Presenter(s): Ashley Dresen − Psychology
Faculty Mentor(s): Michael Posner, Pascale Voelker
Oral Session 2SW
Research Area: Cognitive Psychology
Funding: ONR Grant N00014-15-1-2148 to the University of Oregon
Theta frequencies are associated with internalized attention and positive emotional states. In our laboratory, mice receiving theta frequency stimulation of the anterior cingulate cortex (ACC) showed increased myelin and improved connectivity as measured by g-ratio (axon diameter/axon diamenter + myelin). To extend these results to humans, we stimulated the
ACC by applying electrical stimulation at a theta frequency (6Hz) to a set of scalp electrodes overlying that area. Following stimulation, we found enhanced low frequency power in ACC sites compared to baseline, and this power increased when a task known to stimulate the ACC was performed. To test whether this method could be applied to other brain areas, we chose a task activating the hand region of the primary motor cortex and electrodes stimulating the motor area. We are testing 12 undergraduates using a generic set of electrodes known to stimulate the motor area, and comparing this with electrodes selected for each person based on structural brain images. We plan to determine if stimulation increases low frequency theta rhythms during non-stimulated periods, and whether the electrodes chosen individually produce superior effects to the generic ones. We are currently summarizing the results from 12 subjects. We expect that intrinsic theta will be increased in the motor area in the minute following electrical stimulation and this will be greater when performing the task. We expect these effects to be larger for individually selected electrodes. If results are as expected, it will suggest that many cortical and subcortical areas show increased theta following stimulation and allow us to test whether long term use of such stimulation can alter white matter connectivity as found in our mouse model.