Abstract
Fundamentals of Laparoscopic Surgery (FLS) is a prerequisite for board certification in general surgery in the USA. It includes a motor skills portion with five psychomotor tasks of increasing task complexity: (i) pegboard transfers, (ii) pattern cutting, (iii) placement of a ligating loop, (iv) suturing with extracorporeal knot tying, and (v) suturing with intracorporal knot tying. Learning these tasks typically relies on extensive practice [1]. Nemani et al. [2] showed that the wavelet coherence based functional connectivity from functional near-infrared spectroscopy (fNIRS) data between the medial prefrontal cortex and the supplementary motor area (SMA) was lower for experts than novices during FLS pattern cutting task. Here, SMA is known for the plasticity of interhemispheric connectivity involving sensorimotor network [3] relevant in learning bimanual laparoscopic tasks; however, transcranial direct current (tDCS) of SMA resulted in more variability during FLS pegboard transfers than bilateral primary motor cortex tDCS. Here, it is essential to differentiate tDCS effects on the pre-SMA from SMA proper in the SMA complex during laparoscopic skill acquisition due to differences in their fiber tracts [4] and their relevance to motor task complexity. Prior work using fNIRS-based activation during most complex FLS suturing task with intracorporeal knot tying [5] showed the involvement of premotor/frontal module [4] related Brodmann areas (BA), shown in Figure 1c, including ventrolateral PFC (VLPFC; BA: 44, 45, 47), frontopolar (FP; BA: 10), dorsolateral PFC (DLPFC; BA: 9, 46) as well as a part of the orbitofrontal cortex (OFC; BA: 11) on the lateral brain surface in addition to SMA complex. However, the effective connectivity of this cognitive-motor control network was not investigated based on dynamic causal modeling (DCM) [6], where the temporal resolution of electroencephalogram (EEG) can capture fast interactions expected via short frontal lobe connections [4]. Therefore, our research aimed to identify hidden brain networks during FLS suturing with intracorporeal knot tying skill acquisition using DCM of EEG.