Dr. Appelbaum's research interests primarily concern the brain mechanisms underlying visual cognition, how these capabilities differ among individuals, and how they can be improved through behavioral, neurofeedback, and neuromodulation interventions. Within the field of cognitive neuroscience, his research has addressed visual perception, sensorimotor function, executive function, decision-making, and learning/expertise. In this research, he has utilized a combination of behavioral psychophysics coupled with the neuroscience techniques of electroencephalography (EEG), transcranial magnetic stimulation (TMS), functional magnetic resonance imaging (fMRI), and functional near infrared spectroscopy (fNIRS).