Project Summary/Abstract Recent technological advancements have allowed for single-neuron and intracranial electroencephalographic (iEEG) recordings in freely moving humans. However, these implanted neural recording devices have not been integrated with non-invasive peripheral biochemical recordings. The emergence of an experimental platform combining mobile deep brain recordings with wearable biochemical and biophysical sensors for use in real-world settings is unprecedented. The proposed project will develop a novel platform that enables simultaneous single- neuron or iEEG, biochemical (cortisol, epinephrine), and biophysical (heart rate, skin conductance, and body and eye movements) activity to be recorded in freely moving human participants. As proof-of-concept, we will use this platform to investigate the neural and peripheral biomarker mechanisms underlying approach-avoidance behaviors during spatial navigation. Through an interdisciplinary collaboration between UCLA, Stanford University, and the Veteran’s Administration Greater Los Angeles Healthcare System (VAGLAHS), the program will have access to human participants whom will have implanted electrodes within prefrontal cortex, amygdala, hippocampus, or nucleus accumbens regions. The proposed project outcomes will empower future studies and other researchers to investigate, for the first-time, deep brain and peripheral biomarker mechanisms underlying freely moving human behavior in naturalistic and ecologically valid environments.