This study aims to investigate which of two brain regions is important for which decision-making strategy. The investigators suppose that one brain region - the *striatum* - is important for repeatedly choosing objects that have previously been paired with rewards (strategy 1). They suppose that a different region - the *hippocampus* - is important for extending such reasoning to RELATED objects (strategy 2).
The investigators will repeatedly ask young and healthy subjects to choose between two objects. The two objects are repeatedly drawn from a pool of seven. Relations between the seven objects have been learned on the first day of the experiment. The investigators will record subjects' choices and will use an automated way to assess the extent to which any given subject uses either decision-making strategy.
Which stimulation (A, B, C) happens on which day is assigned by computer code and differs between subjects. Subjects do not know, and investigators mostly do not know, whether real or control stimulation is applied on each day.
The investigators will check whether subjects use strategy 1 more when their striatum is being stimulated and strategy 2 more when their hippocampus is being stimulated, as compared to when the control stimulation is applied.
Inclusion Criteria:
Exclusion Criteria:
Subjects included in the study will be excluded from analyses if their datasets are incomplete. To ensure full counterbalancing, excluded subjects will be replaced by new ones.
ludwig_j5@ukw.de
All parties are blind to the type of stimulation (tTIS vs. high-frequency control stimulation). The investigator arranges and the subject experiences - they are hence not blind to - the electrode set-up (hippocampal vs. striatal). In the event that a given subject has already received the hippocampal set-up in their first two sessions, the investigator may conclude that the unique striatal set-up in this particular subject's third session must be associated with real (= temporal interference) rather than control stimulation. This is because each brain region must receive the real stimulation exactly once. This limitation to blinding applies whenever the unique set-up (= the one that a given subject receives only once instead of twice) is administered in the LAST of the three sessions (because it is only then that the investigator may know which one is the unique set-up). This will be true in one-third of the subjects and will equally concern hippocampal and striatal stimulations.
Striatal tTIS and hippocampal tTIS are active experimental conditions. High-frequency control is a placebo comparator. "Striatal" in "striatal high-frequency control" refers to the electrode set-up (no actual stimulation of the striatum occurs in that condition).
Striatal tTIS and hippocampal tTIS are active experimental conditions. High-frequency control is a placebo comparator. "Striatal" in "striatal high-frequency control" refers to the electrode set-up (no actual stimulation of the striatum occurs in that condition).
Striatal tTIS and hippocampal tTIS are active experimental conditions. High-frequency control is a placebo comparator. "Striatal" in "striatal high-frequency control" refers to the electrode set-up (no actual stimulation of the striatum occurs in that condition).
Striatal tTIS and hippocampal tTIS are active experimental conditions. High-frequency control is a placebo comparator. "Striatal" in "striatal high-frequency control" refers to the electrode set-up (no actual stimulation of the striatum occurs in that condition).
Striatal tTIS and hippocampal tTIS are active experimental conditions. High-frequency control is a placebo comparator. "Striatal" in "striatal high-frequency control" refers to the electrode set-up (no actual stimulation of the striatum occurs in that condition).
Striatal tTIS and hippocampal tTIS are active experimental conditions. High-frequency control is a placebo comparator. "Striatal" in "striatal high-frequency control" refers to the electrode set-up (no actual stimulation of the striatum occurs in that condition).
Striatal tTIS and hippocampal tTIS are active experimental conditions. High-frequency control is a placebo comparator. "Hippocampal" in "hippocampal high-frequency control" refers to the electrode set-up (no actual stimulation of the hippocampus occurs in that condition).
Striatal tTIS and hippocampal tTIS are active experimental conditions. High-frequency control is a placebo comparator. "Hippocampal" in "hippocampal high-frequency control" refers to the electrode set-up (no actual stimulation of the hippocampus occurs in that condition).
Striatal tTIS and hippocampal tTIS are active experimental conditions. High-frequency control is a placebo comparator. "Hippocampal" in "hippocampal high-frequency control" refers to the electrode set-up (no actual stimulation of the hippocampus occurs in that condition).
Striatal tTIS and hippocampal tTIS are active experimental conditions. High-frequency control is a placebo comparator. "Hippocampal" in "hippocampal high-frequency control" refers to the electrode set-up (no actual stimulation of the hippocampus occurs in that condition).
Striatal tTIS and hippocampal tTIS are active experimental conditions. High-frequency control is a placebo comparator. "Hippocampal" in "hippocampal high-frequency control" refers to the electrode set-up (no actual stimulation of the hippocampus occurs in that condition).
Striatal tTIS and hippocampal tTIS are active experimental conditions. High-frequency control is a placebo comparator. "Hippocampal" in "hippocampal high-frequency control" refers to the electrode set-up (no actual stimulation of the hippocampus occurs in that condition).
Evaluating the Neurocomputational Mechanisms of Explore-Exploit Decision Making in Older Adults
Developing Transcranial Neuromodulation Protocols for Learning and Decision-Making
Brain Network Mechanisms Causally Underlying Human Decisions Revealed by Brain Stimulation and Functional MRI