Periodic Reporting for period 1 - NEURO-SOCIETY (The encoding of social networks in the brain)
Okres sprawozdawczy: 2023-01-01 do 2025-06-30
In social species, peers represent a major part of the external environment and adaptation to the environment requires adaptation to peers. One striking example is that not only other species can be deadly predators, but members from our own society can pose a deadly threat to us. On the other hand, not only family members can be our allies but also friends we choose from non-kin related group members. This matter of fact exemplifies the importance of tracking others and their relations, and possessing a structured knowledge about our societies. Primates, including humans and monkeys, spend most of their time watching others. While several neural circuits for social perception have been unraveled in their brains, we don’t know how neural circuits further transform social percepts into a meaningful set of social concepts used spontaneously to represent social networks. This question calls for an investigation at multiple levels. An exploratory approach at the whole brain level, using functional magnetic resonance imaging (fMRI), will enable us to chart the brain territories involved in processing social concepts of increasing levels of abstraction, whereby concepts about individuals are less abstract than concepts about relationships, which are in turn less abstract than concepts about social networks topology. Next a nailed down approach to the level of neurons, using fMRI-guided neurophysiology, will enable us to understand the neuronal network mechanisms by which the transformation from multi-sensory social percepts to social concepts is implemented. Finally, exploiting real-world social knowledge, will enable us to track the encoding of social network topology by neuronal networks. Understanding how neural circuits and single-neurons within these circuits are encoding social networks will provide fundamental mechanistic insights into the toolkit for smoothly maneuvering our primate societies.
During the first period of this grant, we made progress towards understanding the neural bases for representing social concepts about individuals and for representing social networks topology. We created a collection of primate odor samples that we characterized in terms of their chemical profile. We further correlated these profiles to the demographics of the individuals and found which could be retrieved from body odors. Comparison between primate species is ongoing. We made progress in designing and building a connected apparatus for recording touch on soft surfaces of various types. Further we performed MRI scans to acquire brain anatomy, and carried all the segmentation, inflation, flattening, parcellation and atlas registration steps to prepare for functional imaging experiments. We successfully localized face, body and object areas bilaterally in temporal and frontal cortices, in locations fitting classical studies in a first animal. We fully documented a monkey social network structure in terms of centrality, brokerage and several measures of social distances and friendship between individuals, using an in-house designed software to analyze animal multi-layered social networks based on focal observations. We designed two visual tasks to probe the neural representation of social network. One animal was scanned while performing these tasks, and we are now analyzing which brain areas encode preferentially which type of social concept about the network.
While preliminary, our advancements are promising. To our knowledge, it is the first time an animal was scanned for assessing representation of his knowledge of the social network, and that monkey odours are analysed in the context of the social network. Further our innovative MR-safe soft-touch apparatus would allow for testing soft-touch in the scanner. We therefore expect that completion of the proposed project, and pursuing the development of the promising results already achieved, will provide fundamental mechanistic insights into how brains of social beings create a shared world and will supply human clinical neuroscience with valuable new hypotheses to understand how social mechanisms and access to them are disturbed in disease.