Amygdala functional connectivity is associated with locus of control in the context of cognitive aging

Abstract

Locus of control (LOC) measures the extent to which individuals perceive control over their lives. Those with a more “internal” LOC feel self-sufficient and able to determine important aspects of their own future, while those with a more “external” LOC feel that their lives are governed by events beyond their control. Reduced internal LOC and increased external LOC have been found in cognitive disorders, but the neural substrates of these control perceptions are yet unknown. In the present study, we explored the relationship between amygdala functional connectivity and LOC in 18 amnestic mild cognitive impairment (MCI) and age-, sex-, and education-matched, 22 cognitively healthy controls (HC). Participants completed cognitive challenge tasks (Stroop Word Color task and Dual 1-back) for 20 minutes, and underwent resting-state functional magnetic resonance imaging immediately before and after the tasks. We found significantly lower internal LOC and higher external LOC in the MCI group than the HC group. Compared to HC, MCI group showed significantly stronger positive associations between internal LOC and baseline right amygdala connections (including right middle frontal gyrus and anterior cingulate cortex), and stronger negative associations between internal LOC and change of these right amygdala connections. Across all participants, external LOC explained the relationships between associations of another set of right amygdala connections (including middle cingulate cortex and right superior frontal gyrus), both at baseline and for change, and performance in the cognitive challenge tasks. Our findings indicate that the right amygdala networks might be critical in understanding the neural mechanisms underlying LOC’s role in cognitive aging.

Functional and structural connectivity of the amygdala underpins locus of control in mild cognitive impairment

“…The MPFC-amygdala connectivity may therefore reflect an anatomical substrate that synthesizes information from multiple resources – value of the self, emotional responses to experience related the controllability, and cognitive appraisal of controllability. Interestingly, the relationships between the amygdala-frontal functional connectivity and external LOC were different from those observed in our prior study that combined aMCI patients with cognitively healthy older adults ( Ren et al, 2017 ). For external LOC, the correlation was positive with the functional connectivity of ventral frontal region (MPFC)-amygdala in the current study, while the correlation was negative with the functional connectivity of the dorsal frontal regions (middle cingulate cortex and superior frontal gyrus)-amygdala in our previous study.…”

“…These divergent findings may be due to different sample characteristics (i.e., using a cognitively diverse sample in our previous study compared to studying aMCI alone in the current study), but both of them may shed light on the altered LOC in the neurodegenerative process. Of note, we did not find any neural correlates of internal LOC in the current study; in our previous study, however, we found a positive relationship between internal LOC and anterior cingulate cortex/middle frontal gyrus ( Ren et al, 2017 ). It may be due to the difference in the sample characteristics as well.…”

“…Items of a subscale were averaged so that higher scores in all subscales indicated higher levels of LOC. We used averaged scores of chance and powerful others to reflect external LOC ( Ren et al, 2017 ; Zahodne et al, 2015 ). Cronbach's α was 0.68 for internal LOC and 0.81 for external LOC in the present study.…”

“…Aging-associated neurodegeneration, such as dementia, further exaggerates older adults' reliance on external LOC. Older adults with amnestic mild cognitive impairment (aMCI), as an intermediate stage between cognitively normal aging and dementia, tend to have lower internal LOC and higher external LOC than their cognitively normal counterparts ( Ren et al, 2017 ; Trivedi et al, 2016 ). Notably, higher external LOC is related to ineffective stress management, psychotic experience, and prospective frailty incidence ( Sullivan et al, 2017 ; Twenge et al, 2004 ; Wu et al, 2004 ; Elliot et al, 2018 , in press), and worsens the link between socioeconomic deprivation and reduced longevity ( Turiano et al, 2014 ).…”

“…To better understand the phenomenon of “overreliance on external LOC” in aging and aging-associated neurodegeneration, recent effort has been made to understand the neural substrates of LOC. Emerging evidence has suggested that frontal-subcortical circuitry, especially the amygdala-related, is associated with perception of control ( Declerck et al, 2006 ; Ren et al, 2017 ). Previous studies have reported that the amygdala can modulate the efficiency of the executive control network ( Fales et al, 2008 ; Herwig et al, 2007 ; Krug and Carter, 2010 ).…”