Amir Jahanian Najafabadi, Hanseul Oh, Hadis Imani, Ben Godde

• As insomnia is recognized as a globally prevalent mental disorder with a high comorbidity rate, attempts to cure insomnia have been increasing. Primary insomnia is not attributed to other medical conditions or substance usage but may be due to impaired brain network and dysregulated brain activities. Normally, a bottom-up thalamocortical pathway is targeted with pharmaceutical interventions for neurological and psychiatric disorders, but possibilities to modulate brain mechanisms with a top-down corticothalamic pathway are re-gaining attention and being considered as a potential treatment option. This study focuses on identification of hallmarks of EEG patterns in insomniacs and effects of a combination of two neuromodulation methods: Neurofeedback (NFT) and transcranial direct current stimulation (tDCS). The 12 participants diagnosed with primary insomnia first received 20 sessions of NFT, which was followed by additional 10 sessions of tDCS, and their EEG patterns were measured at baseline and after the completion of the training. The EEG power and coherence in each of theta (1-4 Hz), delta (4-8 Hz), alpha (8-12 Hz), beta (12-30 Hz), gamma (30-50 Hz) frequency bands was analyzed and compared with the EEG of healthy control group. Throughout the research, I found that primary insomniacs tend to have elevated beta and high beta relative power and excessive coherence compared to the norm of healthy population saved in the NeuroGuide database and the healthy control group, respectively. After the intervention, a noticeable reduction in beta power and coherence was observed.