Poster 2022#5 – Anna-Thekla JÄGER – Self-Similar Properties of the rs-fMRI Signal Reflect Functional Changes in Neuroplasticity Following Motor Sequence Learning

Recent research in functional magnetic resonance imaging (fMRI) shows that scale-free properties of brain signals can meaningfully reflect human brain activity in health and disease. Here, we sought to examine whether changes in scale-free temporal dynamics within resting-state fMRI (rsfMRI) data are reflective of functional neuroplasticity following sequence-specific motor sequence learning (MSL). Using the Hurst Exponent (HE), we estimated voxel-wise scale-free functional dynamics and assessed changes over 5 consecutive days of MSL, followed by a retention scan (12 days later). The experimental group learned a complex visuomotor sequence while a complementary control group performed tightly matched motor movements. An interaction analysis revealed that HE decreases were specific to the complex sequence only and occurred in well-known MSL-associated regions. Five of these regions exhibited moderately strong negative correlations with overall behavioral performance improvements on the complex sequence. A final investigation of the recovery of HE following learning showed that only some regions returned to pre-training levels while others remained decreased even two weeks after training. Our study presents new evidence of HE’s relevance for functional plasticity and suggests that the sequence-specific cortical subset of regions may continue to represent a functional signature of learning after a period of inactivity reflected by unchanging HE levels following learning.