Hippocampal Subfield Volumes and Cognitive Function in Schizophrenia and Mood Disorders

Abstract

<b><i>Introduction:</i></b> The hippocampus is relevant to cognitive function in schizophrenia (SCZ) and mood disorder patients. Although not anatomically uniform, it is clearly divided into subfields. This study aimed to elucidate the relationship between hippocampal subfield volume and cognitive function in patients with SCZ, bipolar disorder (BP), and major depressive disorder (MDD). <b><i>Methods:</i></b> The study included 21 patients with SCZ, 22 with BP, and 21 with MDD and 25 healthy controls (HCs). Neurocognitive function was assessed using the Brief Assessment of Cognition in Schizophrenia. We obtained hippocampal subfield volumes using FreeSurfer 6.0. We compared the volumes of the hippocampal subfield between the 4 groups and ascertained correlation between the cognitive composite score and hippocampal subfield volume in each group. <b><i>Results:</i></b> The SCZ group had significantly lower cognitive composite score than the BP, MDD, and HC groups. In the SCZ group, the left and right hippocampus-amygdala transition area and right subiculum and right presubiculum volumes were significantly reduced compared to those in the HC group. The left presubiculum volumes in the SCZ group were significantly reduced compared to those in the MDD group. Subfield volumes did not significantly differ between the BP, MDD, and HC groups. Interestingly, in the SCZ group, volumes of the right CA1, right molecular layer of the hippocampus, and right granule cell and molecular layer of the dentate gyrus were significantly correlated with the cognitive composite score. <b><i>Conclusion:</i></b> Patients with SCZ had poorer cognitive function, which is related to their hippocampal pathology, than those with mood disorders.

Structural connectivity between the hippocampus and cortical/subcortical area relates to cognitive impairment in schizophrenia but not in mood disorders

“…To the best of our knowledge, this study is first to report correlation between reduced hippocampal structural connectivity and cognitive impairment in patients with schizophrenia. Reduced hippocampal volume in schizophrenia has been widely reported (Adriano et al, 2012; Narr et al, 2004), and its association with cognitive impairment has been shown in previous studies (Thoma et al, 2009; Yasuda et al, 2022). Reduced FA values in the fornix and cingulum were reported in one such study indicating abnormal integration of white matter between the hippocampus and cortex in patients with schizophrenia (Qiu et al, 2010).…”

“…Structural and functional connectivity between the hippocampus and the cortical and subcortical areas has been demonstrated (Burwell, 2000;Kahn et al, 2008;Lavenex & Amaral, 2000;Witter et al, 2000). Hippocampal pathology is related to some of the cognitive deficits in schizophrenia (Harrison, 2004;Yasuda et al, 2022), major depression disorder (O'Brien et al, 2004) and bipolar disorder (Cao et al, 2016). Recently, it has become possible to estimate structural probabilistic connectivity between brain regions by ProbtrackX program in FMRIB Software Library (FSL; Behrens group but not in the healthy control, major depressive disorder or bipolar disorder groups.…”

Lack of correlation between hippocampal substructure atrophy and attention dysfunction in deficit schizophrenia

“…Hippocampal substructure volume atrophy has also been confirmed in first-episode drug-naive psychotic patients; moreover, the same study found a non-linear relationship between dentate gyrus/CA4 volume changes and antipsychotic dose after 12 weeks of risperidone or aripiprazole treatment 29 . Further, more recent studies have found significant associations of cognitive composite and declarative memory scores with the volumes of multiple hippocampal substructures in schizophrenia 25,30 .…”

Fitness is positively associated with hippocampal formation subfield volumes in schizophrenia: a multiparametric magnetic resonance imaging study

“…An association between HF morphologic and physiological abnormalities and cognitive deficits in individuals with schizophrenia has been consistently shown [ 14 – 18 ]. At the subfield level, negative correlations between CA1, CA2/3, CA4/DG, and subiculum volumes and cognitive functioning in individuals with schizophrenia have been demonstrated, whereby verbal memory seems to be particularly affected [ 19 – 21 ].…”