Correlated connectivity and the distribution of firing rates in the neocortex.
Correlated connectivity and the distribution of firing rates in the neocortex.
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DOI：
10.1523/jneurosci.4500-08.2009
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发表时间：
2009-03-25
期刊：
影响因子：
--
通讯作者：
Zador AM
中科院分区：
文献类型：
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作者：
Koulakov AA;Hromádka T;Zador AM
最近的两个实验观察对许多皮层模型提出了挑战。首先，听觉皮层的活动是稀疏的，放电率可以用对数正态分布来描述。其次，相邻皮层神经元之间的非零突触强度的分布也可以用对数正态分布来描述。在这里，我们使用一个简单的皮质活动模型来调和这些观察结果。该模型做出了实验上可检验的预测，即给定皮层神经元上的突触功效是统计相关的，即它预测一些神经元比其他神经元接收更强的突触。我们提出了一个简单的Hebb样的学习规则，产生这样的相关性，并产生对数正态发射率和突触功效。我们的研究结果代表了在皮层网络中协调稀疏活动和稀疏连接的第一步。
Two recent experimental observations pose a challenge to many cortical models. First, the activity in the auditory cortex is sparse, and firing rates can be described by a lognormal distribution. Second, the distribution of non-zero synaptic strengths between nearby cortical neurons can also be described by a lognormal distribution. Here we use a simple model of cortical activity to reconcile these observations. The model makes the experimentally testable prediction that synaptic efficacies onto a given cortical neuron are statistically correlated, i.e. it predicts that some neurons receive stronger synapses than other neurons. We propose a simple Hebb-like learning rule which gives rise to such correlations and yields both lognormal firing rates and synaptic efficacies. Our results represent a first step toward reconciling sparse activity and sparse connectivity in cortical networks.