Cortical oscillations arise from contextual interactions that regulate sparse coding
Cortical oscillations arise from contextual interactions that regulate sparse coding
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DOI：
10.1073/pnas.1405300111
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发表时间：
2014-05-06
影响因子：
11.1
通讯作者：
Sejnowski, Terrence J.
中科院分区：
文献类型：
--
作者：
Jadi, Monika P.;Sejnowski, Terrence J.
准确的尖峰时间携带信息，对突触的可塑性很重要。伽马爆发等同步振荡可以协调尖峰时间，从而调节大脑皮层的信息传输。振荡由抑制性神经元驱动，并受感觉刺激和行为状态的调节。他们的功率和频率是如何受到监管的，这是一个悬而未决的问题。利用一个模型皮层回路，我们提出了一种依赖于单突触和双突触通路到抑制性神经元的活动平衡的调节机制：单突触输入引起更强大的振荡，而双突触输入增加振荡的频率。对两条通路的刺激平衡调节了棘波的整体分布，较强的双突触刺激(例如，视觉感受野内的首选刺激)产生高放电率和弱振荡；相反，较强的单突触刺激(例如，来自视觉感受野外的抑制性上下文刺激)产生低放电率和对峰时序的强烈振荡调节，如在警觉皮层处理复杂自然刺激中观察到的那样。通过解释其他自相矛盾的实验发现，我们的结果表明，振荡的频率和功率，因此，尖峰时间，可以被感觉输入和行为背景调制，强大的振荡意味着在抑制性控制下的皮质状态，其中尖峰脉冲稀疏，尖峰时刻精确。
Precise spike times carry information and are important for synaptic plasticity. Synchronizing oscillations such as gamma bursts could coordinate spike times, thus regulating information transmission in the cortex. Oscillations are driven by inhibitory neurons and are modulated by sensory stimuli and behavioral states. How their power and frequency are regulated is an open question. Using a model cortical circuit, we propose a regulatory mechanism that depends on the activity balance of monosynaptic and disynaptic pathways to inhibitory neurons: Monosynaptic input causes more powerful oscillations whereas disynaptic input increases the frequency of oscillations. The balance of stimulation to the two pathways modulates the overall distribution of spikes, with stronger disynaptic stimulation (e.g., preferred stimuli inside visual receptive fields) producing high firing rates and weak oscillations; in contrast, stronger monosynaptic stimulation (e.g., suppressive contextual stimulation from outside visual receptive fields) generates low firing rates and strong oscillatory regulation of spike timing, as observed in alert cortex processing complex natural stimuli. By accounting for otherwise paradoxical experimental findings, our results demonstrate how the frequency and power of oscillations, and hence spike times, can be modulated by both sensory input and behavioral context, with powerful oscillations signifying a cortical state under inhibitory control in which spikes are sparse and spike timing is precise.