Submitted on July 19, 2007
Accepted on October 8, 2007
Resonant antidromic cortical circuit activation as a consequence of high-frequency subthalamic deep-brain stimulation
Su Li1, Gordon W Arbuthnott2, Michael J Jutras1, Joshua A Goldberg3, and Dieter Jaeger1*
1 Biology, Emory University, Atlanta, Georgia, United States
2 Division of Neuroscience, University of Edinburgh, United Kingdom
3 Biology, University of Texas at San Antonio, San Antonio, Texas, United States
* To whom correspondence should be addressed. E-mail: djaeger{at}emory.edu.
Deep brain stimulation (DBS) is an effective treatment of Parkinson's disease (PD) for many patients. The most effective stimulation consists of high-frequency biphasic stimulation pulses around 130 Hz delivered between two active sites of an implanted depth electrode to the subthalamic nucleus (STN-DBS). Multiple studies have shown that a key effect of STN-DBS that correlates well with clinical outcome is the reduction of synchronous and oscillatory activity in cortical and basal ganglia networks. We hypothesized that antidromic cortical activation may provide an underlying mechanism responsible for this effect, as stimulation is usually performed in proximity to cortical efferent pathways. We show with intracellular cortical recordings in rats that STN-DBS did in fact lead to antidromic spiking of deep layer cortical neurons. Furthermore, antidromic spikes triggered a dampened oscillation of local field potentials in cortex with a resonant frequency around 120 Hz. The amplitude of antidromic activation was significantly correlated with an observed suppression of slow wave and beta band activity during STN-DBS. These findings were seen in ketamine-xylazine or isoflurane anesthesia in both normal and 6-OHDA lesioned rats. Thus, antidromic resonant activation of cortical microcircuits may make an important contribution towards counteracting the overly synchronous and oscillatory activity characteristic of cortical activity in PD.
