Topology of emergent properties: a multidimensional study

A higher, unpredictable dimension exists where properties emerging from interactions among units unfold and acquire a valence that manifests on multiple levels of biological organization. This perspective pushed neuroscientific research towards new explorative approaches, aimed at complementing the reductionist search for physico-chemical substrates of brain functions with emergentist evidence of multiscale interactions producing complex and irreducible effects. This work aims at investigating emergent properties on two levels. The first study explores temporally patterned architectures of inter-neuronal coordination, the so-called ‘cell assemblies’, as functional elements reshaping their distribution according to cognitive demands. Characterizing cell assemblies, emerging from either pairwise or higher order interactions, spanning the zona incerta and a constellation of other rodent brain regions contextually to the execution of a discrimination task, allows to correlate the occurrence of peculiar motifs of coordination with specific processing mechanisms. The second study explores the impact that hormones and biological sex play in shaping inter-individual variability in brain functional recruitment upon cognitive stimulation. Employing a framework based on correlative relationships between individual profiles of brain wide activation and inactivation, this study derives network properties that reveals that the dimension of the repertoire of task-related brain configurations emerges from a population as an additional level where sexual dimorphism unfolds.