Neuronal networks for control of eye movement

外侧缰核神经元在预测奖励信息时发出错误信号：人类和动物具有预测未来事件的能力，它们通过不断搜索环境中的预测信息来源来培养这种能力。然而，人们对激发这种行为的神经系统知之甚少。我们假设，信息寻求是由支持奖励寻求的相同电路分配的值，因此编码奖励预测错误（RPE）的神经信号包括类似的信息预测错误（IPE）。为了验证这一点，我们记录了外侧缰核（一个编码RPE的核团）中的神经元，而猴子则在提供不同机会的线索之间进行选择，以查看即将到来的奖励信息。我们发现外侧缰核神经元的一个亚群传递类似IPE的信号，当奖励信息被意外提示、传递或拒绝时做出反应。这些信号可靠地评估了信息源，即使猴子的决定并非如此。这些神经元可以为奖赏寻求和信息寻求行为提供共同的指导信号。 在灵长类动物中，从外侧缰核到多巴胺神经元的负性奖赏信号由头内侧被盖核介导：外侧缰核（LHb）神经元发出负性“奖赏预测错误”信号并抑制中脑多巴胺（DA）神经元。然而，LHb神经元主要是谷氨酸能的，表明这种抑制可能通过中间结构发生。最近在大鼠中的研究表明，GABA能的头内侧被盖核（RMTg）是这种作用的候选者，但这种神经通路尚未得到直接测试。我们现在使用电生理学和解剖学追踪表明：（1）猴子具有与大鼠RMTg相似的抑制性结构;（2）RMTg神经元从LHb接收兴奋性输入，表现出负的奖励预测误差，并向DA索马体附近发送轴突投射;（3）刺激该结构抑制DA神经元。令人惊讶的是，一些RMTg神经元比LHb更早地对奖励线索做出反应，并且携带在DA神经元中未发现的“状态值”信号。因此，我们的数据表明，RMTg将LHb奖励预测误差（负）转化为DA奖励预测误差（正），同时向非DA网络传输额外的激励信号。 灵长类动物腹内侧前额叶皮层（ventromedial prefrontal cortex，vmPFC）对奖励和惩罚的区域性不同处理：腹内侧前额叶皮层（ventromedial prefrontal cortex，vmPFC）被认为与情绪体验以及刺激和动作值的处理有关。然而，人们对单个vmPFC神经元如何处理奖励和惩罚的预测和接收知之甚少。我们记录了猴子的vmPFC神经元在一个实验的情况下，交替块，一个在其中提供奖励和一个在其中提供惩罚。许多vmPFC神经元在块之间改变了它们的活动。重要的是，在腹侧VMPFC的神经元持续更活跃的食欲“奖励”块，而在背侧VMPFC的神经元持续更活跃的厌恶“惩罚”块。此外，在腹侧vmPFC，后部神经元相位编码的奖励的概率，而前部神经元紧张性编码的奖励的可能性。我们在灵长类前额叶皮层中发现了多种不同的非线性评价机制。我们的研究结果表明，不同的亚区的vmPFC有助于差异的处理价。通过传递这种多维和非线性信号，vmPFC可以实现对决策和情绪的灵活控制，以适应复杂的环境。 尾状核中的什么和哪里的信息引导扫视视觉对象：我们通过对各种物体进行扫视眼球运动来理解世界。然而，目前还不清楚眼跳如何瞄准特定的物体，因为两种视觉信息，物体是什么和它在哪里，分别在背侧和腹侧视觉皮层通路中处理。在这里，我们提供的证据表明，通过猴尾状核（CDt）的尾巴基底神经节电路指导这种对象定向扫视。首先，许多CDt神经元对视觉对象的反应取决于对象的位置和内容。第二，在CDt的电刺激诱导扫视的方向相匹配的神经元在刺激部位的首选方向。第三，许多CDt神经元在自由观看条件下针对神经元的首选对象和方向的扫视之前增加了它们的活性。我们的研究结果表明，CDt神经元接收“什么”和“在哪里”的信息，并指导扫视视觉对象。

Lateral habenula neurons signal errors in the prediction of reward information: Humans and animals have the ability to predict future events, which they cultivate by continuously searching their environment for sources of predictive information. However, little is known about the neural systems that motivate this behavior. We hypothesized that information-seeking is assigned value by the same circuits that support reward-seeking, such that neural signals encoding reward prediction errors (RPEs) include analogous information prediction errors (IPEs). To test this, we recorded from neurons in the lateral habenula, a nucleus that encodes RPEs, while monkeys chose between cues that provided different chances to view information about upcoming rewards. We found that a subpopulation of lateral habenula neurons transmitted signals resembling IPEs, responding when reward information was unexpectedly cued, delivered or denied. These signals evaluated information sources reliably, even when the monkey's decisions did not. These neurons could provide a common instructive signal for reward-seeking and information-seeking behavior. Negative reward signals from the lateral habenula to dopamine neurons are mediated by rostromedial tegmental nucleus in primates: Lateral habenula (LHb) neurons signal negative "reward-prediction errors" and inhibit midbrain dopamine (DA) neurons. Yet LHb neurons are largely glutamatergic, indicating that this inhibition may occur through an intermediate structure. Recent studies in rats have suggested a candidate for this role, the GABAergic rostromedial tegmental nucleus (RMTg), but this neural pathway has not yet been tested directly. We now show using electrophysiology and anatomic tracing that (1) the monkey has an inhibitory structure similar to the rat RMTg; (2) RMTg neurons receive excitatory input from the LHb, exhibit negative reward-prediction errors, and send axonal projections near DA soma; and (3) stimulating this structure inhibits DA neurons. Surprisingly, some RMTg neurons responded to reward cues earlier than the LHb, and carry "state-value" signals not found in DA neurons. Thus, our data suggest that the RMTg translates LHb reward-prediction errors (negative) into DA reward-prediction errors (positive), while transmitting additional motivational signals to non-DA networks. Regionally distinct processing of rewards and punishments by the primate ventromedial prefrontal cortex: The ventromedial prefrontal cortex (vmPFC) is thought to be related to emotional experience and to the processing of stimulus and action values. However, little is known about how single vmPFC neurons process the prediction and reception of rewards and punishments. We recorded from monkey vmPFC neurons in an experimental situation with alternating blocks, one in which rewards were delivered and one in which punishments were delivered. Many vmPFC neurons changed their activity between blocks. Importantly, neurons in ventral vmPFC were persistently more active in the appetitive "reward" block, whereas neurons in dorsal vmPFC were persistently more active in the aversive "punishment" block. Furthermore, within ventral vmPFC, posterior neurons phasically encoded probability of reward, whereas anterior neurons tonically encoded possibility of reward. We found multiple distinct nonlinear valuation mechanisms within the primate prefrontal cortex. Our findings suggest that different subregions of vmPFC contribute differentially to the processing of valence. By conveying such multidimensional and nonlinear signals, the vmPFC may enable flexible control of decisions and emotions to adapt to complex environments. What and where information in the caudate tail guides saccades to visual objects: We understand the world by making saccadic eye movements to various objects. However, it is unclear how a saccade can be aimed at a particular object, because two kinds of visual information, what the object is and where it is, are processed separately in the dorsal and ventral visual cortical pathways. Here, we provide evidence suggesting that a basal ganglia circuit through the tail of the monkey caudate nucleus (CDt) guides such object-directed saccades. First, many CDt neurons responded to visual objects depending on where and what the objects were. Second, electrical stimulation in the CDt induced saccades whose directions matched the preferred directions of neurons at the stimulation site. Third, many CDt neurons increased their activity before saccades directed to the preferred objects and directions of the neurons in a free-viewing condition. Our results suggest that CDt neurons receive both "what" and "where" information and guide saccades to visual objects.