Comparable reduction in Zif268 levels and cytochrome oxidase activity in the retrosplenial cortex following mammillothalamic tract lesions.
Comparable reduction in Zif268 levels and cytochrome oxidase activity in the retrosplenial cortex following mammillothalamic tract lesions.
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DOI：
10.1016/j.neuroscience.2016.05.030
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发表时间：
2016-08-25
期刊：
影响因子：
3.3
通讯作者：
Vann SD
中科院分区：
文献类型：
--
作者：
Frizzati A;Milczarek MM;Sengpiel F;Thomas KL;Dillingham CM;Vann SD
乳头丘脑束病变损害T-迷宫交替性能。乳头丘脑束病变降低了压后皮质中的Zif 268水平。乳头丘脑束损伤减少压后皮质细胞色素氧化酶。背侧海马无变化。这些远端变化可能会导致记忆障碍。对乳头丘脑束（MTT）的损伤会导致人类和大鼠的记忆障碍，但目前还不清楚为什么间脑通路对记忆至关重要。一种观点认为，这是中脑输入到达支持记忆的更广泛的皮层和皮层下网络的重要途径。与这一观点相一致，MTT损伤在远端脑区产生广泛的低活性，如通过即刻早期基因c-fos所测量的。为了确定这些发现是否对c-fos具有选择性或反映神经元功能的更普遍变化，我们评估了MTT损伤对压后皮质和海马中即刻早期基因蛋白Zif 268和代谢标志物细胞色素氧化酶表达的影响。病变降低了两个活性标志物的水平在浅层和深层的压后皮质在其颗粒和dysgranular亚区。相比之下，没有观察到显着的变化，在海马中，尽管MTT损伤的动物显示出显着的损伤T-迷宫交替。这些发现与MTT损伤为正常压后皮质功能提供重要的间接输入一致。这些远端功能变化可能有助于MTT损伤后观察到的记忆障碍。
Mammillothalamic tract lesions impaired T-maze alternation performance. Mammillothalamic tract lesions reduced Zif268 levels in retrosplenial cortex. Mammillothalamic tract lesions reduced cytochrome oxidase in retrosplenial cortex. No changes were found in the dorsal hippocampus. These distal changes may contribute to the memory impairments. Damage to the mammillothalamic tract (MTT) produces memory impairments in both humans and rats, yet it is still not clear why this diencephalic pathway is vital for memory. One suggestion is that it is an important route for midbrain inputs to reach a wider cortical and subcortical network that supports memory. Consistent with this idea, MTT lesions produce widespread hypoactivity in distal brain regions as measured by the immediate-early gene, c-fos. To determine whether these findings were selective to c-fos or reflected more general changes in neuronal function, we assessed the effects of MTT lesions on the expression of the immediate-early gene protein, Zif268 and the metabolic marker, cytochrome oxidase, in the retrosplenial cortex and hippocampus. The lesions decreased levels of both activity markers in the superficial and deep layers of the retrosplenial cortex in both its granular and dysgranular subregions. In contrast, no significant changes were observed in the hippocampus, despite the MTT-lesioned animals showing marked impairments on T-maze alternation. These findings are consistent with MTT lesions providing important, indirect inputs for normal retrosplenial cortex functioning. These distal functional changes may contribute to the memory impairments observed after MTT lesions.