Neuronal representation of audio-place associations in the medial prefrontal cortex of rats

Stimulus-place associative task requires humans or animals to associate or map different stimuli with different locations. It is know that the medial prefrontal cortex (mPFC) in rats, also termed prelimbic cortex (PrL), is important for performing stimulus-place associations. However, little is known about how mPFC neurons encode stimulus-palce associations. To address this, the present study trained rats on an audio-place associative task, whereby the animals were required to associate two different tones with entering two different arms in a Y-shaped maze. Reversible inactivation of the mPFC by local infusion of the GABA(A) receptor agonist muscimol severely impaired the performance of rats on the associative task, again indicating an important role of mPFC in the task performance. Single-unit recording showed that a group of mPFC neurons (40/275, 14.5 %) fired preferentially for the audio-place associations, providing the first electrophysiological evidence for the involvement of mPFC cells in representing audio-place associations.