Multiple forms of short-term plasticity at excitatory synapses in rat medial prefrontal cortex
Multiple forms of short-term plasticity at excitatory synapses in rat medial prefrontal cortex
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DOI：
10.1152/jn.2000.83.5.3031
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发表时间：
2000-05-01
影响因子：
2.5
通讯作者：
Nelson, SB
中科院分区：
文献类型：
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作者：
Hempel, CM;Hartman, KH;Nelson, SB
短期突触可塑性，特别是短期抑制和促进，强烈影响大脑皮层回路中的神经元活动。我们研究了大鼠内侧前额叶皮层V层锥体细胞兴奋性突触的短期可塑性，这一区域的突触动态特性尚未被系统地研究过。利用体外II/III层刺激引起的突触反应的细胞内和细胞外记录，我们发现短期抑郁和短期促进与之前在皮层其他区域描述的相似。此外，前额叶皮层的突触显著表达增强，这是一种更持久的短期突触增强形式。这包括40-60%的突触传递增强，持续数秒到数分钟，可以由中等持续时间和频率的刺激序列诱导。初级视觉皮层第三层神经元上的突触表达的增强明显较少，表明这是突触特有的特性。来自前额叶皮层连接的V层锥体细胞对的细胞内记录表明，增强是单个突触的特性，不需要激活多个突触输入或神经调节纤维。我们提出突触增强可以增强神经元回路在短暂刺激后维持持续活动的能力。这个想法是探索使用计算机模拟一个简化的递归皮层网络。
Short-term synaptic plasticity, in particular short-term depression and facilitation, strongly influences neuronal activity in cerebral cortical circuits. We investigated shortterm plasticity at excitatory synapses onto layer V pyramidal cells in the rat medial prefrontal cortex, a region whose synaptic dynamic properties have not been systematically examined. Using intracellular and extracellular recordings of synaptic responses evoked by stimulation in layers II/III in vitro, we found that short-term depression and short-term facilitation are similar to those described previously in other regions of the cortex. In addition, synapses in the prefrontal cortex prominently express augmentation, a longer lasting form of short-term synaptic enhancement. This consists of a 40-60% enhancement of synaptic transmission which lasts seconds to minutes and which can be induced by stimulus trains of moderate duration and frequency. Synapses onto layer III neurons in the primary visual cortex express substantially less augmentation, indicating that this is a synapse-specific property. Intracellular recordings from connected pairs of layer V pyramidal cells in the prefrontal cortex suggest that augmentation is a property of individual synapses that does not require activation of multiple synaptic inputs or neuromodulatory fibers. We propose that synaptic augmentation could function to enhance the ability of a neuronal circuit to sustain persistent activity after a transient stimulus. This idea is explored using a computer simulation of a simplified recurrent cortical network.