Network-targeted stimulation engages neurobehavioral hallmarks of age-related memory decline

Objective: To test whether targeting hippocampal-cortical brain networks with high-frequency transcranial magnetic stimulation (TMS) in older adults influences behavioral and neural measures characteristic of age-related memory impairment. Methods: Fifteen adults aged 64 – 80 years (mean = 72 years) completed a single-blind, sham-controlled experiment. Stimulation targets in parietal cortex were determined based on functional magnetic resonance imaging (fMRI) connectivity with the hippocampus. Recollection and recognition memory were assessed after five consecutive daily sessions of full-intensity stimulation versus low-intensity sham stimulation using a within-subjects crossover design. Neural correlates of recollection and recognition memory formation were obtained via fMRI, measured within the targeted hippocampal-cortical network versus a control frontal-parietal network. These outcomes were measured ~24 hours after the final stimulation session. Results: Recollection was specifica...