Deficits in cognition are a core feature of many psychiatric conditions, including schizophrenia, where the severity of such deficits is a strong predictor of long-term outcome. Impairment in cognitive domains such as working memory and behavioral flexibility has typically been associated with prefrontal cortex (PFC) dysfunction. However, there is increasing evidence that the PFC cannot be dissociated from its main thalamic counterpart, the mediodorsal thalamus (MD). Since the causal relationships between MD-PFC abnormalities and cognitive impairment, as well as the neuronal mechanisms underlying them, are difficult to address in humans, animal models have been employed for mechanistic insight. In this review, we discuss anatomical, behavioral, and electrophysiological findings from animal studies that provide a new understanding on how MD-PFC circuits support higher-order cognitive function. We argue that the MD may be required for amplifying and sustaining cortical representations under different behavioral conditions. These findings advance a new framework for the broader involvement of distributed thalamo-frontal circuits in cognition and point to the MD as a potential therapeutic target for improving cognitive deficits in schizophrenia and other disorders.

中文翻译：

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内侧丘脑：前额皮质认知的重要伙伴


认知缺陷是包括精神分裂症在内的许多精神疾病的核心特征，这种缺陷的严重程度是长期结果的有力预测因素。工作记忆和行为灵活性等认知领域的损伤通常与前额皮质（PFC）功能障碍有关。然而，越来越多的证据表明，PFC 不能与其主要丘脑对应物——内侧丘脑 (MD) 分离。由于 MD-PFC 异常与认知障碍之间的因果关系以及其背后的神经元机制在人类中很难解决，因此动物模型已被用来进行机制洞察。在这篇综述中，我们讨论了动物研究中的解剖学、行为学和电生理学发现，这些发现为 MD-PFC 回路如何支持高阶认知功能提供了新的理解。我们认为，MD 可能需要在不同的行为条件下放大和维持皮质表征。这些发现为分布式丘脑额叶回路更广泛地参与认知提出了一个新框架，并指出 MD 作为改善精神分裂症和其他疾病认知缺陷的潜在治疗目标。