Age-differential relationships among dopamine D1 binding potential, fusiform BOLD signal, and face-recognition performance

Authors

Monroe P. Turner, University of Texas at DallasFollow
Håkan Fischer, Stockholm University, Stockholm
Dinesh K. Sivakolundu, University of Texas at Dallas
Nicholas A. Hubbard, Massachusetts Institute of Technology & University of Nebraska-LincolnFollow
Yuguang Zhao, University of Texas at Dallas
Bart Rypma, University of Texas at Dallas & University of Texas Southwestern Medical Center
Lars Backman, Karolinska Institute, Stockholm

Document Type

Article

Date of this Version

2020

Citation

2019 Published by Elsevier Inc

Comments

NeuroImage 206 (2020) 116232

https://doi.org/10.1016/j.neuroimage.2019.116232

Abstract

Facial recognition ability declines in adult aging, but the neural basis for this decline remains unknown. Cortical areas involved in face recognition exhibit lower dopamine (DA) receptor availability and lower blood-oxygen-level-dependent (BOLD) signal during task performance with advancing adult age. We hypothesized that changes in the relationship between these two neural systems are related to age differences in face-recognition ability. To test this hypothesis, we leveraged positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) to measure D1 receptor binding potential (BPND) and BOLD signal during facerecognition performance. Twenty younger and 20 older participants performed a face-recognition task during fMRI scanning. Face recognition accuracy was lower in older than in younger adults, as were D1 BPND and BOLD signal across the brain. Using linear regression, significant relationships between DA and BOLD were found in both age-groups in face-processing regions. Interestingly, although the relationship was positive in younger adults, it was negative in older adults (i.e., as D1 BPND decreased, BOLD signal increased). Ratios of BOLD:D1 BPND were calculated and relationships to face-recognition performance were tested. Multiple linear regression revealed a significant Group BOLD:D1 BPND Ratio interaction. These results suggest that, in the healthy system, synchrony between neurotransmitter (DA) and hemodynamic (BOLD) systems optimizes the level of BOLD activation evoked for a given DA input (i.e., the gain parameter of the DA input-neural activation function), facilitating task performance. In the aged system, however, desynchronization between these brain systems would reduce the gain parameter of this function, adversely impacting task performance and contributing to reduced face recognition in older adults.