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An fMRI paradigm based on Williams inhibition test to study the neural substrates of attention and inhibitory control

Publication . Dores, Artemisa Rocha; Barbosa, Fernando; Carvalho, Irene P.; Almeida, Isabel; Guerreiro, Sandra; da Rocha, Benedita Martins; Cunha, Gil; Castelo Branco, Miguel; de Sousa, Liliana; Castro Caldas, Alexandre

The purpose of this study is to present an fMRI paradigm, based on the Williams inhibition test (WIT), to study attentional and inhibitory control and their neuroanatomical substrates. We present an index of the validity of the proposed paradigm and test whether the experimental task discriminates the behavioral performances of healthy participants from those of individuals with acquired brain injury. Stroop and Simon tests present similarities with WIT, but this latter is more demanding. We analyze the BOLD signal in 10 healthy participants performing the WIT. The dorsolateral prefrontal cortex, the inferior prefrontal cortex, the anterior cingulate cortex, and the posterior cingulate cortex were defined for specified region of interest analysis. We additionally compare behavioral data (hits, errors, reaction times) of the healthy participants with those of eight acquired brain injury patients. Data were analyzed with GLM-based random effects and Mann-Whitney tests. Results show the involvement of the defined regions and indicate that the WIT is sensitive to brain lesions. This WIT-based block design paradigm can be used as a research methodology for behavioral and neuroimaging studies of the attentional and inhibitory components of executive functions.

2017Journal article

Open access

Conceptualization and rehabilitation of executive functions: A review of the literature

Publication . Dores, Artemisa Rocha; Carvalho, Irene Palmares; Barbosa, Fernando; Martins, Claúdia; de Sousa, Liliana; Castro-Caldas, Alexandre

Publications on executive functions have increased in the last few years, reflecting the importance of this area of study. The scientific output on executive functions is now extremely diverse, comprising variations around terminology, assessment, and rehabilitation practices, and ranging in topics from neuroanatomical correlates of executive functions to effects of executive dysfunction. This review seeks to explore this diversity around executive functions in order to provide an integrative overview of the topic that systematizes the current knowledge in this area, and to point to trends and future directions for research and practice. The literature review was conducted in the ISI Web of Knowledge databases. The analysis was conducted in NVivo9. Two independent coders applied an inductive analysis to all relevant papers, building a hierarchical model with categories and subcategories of themes emerging from the literature. A confirmatory analysis followed, with the same independent coders applying the model to the papers. The process was validated by a third expert researcher. Out of 187 titles and abstracts, 91 were analyzed. The outcomes were structured in six main categories: central nervous system, diagnosis, population, assessment, intervention, and theoretical models. Key findings included promising trends in executive function assessment and rehabilitation as well as potential implications for current health approaches and future research.

2014Journal article

Open access