PT  - JOURNAL ARTICLE
AU  - Koulakov, Alexei A.
AU  - Hromádka, Tomáš
AU  - Zador, Anthony M.
TI  - Correlated Connectivity and the Distribution of Firing Rates in the Neocortex
AID  - 10.1523/JNEUROSCI.4500-08.2009
DP  - 2009 Mar 25
TA  - The Journal of Neuroscience
PG  - 3685--3694
VI  - 29
IP  - 12
4099  - http://www.jneurosci.org/content/29/12/3685.short
4100  - http://www.jneurosci.org/content/29/12/3685.full
SO  - J. Neurosci.2009 Mar 25; 29
AB  - 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 nonzero 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 that 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.