Food-related salience processing in healthy subjects during word recognition: Fronto-parietal network activation as revealed by independent component analysis.

Background: The study aimed to isolate and localize mutually independent cognitive processes evoked during a word recognition task involving food-related and food-neutral words using independent component analysis (ICA) for continuously recorded EEG data. Recognition memory (old/new effect) involves cognitive subcomponents-familiarity and recollection-which may be temporally and spatially dissociated in the brain. Food words may evoke additional attentional salience which may interact with the old/new effect. Methods: Sixteen satiated female participants undertook a word recognition task consisting of an encoding phase (learning of presented words, 40 food-related and 40 food neutral) and a test phase (recognition of previously learned words and new words). Simultaneously recorded 64-channel EEG data were decomposed into mutually independent components using the Infomax algorithm in EEGLAB. The components were localized using single dipole fitting using a four-shell BESA head model. The resulting (nonartefactual) components with <15% residual variance were clustered across subjects using the kmeans algorithm resulting in five meaningful clusters localized to fronto-parietal regions. Repeated-measures anova was employed to test main effects (old/new and food relevance) and their interaction on cluster time courses. Results: Early task-relevant old/new effects were localized to the medial frontal gyrus (MFG) and later old/new effects to the right parietal regions (precuneus). Food-related (nontask-relevant) salience effects were localized to bilateral parietal regions (left precuneus and right postcentral gyrus). Food-related salience interacted with task relevance, the old/new effect in MFG being significant only for food-neutral words highlighting central the role of MFG as the converging site of endogenous and exogenous salience inputs. Conclusion: Our results indicate ICA to be a valid technique to decompose complex neurophysiological signals involving multiple cognitive processes and implicate the fronto-parietal network as an important attentional network for processing salience and task demands.

Peyton's four-step approach: differential effects of single instructional steps on procedural and memory performance - a clarification study.

BACKGROUND: Although Peyton's four-step approach is a widely used method for skills-lab training in undergraduate medical education and has been shown to be more effective than standard instruction, it is unclear whether its superiority can be attributed to a specific single step. PURPOSE: We conducted a randomized controlled trial to investigate the differential learning outcomes of the separate steps of Peyton's four-step approach. METHODS: Volunteer medical students were randomly assigned to four different groups. Step-1 group received Peyton's Step 1, Step-2 group received Peyton's Steps 1 and 2, Step-3 group received Peyton's Steps 1, 2, and 3, and Step-3mod group received Peyton's Steps 1 and 2, followed by a repetition of Step 2. Following the training, the first independent performance of a central venous catheter (CVC) insertion using a manikin was video-recorded and scored by independent video assessors using binary checklists. The day after the training, memory performance during delayed recall was assessed with an incidental free recall test. RESULTS: A total of 97 participants agreed to participate in the trial. There were no statistically significant group differences with regard to age, sex, completed education in a medical profession, completed medical clerkships, preliminary memory tests, or self-efficacy ratings. Regarding checklist ratings, Step-2 group showed a superior first independent performance of CVC placement compared to Step-1 group (P<0.001), and Step-3 group showed a superior performance to Step-2 group (P<0.009), while Step-2 group and Step-3mod group did not differ (P=0.055). The findings were similar in the incidental free recall test. CONCLUSION: Our study identified Peyton's Step 3 as being the most crucial part within Peyton's four-step approach, contributing significantly more to learning success than the previous steps and reaching beyond the benefit of a mere repetition of skills demonstration.