Baby Brain Recovery Study

3 Tesla Discovery MR750 MRI scanner (GE Healthcare, Waukesha, WI) will be used to perform structural imaging, diffusion MRI, relaxometry and microstructural imaging. The exact scan length and parameters of each scan type (T1, T2, DWI) will be set for this study to optimize the quality of data and decrease the length of scanning session for each type of scan. All of the imaging methods have been previously implemented at UW-Madison. Each sequence will take approximately 5-10 minutes.

The behavioral assessments (GMA: General Movements Assessment; HINE: Hammersmith Infant Neurological Examination; Baby Observation of Selective Control AppRaisal (BabyOSCAR); Bayley-4 / Bayley Scales of Infant and Toddler Development 4th ed; Pediatric Evaluation of Disability Inventory -Computer Adaptive Test (PEDI-CAT)) are infant and age-specific and will be administered by trained pediatric occupational and physical therapists.

TMS will be used to assess cortical excitability and circuitry (not as a neuromodulation intervention). Single-pulse TMS (Magstim 200², Magstim, UK) with a scalp surface coil will be used to assess how the brain is developing and how connected the tract is, between the brain and a target muscle on the arm. 10-20 TMS stimulation pulses will be delivered at a range of stimulation intensities (50-100%) increasing by 5% maximal stimulator output (MSO) at each stage. After this assessment, a brief assessment of peripheral nerve excitability will be performed. Peripheral stimulation will begin at 40% MSO. Stimulation intensity will be adjusted in increments of 5% until motor responses are evident on the EMG. Once motor responses are identified, 10 pulses will be delivered at the stimulation intensity that produced the response. In sum, around 150 stimulation pulses per hemisphere of brain stimulation and 22-60 pulses of peripheral stimulation are expected for TMS assessment of each infant.