title: Correlated connectivity and the distribution of firing rates in the neocortex.
abstract: 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.
authors.affiliation: Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA. akula@cshl.edu
authors.forename: Alexei A
authors.initials: AA
authors.lastname: Koulakov
authors.forename: Tomás
authors.initials: T
authors.lastname: Hromádka
authors.forename: Anthony M
authors.initials: AM
authors.lastname: Zador