Intracellular and computational characterization of the intracortical inhibitory control of synchronized thalamic inputs in vivo
Intracellular and computational characterization of the intracortical inhibitory control of synchronized thalamic inputs in vivo
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DOI：
10.1152/jn.1997.78.1.335
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发表时间：
1997-07-01
影响因子：
2.5
通讯作者：
Steriade, M
中科院分区：
文献类型：
--
作者：
Contreras, D;Destexhe, A;Steriade, M
我们通过结合巴比妥钠麻醉猫的锥体细胞内记录和计算模型，研究了在纺锤波(7-14赫兹)期间，局部抑制皮质对丘脑同步输入的控制的存在和作用。记录表明：1)类似的兴奋性突触后电位(EPSP)/抑制性突触后电位(IPSP)序列出现在纺锤波或丘脑刺激后；2)用含氯吸管的反向IPSP将纺锤波相关的EPSP/IPSP序列转化为强健的爆发与峰灭活，类似于癫痫发作时的PAR阵发性去极化转移；以及3)双重同时电刺激表明与丘脑同步输入相关的抑制是局部的。计算模型基于重建的锥体细胞，这些细胞受到来自相同细胞的记录的约束。这些模型表明，EPSP/IPSP序列转变为完全发育的棘波爆发，关键需要在胞体和近端树突中有相对高密度的抑制电流。此外，模型预测，由于丘脑的同步输入，树突中存在显著的钙瞬变。我们的结论是，丘脑的同步化输入在皮质内受到强烈的抑制控制，并提出1)局部抑制的损害有助于纺锤波向棘波型放电的转变，2)纺锤相关的输入触发皮质树突中的钙事件，这可能有助于睡眠中的可塑性现象。
We investigated the presence and role of local inhibitory cortical control over synchronized thalamic inputs during spindle oscillations (7-14 Hz) by combining intra cellular recordings of pyramidal cells in barbiturate-anesthetized cats and computational models. The recordings showed that 1) similar excitatory postsynaptic potential (EPSP)/inhibitory post synaptic potential (IPSP) sequences occurred either during spindles or following thalamic stimulation; 2) reversed IPSPs with chloride-filled pipettes transformed spindle-related EPSP/IPSP sequences into robust bursts with spike inactivation, resembling par paroxysmal depolarizing shifts during seizures; and 3) dual simultaneous impalements showed that inhibition associated with synchronized thalamic inputs is local. Computational models were based on reconstructed pyramidal cells constrained by recordings from the same cells. These models showed that the transformation of EPSP/IPSP sequences into fully developed spike bursts critically needs a relatively high density of inhibitory currents in the soma and proximal dendrites. In addition, models predict significant Ca2+ transients in dendrites due to synchronized thalamic inputs. We conclude that synchronized thalamic inputs are subject to strong inhibitory control within the cortex and propose that 1) local impairment of inhibition contributes to the transformation of spindles into spike-wave-type discharges, and 2) spindle-related inputs trigger Ca2+ events in cortical dendrites that may subserve plasticity phenomena during sleep.