Xu Wei, Wang Mixia, Yang Gucheng, Mo Fan, Liu Yaoyao, Shan Jin, Jing Luyi, Li Ming, Liu Juntao, Lv Shiya, Duan Yiming, Han Meiqi, Xu Zhaojie, Song Yilin, Cai Xinxia
State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, 100190, China.
School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.
Microsyst Nanoeng. 2024 Oct 14;10(1):145. doi: 10.1038/s41378-024-00778-2.
Navigating toward destinations with rewards is a common behavior among animals. The ventral tegmental area (VTA) has been shown to be responsible for reward coding and reward cue learning, and its response to other variables, such as kinematics, has also been increasingly studied. These findings suggest a potential relationship between animal navigation behavior and VTA activity. However, the deep location and small volume of the VTA pose significant challenges to the precision of electrode implantation, increasing the uncertainty of measurement results during animal navigation and thus limiting research on the role of the VTA in goal-directed navigation. To address this gap, we innovatively designed and fabricated low-curvature microelectrode arrays (MEAs) via a novel backside dry etching technique to release residual stress. Histological verification confirmed that low-curvature MEAs indeed improved electrode implantation precision. These low-curvature MEAs were subsequently implanted into the VTA of the rats to observe their electrophysiological activity in a freely chosen modified T-maze. The results of the behavioral experiments revealed that the rats could quickly learn the reward probability corresponding to the left and right paths and that VTA neurons were deeply involved in goal-directed navigation. Compared with those in no-reward trials, VTA neurons in reward trials presented a significantly greater firing rate and larger local field potential (LFP) amplitude during the reward-consuming period. Notably, we discovered place fields mapped by VTA neurons, which disappeared or were reconstructed with changes in the path-outcome relationship. These results provide new insights into the VTA and its role in goal-directed navigation. Our designed and fabricated low-curvature microelectrode arrays can serve as a new device for precise deep brain implantation in the future.
朝着有奖励的目的地导航是动物的常见行为。腹侧被盖区（VTA）已被证明负责奖励编码和奖励线索学习，并且其对其他变量（如运动学）的反应也越来越受到研究。这些发现表明动物导航行为与VTA活动之间存在潜在关系。然而，VTA的深部位置和小体积对电极植入的精度提出了重大挑战，增加了动物导航过程中测量结果的不确定性，从而限制了对VTA在目标导向导航中作用的研究。为了弥补这一差距，我们通过一种新颖的背面干法蚀刻技术创新性地设计并制造了低曲率微电极阵列（MEA）以释放残余应力。组织学验证证实低曲率MEA确实提高了电极植入精度。随后将这些低曲率MEA植入大鼠的VTA中，以观察它们在自由选择的改良T型迷宫中的电生理活动。行为实验结果表明，大鼠能够快速学习与左右路径相对应的奖励概率，并且VTA神经元深度参与目标导向导航。与无奖励试验相比，奖励试验中的VTA神经元在奖励消耗期呈现出明显更高的放电率和更大的局部场电位（LFP）幅度。值得注意的是，我们发现了由VTA神经元映射的位置场，它们会随着路径-结果关系的变化而消失或重建。这些结果为VTA及其在目标导向导航中的作用提供了新的见解。我们设计和制造的低曲率微电极阵列可作为未来精确深部脑植入的新设备。
