Figure 7 depicts the number of studies that utilized biomarkers as part of clinical care or through experimental research. Biomarkers were stratified into first generation (FG) MRI structural sequences (T-weighted,-weighted,proton density), second generation (SG) MRI structural sequences (fluid attention inversion recovery, susceptibility weighted imaging, 2*-weighted/gradient-recalled echo), diffusion MRI (dMRI), magnetic resonance spectroscopy (MRS), positron emission tomography (PET), hemodynamics (CBF; arterial spin labeling, single photon emission computerized tomography, sonography, and cranial accelerometry), task-based functional MRI (fMRI), functional connectivity MRI (fcMRI), near infrared (NIR), electroencephalography (EEG), magnetoencephalography (MEG), and neuromodulation (NM). The utilization of each modality was summed within and across all 56 articles. Therefore, the total sum is greater than the total number of articles (e.g., an article that utilized fMRI, MRS and dMRI was assigned a value of 1 for each biomarker category).