Hippocampal structural and functional changes associated with electroconvulsive therapy response

Abstract

Previous animal models and structural imaging investigations have linked hippocampal neuroplasticity to electroconvulsive therapy (ECT) response, but the relationship between changes in hippocampal volume and temporal coherence in the context of ECT response is unknown. We hypothesized that ECT response would increase both hippocampal resting-state functional magnetic resonance imaging connectivity and hippocampal volumes. Patients with major depressive disorder (n=19) were scanned before and after the ECT series. Healthy, demographically matched comparisons (n=20) were scanned at one-time interval. Longitudinal changes in functional connectivity of hippocampal regions and volumes of hippocampal subfields were compared with reductions in ratings of depressive symptoms. Right hippocampal connectivity increased (normalized) after the ECT series and correlated with depressive symptom reduction. Similarly, the volumes of the right hippocampal cornu ammonis (CA2/3), dentate gyrus and subiculum regions increased, but the hippocampal subfields were unchanged relative to the comparison group. Connectivity changes were not evident in the left hippocampus, and volume changes were limited to the left CA2/3 subfields. The laterality of the right hippocampal functional connectivity and volume increases may be related to stimulus delivery method, which was predominately right unilateral in this investigation. The findings suggested that increased hippocampal functional connectivity and volumes may be biomarkers for ECT response.

Relationship Between Hippocampal Volume, Serum BDNF, and Depression Severity Following Electroconvulsive Therapy in Late-Life Depression

“…This is in line with previous studies (Nordanskog et al, 2010;Tendolkar et al, 2013;Abbott et al, 2014;Dukart et al, 2014;Nordanskog et al, 2014;Bouckaert et al, 2015;Jorgensen et al, 2015;Ota et al, 2015;Sartorius et al, 2016). Only two studies found an association between hippocampal volume increase and therapeutic efficacy (Dukart et al, 2014;Joshi et al, 2015).…”

“…Moreover, the hippocampus and brain regions that mediate emotional and cognitive regulation are anatomically connected, lending support to the role of the hippocampus in depressionrelated circuitry (Price and Drevets, 2010;Abbott et al, 2014). Several recent magnetic resonance imaging (MRI) studies have described hippocampal volume changes following ECT (Nordanskog et al, 2010;Tendolkar et al, 2013;Abbott et al, 2014;Dukart et al, 2014;Nordanskog et al, 2014;Joshi et al, 2015;Jorgensen et al, 2015;Ota et al, 2015;Bouckaert et al, 2015;Sartorius et al, 2016).…”

“…Moreover, the hippocampus and brain regions that mediate emotional and cognitive regulation are anatomically connected, lending support to the role of the hippocampus in depressionrelated circuitry (Price and Drevets, 2010;Abbott et al, 2014). Several recent magnetic resonance imaging (MRI) studies have described hippocampal volume changes following ECT (Nordanskog et al, 2010;Tendolkar et al, 2013;Abbott et al, 2014;Dukart et al, 2014;Nordanskog et al, 2014;Joshi et al, 2015;Jorgensen et al, 2015;Ota et al, 2015;Bouckaert et al, 2015;Sartorius et al, 2016). Some of these studies have also addressed structural changes in other brain areas relevant to depressive disorders, such as dorsolateral prefrontal cortex, orbitofrontal cortex (Jorgensen et al, 2015), lateral temporal cortex (Bouckaert et al, 2015), caudate nucleus (Bouckaert et al, 2015), and amygdala (Tendolkar et al, 2013;Jorgensen et al, 2015;Joshi et al, 2015;Ota et al, 2015;Sartorius et al, 2016).…”

Can We Find Any Sustained Neurofunctional Alteration in Remitted Depressive Patients with a History of Modified Electroconvulsive Therapy?

“…Moreover, recent functional magnetic resonance imaging (MRI) studies of ECT in depression have shown some laterality of neuronal connectivity of HPC. That is, the right hippocampal connectivity with the left superior temporal lobe increased after an ECT series and correlated with the amelioration of depressive symptom, but no such increase in the left hippocampal connectivity with any brain regions was found (Abbott et al, 2014).…”

“…Recent neuroimaging studies have revealed structural and functional differences in the human brain before and after an ECT series (Dukart et al, 2014;Jorgensen et al, 2016;Ota et al, 2015). Some studies have shown an increase in the GM volume of bilateral HPCs after ECT (Jorgensen et al, 2016;Ota et al, 2015); others have shown that an ECT series significantly contributes to the increase in the GM volume of the right HPC, but not to that of the left HPC (Dukart et al, 2014;Abbott et al, 2014). Moreover, recent functional magnetic resonance imaging (MRI) studies of ECT in depression have shown some laterality of neuronal connectivity of HPC.…”