The goal of this study is to establish if non-invasive closed-loop neuromodulation is an effective approach to enhance cognitive function in healthy 18-40 years old volunteers. The main questions it aims to answer are:
* Can closed-loop stimulation increase stimulation effectiveness?
* Can closed-loop focused ultrasound specifically engage with excitatory or inhibitory neural populations in the target structure as measured through MRS?
* Can observed stimulation outcomes for FUS be predicted through connectome analysis and computational models of indirect changes?
Researchers will compare different closed-loop options to their open-loop counterpart to see if closed-loop approaches can increase efficacy and reduce the variability of the stimulation compared to open-loop approaches.
Participants will:
* Answer some questionnaires at the start of the study and after each intervention session.
* Undertake a MRI scanning session.
* Undertake one open-loop FUS session.
* Undertake one tES session.
* Undertake one closed-loop FUS sessions involving tES and FUS, followed by a MRI scanning
* Undertake one sham FUS session
* Attend one visit in person to assess eligibility through questionnaires and one cognitive task