Department of Neurosurgery, Johns Hopkins University, 600 North Wolfe Street, Baltimore, MD 2105, USA.
Neuroscience. 2011 Mar 31;178:208-17. doi: 10.1016/j.neuroscience.2011.01.029. Epub 2011 Jan 20.
The pathways by which painful stimuli are signaled within the human medial temporal lobe are unknown. Rodent studies have shown that nociceptive inputs are transmitted from the brainstem or thalamus through one of two pathways to the central nucleus of the amygdala. The indirect pathway projects from the basal and lateral nuclei of the amygdala to the central nucleus, while the direct pathway projects directly to the central nucleus. We now test the hypothesis that the human ventral amygdala (putative basal and lateral nuclei) exerts a causal influence upon the dorsal amygdala (putative central nucleus), during the application of a painful laser stimulus. Local field potentials (LFPs) were recorded from depth electrode contacts implanted in the medial temporal lobe for the treatment of epilepsy, and causal influences were analyzed by Granger causality (GRC). This analysis indicates that the dorsal amygdala exerts a pre-stimulus causal influence upon the hippocampus, consistent with an attention-related response to the painful laser. Within the amygdala, the analysis indicates that the ventral contacts exert a causal influence upon dorsal contacts, consistent with the human (putative) indirect pathway. Potentials evoked by the laser (LEPs) were not recorded in the ventral nuclei, but were recorded at dorsal amygdala contacts which were not preferentially those receiving causal influences from the ventral contacts. Therefore, it seems likely that the putative indirect pathway is associated with causal influences from the ventral to the dorsal amygdala, and is distinct from the human (putative) indirect pathway which mediates LEPs in the dorsal amygdala.
目前尚不清楚人类内侧颞叶中疼痛刺激信号的传递途径。啮齿动物研究表明，伤害性传入信息通过两条通路之一从脑干或丘脑传递到杏仁核中央核。间接通路从杏仁核的基底核和外侧核投射到中央核，而直接通路则直接投射到中央核。我们现在测试这样一个假设，即在应用疼痛激光刺激时，人类腹侧杏仁核（假定的基底核和外侧核）对背侧杏仁核（假定的中央核）施加因果影响。局部场电位（LFPs）是从植入内侧颞叶以治疗癫痫的深部电极触点中记录的，并通过格兰杰因果关系（GRC）分析因果关系。该分析表明，背侧杏仁核对海马施加了预刺激的因果影响，这与对疼痛激光的注意力相关反应一致。在杏仁核内，分析表明腹侧触点对背侧触点施加了因果影响，这与人类（假定的）间接通路一致。激光诱发的电位（LEPs）未在腹侧核中记录到，但在背侧杏仁核触点中记录到，这些触点并非优先接收来自腹侧触点的因果影响。因此，似乎间接通路与腹侧到背侧杏仁核的因果影响有关，并且与在背侧杏仁核中介导 LEPs 的人类（假定的）间接通路不同。
