Foraging entails a complex balance between approach and avoidance alongside sensorimotor and homeostatic processes under the control of multiple cortical and subcortical areas. Recently, it has become clear that several thalamic nuclei located near the midline regulate motivated behaviors. However, one midline thalamic nucleus that projects to key nodes in the foraging network, the central medial thalamic nucleus (CMT), has received little attention so far. Therefore, the present study examined CMT contributions to foraging behavior using inactivation and unit recording techniques in male rats. Inactivation of CMT or the basolateral amygdala (BLA) with muscimol abolished the normally cautious behavior of rats in the foraging task. Moreover, CMT neurons showed large but heterogeneous activity changes during the foraging task, with many neurons decreasing or increasing their discharge rates, with a modest bias for the latter. A generalized linear model revealed that the nature (inhibitory vs excitatory) and relative magnitude of the activity modulations seen in CMT neurons differed markedly from those of principal BLA cells but were very similar to those of fast-spiking BLA interneurons. Together, these findings suggest that CMT is an important regulator of foraging behavior. In the Discussion, we consider how CMT is integrated into the network of structures that regulate foraging.

SIGNIFICANCE STATEMENT Foraging entails a complex balance between approach and avoidance alongside sensorimotor and homeostatic processes under the control of multiple cortical and subcortical areas. Although the central medial thalamic nucleus (CMT) is connected to many nodes in this network, its role in the regulation of foraging behavior has not been investigated so far. Here, we examined CMT contributions to foraging behavior using inactivation and unit recording techniques. We found that CMT inactivation abolishes the normally cautious foraging behavior of rats and that CMT neurons show large but heterogeneous changes in firing rates during the foraging task. Together, these results suggest that CMT is an important regulator of foraging behavior.

在多个皮层和皮层下区域的控制下，觅食需要接近和回避之间的复杂平衡，以及感觉运动和稳态过程。最近，很明显位于中线附近的几个丘脑核调节动机行为。然而，投射到觅食网络中关键节点的一个中线丘脑核，中央内侧丘脑核 (CMT)，到目前为止很少受到关注。因此，本研究使用失活和单位记录技术检查了 CMT 对雄性大鼠觅食行为的贡献。用蝇蕈醇使 CMT 或基底外侧杏仁核 (BLA) 失活，消除了大鼠在觅食任务中通常的谨慎行为。此外，CMT 神经元在觅食任务期间表现出大而异的活动变化，许多神经元降低或增加它们的放电率，后者有适度的偏差。广义线性模型显示，在 CMT 神经元中观察到的活动调制的性质（抑制性与兴奋性）和相对幅度与主要 BLA 细胞明显不同，但与快速刺激的 BLA 中间神经元非常相似。总之，这些发现表明 CMT 是觅食行为的重要调节因子。在讨论中，我们考虑 CMT 如何整合到调节觅食的结构网络中。广义线性模型显示，在 CMT 神经元中观察到的活动调制的性质（抑制性与兴奋性）和相对幅度与主要 BLA 细胞明显不同，但与快速刺激的 BLA 中间神经元非常相似。总之，这些发现表明 CMT 是觅食行为的重要调节因子。在讨论中，我们考虑 CMT 如何整合到调节觅食的结构网络中。广义线性模型显示，在 CMT 神经元中观察到的活动调制的性质（抑制性与兴奋性）和相对幅度与主要 BLA 细胞明显不同，但与快速刺激的 BLA 中间神经元非常相似。总之，这些发现表明 CMT 是觅食行为的重要调节因子。在讨论中，我们考虑 CMT 如何整合到调节觅食的结构网络中。

意义声明觅食需要在多个皮质和皮质下区域的控制下，在接近和回避之间以及感觉运动和稳态过程之间的复杂平衡。尽管中央内侧丘脑核 (CMT) 连接到该网络中的许多节点，但迄今为止尚未研究其在调节觅食行为中的作用。在这里，我们使用失活和单位记录技术检查了 CMT 对觅食行为的贡献。我们发现 CMT 失活消除了大鼠通常谨慎的觅食行为，并且 CMT 神经元在觅食任务期间显示出大而异的放电率变化。总之，这些结果表明 CMT 是觅食行为的重要调节因子。