Stimulating thought: a functional MRI study of transcranial direct current stimulation in schizophrenia

Abstract

Individuals with schizophrenia typically suffer a range of cognitive deficits, including prominent deficits in working memory and executive function. These difficulties are strongly predictive of functional outcomes, but there is a paucity of effective therapeutic interventions targeting these deficits. Transcranial direct current stimulation is a novel neuromodulatory technique with emerging evidence of potential pro-cognitive effects; however, there is limited understanding of its mechanism. This was a double-blind randomized sham controlled pilot study of transcranial direct current stimulation on a working memory (n-back) and executive function (Stroop) task in 28 individuals with schizophrenia using functional magnetic resonance imaging. Study participants received 30 min of real or sham transcranial direct current stimulation applied to the left frontal cortex. The 'real' and 'sham' groups did not differ in online working memory task performance, but the transcranial direct current stimulation group demonstrated significant improvement in performance at 24 h post-transcranial direct current stimulation. Transcranial direct current stimulation was associated with increased activation in the medial frontal cortex beneath the anode; showing a positive correlation with consolidated working memory performance 24 h post-stimulation. There was reduced activation in the left cerebellum in the transcranial direct current stimulation group, with no change in the middle frontal gyrus or parietal cortices. Improved performance on the executive function task was associated with reduced activity in the anterior cingulate cortex. Transcranial direct current stimulation modulated functional activation in local task-related regions, and in more distal nodes in the network. Transcranial direct current stimulation offers a potential novel approach to altering frontal cortical activity and exerting pro-cognitive effects in schizophrenia.

Targeting cognition in schizophrenia through transcranial direct current stimulation: A systematic review and perspective

“…Three studies did not include a sham condition, comparing only baseline to stimulation (Narita et al, 2017, Subramaniam et al, 2015, Moon et al, 2019. 17 studies used a multi-session tDCS design (Dunn et al, 2016, Gomes et al, 2015, Mondino et al, 2015, Narita et al, 2017, Nienow et al, 2016, Smith et al, 2015, Subramaniam et al, 2015, Rassovsky et al, 2018, Orlov et al, 2017a, Orlov et al, 2017b, Mellin et al, 2018, Koops et al, 2018, Jeon et al, 2018, Moon et al, 2019, Lindenmayer et al, 2019, Chang et al, 2019, whereas 15 implemented single sessions of tDCS (Dunn et al, 2017, Gögler et al, 2017, Hoy et al, 2014, Hoy et al, 2015, Impey et al, 2017, Rassovsky et al, 2015, Reinhart et al, 2015, Ribolsi et al, 2012, Vercammen et al, 2011, Hoy et al, 2016, Reinhart et al, 2018, Schülke and Straube, 2018.…”

“…Cognitive tasks were administered concurrently with tDCS in 7 studies (Hoy et al, 2016, Orlov et al, 2017a, Vercammen et al, 2011, Orlov et al, 2017b, Schülke and Straube, 2018). An offline stimulation protocol with pre/post tDCS measurements was used in 29 studies.…”

“…WM was explored in 14 studies, 8 of which used an N-back task (Hoy et al, 2014, Hoy et al, 2015, Hoy et al, 2016, Orlov et al, 2017a, Nienow et al, 2016, Impey et al, 2017. In addition, 4 studies examined learning with a feedback-based learning task (Reinhart et al, 2015), source monitoring (Mondino et al, 2015), probabilistic category learning (Vercammen et al, 2011), and the California verbal learning test -CVLT (Moon et al, 2019).…”

“…Twelve studies evaluated cognitive control/attention processing which included a STROOP task (Orlov et al, 2017a, Koops et al, 2018, a trail-making test (Palm et al, 2016, Koops et al, 2018, Moon et al, 2019, Chang et al, 2019, a d2 test , a visual attention task (Gögler et al, 2017), line and number bisection (Ribolsi et al, 2012), a go/no-go task (Reinhart et al, 2015), a tone discrimination (Dunn et al, 2017) an antisaccade task (Subramaniam et al, 2015), and a visual search task (Reinhart et al, 2018). Rassovsky et al (2015), Rassovsky et al (2018) and Schülke and Straube (2018) examined the effects of tDCS on social cognition.…”

Detecting Abnormal Brain Regions in Schizophrenia Using Structural MRI via Machine Learning

“…In other words, this subjective judgment may add risk to the diagnosis and treatment of SZ. For a more accurate diagnosis, neuroimaging methods have been widely used to study brain morphology, which provides important information about possible pathophysiologic mechanisms [15][16][17][18].…”