AbstractThe claustrum is an irregular and fine sheet of grey matter in the basolateral telencephalon present in almost all mammals. The claustrum has been the object of several studies using animal models and more recently in human beings using neuroimaging. Believed to be involved in cognition and disease such as fear recognition, suppression of natural urges, multisensory integration, conceptual integration, seizures, multiple sclerosis, and Parkinson’s disease. Nevertheless, the function of the claustrum still remains unclear. We present a functional connectivity study of the claustrum in order to identify its main networks. Resting state functional and anatomical MRI data from 100 healthy subjects were analyzed; taken from the Human Connectome Project (HCP, NIH Blueprint: The Human Connectome Project), with 2×2×2 mm3 voxel resolution. Positive functional connectivity was found (p<0.05, FDR corrected) between the claustrum and the insula, anterior cingulate cortex, pre-central and postcentral gyrus, superior temporal gyrus, and subcortical areas. Our findings coincide with the results previously reported in both animal models and studies with humans. Showing the claustrum as a well-connected structure not only structurally but also functionally. Evidencing the claustrum as a node participating in different neural networks.