Shared and distinct functional connectivity of hippocampal subregions in schizophrenia, bipolar disorder, and major depressive disorder

Abstract

Schizophrenia (SZ), bipolar disorder (BD), and major depressive disorder (MDD) share etiological and pathophysiological characteristics. Although neuroimaging studies have reported hippocampal alterations in SZ, BD, and MDD, little is known about how different hippocampal subregions are affected in these conditions because such subregions, namely, the cornu ammonis (CA), dentate gyrus (DG), and subiculum (SUB), have different structural foundations and perform different functions. Here, we hypothesize that different hippocampal subregions may reflect some intrinsic features among the major psychiatric disorders, such as SZ, BD, and MDD. By investigating resting functional connectivity (FC) of each hippocampal subregion among 117 SZ, 103 BD, 96 MDD, and 159 healthy controls, we found similarly and distinctly changed FC of hippocampal subregions in the three disorders. The abnormal functions of middle frontal gyrus might be the core feature of the psychopathological mechanisms of SZ, BD, and MDD. Anterior cingulate cortex and inferior orbital frontal gyrus might be the shared abnormalities of SZ and BD, and inferior orbital frontal gyrus is also positively correlated with depression and anxiety symptoms in SZ and BD. Caudate might be the unique feature of SZ and showed a positive correlation with the cognitive function in SZ. Middle temporal gyrus and supplemental motor area are the differentiating features of BD. Our study provides evidence for the different functions of different hippocampal subregions in psychiatric pathology.

Three-dimensional pseudocontinuous arterial spin labeling perfusion imaging shows cerebral blood flow perfusion decline in attention-deficit/hyperactivity disorder children

“…The results showed that the temporal lobe volume and CBF values were lower in ADHD children than in healthy children, suggesting that the temporal lobe is less developed in ADHD children; the temporal lobe is mainly responsible for processing auditory information, while the temporal lobe also has some relationship with memory and emotion ( 35 ). Generally, the temporal lobe is supplied by the middle cerebral artery, which is part of the blood supply of the cerebral anterior circulation ( 36 ). Patients with temporal lobe lesions may experience memory loss or emotional disorders, such as mental excitement or depression and emotional disturbance, and in severe cases, hallucinations or delusions may occur, and some patients may also present with temporal lobe epilepsy ( 37 , 38 ).…”

Gut proinflammatory bacteria is associated with abnormal functional connectivity of hippocampus in unmedicated patients with major depressive disorder

“…Hao et al [ 32 ] found increased FC between the bilateral hippocampus (mainly CA regions) and between the hippocampal CA regions and right insula in patients with MDD. Song et al [ 33 ] revealed decreased FC between the right hippocampal Subc and right middle frontal gyrus in MDD patients with anti-depressant treatment. Wang et al [ 34 ] demonstrated greater changes in the FC between the left hippocampal CA and bilateral posterior cingulate cortex (PCC) in remitted late-onset depression.…”

The altered network complexity of resting-state functional brain activity in schizophrenia and bipolar disorder patients

“…Neuroimaging has been widely employed to investigate the mechanisms that contribute to brain abnormalities in mental disorders [5]. Pathophysiological problems in brain activity have been frequently observed 79 utilizing neuroimaging methods in SZ patients and BD patients with abnormal functional connections may lead to [6,7].…”