Neuroimaging studies suggest that the increment of the cognitive load associated with a specific task may induce the recruitment of a more bilateral brain network. In most studies, however, task demand has been manipulated in a static and pre-specified way, regardless of individual cognitive resources. Here we implemented a new paradigm based on a pre-experimental assessment to set up subject-specific levels of task demand and applied tDCS (transcranial direct current stimulation) to assess each hemisphere involvement in task performance. 24 young participants performed a digit span backward (DSB, complex cognitive function) and a paced finger tapping task (pFT, basic motor function) at 3 levels of subject-specific task demand ("low" 5/5 correct answers, "medium" 3/5, "high" 1/5). Anodal tDCS (20min, 1.5mA) was delivered through a target electrode (5 × 5cm) positioned to stimulate both the inferior frontal gyrus and the primary motor area over left and right hemisphere and in sham condition in three different days. A 3 (left, right, sham) × 3 (low, medium, high) mixed-model with random intercept for subjects was run with R software. As expected, in both tasks accuracy decreased with the increment of subject-specific task demand. Moreover, a significant interaction between type of stimulation and subject-specific task demand was found for the reaction times recorded during the DSB and for the accuracy in the pFT: in the most demanding conditions, right anodal tDCS significantly interfered with behavioural performance. Our results suggest that hemispheric lateralization is modulated by the subject-specific level of task demand and this modulation is not task-specific.

What is difficult for you can be easy for me. Effects of increasing individual task demand on prefrontal lateralization: A tDCS study

Berlingeri, Manuela
2018-01-01

Abstract

Neuroimaging studies suggest that the increment of the cognitive load associated with a specific task may induce the recruitment of a more bilateral brain network. In most studies, however, task demand has been manipulated in a static and pre-specified way, regardless of individual cognitive resources. Here we implemented a new paradigm based on a pre-experimental assessment to set up subject-specific levels of task demand and applied tDCS (transcranial direct current stimulation) to assess each hemisphere involvement in task performance. 24 young participants performed a digit span backward (DSB, complex cognitive function) and a paced finger tapping task (pFT, basic motor function) at 3 levels of subject-specific task demand ("low" 5/5 correct answers, "medium" 3/5, "high" 1/5). Anodal tDCS (20min, 1.5mA) was delivered through a target electrode (5 × 5cm) positioned to stimulate both the inferior frontal gyrus and the primary motor area over left and right hemisphere and in sham condition in three different days. A 3 (left, right, sham) × 3 (low, medium, high) mixed-model with random intercept for subjects was run with R software. As expected, in both tasks accuracy decreased with the increment of subject-specific task demand. Moreover, a significant interaction between type of stimulation and subject-specific task demand was found for the reaction times recorded during the DSB and for the accuracy in the pFT: in the most demanding conditions, right anodal tDCS significantly interfered with behavioural performance. Our results suggest that hemispheric lateralization is modulated by the subject-specific level of task demand and this modulation is not task-specific.
File in questo prodotto:
File Dimensione Formato  
Vergallito_preprint.pdf

accesso aperto

Descrizione: Versione accettata
Tipologia: Versione referata/accettata
Licenza: Creative commons
Dimensione 2.45 MB
Formato Adobe PDF
2.45 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11576/2656889
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 12
  • ???jsp.display-item.citation.isi??? 12
social impact