Measuring changes in neural co-activation to examine verbal overshadowing following learning of a surgical laparoscopy task

Abstract

OBJECTIVES: Verbalising a difficult-to-describe perceptual memory disrupts performance. This phenomenon, verbal overshadowing, has been demonstrated in cognitive tasks. Processing shift explanations propose that performance is disrupted because the processing operations used to retrieve the memory differ from those used to encode it. However, in recent findings verbal overshadowing disrupted performance of a golf-putting task learned explicitly but not implicitly. Possibly, overshadowing induced a shift in processing to effortful, inefficient conscious control of movements in the explicit motor learners but did not induce such a shift in implicit motor learners. This study examined EEG communication between the verbal-analytical (T3) and motor planning (Fz) regions of the cortex in a fundamental laparoscopic skill. It was hypothesised that following verbal overshadowing a shift in processing operations would be reflected by increased communication between the verbal and motor areas (T3-Fz coherence) in explicit learners but not implicit learners. DESIGN AND METHOD: Novices were randomly assigned to an implicit learning condition (neurofeedback-training) or an explicit learning condition (neurofeedback-control), and completed 240 laparoscopic peg transfer trials. The neurofeedback-training required students to terminate an auditory tone before initiating each practice trial by lowering T3-Fz coherence below a baseline-derived threshold. Completion time and T3-Fz coherence were assessed in a delayed retention test and after verbal overshadowing. RESULTS AND CONCLUSION: Preliminary results suggest that overshadowing disrupted performance and heightened T3-Fz coherence in the explicit condition, but not the implicit condition. Verbal overshadowing may cause a shift in information processing operations when motor performance is controlled declaratively rather than procedurally.