Parkinson's disease (PD) is associated with irreparable damage to dopaminergic neurons in brain areas involved in movement. Frequently, a very early symptom of PD involves an impaired sense of smell, while other studies suggest a broader impairment of other sensory modalities. Still, the associated brain-wide mechanisms underlying this phenomenon remain unclear. Here, we harness in vivo functional Magnetic Resonance Imaging (fMRI) at 9.4T to investigate how the olfactory and visual systems are affected in an α-Synuclein (αSyn) mouse model of PD. We find significant aberrations in fMRI responses along both sensory pathways including decreases in activation extent and in activation amplitude. Deficits in the olfactory system were larger than in the visual pathway, but nevertheless both sensory systems were clearly impacted, suggesting a more overarching mechanism may be involved. To further ensure that the aberrations observed in the fMRI signals were not driven solely by putative vascular deficiency, we quantified c-FOS expression in the olfactory system and found statistically significant decreases in the PD group when compared to age-matched controls. Hence, our findings indicate a neural origin for the observed fMRI aberrations. Our findings thus demonstrate a more global deficiency in sensory systems in the (αSyn) mouse model.

Summary A simple PCR‐RFLP consisting in the digestion of a fragment of the 12S ribosomal RNA (12SrRNA) with species‐specific restriction enzymes (MboII and HinfI) was developed to distinguish northeastern Atlantic species in the genus Atherina. Unambiguous identification of morphologically similar sympatric species is frequently difficult, especially when younger specimens are included in the analysis. Genetic and morphological analysis of a total of 123 atherinids collected near the mouth of the Tagus estuary (west Portugal) confirmed that only Atherina presbyter (sand smelt) adults and juveniles are recurrently using these marine rocky habitats as spawning and nursery grounds, respectively. The importance of applying non‐destructive methods is emphasized. In the future, the conditions involved in the transition from marine A. presbyter to estuarine/riverine A. boyeri should be further evaluated along with the ability of larvae and juveniles to cope with river flow and tidal currents drift.

Parkinson's disease (PD) is associated with irreparable damage to dopaminergic neurons in brain areas involved in movement. Frequently, a very early symptom is an impaired sense of smell, but the associated brain-wide mechanisms remain unclear. Here, we report on aberrations in BOLD-fMRI responses along olfactory pathway in a PD mouse model. We find decreased activation, especially in the main olfactory bulb, olfactory tubercle and piriform cortex in PD mice when compared to healthy controls upon olfactory stimulation.

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