Physiological functions and underlying cellular/molecular mechanisms of retrograde inputs from higher cortical areas toe sensory cortices

通过小鼠经颅黄素蛋白荧光成像，获得了以下结果。我们研究了受声环境调节的听觉皮质可塑性。小鼠出生后在不同的声环境中饲养至少4周。纯音刺激(5、10和20 kHz)引起的皮层反应在初级听觉皮质(AI)显示出纯音地形图。与在正常声学环境中饲养的幼小鼠相比，在声音剥夺的小鼠中观察到听觉皮质反应的抑制。当小鼠出生后暴露在10 kHz的环境音调刺激下超过4周时，大脑皮层的反应以一种特定频率的方式增强。这些结果表明，声学环境调节小鼠听皮层内回路的发育。我们在老鼠身上观察了大脑皮质对缺失的基本原理的反应。5…和20 kHz诱发的AI的活动模式不同更多的千赫或25千赫。然而，5 kHz激活的区域也可以被20 kHz+25 kHz的混合物激活，但不能被19 kHz+26 kHz的混合物激活，这表明大脑皮质对AI中缺失的基础的反应可以用黄素蛋白荧光成像3可视化。对视皮层的经验依赖性可塑性进行了研究。从P28开始的单眼剥夺(MD)4天后，与非剥夺眼反应相比，剥夺眼反应在双眼区受到抑制，但在单眼区没有。影像忠实地再现了一个可塑性的关键期，在P28左右观察到MD的最大影响，即使在乌拉坦麻醉下也不会在成年期观察到MD。这些结果表明，经颅黄素蛋白荧光成像是研究小鼠视皮层经验依赖性可塑性的有力工具。我们为小鼠设计了一种半边棱镜。在关键时期，这个护目镜被固定在小鼠的头骨上。与对侧正常眼相比，由棱镜眼引起的视觉皮质反应明显受到抑制。然而，在胡须被修剪的老鼠身上没有观察到这种抑制。在空间再认中，体感输入与视觉输入之间的多通道感觉失配可能抑制了视觉反应。较少

Using transcranial flavoprotein fluorescence imaging in mice, the following results have been obtained.1. We investigated auditory cortical plasticity regulated by acoustic environments. Mice were reared in various acoustic environments for at least 4 weeks after birth. Cortical responses elicited by tonal stimuli (5, 10 and 20 kHz) exhibited tonotopic maps in the primary auditory cortex (AI). Depression of auditory cortical responses was observed in sound-deprived mice compared with naive mice reared in a normal acoustic environment. When mice were exposed to an environmental tonal stimulus at 10 kHz for more than 4 weeks after birth, the cortical responses were potentiated in a frequency-specific manner. These results suggest that acoustic environments regulate the development of intracortical circuits in the mouse auditory cortex.2. We visualized cortical responses to missing fundamentals in mice. The activity patterns in AI elicited by 5 kHz were different from those elicited by 20 … More kHz or 25 kHz. However, the areas activated by 5 kHz were also activated by the mixture of 20 kHz plus 25 kHz but not by that of 19 kHz plus 26 kHz, suggesting that cortical responses to missing fundamentals in AI were visualized using flavoprotein fluorescence imaging3. Experience-dependent plasticity in the visual cortex was investigated. After monocular deprivation (MD) of 4 days starting from P28, deprived eye responses were suppressed compared to non-deprived eye responses in the binocular zone, but not in the monocular zone. Imaging faithfully recapitulated a critical period for plasticity with maximal effects of MD observed around P28 and not in adulthood even under urethane anesthesia. These results indicate that transcranial flavoprotein fluorescence imaging is a powerful tool for investigating experience-dependent plasticity in the mouse visual cortex.4. We designed a hemilateral prism goggle for mice. This goggle was attached on the skull of mice during the critical period. The visual cortical responses elicited via the eye with a prism were significantly suppressed compared with those elicited via the contralateral normal eye. However, this suppression was not observed in mice, in which whiskers were trimmed. It was suggested that the visual responses might be suppressed by multimodal sensory mismatching between somatosensory inputs and visual inputs regarding spatial recognition. Less