Deciphering Social Influence: Insights from NeuroFUS Research

In the realm of decision-making, our choices often pivot on a myriad of cues, including social influences and prior experiences. A recent study by Mahmoodi et al. (2024), delves into the intricate mechanisms underpinning how non-human primates navigate social cues, shedding light on the neural processes guiding decision-making. This ground-breaking research, bolstered by the innovative NeuroFUS technology, offers a deeper understanding of how social information shapes behaviour. 

Published in Neuron, the study leveraged minimally invasive transcranial ultrasound stimulation (TUS) to demonstrate the neural substrates governing social influence in macaque monkeys. By combining behavioural tasks with functional magnetic resonance imaging (fMRI) scans, researchers embarked on a journey to unravel the complexities of social decision-making. 

Experiment 1 elucidated brain regions encoding other animals' face direction, a crucial social cue in primate interactions. Employing advanced imaging techniques, researchers pinpointed the involvement of the mid-portion of the superior temporal sulcus (mSTS) in encoding face direction. This discovery laid the groundwork for subsequent investigations into the interplay between social and non-social cues. 

Experiment 2 delved into how animals navigate conflicting social and non-social information. Through meticulous analysis of fMRI data, researchers uncovered a nuanced pattern of decision-making, wherein reliance on social or non-social cues varied based on their reliability. Notably, the default strategy leaned towards object-based information, highlighting the intricate interplay between different sources of input. 

Further exploration in Experiment 3 delved into the causal role of the dorsomedial frontopolar cortex (dmFPC) in mediating social influence. Utilising NeuroFUS technology, researchers transiently disrupted neural activity in specific brain regions, illuminating the pivotal role of dmFPC in evaluating and integrating social information into decision-making processes. 

The study's findings shed light on the underlying mechanisms of social influence, offering insights into how the brain weighs and integrates different sources of information. The utilisation of NeuroFUS played a pivotal role in unravelling these complex neural circuits, underscoring its significance in advancing neuroscientific research. The implications of this research extend beyond primate behaviour, offering valuable insights into human decision-making processes. By elucidating the neural underpinnings of social influence, this study paves the way for future investigations into the complexities of social cognition and decision-making. 

Mahmoodi, A., Harbison, C. and Bongioanni, A. et al. (2024). A frontopolar-temporal circuit determines the impact of social information in macaque decision making. Neuron 112: 84-92. DOI: https://doi.org/10.1016/j.neuron.2023.09.035