Brain-behavior analysis of transcranial direct current stimulation effects on a complex surgical motor task

Abstract Transcranial direct current stimulation (tDCS) has been shown to facilitate surgical training and performance when compared to sham tDCS; however, the potency may be improved by selecting appropriate brain targets based on neuroimaging and mechanistic insights. Published studies have shown the feasibility of portable brain imaging in conjunction with tDCS during Fundamentals of Laparoscopic Surgery (FLS) tasks for concurrently monitoring the cortical activations via functional near-infrared spectroscopy (fNIRS). Then, fNIRS can be combined with electroencephalogram (EEG) where EEG band power changes have been shown to correspond to the changes in oxyhemoglobin (HbO) concentration, found from the fNIRS. In principal accordance with these prior works, our current study aimed to investigate multi-modal imaging of the brain response to cerebellar (CER) and ventrolateral prefrontal cortex (PFC) tDCS that may facilitate the most complex FLS suturing with intracorporal knot tying task. Our healthy human study on twelve novices (age: 22-28 years, 2 males, 1 female with left-hand dominance) from medical/premedical backgrounds aimed for mechanistic insights from neuroimaging brain areas that are related to error-based learning – one of the basic skill acquisition mechanisms. We found that right CER tDCS of the posterior lobe facilitated a statistically significant (q<0.05) brain response at the bilateral prefrontal areas at the start of the FLS task that was higher than sham tDCS. Also, right CER tDCS significantly (p<0.05) improved FLS score when compared to sham tDCS. In contrast, left PFC tDCS failed to facilitate a significant brain response and FLS performance improvement. Moreover, right CER tDCS facilitated activation of the bilateral prefrontal brain areas related to FLS performance improvement provided mechanistic insights into the CER tDCS effects. The mechanistic insights motivated future investigation of CER tDCS effects on the error-related perception action coupling based on directed functional connectivity studies.