Séminaire : Bernard THIRION

Anatomical and functional inter-individual variability poses a significant challenge to group analysis in neuroimaging studies.  While anatomical templates help mitigate morphological differences by coregistering subjects in fMRI, they fail to account for functional variability, often leading to blurred activation patterns on the template due to group-level averaging.  To address this problem, hyperalignment identifies fine-grained correspondences between functional brain maps of different subjects, with Procrustes analysis and optimal transport being among the most effective approaches.  However, many hyperalignment based imaging studies rely on the selection of a single target subject as the reference to which all other subjects' data are aligned; the introduction of functional templates eliminates the need for this arbitrary selection, effectively encapsulating population similarities while preserving anatomical coherence.
In this talk, we first review the strongest brain alignment techniques and the resulting template estimation procedures.  We discuss the validation of such templates through decoding experiments, both in standard classification settings and using recent generative decoding approaches, where functional alignment integrates well with deep phenotyping approaches.  We present preliminary results on the impact of functional alignment on cross-species brain data analysis.