PROJECT SUMMARY/ABSTRACT Primates use their hands together or independently, so the nervous system must support flexible sensory modes to coordinate signal processing from the two hands. Conceivably, specialized circuits exist to coordinate central processing of sensory inputs from the two hands (bimanual touch), resembling dedicated mechanisms supporting binocular vision and binaural hearing. Prior efforts have focused primarily on understanding somatosensory processing on a single hand, so how the nervous system supports bimanual touch is essentially unknown. The long-term goal of this research program is to establish an understanding of how bimanual touch signals are encoded and elaborated in the primate brain. Because human and non-human primates (NHP) share the ability to sense touch using their hands, NHP are an ideal model for studying the neural constructs of touch. The immediate goal of this project is to establish an experimental platform for manipulating and measuring bimanual perception and neural coding in NHP. The proposed work combines behavior and neural recordings in macaque monkeys. The first aim of the work is to investigate how monkeys perceive tactile cues presented on two hands. We will leverage a paradigm that has previously revealed bimanual perceptual interactions in humans. The second aim of the work is to investigate how neural populations in primary somatosensory cortex (S1) represent bimanual touch. These experiments are premised on prior work showing that S1 neural activity to stimulation on the contralateral hand can be modulated by stimulation on the ipsilateral hand. We will test the hypothesis that bimanual interactions in S1 are context- dependent by characterizing how the animal’s use of the tactile cues determines S1 responses to bimanual touch. Significance: The proposed work will unveil novel correspondent sensibilities between NHP and humans to establish a tractable model for investigating the neural basis of bimanual touch. Establishing how ipsilateral and contralateral hand signals interact in S1 can inform a conceptual framework for understanding the functional role of bimanual neurons in higher-order somatosensory regions and how the somatosensory system supports flexible sensory behavior. Broad Impact: This project lays the groundwork for future investigations on how bimanual signals are combined or segregated in the primate brain to mediate perception and motor function. This may yield insight into developmental and psychiatric disorders that are characterized by aberrant sensorimotor processing such as ADHD, ASD, and schizophrenia. A network-level understanding of somatosensory communication can inform how sensorimotor functions changes with aging and age-related cognitive decline. Crucially, this work will inform the design of bimanual neuroprostheses to restore dexterous hand function in those who has lost it.