Structure–function associations in hippocampus in bipolar disorder

Abstract

Hippocampus volume decreases and verbal memory deficits have been reported in bipolar disorder (BD) as independent observations. We investigated potential associations between these deficits in subjects with BD. Hippocampus volumes were measured on magnetic resonance images of 31 subjects with BD and 32 healthy comparison (HC) subjects. The California Verbal Learning Test-Second Edition (CVLT) assessed verbal memory function in these subjects. Compared to the HC group, the BD group showed both significantly smaller hippocampus volumes and impaired performance on CVLT tests of immediate, short delay and long delay cued and free recall. Further, smaller hippocampus volume correlated with impaired performance in BD. Post-hoc analyses revealed a trend towards improved memory in BD subjects taking antidepressant medications. These results support associations between morphological changes in hippocampus structure in BD and verbal memory impairment. They provide preliminary evidence pharmacotherapy may reverse hippocampus-related memory deficits.

Combined analyses of gray matter voxel-based morphometry and white matter tract-based spatial statistics in pediatric bipolar mania

“…In addition, in a sample of adolescents with bipolar disorder (two with depressive episode and 14 with euthymic state), Bearden et al (2008a) also found a decreased total hippocampal volume predominantly on the left side. Our finding is in agreement with three recent studies that detected decreased hippocampal volume in adult BD (Chepenik et al, 2012;Hajek et al, 2012;Wijeratne et al, 2013) as well. Nevertheless, some other studies that recruited BD patients as a whole without classify the mood state observed inconsistent results: both no volumetric change of the hippocampus (Dickstein et al, 2005) and even increased volume were found (Beyer et al, 2004;Javadapour et al, 2010), which suggested that further research stratifying BD patients by episode state was urgent.…”

“…Moreover, there has been a vital limitation that most previous studies recruited patients with BD as a whole without considering the effect of the different episode states (mania, depression, or remission) on brain structural changes (Chepenik et al, 2012;Wang et al, 2008b). One thing to be noted is that limited studies which carefully classify the episode states of BD have provided evidence to prove that different mood episodes may cause different microstructural abnormalities of brain (Foland-Ross et al, 2012;Nery et al, 2009;Zanetti et al, 2009).…”

Verbal memory impairment in new onset bipolar disorder: Relationship with frontal and medial temporal morphology

“…Two previous studies in patients with bdi have reported positive correlation between hippocampal volumes and CvLT-ii performance (yucel et al 2007;Chepenik et al 2012). smaller hippocampal volumes have also been correlated with worsened vM in alzheimer's disease and other neurodegenerative conditions (Jokinen et al 2009;sexton et al 2010).…”

“…These patients also generally, though not universally (Wheeler et al 1995), display proportionately better performance on recognition tasks (which are less taxing to these apparent contradictions; however, these studies have been few and their findings inconsistent. hippocampal volumes have been positively (yucel et al 2007;Chepenik et al 2012Chepenik et al ), negatively (ali et al 2000 or not correlated at all (killgore et al 2009) with vM scores. While there is evidence of decreased metabolic activity in dorsolateral prefrontal cortex in bdi patients with impaired vM (deckersbach et al 2006; brooks et al 2010), there has only been one study examining a potential association with frontal volumes that found no relationship (Chepenik et al 2012).…”

“…hippocampal volumes have been positively (yucel et al 2007;Chepenik et al 2012Chepenik et al ), negatively (ali et al 2000 or not correlated at all (killgore et al 2009) with vM scores. While there is evidence of decreased metabolic activity in dorsolateral prefrontal cortex in bdi patients with impaired vM (deckersbach et al 2006; brooks et al 2010), there has only been one study examining a potential association with frontal volumes that found no relationship (Chepenik et al 2012). These variable findings make it difficult to draw conclusions from the current literature; moreover, these studies have typically looked at overall measures of vM performance and not examined the separate frontal and MT components of vM discussed above.…”