Altered dynamics of brain connectivity in major depressive disorder at-rest and during task performance

Abstract

Major depressive disorder (MDD) has been associated with alterations in several functional brain networks. Previous studies investigating brain networks in MDD during the performance of a task have yielded inconsistent results with the function of the brain at rest. In this study, we used functional magnetic resonance imaging at rest and during a goal-directed task to investigate dynamics of functional connectivity in 19 unmedicated patients with MDD and 19 healthy controls across both experimental paradigms. Patients had spatial differences in the default mode network (DMN), in the executive network (EN), and in the dorsal attention network (DAN) compared to controls at rest and during task performance. In patients the amplitude of the low frequency (LFO) oscillations was reduced in the motor and in the DAN networks during both paradigms. There was a diagnosis by paradigm interaction on the LFOs amplitude of the salience network, with increased amplitude change between task and rest in patients relative to controls. Our findings suggest that the function of several networks could be intrinsically affected in MDD and this could be viable phenotype for the investigation on the neurobiological mechanisms of this disorder and its treatment.

Information processing speed in multiple sclerosis: Relevance of default mode network dynamics

“…Changes in RS DMN dynamics have been observed in other neurological disorders, including schizophrenia, autism, attention deficit hyperactivity disorder, depression, and epilepsy. Often, these changes were related to the severity of symptoms ( Zhang et al, 2016 ; Sambataro et al, 2017 ; Douw et al, 2015 ; Liu et al, 2017 ). A large challenge to directly compare between study results is differences in operationalization of DMN dynamics (e.g.…”

“…With this latter measure, the changes in connectivity strength during a time series are obtained, from here on referred to as dynamic FC (dFC). As dFC seems to be behaviorally relevant with respect to cognition in healthy subjects ( Cohen, 2017 ; Jia et al, 2014 ; Gonzalez-Castillo and Bandettini, 2017 ) or symptoms in neurological disorders ( Zhang et al, 2016 ; Sambataro et al, 2017 ; Douw et al, 2015 ), we argue that dFC could also be of importance for maintained IPS in pwMS, as it could reflect the fast changing connectivity patterns within the brain that cannot be captured with sFC ( Cohen, 2017 ).…”

Multivariate Classification of Major Depressive Disorder Using the Effective Connectivity and Functional Connectivity

“…One recent study found that the left motor and the DAN showed reduced power in the low-frequency range in patients with MDD compared to healthy controls. Considering the role of DAN in orienting attention based on internal goals, those connections may contribute to the limited engagement with the external environment and potentially to increased self-reflection in MDD (Sambataro et al, 2017 ).…”

“…DMN activates “by default” when a person is not involved in a specific task and deactivates during specific tasks, such as a cognitive task and attention task, which commonly consists of the medial prefrontal cortex (mPFC), bilateral inferior parietal lobule (LP) and posterior cingulate cortex (PCC) (Raichle, 2015 ). Besides, the altered dynamics functional brain networks in MDD patients have been reported in the dorsal attention network (DAN), FPN, and SN (Sambataro et al, 2017 ). SN consisting of the anterior cingulate cortex (ACC) and bilateral rostrolateral prefrontal cortex (RPFC), shows a significant increased power of the low frequency oscillations (LFO) during the task performance in MDD patients (Zhang et al, 2014 ).…”

“…Ineffective transmission of information between prefrontal and parietal regions may be a main reason for MDD (Brzezicka, 2013 ). Many studies have found significantly altered connections in other resting-state network such as SMN and VN in MDD patients (Yao et al, 2009 ; Veer et al, 2010 ; Wei et al, 2015 ; Sambataro et al, 2017 ). Abnormal FC in MDD patients in the resting-state networks has been used as a biomarker for MDD diagnosis (Dørum et al, 2017 ).…”