Ji Zhanxin, Boyd Tiffany E, Froc David J, Racine Ronald J
Department of Psychology, McMaster University, Hamilton, ON L8S 4K1, Canada.
Eur J Neurosci. 2005 Sep;22(6):1455-62. doi: 10.1111/j.1460-9568.2005.04329.x.
We have reported that long-term potentiation (LTP) can be reliably induced in motor cortex of adult, freely moving rats by the application of spaced and repeated high frequency stimulating trains to the white matter. In the present study, we monitored field potentials (FPs) and LTP in both layer II/III and V in coronal slices of motor cortex taken from implanted control and previously potentiated Long-Evans rats. The baseline FP amplitudes were decreased in layer II/III, and the amplitude of small spikes was significantly increased in layer V in slices from previously potentiated rats compared to unpotentiated control rats. In response to high frequency stimulation applied to the slice itself, both implanted control and previously potentiated rats showed similar levels of LTP in layer II/III. LTP could not be induced in layer V. These results show that layer II/III and V respond differently to high frequency stimulation in vitro. In addition, layer II/III responds very differently in slice compared to chronic preparations.
我们曾报道，通过对白质施加间隔且重复的高频刺激串，可在成年自由活动大鼠的运动皮层可靠地诱导出长时程增强（LTP）。在本研究中，我们监测了取自植入对照大鼠和先前已产生LTP的Long-Evans大鼠的运动皮层冠状切片中II/III层和V层的场电位（FP）及LTP。与未产生LTP的对照大鼠相比，先前已产生LTP的大鼠切片中，II/III层的基线FP幅度降低，V层的小棘波幅度显著增加。针对施加于切片本身的高频刺激，植入对照大鼠和先前已产生LTP的大鼠在II/III层均表现出相似水平的LTP。V层无法诱导出LTP。这些结果表明，II/III层和V层在体外对高频刺激的反应不同。此外，与慢性制备相比，II/III层在切片中的反应差异很大。
