Subthalamic stimulation elicits different transient properties of cortical rhythms during open-eyes and closed-eyes resting states

Resumen

Background: Several studies have emphasized on variations in brain functional features between spontaneous brain activity between the eyes-open (EO) and eyes-closed (EC) resting states, assuming that brain activity is a static phenomenon. Besides, Parkinson’s disease (PD) has been associated with characteristic patterns of synchronous oscillatory activity within cortico-basal-ganglia circuits, but the functional relationship between STN-DBS and the brain’s resting state activity is still unclear. The purpose of this study was to investigate the dynamic nature of brain activity in different EO and EC resting conditions and the transient effects on sensorimotor and cortical networks in response to subthalamic stimulation in unmedicated PD patients.Methods: Fifteen unmedicated PD patients treated with bilateral STN-DBS and 17 matched-healthy controls were recruited. Spontaneous electroencephalographic (EEG) activity at rest was recorded during 4 min EC and 4 min EO and during STN-DBS On/Off states in the case of PD patients. Grand average topographical maps were analyzed for extraction of logarithmic spectral power of each EEG frequency band at posterior, central and frontocentral regions.Results: Compared to DBS ‘Off’ state, STN stimulation modulated activity in all frequency bands was unaltered between EC and EO states while dopamine depleted patients power in alpha and theta bands differed. Low and high beta and gamma activity of PD patients in the stimulation OFF condition showed no increases or reductions in comparison with healthy controls while activation in all those frequency bands were modulated by the stimulator state.Conclusions: Our findings may provide insights into the dynamic nature of the resting-state brain activity in PD and suggest that STN-DBS in a dopamine deprived state can selectively regulate the focal character of cortical frequency bands in addition to between EC and EO resting states and particularly for posterior cortical alpha activity, which would rise during PD disease progression.