Spectral signatures of mirror movements in the sensori-motor connectivity in kallmann syndrome.

Mirror movements (MM) might be observed in congenital and acquired neurodegenerative conditions but their anatomic-functional underpinnings are still largely elusive. This study investigated the spectral changes of resting-state functional connectivity in Kallmann Syndrome (hypogonadotropic hypogonadism with hypo/anosmia with or without congenital MM) searching for insights into the phenomenon of MM. Forty-four Kallmann syndrome patients (21 with MM) and 24 healthy control subjects underwent task (finger tapping) and resting-state functional MRI. The spatial pattern of task-related activations was used to mask regions and select putative motor networks in a spatially independent component analysis of resting-state signals. For each resting-state independent component time-course power spectrum, we extracted the relative contribution of four separate bands: slow-5 (0.01-0.027 Hz), slow-4 (0.027-0.073 Hz), slow-3 (0.073-0.198 Hz), slow-2 (0.198-0.25 Hz), and analyzed the variance between groups. For the sensorimotor network, the analysis revealed a significant group by frequency interaction (P = 0.002) pointing to a frequency shift in the spectral content among subgroups with lower slow-5 band and higher slow-3 band contribution in Kallmann patients with MM versus controls (P = 0.028) and with lower slow-5 band contribution between patients with and without MM (P = 0.057). In specific regions, as obtained from hand motor activation task analysis, spectral analyses demonstrated a lower slow-5 band contribution in Kallmann patients with MM versus both controls and patients without MM (P < 0.05). In Kallmann syndrome, the peculiar phenomenon of bimanual synkinesis is associated at rest with regionally and spectrally selective functional connectivity changes pointing to a distinctive cortical and subcortical functional reorganization. Hum Brain Mapp 39:42-53, 2018.