TMS activation site estimation using multiscale realistic head models
JOURNAL OF NEURAL ENGINEERING
Authors: Gomez-Tames, Jose; Laakso, Ilkka; Murakami, Takenobu; Ugawa, Yoshikazu; Hirata, Akimasa
Abstract
Objective. Transcranial magnetic stimulation (TMS) activates brain structures non-invasively. Computational models can be used to elucidate the activation site; however, the exact activation site is controversial. The aim is to present an imaging technique of the TMS activation cortical site estimation using individualized multi-scale realistic head models based on experimentally-derived TMS fields. Approach. The induced electric field (EF) was computed using subject-specific head models and experimental-specific TMS coil configuration during suprathreshold stimulation for relaxed muscles. The experimentally-derived EFs were used to calculate the activation of pyramidal tract model embedded in the head models to derive the activation site on the cortical surface at the macroscopic level. Main results. The TMS activation site was located at the anterior wall of the central sulcus, which agreed with a concurrent TMS/fMRI study. In contrast, the EF strength was not entirely consistent with TMS/fMRI studies. Multiscale physical modelling is a feasible imaging technique to investigate the activation site for TMS. Significance. By combining subject-specific multiscale modelling with experimental TMS measurements, we showed that this method could serve as a TMS imaging technique at suprathreshold condition.
Task-Specific and Latent Relationships Between Motor Skills and Executive Functions in Preschool Children
FRONTIERS IN PSYCHOLOGY
Authors: Van der Veer, Gerda; Kamphorst, Erica; Cantell, Marja; Minnaert, Alexander; Houwen, Suzanne
Abstract
There has been an increasing interest in the relationship between motor skills and executive functions (EFs) in young children over the years. However, no clear picture on the relationship between both domains has emerged from these studies. We have extended previous findings by conducting a comprehensive examination of task-specific and latent relationships between a range of motor skills and EFs in preschool children. The sample consisted of 198 3- to 5-year-old children (102 boys; 51.5%). Motor skills were assessed using the Movement Assessment Battery for Children Second Edition. EFs were assessed with the performance-based tasks 'Day/Night,' 'Hand Tapping,' 'Forward Corsi Block,' 'Forward Digit Recall,' and 'Conflict Task,' and a rating-based EF measure (i.e., the Behavior Rating Inventory of Executive Functioning - Preschool version). Task-specific relationships were examined using zero-order Pearson correlations. Latent factors of motor skills and EFs were examined using confirmatory factor analysis and exploratory structural equation modeling. Structural equation modeling (SEM) was used to examine latent relationships. The results of the Pearson correlation analyses showed statistically significant albeit weak correlations between specific motor and EF items (r= 0.15 tor=0.23). SEM showed non-significant weak relationships between a general motor factor (as a unitary latent construct) on the one hand, and performance-based EFs and rating-based EFs (as latent EF components) on the other hand. In conclusion, this study suggested only weak relationships between motor skills and EFs in preschool children with no clear differences between their task-specific and latent relationships.