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- Ebner, Natalie C., et al.
(författare)
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Oxytocin’s effect on resting-state functional connectivity varies by age and sex
- 2016
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Ingår i: Psychoneuroendocrinology. - : Elsevier BV. - 0306-4530 .- 1873-3360. ; 69, s. 50-59
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Tidskriftsartikel (refereegranskat)abstract
- The neuropeptide oxytocin plays a role in social cognition and affective processing. The neural processes underlying these effects are not well understood. Modulation of connectivity strength between subcortical and cortical regions has been suggested as one possible mechanism. The current study investigated effects of intranasal oxytocin administration on resting-state functional connectivity between amygdala and medial prefrontal cortex (mPFC), as two regions involved in social-cognitive and affective processing. Going beyond previous work that largely examined young male participants, our study comprised young and older men and women to identify age and sex variations in oxytocin’s central processes. This approach was based on known hormonal differences among these groups and emerging evidence of sex differences in oxytocin’s effects on amygdala reactivity and age-by-sex-modulated effects of oxytocin in affective processing. In a double-blind design, 79 participants were randomly assigned to self-administer either intranasal oxytocin or placebo before undergoing resting-state functional magnetic resonance imaging. Using a targeted region-to-region approach, resting-state functional connectivity strength between bilateral amygdala and mPFC was examined. Participants in the oxytocin compared to the placebo group and men compared to women had overall greater amygdala–mPFC connectivity strength at rest. These main effects were qualified by a significant three-way interaction: while oxytocin compared to placebo administration increased resting-state amygdala–mPFC connectivity for young women, oxytocin did not significantly influence connectivity in the other age-by-sex subgroups. This study provides novel evidence of age-by-sex differences in how oxytocin modulates resting-state brain connectivity, furthering our understanding of how oxytocin affects brain networks at rest.
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| 2. |
- Gulliford, Desiree, et al.
(författare)
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Gender-differential effects of intranasal oxytocin on resting-state anterior cingulate activity
- 2017
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Konferensbidrag (refereegranskat)abstract
- Introduction: As individuals age, there is an increased focus on social relationships (Carstensen, 2006). However, age-related changes in the brain can interfere with social functioning (Ebner, et al, 2012; Mather, et al, 2005; Ruffman, et al, 2008). While age-related changes in cognition are well studied, social-cognitive changes in aging are still underinvestigated, especially the brain mechanisms underlying this phenomenon. The administration of intranasal oxytocin (OT) has the potential to modulate social cognition (De Dreu, 2014) by altering BOLD signal in regions of the social brain (eg. amygdala and vmPFC) (Ebner, et al, 2016). Currently, there is very little known about the role of OT in human development in aging (Campbell, et al, 2014; Huffmeijer, et al, 2012). Methods: 40 young (18–31 years, 50% female) and 39 older (63–81 years, 59% female) were randomly assigned (in a double-blind design) to self-administer either 24 UIs of intranasal OT or placebo (P) 70-90 minutes prior to resting-state fMRI. T1-weighted anatomical reference images, using an MP-RAGE sequence (sagittal plane, FOV = 240 mm × 240 mm × 170; 1 × 1 × 1 mm isotropic voxels), and functional gradient-echo-planar imaging (EPI) data, during an open-eye, white cross-hair on black background, 8 minute resting-state scan (38 interleaved slices, TR 2 sec, TE 30 msec, FOV 252 × 252 × 133 mm, 80 × 80 × 38 mm matrix, flip angle 90°, in plane resolution of 3.15 × 3.15 mm, slice thickness 3.5 mm, 0 mm skip), were acquired with a 3T Philips Achieva MR Scanner using a 32-channel head coil. Preprocessing, including slice time correction, motion correction with artifact rejection, spatial normalization, and smoothing with an 8 mm Gaussian kernel, were implemented with Functional Connectivity Toolbox (Whitfield-Gabrieli, et al, 2012; http://www.nitrc.org/projects/conn/). Results: Younger individuals showed significantly greater overall anterior cingulate (AC) activity in P condition (p=.044). Intranasal OT administration significantly increased activity in the AC in both younger and older women (p=.024), but not men, when compared to P. The effect was slightly greater in older women than younger, but this effect was not significant potentially due to sample size.There were no significant gender effects in AC activity during rest between males and females in either younger or older P control groups. Conclusions: Intranasal OT has differential gender effects on AC activity during resting-state, increasing activity in women but not men. Additionally, there is evidence for age differences in overall AC activity at rest.
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