rule. Less