Functional insights into aberrant brain responses and integration in patients with lifelong premature ejaculation

Abstract

Even though lifelong premature ejaculation (PE) is highly prevalent, few studies have investigated the neural mechanisms underlying PE. The extent and pattern of brain activation can be determined through a version of functional magnetic resonance imaging (fMRI) with erotic picture stimuli (task fMRI) and a resting-state fMRI (rs fMRI). We showed that the brain activity in the left inferior frontal gyrus and left insula was decreased both during the task and in the resting state, while there was higher activation in the right middle temporal gyrus during the task. Higher functional connectivity was found in PE between those three brain areas and the bilateral middle cingulate cortex, right middle frontal gyrus and supplementary motor area. Moreover, the brain activity had positive correlation with clinical rating scales, such as intravaginal ejaculatory latency time (IELT) and the Chinese Index of Premature Ejaculation (CIPE). These findings revealed that brain responses and functional integration in certain brain areas are impaired in cases of PE, which was consistently supported by multiple measurements obtained using a task and rs fMRI approach.

Figure 1

Brain responses to erotic pictures. The mean task fMRI activation maps of (A) PE patients and (B) NC subjects. (C,E) Independent sample t-test results indicating the voxels in which the PE patients demonstrated significantly altered activation compared to the NC group (T maps threshold at p < 0.05, AlphaSim corrected). (D) The beta values for the left inferior frontal gyrus, left insula and right middle temporal gyrus. rMTG: right middle temporal gyrus; lIFG: left inferior frontal gyrus; lIn: left insula.

Figure 2

Resting brain spontaneous activity. The mean rs fMRI activation maps (ReHo) of (A) PE patients and (B) the NC group. (C,E) t-test results of independent samples indicating the voxels in which the PE patients demonstrated significantly decreased activation compared to the NC group (T map threshold at p < 0.05, AlphaSim corrected). (D) The ReHo value in the left inferior frontal gyrus and left insula. lIFG: left inferior frontal gyrus; lIn: left insula.

Figure 3

Functional connections altered in the resting state. Based on using the (A) lIFG, (B) lIn and (C) rMTG as seeds, the functional connectivity was enhanced in the PE patients compared with the NC group. An independent sample t-test was applied between the two groups (T maps threshold at p < 0.05, AlphaSim corrected). (D) The brain areas where functional connectivity was enhanced in the left inferior frontal gyrus and left insula. rMTG: right middle temporal gyrus; lIFG: left inferior frontal gyrus; lIn: left insula.

Figure 4

Correlation between clinical scale score and brain activity (ReHo and beta values). (A) ReHo, A.1 and A.4: the ReHo value in the lIFG correlated with the CIPE and IELT; A.2 and A.5: the ReHo value in the lIn correlated with the CIPE and IELT; A.3 and A.6: the ReHo value in the rMTG correlated with the CIPE and IELT. (B) Beta, B.1 and B.4: the beta value in the lIFG correlated with the CIPE and IELT; B.2 and B.5: the beta value in the lIn correlated with the CIPE and IELT; B.3 and B.6: the beta value in the rMTG correlated with the CIPE and IELT. rMTG: right middle temporal gyrus; lIFG: left inferior frontal gyrus; lIn: left insula, CIPE = Chinese Index of Premature Ejaculation; IELT = intravaginal ejaculatory latency time.

Figure 5

Erotic picture stimuli task. The blue bars represent the scenic pictures, and the red bars represent the erotic pictures. Subjects first saw two random scenic pictures for 15 s each (blue pictogram). Then, the participants saw two random erotic pictures, also for 15 s each (red pictogram). These two sections were counted as one set, and there were six sets in the whole paradigm for a total of 360 s.