Recently, the “social brain” (i.e., how the brain works in social context and the mechanisms for our social behavior) has gained focus in neuroscience literature – largely due to the fact that recently developed techniques allow studying different aspects of human social cognition and its brain correlates. In this context, hyperscanning techniques (Montague et al., Neuroimage 16(4):1159–1164, 2002) open the horizon for human interaction studies, allowing for the evaluation of interbrain connectivity. These techniques represent methods for simultaneously recording signals from different brains when subjects are interacting. In this chapter, we will explore the potentials of functional magnetic resonance imaging (fMRI) and functional near-infrared spectroscopy (fNIRS), which are techniques based on blood-oxygen-level-dependent (BOLD) signal. We will start with a brief explanation of the BOLD response basic principles and the mechanisms involved in fMRI and fNIRS measurements related to brain function. We will then discuss the foundation of the social brain, based on the first studies, with one subject per data acquisition, to allow for understanding the new possibilities that hyperscanning techniques offer. Finally, we will focus on the scientific literature reporting fMRI and fNIRS hyperscanning contribution to understand the social brain.
Copyright 2023, The Author(s).