Rewarding stimulation of the lateral hypothalamus induces a dopamine-dependent suppression of synaptic responses in the entorhinal cortex.

The entorhinal cortex receives inputs from sensory and associational cortices, as well as a substantial input from midbrain dopaminergic neurons. Dopamine is likely to modulate the responsiveness of entorhinal cortex neurons to sensory inputs, and excitatory synaptic responses in layers I/II of the entorhinal cortex in vitro can be either facilitated or suppressed by dopamine depending upon the concentration applied. Rewarding stimulation of the lateral hypothalamus leads to activation of dopamine neurons, and the present study evaluated the effect of rewarding stimulation on synaptic responses in the lateral entorhinal cortex evoked by stimulation of the primary olfactory (piriform) cortex in behaving rats.