Browning Philip G F, Chakraborty Subhojit, Mitchell Anna S
Glickenhaus Laboratory of Neuropsychology and Friedman Brain Institute, Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
Department of Bioengineering, Imperial College London, South Kensington, London SW7 2BP, UK.
Cereb Cortex. 2015 Nov;25(11):4519-34. doi: 10.1093/cercor/bhv093. Epub 2015 May 15.
It is proposed that mediodorsal thalamus contributes to cognition via interactions with prefrontal cortex. However, there is relatively little evidence detailing the interactions between mediodorsal thalamus and prefrontal cortex linked to cognition in primates. This study investigated these interactions during learning, memory, and decision-making tasks in rhesus monkeys using a disconnection lesion approach. Preoperatively, monkeys learned object-in-place scene discriminations embedded within colorful visual backgrounds. Unilateral neurotoxic lesions to magnocellular mediodorsal thalamus (MDmc) impaired the ability to learn new object-in-place scene discriminations. In contrast, unilateral ablations to ventrolateral and orbital prefrontal cortex (PFv+o) left learning intact. A second unilateral MDmc or PFv+o lesion in the contralateral hemisphere to the first operation, causing functional MDmc-PFv+o disconnection across hemispheres, further impaired learning object-in-place scene discriminations, although object discrimination learning remained intact. Adaptive decision-making after reward satiety devaluation was also reduced. These data highlight the functional importance of interactions between MDmc and PFv+o during learning object-in-place scene discriminations and adaptive decision-making but not object discrimination learning. Moreover, learning deficits observed after unilateral removal of MDmc but not PFv+o provide direct behavioral evidence of the MDmc role influencing more widespread regions of the frontal lobes in cognition.
有人提出，丘脑背内侧核通过与前额叶皮质的相互作用对认知产生影响。然而，相对较少有证据详细说明灵长类动物中丘脑背内侧核与前额叶皮质之间与认知相关的相互作用。本研究使用去连接损伤方法，在恒河猴的学习、记忆和决策任务中研究了这些相互作用。术前，猴子学习嵌入在彩色视觉背景中的物体位置场景辨别。对大细胞丘脑背内侧核（MDmc）进行单侧神经毒性损伤会损害学习新的物体位置场景辨别的能力。相比之下，对腹外侧和眶前额叶皮质（PFv+o）进行单侧切除后学习能力保持完好。在对侧半球进行第二次单侧MDmc或PFv+o损伤，导致跨半球的功能性MDmc-PFv+o去连接，尽管物体辨别学习仍然完好，但进一步损害了学习物体位置场景辨别的能力。奖励饱腹感贬值后的适应性决策也降低了。这些数据突出了MDmc和PFv+o之间在学习物体位置场景辨别和适应性决策过程中的相互作用的功能重要性，但在物体辨别学习中并非如此。此外，单侧切除MDmc而非PFv+o后观察到的学习缺陷为MDmc在影响额叶更广泛区域的认知中的作用提供了直接的行为证据。
