Disturbances of Dynamic Function in Patients With Bipolar Disorder I and Its Relationship With Executive-Function Deficit

Abstract

Abnormity in brain regional function and interregional cooperation have been linked with the dysfunction during cognitive and emotional processing in bipolar disorder (BD) patients. Recent evidences have suggested that brain function is not static but temporal dynamic. In present study, we aimed to characterize the temporal dynamics of regional function and interregional cooperation in BD and its relationship with executive dysfunction, an important deficit in BD. Resting-state functional MRI was performed in patients with bipolar I disorder (BDI) (n = 18) and healthy controls (HCs, n = 19). We first assessed local-function temporal variety with dynamic amplitude of low-frequency fluctuation (dALFF). Region with significant inter-groups difference in dALFF was chosen as a seed to calculate inter-regions connective temporal variety with dynamic functional connectivity (dFC). The executive function was measured by Verbal Fluency Test (VFT). The relationship between executive function and brain dynamics were examined. Compared with HC, the BDI group showed decreased dALFF (less temporal variability) in the posterior cingulate cortex (PCC) and decreased dFC between PCC and medial prefrontal cortex (mPFC). The PCC-mPFC dFC was positively associated with VFT in BDI patients, but not in HC. These findings implicated the reduced temporal variability in local region and inter-regions cooperation in BDI, which may be a neural substrate of executive-function deficit in BDI.

Executive Function Deficits in Bipolar Disorder

“…Simultaneously, since mPFC is a component of DMN, brain regions exhibit strong low-frequency oscillations in a static state, and are thought to focus on internal mental state processes including mutual inductance, autobiographical memory retrieval or imagining the future. The positive correlation between mPFC and executive performance may indirectly demonstrate that the dysfunctions of DMN are closely related to emotional and executive impairment of BD I to some degree [19]. Moreover, BD subtypes differ in brain structure-function relationships.…”

“…Compared to other subtypes of BD, BDI patients demonstrate unique neural abnormalities related with executive functioning. Previous research showed that Euthymic BDI patients are impaired in verbal memory and executive functioning [19]. According to Liang and colleagues, BDI patients have abnormal DMN temporal dynamics of spontaneous activity, declined PCC-mPFC connection variety and the connection between the medial prefrontal cortex (mPFC) which is the main source of cardiovascular sympathetic neurons and involve in numerous sensorimotor, cognitive, and affective processes.…”

“…BD II patients tend to have lower executive functioning, compared to BD I patients; the corresponding cluster that demonstrates this phenomenon is detected in the right lateral prefrontal area in the rostral middle frontal cortex. The decreased temporal variability in local region and inter-regional cooperation in BD I is likely to be the neural substrate of executive-function deficits [19].…”

The aberrant dynamic amplitude of low-frequency fluctuations in melancholic major depressive disorder with insomnia

“…Furthermore, a previous study demonstrated that dALFF changes are related to changes in EEG band power ( 50 ). Recently, many psychiatric illnesses have discovered a significant change in dALFF, such as MDD ( 51 ), bipolar disorder ( 52 ), Schizophrenia ( 53 ), primary insomnia ( 54 ), and generalized anxiety disorder ( 55 ). For an instance, Staner found that temporal dALFF can predict suicidal thoughts in depressed patients, while static ALFF cannot ( 16 ).…”

Altered frequency-specific/universal amplitude characteristics of spontaneous brain oscillations in patients with bipolar disorder

“…Studies on dALFF have rarely been conducted in patients with BD. Limited to the routine frequency band (0.01–0.1 Hz), two studies found that patients with depressed BD have decreased dALFF values in bilateral PCu/PCC ( Gong et al, 2020a , Luo et al, 2021 ); two studies found that the patients with depressed BD have decreased dALFF values in the left and right temporal/fusiform gyrus ( Sun et al, 2022 , Tian et al, 2021 ); one study found that patients with manic BD have decreased dALFF values in the PCu/PCC ( Liang et al, 2020 ); one study did not distinguish the patients’ mood states and found that the patients have increased dALFF values in the right fusiform, right hippocampus, and right parahippocampus ( Zhang et al, 2021a ). These previous studies suggest that the dALFF in the PCu/PCC may be consistently decreased in patients with BD.…”