Neuromodulation-assisted Ego-disengagement: The NEURO-EGO Study Stage 1

The goal of this clinical trial is to learn whether brain stimulation technology can help people reach a meditative state quickly and easily without years of meditation training. The researchers want to see if this will help people distance themselves from their thoughts and feeling, and if this will lead to improvements in openness and wellbeing the same way meditation can.

Participants will:

* Complete questionnaires
* Perform a guided meditation task (The Bell Task)
* Wear a high density electrocochleography (hdEEG) cap
* Undergo brain stimulation
* Perform cognitive tasks

This study is being done to evaluate the relative effectiveness of distinct types of non-invasive brain stimulation - NIBS (TES-TI and TES) on subjective ego disengagement and cortical activity in experienced meditators.

Phase 1 (registered to this record) involves administering 2 distinct types of deep brain stimulation techniques to a small sample (N=12) of experienced meditators to determine which type of neuromodulation, when focused on disruption of posteromedial cortex (PMC) activity, most robustly facilitates positive ego-disengagement compared to sham; and to discern the region of the PMC where disruption is most effective in achieving ego disengagement.

Phase 2 (registered to a separate record, NCT06601699) will use the most effective stimulation and PMC parameters to meditation naïve healthy adults.

Eligibility Criteria:
Inclusion Criteria:

* Adults, ages 18 to 55 of any identified gender
* Medically healthy
* English-speaking (able to provide consent and complete questionnaires)
* Healthy adults with a consistent meditation practice

Exclusion Criteria:

* Any current or past history of neurological disorders or acquired neurological disease (e.g. stroke, traumatic brain injury), including intracranial lesions
* Any current or past history of bipolar disorder and/or hypomania
* Any current or past history of psychosis
* History of head trauma resulting in prolonged loss of consciousness; or a history of \&gt;3 grade I concussions
* Current history of poorly controlled headaches including intractable or poorly controlled migraines
* Any systemic illness or unstable medical condition that may cause a medical emergency in case of a provoked seizure (cardiac malformation, cardiac dysrhythmia, asthma, etc.)
* History of fainting spells of unknown or undetermined etiology that might constitute seizures
* History of seizures, diagnosis of epilepsy, history of abnormal (epileptiform) EEG, or family history of treatment resistant epilepsy with the exception of a single seizure of benign etiology (e.g. febrile seizures) in the judgment of a board-certified neurologist
* Possible pregnancy. All female participants of child-bearing age are required to have a pregnancy test
* Any metal in the brain, skull or head
* Any contraindications to MRI
* Any medical devices or implants (i.e. cardiac pacemaker, medication infusion pump, cochlear implant, vagal nerve stimulator, dental implants) unless otherwise approved by the responsible MD
* Substance abuse or dependence within the past six months
* Any medication that may alter seizure threshold i.e., ADHD stimulants (Adderall, amphetamine); Tricyclic/atypical antidepressants (Amitriptyline, Dioxepine, Imipramine Maprotiline, Nortriptyline, Bupropion); Antipsychotics (Chlorpromazine, Clozapine), Bronchodilators (theophylline, aminophylline); Antibiotics (fluoroquinolones, imipenem, penicillin, cephalosporins, metronidazole, isoniazid); Antiviral (Valacyclovir, Ritonavir); OTC (Diphenhydramine)
* Claustrophobia (a fear of small or closed places)
* Back problems that would prevent lying flat for up to two hours