Title: Anovel role for dopamine regulation of cortical information processing.
Abstract
Dopamine neurotransmission in the prefrontal cortex (PFC) is critical to cognitive processes such as attention, working memory as well as behavioral flexibility and has been implicated in cognitive deficits observed in addiction, schizophrenia, and ADHD. These cognitive processes and deficits have been linked to network oscillations in PFC. However, experimental evidence describing a causal relationship between the activity of dopamine neurons and oscillations in the prefrontal cortex is lacking. In freely moving TH::Cre rats, we optogenetically stimulated dopamine neurons in the ventral tegmental area (VTA) and simultaneously recorded local field potentials (LFPs) in the medial prefrontal cortex (mPFC). Dopamine neurons were stimulated using bursting paradigms that resemble the activity patterns of these neurons during motivated behaviors. We found that burst activity of VTA dopamine neurons is sufficient for increasing the power of high gamma (> 55 Hz) but not low gamma (35–55 Hz) oscillations in the mPFC. In addition, a corresponding elevation in the power of theta oscillations (4–11 Hz) was observed at the peak of high gamma power. Thus, bursting of dopamine neurons might modulate cortical network activity relevant to goal directed behaviors and cognitive processes via this coordinated increase in PFC high gamma and theta power. Examination of single unit activity and spike-field coherence is ongoing and will provide further insight into the effects of VTA dopamine neurotransmission on PFC network activity.