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

利用经颅黄蛋白荧光成像技术，获得了以下结果：我们研究了听觉皮层可塑性受声环境的调节。小鼠出生后在不同的声环境中饲养至少4周。音调刺激（5、10和20 kHz）引起的皮层反应在初级听觉皮层（AI）中表现出音调位图。与在正常声环境中饲养的幼年小鼠相比，在无声环境中观察到听觉皮层反应的抑制。当小鼠出生后连续4周暴露于10 kHz的环境音调刺激时，皮质反应以频率特异性方式增强。这些结果表明，声环境调节了小鼠听觉皮层内回路的发育。我们可视化了小鼠对基本原理缺失的皮质反应。5 kHz诱发的人工智能活动模式与20 ~ 25 kHz诱发的人工智能活动模式不同。然而，被5 kHz激活的区域也被20 kHz加25 kHz激活，而不是被19 kHz加26 kHz激活，这表明使用黄蛋白荧光成像可以可视化AI中对缺失基础的皮质反应3。研究了视觉皮层的经验依赖可塑性。从P28开始进行4天的单眼剥夺（MD）后，双眼区被剥夺的眼睛反应与未被剥夺的眼睛反应相比受到抑制，但单眼区没有。成像忠实地再现了可塑性的关键时期，在P28左右观察到最大的MD效应，即使在聚氨酯麻醉下也没有在成年期观察到。这些结果表明，经颅黄蛋白荧光成像是研究小鼠视觉皮层经验依赖性可塑性的有力工具。我们设计了一种用于小鼠的半棱镜护目镜。在关键时期，将这种护目镜贴在小鼠的颅骨上。与对侧正常眼相比，棱镜眼诱发的视觉皮层反应明显受到抑制。然而，在修剪胡须的小鼠中没有观察到这种抑制。在空间识别方面，视觉反应可能受到躯体感觉输入与视觉输入的多模态不匹配的抑制。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