  Networks of excitatory and inhibitory neurons display asynchronous irregular
(AI) states, where the activities of the two populations are balanced. At the
single cell level, it was shown that neurons subject to balanced and noisy
synaptic inputs can display enhanced responsiveness. We show here that this
enhanced responsiveness is also present at the network level, but only when
single neurons are in a conductance state and fluctuation regime consistent
with experimental measurements. In such states, the entire population of
neurons is globally influenced by the external input. We suggest that this
network-level enhanced responsiveness constitute a low-level form of sensory
awareness.
