Rey et al recorded local field potentials and neuron spikes from the human medial temporal lobe during a recognition task.  Single-neuron responses were preceded by a global increase in theta oscillations and a local and stimulus-specific increase in gamma oscillations.  The LFPs responses were correlated with conscious recognition and neuron spiking was time-locked to the LFPs.  They suggest that theta reflects a global recognition signal whereas phase-locked of neurons to gamma reflects activation of local circuits that represent the recognized stimulus.