Functional identification of synaptic plasticity in the rat auditory cortex

大鼠听觉皮层突触可塑性的功能鉴定

基本信息

批准号：
10480225
负责人：
SHIBUKI Katsuei
金额：
$ 7.68万
依托单位：
NIIGATA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

In this study, we investigated the physiological roles of synaptic plasticity in the rat auditory cortex. We studied long-term depression (LTD). The synaptic inputs to pyramidal neurons from the medial geniculate body exhibited LTD, which was sensitive to an antagonist of NMDA receptors. In contrast, LTD was sensitive to an antagonist of metabotropic glutamate receptors in the synapses between cortical pyramidal neurons. We further investigated sequence-dependent properties of long-term potentiation (LTP). The sequence-dependence was observed on the scale of seconds, so that LTP was observed only in the synapses stimulated earlier. The sequence-dependence of LTP was abolished in the presence of antagonists of muscarinic acetylcholine receptors. The importance of endogenous cholinergic was also shown in the sound-sequence discrimination ability of rats using behavioral analyses. These results suggest that the sequence-dependent LTP may have a role in temporal information processing in the auditory cortex. Finally, we investigated the properties between the auditory cortex and higher cortices. Primary sensory cortices can be activated by memory recall or imagery via feedback projections from higher cortices. We studied the properties of the cortical boundary between the auditory cortex and area 18a in rat cerebral slices. Activities in the auditory cortex were usually not elicited by the stimulation of area 18a. However, the whole auditory cortex was invaded by polysynaptic feedback activities triggered in area 18a, after area 18a and the auditory cortex were alternately stimulated several times. Our findings indicate that different cortical areas are quickly bound with feedback activities depending on previous activities.

在这项研究中，我们研究了突触可塑性在大鼠听觉皮层中的生理作用。我们研究了长期抑郁症（LTD）。内侧遗传体的锥体神经元的突触输入表现出LTD，对NMDA受体的拮抗剂敏感。相比之下，LTD对皮质金字塔神经元之间突触中的代谢性谷氨酸受体的拮抗剂敏感。我们进一步研究了长期增强（LTP）的序列依赖性特性。在秒的尺度上观察到了序列依赖性，因此仅在先前刺激的突触中观察到LTP。在存在毒蕈碱乙酰胆碱受体的拮抗剂的情况下，消除了LTP的序列依赖性。使用行为分析的大鼠的声音序列歧视能力也表明了内源性胆碱能的重要性。这些结果表明，依赖序列的LTP可能在听觉皮层中的时间信息处理中起作用。最后，我们研究了听觉皮层和高层皮质之间的特性。主感觉皮质可以通过内存回忆或图像通过来自高层皮质的反馈投影激活。我们研究了大鼠脑切片中听觉皮层和区域18a之间皮质边界的性质。听觉皮层中的活性通常不会因刺激18a的刺激而引起。但是，整个听觉皮层被18A区域触发的多突触反馈活动入侵，在区域18a和听觉皮层后交替刺激了几次。我们的发现表明，根据以前的活动，不同的皮质区域很快与反馈活动约束。