BACKGROUND Deep brain stimulation (DBS) is an effective treatment for movement disorders, yet its mechanisms of action remain unclear. One method used to study its circuit-wide neuromodulatory effects is functional magnetic resonance imaging (fMRI) which measures hemodynamics as a proxy of neural activity. To interpret functional imaging data, we must understand the relationship between neural and vascular responses, which has never been studied with the high frequencies used for DBS. OBJECTIVE To measure neurovascular coupling in the rat motor cortex during thalamic DBS. METHOD Simultaneous intrinsic optical imaging and extracellular electrophysiology was performed in the motor cortex of urethane-anesthetized rats during thalamic DBS at 7 different frequencies. We related Maximum Change in Reflectance (MCR) from the imaging data to Integrated Evoked Potential (IEP) and change in broadband power of multi-unit (MU) activity, computing Spearman's correlation to determine the strength of these relationships. To determine the source of these effects, we studied the contributions of antidromic versus orthodromic activation in motor cortex perfusion using synaptic blockers. RESULTS MCR, IEP and change in MU power increased linearly to 60 Hz and saturated at higher frequencies of stimulation. Blocking orthodromic transmission only reduced the DBS-induced change in optical signal by ∼25%, suggesting that activation of corticofugal fibers have a major contribution in thalamic-induced cortical activation. CONCLUSION DBS-evoked vascular response is related to both evoked field potentials as well as multi-unit activity.

中文翻译：

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深部脑刺激期间的神经血管耦合

背景深部脑刺激（DBS）是一种有效的运动障碍治疗方法，但其作用机制尚不清楚。用于研究其电路范围神经调节作用的一种方法是功能性磁共振成像 (fMRI)，它测量作为神经活动代理的血液动力学。要解释功能成像数据，我们必须了解神经和血管反应之间的关系，而 DBS 所用的高频从未研究过这种关系。目的 测量丘脑 DBS 过程中大鼠运动皮层的神经血管耦合。方法 在丘脑 DBS 期间，以 7 种不同频率在氨基甲酸乙酯麻醉的大鼠的运动皮层中同时进行内在光学成像和细胞外电生理学。我们将成像数据的最大反射率 (MCR) 变化与综合诱发电位 (IEP) 和多单元 (MU) 活动的宽带功率变化相关联，计算 Spearman 相关性以确定这些关系的强度。为了确定这些影响的来源，我们使用突触阻滞剂研究了逆向激活与顺向激活在运动皮层灌注中的贡献。结果 MCR、IEP 和 MU 功率的变化线性增加到 60 Hz，并在更高的刺激频率下饱和。阻断顺向传输仅将 DBS 诱导的光信号变化降低了约 25%，表明皮质纤维的激活在丘脑诱导的皮质激活中起主要作用。