Disentangling the influences of multiple thalamic nuclei on prefrontal cortex and cognitive control
Disentangling the influences of multiple thalamic nuclei on prefrontal cortex and cognitive control
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解开多个丘脑核对前额皮质和认知控制的影响
DOI：
10.1016/j.pneurobio.2022.102215
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发表时间：
2022
影响因子：
6.7
通讯作者：
C., Djuric
中科院分区：
文献类型：
--
作者：
Mofakham, S.;Liu, Y;Hensley, A.;Saadon, J. R.;Adachi, J.;Mohammad, S.;C., Djuric
意识的主要理论预测，复杂的脑电图（EEG）活动是意识所必需的，但尚不清楚这种活动是如何在皮质丘脑系统中产生的。众所周知，丘脑通过层间投射控制皮层兴奋性，但复杂性是否需要丘脑输入尚不清楚。我们假设丘脑通过调节突触连通性来促进复杂活动，从而增加皮层神经元不同配置（皮层“状态”）的可用性，以及状态转换的概率。为了验证这一假设，我们用弥散张量成像（DTI）测量了有或没有丘脑皮质投影损伤的创伤性脑损伤（TBI）患者前额叶皮质（PFC）的脑电图活动。我们发现丘脑突起（尤其是丘脑中背侧突起）的损伤与无意识和δ波段脑电图活动密切相关。利用先进的信号处理技术，我们发现丘脑输入的缺乏导致1.)皮层网络的吸引子动态倾向于访问相同的状态，2.)减少了可能的状态库，以及3.)状态之间转换的高可预测性。这些结果表明，与意识相关的复杂PFC活动取决于丘脑输入。我们的模型表明，大脑损伤后皮层连通性的恢复是丘脑的一个关键功能。我们在丘脑输入和与意识相关的复杂皮层活动之间建立了重要的联系。
Major theories of consciousness predict that complex electroencephalographic (EEG) activity is required for consciousness, yet it is not clear how such activity arises in the corticothalamic system. The thalamus is wellknown to control cortical excitability via interlaminar projections, but whether thalamic input is needed for complexity is not known. We hypothesized that the thalamus facilitates complex activity by adjusting synaptic connectivity, thereby increasing the availability of different configurations of cortical neurons (cortical “states”), as well as the probability of state transitions. To test this hypothesis, we characterized EEG activity from prefrontal cortex (PFC) in traumatic brain injury (TBI) patients with and without injuries to thalamocortical projections, measured with diffusion tensor imaging (DTI). We found that injury to thalamic projections (especially from the mediodorsal thalamus) was strongly associated with unconsciousness and delta-band EEG activity. Using advanced signal processing techniques, we found that lack of thalamic input led to 1.) attractor dynamics for cortical networks with a tendency to visit the same states, 2.) a reduced repertoire of possible states, and 3.) high predictability of transitions between states. These results imply that complex PFC activity associated with consciousness depends on thalamic input. Our model implies that restoration of cortical connectivity is a critical function of the thalamus after brain injury. We draw a critical connection between thalamic input and complex cortical activity associated with consciousness.