Poster C4, Sunday, March 26, 5:00 – 7:00 pm, Pacific Concourse
Contributions of medial prefrontal cortex to internally directed attention
Julia W. Y. Kam1, Jack L. Lin2, Tor Endstead3, Anne-Kristin Solbakk3, Pal G. Larsson4, Sandon Griffin1, Robert T. Knight1; 1University of California, Berkeley, 2University of California, Irvine, 3University of Oslo, 4Oslo University Hospital
Humans spend up to half of their awake time engaging in thoughts unrelated to their current tasks that are strongly associated with personal concerns and goals in everyday life. While neuroimaging evidence implicates the default mode network in these pervasive thoughts, the underlying mechanism of such internally directed attention is still largely unknown. Cross-frequency coupling is a potential neural mechanism underlying internally directed attention given its purported functional role in the integration of spatiotemporal dynamics within and across large-scale brain networks. To address this issue, we recorded intracranial EEG activity in patients undergoing presurgical monitoring for intractable epilepsy who were implanted with subdural and/or depth electrodes. Patients performed an attention task wherein half the time, they had to detect a rare target tone (i.e. externally directed condition); the other half of the time, they were told to ignore all the tones and to allow their minds to wander (i.e. internally directed condition). Cross-frequency coupling was computed between the alpha (8-12Hz) and high frequency range (70-150Hz) for each electrode, which was then examined as a function of condition across patients. We found increased coupling in the medial prefrontal cortex (PFC) during the internally directed relative to externally directed conditions, suggesting that the enhanced spatiotemporal integration of information within the medial PFC as part of the default mode network is one potential mechanism in facilitating internally directed attention.
Topic Area: ATTENTION: Other