Temporal Interference in Psychiatry (TIP): Neuromodulation Using Temporal Interference

Temporal Interference in Psychiatry (TIP): Neuromodulation Using Temporal Interference

This study aims to understand the neural, behavioral and clinical effects of temporal interference (TI), a type of neuromodulation method, in healthy populations and in individuals with anxiety and stress-related conditions.

In this study, the investigators aim to understand the neural, behavioral and clinical effects of temporal interference (TI), a type of neuromodulation method.

This method involves placement of electrodes on the scalp that deliver a low voltage electrical field at different alternating high frequency fields to modulate the function of brain areas. The study will use magnetic resonance imaging (MRI) and electroencephalography (EEG) to assess the effects of TI on brain response. The study team will also assess mood (measured via clinical assessments and self-report ratings), physiology (measured via electrocardiography, galvanic skin response, respiration) behavior and cognition (performance on various cognitive and other behavioral tasks). To do so, the team will stimulate and inhibit brain regions that are relevant to anxiety, mood, and cognition, areas of the brain hypothesized to be selectively engaged with cognition of a given category, or cost-benefit decision-making (depending on the behavioral tasks used). In an optional study, the investigators will use Ecological Momentary Assessment (EMA) to examine a behavioral translation of the neural mechanisms tested using TI by inquiring about individuals' mood and behavior in daily life. This study will recruit healthy controls and patients with psychiatric symptoms to investigate these effects. Psychiatric symptoms will be assessed based on self-report questionnaires. Such an aim will not only provide a deeper understanding of how TI may be used to target different processes of relevance to psychiatric disorders but also the duration of effects.

Temporal Interference (TI) stimulation is an emerging, non-invasive neuromodulation method which allows focal electrical stimulation of deep brain structures without affecting overlying cortical regions. Preclinical studies and early human applications suggest that TI may modulate emotion-related brain activity with the potential to improve symptoms in psychiatric conditions. This study aims to evaluate the preliminary efficacy of TI stimulation in healthy populations and in individuals with anxiety and stress-related conditions (Aim 1) as well as feasibility, safety, and effects of different frequencies and doses of TI (Aim 2). Outcomes will be evaluated using a battery of neural (MRI, EEG), physiological, behavioral (affective tasks), cognitive, and mood assessments. In addition, the study team aim to explore the longitudinal mental-health outcomes of TI using daily assessments (Aim 3). Participants will be invited to electronically respond to questionnaires and compose a diary over a 4-week period, and these data will be compared with neural recordings. This component will assess the validity and feasibility of remote tracking of anxiety symptoms in real-world settings - and perhaps detect nuanced improvements of symptoms from intermittent TI sessions, not as readily seen in weekly in person clinical assessments.

Inclusion Criteria:

• Written informed consent.
• Fluent English speaker.
• Both sexes and all ethnic origins, between 18 and 65 years old.
• Absence of current moderate to severe illicit drug use as assessed by subject history (AUDIT>=8 and/or DAST>2).

Exclusion Criteria:

• Pregnant or currently breast-feeding women or any woman of childbearing potential who is seeking to become pregnant or suspects that she may be pregnant, as assessed by subject report and/or urine pregnancy screen.
• Contraindications to MRI scanning (including presence of a cardiac pacemaker or pacemaker wires, metallic particles in the body, vascular clips in the head or previous neurosurgery, prosthetic heart valves, claustrophobia, as assessed with the standard MRI screening form from the CABI, FERN or CSI.
• Unable to fit comfortably in the scanner.
• Contraindication to TI and/or TMS (including history of epilepsy, metallic implants in the head and/or neck, brain stimulators, vagus nerve stimulators, VP shunt, pacemakers)
• Current use of medications that may increase the risk of seizures (e.g., bupropion, varenicline, chlorpromazine, theophylline).
• History or current serious or unstable medical illness, including cardiovascular, hepatic, renal, respiratory, endocrine, neurologic or hematologic disease, as assessed by subject history.
• History of head injury resulting in more than brief loss of consciousness, as assessed by subject history.
• Current cocaine or stimulant use (e.g., amphetamine, cocaine, methamphetamine), as assessed by subject history.
• Evidence of significant inconsistencies in self-report measures.
• Non-English speakers will be excluded from this study because the research procedures rely heavily on the administration of validated self-report questionnaires, clinical interviews, and task instructions that at this time, are only available in English. Additionally, study staff are trained to administer these assessments and obtain informed consent in English only. Including non-English speakers would therefore pose a risk of misunderstanding study procedures, consent materials, or questionnaire items, which could affect both participant comprehension and data integrity.