Network segregation varies with neural distinctiveness in sensorimotor cortex
Kaitlin Cassady,
Holly Gagnon,
Erin Freiburger,
Poortata Lalwani,
Molly Simmonite,
Denise C. Park,
Scott J. Peltier,
Stephan F. Taylor,
Daniel H. Weissman,
Rachael D. Seidler,
Thad A. Polk
Affiliations
Kaitlin Cassady
Department of Psychology, University of Michigan, Ann Arbor, MI, USA; Corresponding author. University of Michigan, Department of Psychology, Computational and Cognitive Neuroscience Laboratory, 530 Church Street, Ann Arbor, MI, 48109, USA.
Holly Gagnon
Department of Psychology, University of Utah, Salt Lake City, UT, USA
Erin Freiburger
Department of Psychology, University of Michigan, Ann Arbor, MI, USA
Poortata Lalwani
Department of Psychology, University of Michigan, Ann Arbor, MI, USA
Molly Simmonite
Department of Psychology, University of Michigan, Ann Arbor, MI, USA
Denise C. Park
Research of the Center for Vital Longevity, University of Texas at Dallas, Dallas, TX, USA
Scott J. Peltier
Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
Stephan F. Taylor
Department of Psychology, University of Michigan, Ann Arbor, MI, USA; Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA
Daniel H. Weissman
Department of Psychology, University of Michigan, Ann Arbor, MI, USA
Rachael D. Seidler
Department of Applied Physiology & Kinesiology, University of Florida, Gainesville, FL, USA
Thad A. Polk
Department of Psychology, University of Michigan, Ann Arbor, MI, USA
Normal aging is associated with declines in sensorimotor function. Previous studies have linked age-related behavioral declines to decreases in neural differentiation (i.e., dedifferentiation), including decreases in the distinctiveness of neural activation patterns and in the segregation of large-scale neural networks at rest. However, no studies to date have explored the relationship between these two neural measures and whether they explain the same aspects of behavior. To investigate these issues, we collected a battery of sensorimotor behavioral measures in older and younger adults and estimated (a) the distinctiveness of neural representations in sensorimotor cortex and (b) sensorimotor network segregation in the same participants. Consistent with prior findings, sensorimotor representations were less distinct and sensorimotor resting state networks were less segregated in older compared to younger adults. We also found that participants with the most distinct sensorimotor representations exhibited the most segregated sensorimotor networks. However, only sensorimotor network segregation was associated with individual differences in sensorimotor performance, particularly in older adults. These novel findings link network segregation to neural distinctiveness, but also suggest that network segregation may play a larger role in maintaining sensorimotor performance with age.
