Disrupted Spontaneous Neural Activity Related to Cognitive Impairment in Postpartum Women

Abstract

Purpose: Prior research has demonstrated that the postpartum period is associated with an increased risk of cognitive impairment. This study aims to investigate whether disrupted spontaneous neural activity exists in postpartum women without depression using resting-state functional magnetic resonance imaging (rs-fMRI) and to detect the relationship between these abnormalities and cognitive impairment. Materials and Methods: Postpartum women (n = 22) were compared with age- and education-matched nulliparous women (n = 23) using rs-fMRI. We calculated the amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) values to evaluate spontaneous neural activity and detect the relationship between rs-fMRI data and cognitive performance. Results: Relative to nulliparous women, postpartum women had significantly decreased ALFF and ReHo values primarily in the left posterior cingulate cortex (PCC) and prefrontal cortex and increased ALFF values in left cerebellar posterior lobe. We found a positive correlation between the ALFF and ReHo values in the PCC and the complex figure test (CFT)-delayed scores in postpartum women (r = 0.693, p = 0.001; r = 0.569, p = 0.011, respectively). Moreover, the clock-drawing test (CDT) scores showed positive correlations with the ALFF and ReHo values in the right superior frontal gyrus (SFG; r = 0.492, p = 0.033; r = 0.517, p = 0.023, respectively). Conclusion: Our combined ALFF and ReHo analyses revealed decreased spontaneous neural activity, mainly in the PCC and prefrontal cortex, which was correlated with specific impaired cognitive functioning in postpartum women. This study may elucidate the neurophysiological mechanisms underlying postpartum cognitive impairment and enhance our understanding of the neurobiological aspects of the postpartum period.

Keywords: ALFF; ReHo; postpartum women; resting-state fMRI; spontaneous activity.

FIGURE 1

(A) One-sample t-test results of ALFF maps (p < 0.001 corrected by FDR) in nulliparous women and postpartum women. (B) One-sample t-test results of ReHo maps (p < 0.001 corrected by FDR) in nulliparous women and postpartum women. The left side corresponds to the right hemisphere.

FIGURE 2

(A) Regions exhibiting differences in ALFF between the nulliparous women and postpartum women (p < 0.001 corrected by FDR). (B) Regions exhibiting differences in ReHo between nulliparous women and postpartum women (p < 0.001 corrected by FDR). The left side corresponds to the right hemisphere.

FIGURE 3

Correlations between the ALFF and ReHo values in the (A) posterior cingulate cortex (PCC; r = 0.775, p < 0.001) and (B) right superior frontal gyrus (SFG; r = 0.582, p = 0.004).

FIGURE 4

(A) Correlations between the CFT-delayed scores and decreased ALFF values in the PCC (r = 0.693, p = 0.001). (B) Correlations between the CFT-delayed scores and decreased ReHo values in the PCC (r = 0.569, p = 0.011). (C) Correlations between the CDT scores and reduced ALFF in the right SFG (r = 0.492, p = 0.033). (D) Correlations between the CDT scores and reduced ReHo in the right SFG (r = 0.517, p = 0.023).