Autonomic flexibility reflects learning and associated neuroplasticity in old age

Abstract

Effective learning in old age, particularly in those at risk for dementia, is essential for prolonging independent living. Individual variability in learning, however, is remarkable; that is, months of cognitive training to improve learning may be beneficial for some individuals but not others. So far, little is known about which neurophysiological mechanisms account for the observed variability in learning induced by cognitive training in older adults. By combining Lövdén et al.'s (2010, A theoretical framework for the study of adult cognitive plasticity. Psychological Bulletin , 136 , 659–676) framework proposing the role of adaptation capacity in neuroplasticity and a neurovisceral integration model of the relationship between autonomic nervous system (ANS) and brain with a novel shapelet analytical approach that allows for accurate and interpretable analysis of time series data, we discovered an acute, ECG‐derived ANS segment in response to cognitive training tasks at baseline that predicted learning outcomes from a 6‐week cognitive training intervention. The relationship between the ANS segment and learning was robust in both cross‐participant and cross‐task analyses among a group of older adults with amnestic mild cognitive impairment. Furthermore, the revealed ANS shapelet significantly predicted training‐induced neuroplasticity in the dorsal anterior cingulate cortex and select frontal regions during task fMRI. Across outcome measures, individuals were less likely to prospectively benefit from the cognitive training if their ECG data were more similar to this particular ANS segment at baseline. Our findings are among the first empirical evidence to confirm that adaptation capacity, indexed by ANS flexibility, predicts individual differences in learning and associated neuroplasticity beyond individual characteristics (e.g., age, education, neurodegeneration, total training).

Enhancing cortical network-level participation coefficient as a potential mechanism for transfer in cognitive training in aMCI

“…BOLD fMRI data were collected using a gradient echo-planar imaging sequence (TR/TE = 2500 ms/30 ms, FA = 90, 64 × 64 matrix, 4mm 3 in-plane resolution, 4 mm slice thickness, 37 axial slices). Participants underwent a 5-minute resting-state scan, during which they were instructed to relax with their eyes open, followed by a 5-minute block-design “target among distractors” visual attention task (see also ( Chen et al, 2020 ; Lin et al, 2020 )). The stimuli were presented in 5 blocks, each of which consisted of 6 trials, for a total duration of 42 s; blocks were alternated with fixation periods of 20 s. Within each trial, a central fixation cross was presented for 500 ms, followed by 5500 ms presentation of the visual search pattern.…”

Targeting autonomic flexibility to enhance cognitive training outcomes in older adults with mild cognitive impairment: study protocol for a randomized controlled trial

“…Analysis of weekly in-lab resting and task-related ECG data : Degree of similarity between candidate ECG features (sliding window based 2-min segments) and previously revealed ECG shapelet will be calculated for each in-lab session. In our previous study, a higher degree of similarity to the ECG shapelet was related to worse learning from VSOP [ 11 ]. Here, we will model the trajectory of degree of similarity across in-lab sessions and calculate the relationship between the slope of trajectory and intervention effects on outcomes.…”

“…Therefore, adaptation capacity is critical for promoting neuroplasticity underlying various cognitive enhancement activities (e.g., cognitive training) [ 2 ]. Our recently completed study found that ANS flexibility at baseline predicted the training effect of a cognitive training [ 11 ]. Hence, enhancing adaptation capacity may enhance neuroplasticity and slow the progress of dementia in older adults with MCI.…”