A CRITICAL PERIOD FOR LONG-TERM POTENTIATION AT THALAMOCORTICAL SYNAPSES
A CRITICAL PERIOD FOR LONG-TERM POTENTIATION AT THALAMOCORTICAL SYNAPSES
复制标题
DOI：
10.1038/375325a0
复制
发表时间：
1995-05-25
期刊：
影响因子：
64.8
通讯作者：
MALENKA, RC
中科院分区：
文献类型：
--
作者：
CRAIR, MC;MALENKA, RC
在哺乳动物的发育过程中，从丘脑到皮质的地形投射的精细化被认为是通过丘脑轴突竞争皮质靶点的活动依赖性过程产生的（1，2）。为了支持这一观点，如果在早期发育的关键时期活动发生变化，正常的连接就会中断（1，2）。有人提出，在发育过程中，突触连接通过相关的突触前和突触后活动得到加强（3，4），这一过程的可能机制是N-甲基-D-天冬氨酸（NMDA）受体依赖性长时程增强（LTP）（5，6）。然而，LTP参与正常发育的证据仍然不确定。我们研究了大鼠躯体感觉皮层（S1）中形成须桶的丘脑皮层突触的LTP。我们在这里报告，在此期间，LTP可以诱导密切匹配的关键时期，在此期间，桶可以修改感官扰动。此外，随着年龄的增长，LTP易感性的丧失伴随着NMDA受体介导的突触电流的减少。这些发现提供了令人信服的证据，LTP是重要的发展皮层电路。
IN mammalian development, the refinement of topographical projections from the thalamus to the cortex is thought to arise through an activity-dependent process in which thalamic axons compete for cortical targets(1,2). In support of this view, if activity is altered during a critical period in early development, normal connectivity is disrupted(1,2). It has been proposed that synaptic connections are strengthened during development by correlated pre- and postsynaptic activity(3,4), and a likely mechanism for this process would be N-methyl-D-aspartate (NMDA) receptor-dependent long-term potentiation (LTP)(5,6). However, the evidence that LTP is involved in normal development remains inconclusive. We have examined LTP in the thalamocortical synapses that form whisker barrels in rat somatosensory cortex (S1). We report here that the period during which LTP can be induced matches closely the critical period during which the barrels can be modified by sensory perturbations. Moreover, the loss of susceptibility to LTP with age is accompanied by a decrease in NMDA receptor-mediated synaptic currents. These findings provide compelling evidence that LTP is important for the development of cortical circuitry.