Here, we report increases in synchrony between the MD and mPFC during a spatial working memory task in control mice. During task acquisition, synchronized activity between these two structures in the theta- and beta-frequency ranges increased hand in hand with improvements in task performance. After successful acquisition, beta-frequency synchrony was specifically enhanced in the working memory-requiring choice phase of the task, during which mice need to keep information online to make the correct Fulvestrant cell line choice and obtain the reward. Finally,

lag analysis demonstrated that the MD leads the mPFC. These results are consistent with the hypothesis that information flows from the MD to the mPFC in support of working memory, similar to previous findings suggesting that hippocampal-prefrontal interactions are also involved (Jones and Wilson, 2005; Sigurdsson et al., 2010). The precise nature of the information contributed by MD inputs to the m PFC is unclear. Studies of MD single unit activity during visual working memory in non-human primates have suggested the possibility that MD units encode motor planning information (Watanabe and Funahashi, 2012). Considering the known inputs to the MD from the basal ganglia and extrapolating from these findings, it may be that the MD transmits motor information to the PFC about the choice BMN 673 research buy to be made during

spatial working memory. Our findings point to synchrony between the MD and mPFC in the beta-frequency (13 to 30 Hz) range as of particular relevance to the DNMS task. While the oscillations in the theta and gamma bands have been classically linked to working memory, the functional role of beta-band oscillations is less understood. However, recent studies performed in human and nonhuman primates point to a role for beta-band oscillations in cognitive processes. Specifically, elevations of beta-band activity in visual and MRIP prefrontal cortical areas have been observed during the

delay phase of working memory tasks (Deiber et al., 2007; Siegel et al., 2009; Tallon-Baudry et al., 2001; Tallon-Baudry et al., 2004). Interestingly, beta-band activity has also been linked to motor activity. Indeed, numerous studies provided the evidence that beta activity is decreased during voluntary movements and increased during holding periods following movement in a variety of structures belonging to the motor system (for a review see Engel and Fries, 2010). Rather than reflecting a lack of movement, a recent hypothesis proposed that beta rhythm would be related to the active maintenance of the current sensorimotor set. According to this hypothesis, the role of beta oscillations in cognition would be of similar nature and may be enhanced if the status quo is given priority over distractive new signal, whereas gamma band activity may predominate if changes in stimulus are expected (Engel and Fries, 2010).