Biological markers in noninvasive brain stimulation trials in major depressive disorder: a systematic review

Objectives: The therapeutic effects of transcranial magnetic stimulation (TMS) and transcranial direct current stimulation in patients with major depression have shown promising results; however, there is a lack of mechanistic studies using biological markers (BMs) as an outcome. Therefore, our aim was to review noninvasive brain stimulation trials in depression using BMs. Methods: The following databases were used for our systematic review: MEDLINE, Web of Science, Cochrane, and SCIELO. We examined articles published before November 2012 that used TMS and transcranial direct current stimulation as an intervention for depression and had BM as an outcome measure. The search was limited to human studies written in English. Results: Of 1234 potential articles, 52 articles were included. Only studies using TMS were found. Biological markers included immune and endocrine serum markers, neuroimaging techniques, and electrophysiological outcomes. In 12 articles (21.4%), end point BM measurements were not significantly associated with clinical outcomes. All studies reached significant results in the main clinical rating scales. Biological marker outcomes were used as predictors of response, to understand mechanisms of TMS, and as a surrogate of safety. Conclusions: Functional magnetic resonance imaging, single-photon emission computed tomography, positron emission tomography, magnetic resonance spectroscopy, cortical excitability, and brain-derived neurotrophic factor consistently showed positive results. Brain-derived neurotrophic factor was the best predictor of patients’ likeliness to respond. These initial results are promising; however, all studies investigating BMs are small, used heterogeneous samples, and did not take into account confounders such as age, sex, or family history. Based on our findings, we recommend further studies to validate BMs in noninvasive brain stimulation trials in MDD.

Como o videojogo se afastou do jogo, através da narrativa e criatividade

(Excerto) Continuamos a confundir o jogo com o videojogo, assumindo na maior parte das vezes, o segundo como um mero sucedâneo digital do primeiro. Contudo esta não passa de uma ideia simplista da arte dos videojogos que se transformou por completo desde que surgiu em meados do século vinte. O jogo enquanto estrutura sistémica criada pelo ser-humano responde por um lado às necessidades sociais e culturais de aprendizagem (Huizinga, 1939; Caillois, 1958; Gee, 2003), e por outro às necessidades cognitivas de recompensa na forma de resolução de problemas (Kenrick e Griskevicius, 2013). Ou seja, enquanto artefacto cultural o jogo permite-nos apreender o desconhecido, interagir com o outro e optimizar as nossas respostas sociais. Enquanto estímulo cognitivo o jogo atua de forma a recompensar o nosso esforço, engajando-nos através da insistência e da repetição com descargas de prazer. E é por isso que o jogo tem sido visto pela cultura humana como um dos mais importantes exercícios no processo de construção civilizacional.