Anhedonia and Reward-Circuit Connectivity Distinguish Nonresponders from Responders to Dorsomedial Prefrontal Repetitive Transcranial Magnetic Stimulation in Major Depression

Abstract

The results suggest distinct depression subtypes, one with preserved hedonic function and responsive to dorsomedial rTMS and another with disrupted hedonic function, abnormally lateralized connectivity through ventromedial prefrontal cortex, and unresponsive to dorsomedial rTMS. Future research directly comparing the effects of rTMS at different targets, guided by neuroimaging and clinical presentation, may clarify whether hedonia/reward circuit integrity is a reliable marker for optimizing rTMS target selection.

Resting-State Connectivity Predictors of Response to Psychotherapy in Major Depressive Disorder

“…Of note, a number of findings highlight altered connectivity with middle temporal gyrus, a brain area that is involved in imitation, social cognition, and mentalizing, implicating brain regions that code for awareness, salience, and cognitive control of mental states in the pathophysiology of MDD. Additionally, pretreatment connectivity of the anterior insula and intraparietal sulcus predicted response to psychotherapy, a pattern of results consistent with other reports of pretreatment anterior insula metabolism and connectivity (Downar et al, 2013) as predictors of response to psychotherapy and parietal lobe connectivity predicting response to antidepressant medication treatment (Guo et al, 2013a;Wu et al, 2011). More generally, the present study adds to the nascent but growing body of evidence linking pretreatment neuroimaging endophenotypes to antidepressant treatment outcomes .…”

MRI-guided dmPFC-rTMS as a Treatment for Treatment-resistant Major Depressive Disorder

“…Adaptive titration was reported in a larger subset of 47 MDD patients undergoing 10 Hz dmPFC-rTMS 23 . In a case series that included this subset of patients, subjects achieved the target stimulus intensity in 0.91.8 sessions and were able to complete an entire rTMS session at the intended intensity at 4.53.7 sessions 23 .…”

“…In a case series that included this subset of patients, subjects achieved the target stimulus intensity in 0.91.8 sessions and were able to complete an entire rTMS session at the intended intensity at 4.53.7 sessions 23 . Adaptive titration was not correlated to treatment improvement.…”

“…Dorsomedial and subgenual cingulate resting-state functional connectivity have been identified as potential predictors to treatment response 27 . Additionally, graph theoretical measures such as betweenness centrality have been shown to differentiate dmPFC-rTMS responders and non-responders at baseline based on subscales for hedonic responses 23 . Neuroimaging also points to anterior mid-cingulate cortex and dorsomedial thalamic resting state functional connectivity change that correlates to treatment response 27 .…”

“…Adaptively titrate the rTMS stimulus intensity upwards from an initial value of 20% maximum stimulator intensity, to allow the patient to habituate to the pain and scalp discomfort associated with rTMS during the initial sessions 23 . Increment the stimulation intensity by 2-5% on each train of stimulation, as tolerated.…”