Spine Loss in Primary Somatosensory Cortex during Trace Eyeblink Conditioning
Spine Loss in Primary Somatosensory Cortex during Trace Eyeblink Conditioning
复制标题
DOI：
10.1523/jneurosci.2043-14.2015
复制
发表时间：
2015-03-04
影响因子：
5.3
通讯作者：
Schwarz, Cornelius
中科院分区：
文献类型：
--
作者：
Joachimsthaler, Bettina;Brugger, Dominik;Schwarz, Cornelius
经典条件反射涉及记忆处理，即条件刺激和非条件刺激之间的“痕迹”时期，需要意识到要形成的关联，被认为是陈述性学习的简单模型范式。桶皮层，初级躯体感觉皮层的胡须代表，是需要学习的触觉变体的痕迹眨眼条件反射（TTEBC），并在学习过程中经历独特的地图可塑性。为了研究支持TTEBC和并发地图可塑性的细胞机制，我们使用双光子成像的树突棘在清醒的小鼠桶皮质，而条件。监测第5层神经元在第1层的顶端树突，我们表明，桶皮质可塑性的一个细胞表达是一个实质性的棘计数减少类似于15%的学习前存在的树突棘。消除棘的数量和消除棘的时间与学习的成功密切相关。此外，脊柱的可塑性是高度具体的主要桶柱接收来自受刺激的触须的主要信号。位于其他列中的棘，即使是与主列直接相邻的棘，也不受影响。由于第1层脊椎整合了来自丘脑皮层相关回路的信号，因此它们的列特异性消除表明，这种脊椎可塑性可能是与陈述性学习相关的自上而下信号和空间精确的上行触觉信号相关联的结果。
Classical conditioning that involves mnemonic processing, that is, a "trace" period between conditioned and unconditioned stimulus, requires awareness of the association to be formed and is considered a simple model paradigm for declarative learning. Barrel cortex, the whisker representation of primary somatosensory cortex, is required for the learning of a tactile variant of trace eyeblink conditioning (TTEBC) and undergoes distinct map plasticity during learning. To investigate the cellular mechanism underpinning TTEBC and concurrent map plasticity, we used two-photon imaging of dendritic spines in barrel cortex of awake mice while being conditioned. Monitoring layer 5 neurons' apical dendrites in layer 1, we show that one cellular expression of barrel cortex plasticity is a substantial spine count reduction of similar to 15% of the dendritic spines present before learning. The number of eliminated spines and their time of elimination are tightly related to the learning success. Moreover, spine plasticity is highly specific for the principal barrel column receiving the main signals from the stimulated vibrissa. Spines located in other columns, even those directly adjacent to the principal column, are unaffected. Because layer 1 spines integrate signals from associative thalamocortical circuits, their column-specific elimination suggests that this spine plasticity may be the result of an association of top-down signals relevant for declarative learning and spatially precise ascending tactile signals.