Abstract：
BACKGROUND: Population voltage imaging is used for studying brain physiology and brain circuits. Using a genetically encoded voltage indicator (GEVI), \"VSFP\" or \"ASAP2s\", or a voltage-sensitive dye, Di-4-Anepps, we conducted population voltage imaging in brain slices. The resulting optical signals, optical local field potentials (LFPs), were used to evaluate the performances of the 3 voltage indicators.
METHODS: In brain slices prepared from VSFP-transgenic or ASAP2s-transgenic mice, we performed multi-site optical imaging of evoked cortical depolarizations - compound excitatory postsynaptic potentials (cEPSPs). Optical signal amplitudes (ΔF/F) and cEPSP decay rates (OFF rates) were compared using analysis of variance (ANOVA) followed by unpaired Student\'s t test (31-104 data points per voltage indicator).
RESULTS: The ASAP2s signal amplitude (ΔF/F) was on average 3 times greater than Di-4-Anepps, and 7 times greater than VSFP. The optical cEPSP decay (OFF rate) was the slowest in Di-4-Anepps and fastest in ASAP2s. When ASAP2s expression was weak, we observed slow, label-free (autofluorescence, metabolic) optical signals mixed into the ASAP2s traces. Fast hyperpolarizations, that typically follow depolarizing cortical transients (afterhyperpolarizations), were prominent in ASAP2s but not present in the VSFP and Di-4-Anepps experiments.
CONCLUSIONS: Experimental applications for ASAP2s may potentially include systems neuroscience studies that require voltage indicators with large signal amplitude (ΔF/F), fast decay times (fast response time is needed for monitoring high frequency brain oscillations), and/or detection of brain patches in transiently hyperpolarized states (afterhyperpolarization).
METHODS: In brain slices prepared from VSFP-transgenic or ASAP2s-transgenic mice, we performed multi-site optical imaging of evoked cortical depolarizations - compound excitatory postsynaptic potentials (cEPSPs). Optical signal amplitudes (ΔF/F) and cEPSP decay rates (OFF rates) were compared using analysis of variance (ANOVA) followed by unpaired Student\'s t test (31-104 data points per voltage indicator).
RESULTS: The ASAP2s signal amplitude (ΔF/F) was on average 3 times greater than Di-4-Anepps, and 7 times greater than VSFP. The optical cEPSP decay (OFF rate) was the slowest in Di-4-Anepps and fastest in ASAP2s. When ASAP2s expression was weak, we observed slow, label-free (autofluorescence, metabolic) optical signals mixed into the ASAP2s traces. Fast hyperpolarizations, that typically follow depolarizing cortical transients (afterhyperpolarizations), were prominent in ASAP2s but not present in the VSFP and Di-4-Anepps experiments.
CONCLUSIONS: Experimental applications for ASAP2s may potentially include systems neuroscience studies that require voltage indicators with large signal amplitude (ΔF/F), fast decay times (fast response time is needed for monitoring high frequency brain oscillations), and/or detection of brain patches in transiently hyperpolarized states (afterhyperpolarization).
摘要：
背景：人群电压成像用于研究脑生理学和脑回路。使用基因编码电压指示器(GEVI)，\"VSFP\"或\"ASAP2s\",或者电压敏感染料，Di-4-Anepps,我们在脑片中进行了群体电压成像。产生的光信号，光学局部场势(LFP)，分别用于评价3种电压指标的性能。
方法：在由VSFP转基因或ASAP2s转基因小鼠制备的脑切片中，我们对诱发的皮质去极化-复合兴奋性突触后电位(cEPSP)进行了多位点光学成像.使用方差分析(ANOVA)和随后的非配对Studentt检验(每个电压指标31-104个数据点)比较光信号振幅(ΔF/F)和cEPSP衰减率(OFF速率)。
结果：ASAP2s信号幅度（ΔF/F）平均比Di-4-Anepps大3倍，比VSFP大7倍。光学cEPSP衰减（OFF速率）在Di-4-Anepps中最慢，在ASAP2s中最快。当ASAP2s表达较弱时，我们观察到缓慢，无标签(自发荧光，代谢)混合到ASAP2s迹线中的光信号。快速超极化，通常在去极化皮质瞬变（超极化后）之后，在ASAP2中突出，但在VSFP和Di-4-Anepps实验中不存在。
结论：ASAP2s的实验应用可能包括需要具有大信号幅度（ΔF/F）的电压指标的系统神经科学研究，快速衰减时间（监测高频大脑振荡需要快速响应时间），和/或检测处于瞬时超极化状态(超极化后)的脑斑块。
方法：在由VSFP转基因或ASAP2s转基因小鼠制备的脑切片中，我们对诱发的皮质去极化-复合兴奋性突触后电位(cEPSP)进行了多位点光学成像.使用方差分析(ANOVA)和随后的非配对Studentt检验(每个电压指标31-104个数据点)比较光信号振幅(ΔF/F)和cEPSP衰减率(OFF速率)。
结果：ASAP2s信号幅度（ΔF/F）平均比Di-4-Anepps大3倍，比VSFP大7倍。光学cEPSP衰减（OFF速率）在Di-4-Anepps中最慢，在ASAP2s中最快。当ASAP2s表达较弱时，我们观察到缓慢，无标签(自发荧光，代谢)混合到ASAP2s迹线中的光信号。快速超极化，通常在去极化皮质瞬变（超极化后）之后，在ASAP2中突出，但在VSFP和Di-4-Anepps实验中不存在。
结论：ASAP2s的实验应用可能包括需要具有大信号幅度（ΔF/F）的电压指标的系统神经科学研究，快速衰减时间（监测高频大脑振荡需要快速响应时间），和/或检测处于瞬时超极化状态(超极化后)的脑斑块。
