Neurochemical predictors of generalized learning induced by brain stimulation and training

Poster Session B - Sunday, April 14, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Shane Ehrhardt¹ (s.ehrhardt@uq.edu.au), Yohan Wards¹, Reuben Rideaux², Malgorzata Marjanska³, Jin Jin⁴, Martijn Cloos¹, Dinesh Deelchand³, Helge Zollner⁵, Muhammad Saleh⁷, Steve Hui⁶, Tonima Ali², Thomas Shaw¹, Markus Barth¹, Jason Mattingley¹, Hannah Filmer¹, Paul Dux¹; ¹University of Queenland, ²University of Sydney, ³University of Minnesota, ⁴Siemens Australia, ⁵John Hopkins, ⁶Children’s Hospital, Washington, ⁷University of Maryland

Methods of cognitive enhancement are most impactful when they generalise across tasks. However, the extent to which such “transfer” is possible via interventions is widely debated. In addition, the contribution of excitatory and inhibitory processes to such transfer is unknown. Here, in a large-scale neuroimaging individual differences study, we paired multitasking training and non-invasive brain stimulation (transcranial direct current stimulation; tDCS) over multiple days and assessed performance across a range of paradigms. In addition, we varied tDCS dosage (1.0 mA and 2.0 mA), electrode montage (left or right prefrontal regions), and training task (multitasking versus a control task) and assessed GABA and glutamate concentrations via ultra-high field 7T magnetic resonance spectroscopy. Generalised benefits were observed in spatial attention, indexed by visual search performance, when multitasking training was combined with 1.0 mA stimulation applied to either the left or right prefrontal cortex. This transfer effect persisted for ~30 days post-intervention. Critically, transfer benefit associated with right prefrontal tDCS was predicted by pre-training concentrations of glutamate in the prefrontal cortex. Thus, these combined stimulation and training protocols appear to be linked predominantly to excitatory brain processes.

Topic Area: EXECUTIVE PROCESSES: Other