Abstract
IntroductionBrain structural injury and metabolic deficits in the hippocampus and caudate nuclei may contribute to cognitive and emotional deficits found in obstructive sleep apnea (OSA) patients. If such contributions exist, resting‐state interactions of these subcortical sites with cortical areas mediating affective symptoms and cognition should be disturbed. Our aim was to examine resting‐state functional connectivity (FC) of the hippocampus and caudate to other brain areas in OSA relative to control subjects, and to relate these changes to mood and neuropsychological scores.MethodsWe acquired resting‐state functional magnetic resonance imaging (fMRI) data from 70 OSA and 89 healthy controls using a 3.0‐Tesla magnetic resonance imaging scanner, and assessed psychological and behavioral functions, as well as sleep issues. After standard fMRI data preprocessing, FC maps were generated for bilateral hippocampi and caudate nuclei, and compared between groups (ANCOVA; covariates, age and gender).ResultsObstructive sleep apnea subjects showed significantly higher levels of anxiety and depressive symptoms over healthy controls. In OSA subjects, the hippocampus showed disrupted FC with the thalamus, para‐hippocampal gyrus, medial and superior temporal gyrus, insula, and posterior cingulate cortex. Left and right caudate nuclei showed impaired FC with the bilateral inferior frontal gyrus and right angular gyrus. In addition, altered limbic‐striatal‐cortical FC in OSA showed relationships with behavioral and neuropsychological variables.ConclusionsThe compromised hippocampal‐cortical FC in OSA may underlie depression and anxious mood levels in OSA, while impaired caudate‐cortical FC may indicate deficits in reward processing and cognition. These findings provide insights into the neural mechanisms underlying the comorbidity of mood and cognitive deficits in OSA.
Highlights
Brain structural injury and metabolic deficits in the hippocampus and caudate nuclei may contribute to cognitive and emotional deficits found in obstructive sleep apnea (OSA) patients
The distinct hippocampal and caudate nuclei functional network patterns suggest that these two subcortical structures are involved in different neurobiological processes, and functional connectivity (FC) changes from these structures might exert different psychopathological outcomes in OSA
The distribution of positive FC with medial temporal, frontal, and parietal lobes underlie roles in hippocampus-originated memory and mood regulation, while the widespread negative interactions between caudate nuclei and cortical areas indicate the importance of these structures in sensorimotor gating (Buse, Beste, Herrmann, & Roessner, 2016; Hazlett et al, 2008) and cognitive biasing (Dedovic et al, 2016)
Summary
Obstructive sleep apnea (OSA) is common condition, affecting as much as 10% of the population (Lee, Nagubadi, Kryger, & Mokhlesi, 2008), and is characterized by recurrent episodes of complete or partial obstruction of the upper airway, with continued diaphragmatic efforts to breathe during sleep. Reduced brain metabolites, including N-acetyl aspartate and choline appear in these regions in adult and pediatric OSA (Bartlett et al, 2004; Halbower et al, 2006) These findings reflect regional neuronal cell loss and significant morphologic and metabolic changes in untreated OSA subjects induced by hypoxia and neuro-inflammatory responses. How these local sites interact with cortical areas during resting- states to mediate affective symptoms and cognitive deficits at the network level in OSA are unclear. We hypothesized that hippocampal and caudate nuclei interactions to other mood and cognitive regulatory areas would be compromised in OSA subjects, and that these altered functional connections will show associations with sleep and neuropsychological scores
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
