SPATIOTEMPORAL FMRI NETWORK DYNAMICS ​IN THE PIGEON (<EM>COLUMBA LIVIA)</EM>

A recent advance in functional magnetic resonance imaging (fMRI) concerns the investigation of temporal dynamics in spontaneous resting-state activity. In mammals, it has been observed that resting-state is governed by a limited number of recurring states reflecting the coactivation of resting-state networks. Whether this extends to non-mammalian species remains unclear. Birds offer a unique opportunity to address this question, as their cognitive abilities, especially those of parrots and corvids, rival primates. Even pigeons match macaques in domains such as short-term memory, numerical competence and orthographic processing. Taken together, birds can serve as a highly informative animal model to study cognition. However, resting-state fMRI in pigeons was long considered unfeasible due to air cavities in the skull which compromises gradient echo EPI sequences. This work presents not only a solution but, for the first time, also investigates temporal dynamics in the resting avian brain via framewise clustering. Resting-state fMRI data from ten awake pigeons, acquired at 7T, revealed a set of recurring network states at both subject and group level, some of which showed antagonistic relationships. Only certain states were linked to specific phases of the global signal, whereas others were not. Analysing state transitions showed that some states transitioned to specific other states more often than expected by chance, indicating preferred transition sequences. Overall, this work introduces a reliable method for resting-state fMRI in pigeons and demonstrates that, similar to mammals, the avian brain at rest is organised around a limited number of network states with distinct temporal dynamics.