Using neuroimaging to individualize TMS treatment for depression: Toward a new paradigm for imaging-guided intervention

Abstract

The standard clinical technique for using repetitive transcranial magnetic stimulation (rTMS) for major depressive disorder (MDD) is associated with limited efficacy to date. Such limited efficacy may be due to reliance on scalp-based targeting rather than state-of-the-science methods which incorporate fMRI-guided neuronavigation based on a specific model of neurocircuit dysfunction. In this review, we examine such a specific model drawn from regulatory focus theory, which postulates two brain/behavior systems, the promotion and prevention systems, underlying goal pursuit. Individual differences in these systems have been shown to predict vulnerability to MDD as well as to comorbid generalized anxiety disorder (GAD). Activation of an individual's promotion or prevention goals via priming leads to motivational and affective responses modulated by the individual's appraisal of their progress in attaining the goal. In addition, priming promotion vs. prevention goals induces discriminable patterns of brain activation that are sensitive to the effects of depression and anxiety: MDD is associated with promotion system failure, anhedonic/ dysphoric symptoms, and hypoactivation in specific regions in left prefrontal cortex, whereas GAD is associated with prevention system failure, hypervigilant/agitated symptoms, and hyperactivation in right prefrontal cortex (PFC). These left and right PFC locations can be directly targeted in an individualized manner for TMS. Additionally, this individually targeted rTMS can be integrated with cognitive interventions designed to activate the neural circuitry associated with promotion vs. prevention, thus allowing the neuroplasticity induced by the rTMS to benefit the systems likely to be involved in remediating depression. Targeted engagement of cortical systems involved in emotion regulation using individualized fMRI guidance may help increase the efficacy of rTMS in depression.

Frequency‐specific neuromodulation of local and distant connectivity in aging and episodic memory function

“…Beyond increasing the ability to use combined brain imaging and stimulation to investigate brain function in normative populations, the present results suggest that DWI‐based TMS targeting can extend the effectiveness of TMS in therapeutic applications [Luber et al, ]. One obstacle for using TMS for effective treatments in memory disorders is that the brain region most critical for memory, the hippocampus, sits deep inside the brain, beyond the reach of direct TMS effects.…”

Impact of non-brain anatomy and coil orientation on inter- and intra-subject variability in TMS at midline

“…Still, because of the large number of anatomical factors that are related to stimulation and the degree of variance left unexplained by gross non-brain factors, finite element simulations are well suited to quantify differences in the induced E-Field from TMS. Moving beyond biophysics, factors such as state-dependent features (Luber et al, 2017; Siebner et al, 2009) and functional organization (Drysdale et al, 2017; Rosso et al, 2017; Wang et al, 2015) will also affect stimulation outcomes. Although these biological variables unrelated to current modeling efforts will affect stimulation effects, understanding how the site of stimulation differs between individuals is an important step to understand biological contributors to inter-subject variability.…”

A novel low-cost approach for navigated transcranial magnetic stimulation

“…It is to be noted that the system cannot currently utilize magnetic resonance imaging (MRI) data to stimulate specific brain regions based on a participant's anatomy, as there is no provision for co-registering the subject's head to their brain images (Andoh et al, 2009; Luber et al, 2017; Schmidt et al, 2010). However, the open source nature of the software allows this function to be incorporated by a programmer with sufficient knowledge on Unity, signal processing, and neuroimaging.…”