A comprehensive multimodal MRI and EEG-TMS dataset on the impact of parietal cortex inhibition on decision-making under ambiguity

In daily life, we often face decisions where potential outcomes are unclear, creating uncertainty. The complete or partial lack of knowledge regarding outcome probabilities—referred to as ambiguity—poses significant challenges for individuals. While recent studies have linked ambiguity in decision-making to neural activity in the parietal cortex, the precise role of this region and its interactions with other brain areas remain poorly understood. Here, we present a comprehensive dataset on human decision-making under conditions of risk and ambiguity. The dataset includes two experimental sessions. The first one corresponds to the MRI setting, which includes structural MRI (T1- and T2-weighted images, n = 52), diffusion-weighted imaging (n = 45), and task-based functional MRI (n = 38). The second session corresponds to the EEG setting combined with inhibitory transcranial magnetic stimulation (TMS), targeting two parietal regions and the vertex (n = 24). TMS targets were defined from group-level fMRI activations obtained in the first session and then transformed to individual anatomy. Ten participants completed both fMRI and EEG-TMS recordings. This dataset, partially analyzed in previous work, now includes newly acquired and previously unexamined data—such as diffusion-weighted imaging, T2-weighted images—and is fully organized according to the Brain Imaging Data Structure (BIDS) standard. It provides valuable opportunities to investigate the neurobiological decision-making mechanisms under ambiguity, focusing on the parietal cortex.