The purpose of the proposed study is to use transcranial magnetic stimulation (TMS) to evaluate a neurobiological model of spoken word learning in older youth. Specifically, it is hypothesized that: (1) inhibition of the left dorsal stream will impact subsequent learning, processing, and retention of phonologically similar pseudowords; (2) the impact of dorsal stream inhibition on word learning will be associated with baseline levels of variability in neural activity, indicative of underlying differences in cortical excitability.

The proposed study is designed to assess the contribution of the dorsal stream of the language network (i.e., left supramarginal gyrus, or SMG) to different aspects of novel word learning in two groups of participants (16-24 years of age): 20 typically developing older youth (OYTD; tested in Aim 1) and 20 older youth with reading difficulties (OYRD; tested in Aim 2). The investigators will use inhibitory continuous theta burst stimulation (cTBS), a well-established repetitive TMS (rTMS) protocol that reduces cortical excitability in a targeted brain region for up to 60 minutes. Participants will complete a baseline magnetic resonance imaging (MRI) session in Week 1, followed by cTBS or sham stimulation to the left SMG, with order of administration counterbalanced across participants. Immediately following cTBS (or sham), participants will complete a visual pseudoword phonological discrimination task and a spoken word learning task. The following day (i.e., 24 hours later), retention of items learned will be measured. In Week 2, cTBS (or sham) will be administered to the left SMG (whichever stimulation was not administered in Week 1) and then the pseudoword discrimination and word learning tasks will be administered using a different set of novel words from those presented in Week 1. Twenty-four hours later, the retention of this second set of items will be measured.

Inclusion Criteria:

• Native English speaker (who is not fluent in any other language and does not identify as bilingual)
• Normal or corrected to normal vision

Exclusion Criteria:

• Diagnosed with Autism Spectrum Disorder
• Hearing deficits (>25 decibels at 500+ Hz), visual deficits (>20/40), serious emotional problems (e.g., severe, uncontrolled depression) and certain neurological conditions (e.g., uncontrolled seizure disorders)
• Individuals with certain metals in their bodies or with certain health conditions. If an individual has braces on their teeth, a cardiac pacemaker; hearing aid; other metal in their body or eyes (which may include certain metallic-embedded tattoos), including but not limited to pins, screws, shrapnel, plates, dentures or other metal objects
• Individuals taking certain medications that lower seizure threshold
• Individuals with TMS Screening and Contraindication Forms which do not pass TMS Tech review
• Individuals with MRI Screening and Contraindication Forms which do not pass MRI Tech review

The Open Science Framework (OSF) will be engaged to facilitate research integration in multiple aspects including collaboration among personnel, study design, data collection and analyses, and publication access. In addition, neuroimaging and behavioral data will be shared by depositing it in the Collaborative Informatics and Neuroimaging Suite (COINS), a platform hosted by Georgia State University/Georgia Institute of Technology/Emory University Center for Translational Research in Neuroimaging and Data Science (TReNDS). TReNDS allows for safe and secure data sharing with external users without granting access to protected health information. For preprints, platforms such as PsyArXiv and OSF Preprints will be used based on appropriate content area. All personnel will commit to use OSF to publicly share evaluation and research components.

Timely submission of raw data to repositories will provide an additional layer of safety. Neuroimaging data will be uploaded to COINS in real time. Cleaned behavioral datasets will be uploaded to OSF biannually. Metadata, code, small datasets and links to large datasets used in publications will be archived as supplements or on OSF. Publication specific data will be deposited to the OpenNeuro platform upon publication. All shareable data from this project will be made publicly available no later than the end of the project period, and any data associated with a publication will be made available at the time of publication. The latest point at which data will be provided to the archive is when articles using that data are accepted for publication, or at the conclusion of the project (whichever comes first).

Any physical data for this project will be stored within locked filing cabinets for print copies and digital files will be encrypted and stored on password-protected secure servers separately from any participant code keys. Archived data will be stored on a secure server at Georgia State University when primary planned analyses of the data have been completed. The server will be backed up regularly using a tape backup system. The partition where data will sit on the server will not be accessible to anyone outside of the team.

Audit trails are maintained for each file to document changes and deletions, and older versions of files are retrievable in the event of unintentional modification.