We found relationships between putative FSI spiking activity and gamma oscillations using four different approaches: STA, phase preference, firing rate changes with gamma power, and spike-field coherency. The average STA over all neurons exhibited clear structure, consistent with earlier reports (Berke, 2005; Kalenscher et al., 2008); about half of FSIs sampled had a significant phase preference; the majority of FSIs changed their firing rate with changes in gamma power; and many FSIs exhibited significant spike-field coherence in the gamma band. Taken together, these results clearly show that gamma oscillations are relevant to ventral striatal processing, whatever their source; however, these results alone cannot address whether such oscillations are generated elsewhere and affect spiking activity in ventral striatum, or are generated by ventral striatal processes.
