Emotional changes are common in mild cognitive impairment (MCI) and Alzheimer’s disease. Default mode network degradation in Alzheimer’s disease appears to be accompanied by the release of an emotion-relevant salience network. The authors of this study investigated whether emotional contagion, an index of empathic reactivity, is higher in MCI and Alzheimer’s disease secondary to changes in neural networks that support emotion. Emotional contagion was measured in 111 healthy controls, 62 patients with MCI, and 64 patients with Alzheimer’s disease using the Interpersonal Reactivity Index Personal Distress subscale.
Participants underwent structural MRI, and voxel-based morphometry was used to relate whole-brain maps to emotional contagion. Higher emotional contagion was observed at each stage of disease progression. Depressive symptoms were also higher in patients compared with controls. Higher emotional contagion (but not depressive symptoms) was associated with smaller volume in right inferior, middle, and superior temporal gyri, right temporal pole, anterior hippocampus, parahippocampal gyrus; and left middle temporal gyrus. These findings suggest that in MCI and Alzheimer’s, neurodegeneration of temporal lobe structures important for affective signal detection and emotion inhibition are associated with up-regulation of emotion-generating mechanisms.
Sturm VE, Yokoyama JS, Seeley WW, Kramer JH, Miller BL and Rankin KP: Heightened emotional contagion in mild cognitive impairment and Alzheimer’s disease is associated with temporal lobe degeneration. PNAS 110 (24): 9944-9949 (2013).