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| Poster #237 Limited Effects of Isolated Congenital Anosmia on Cerebral White Matter Morphology |
| Anja L. Winter1, Fahimeh Darki1, Johan N. Lundström1,2,3 1Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, --, Sweden 2Department of Otorhinolaryngology, Karolinska University Hospital, Stockholm, --, Sweden 3Monell Chemical Senses Center, Philadelphia, PA, United States |
Individuals with congenital sensory loss experience a persistent absence of input from the affected sense throughout their development. For our non-chemical senses, this lack of sensory input has been associated with alterations in brain morphology, mainly in or near cerebral regions normally devoted to processing of the missing sense. In contrast, we have in multiple studies demonstrated that the only consistent morphological finding within the grey matter of individuals born without the sense of smell (isolated congenital anosmia; ICA), are changes in or near the olfactory sulcus, associated with small or absent olfactory bulbs. For the connecting tissue of the brain, the white matter (WM), previous studies have yielded inconsistent findings. Here, we aimed to establish whether individuals with congenital anosmia exhibit alterations in WM by comparing WM volume between 49 individuals with ICA and 49 age- and sex-matched controls. Consistent evidence from both voxel-based morphometry and multi-voxel pattern analysis demonstrates that individuals with ICA show decreased WM in areas surrounding the olfactory sulcus. Importantly, no WM alterations were found in areas surrounding the olfactory (piriform) cortex. Contrary to the literature on visual and auditory loss, our findings suggest that, despite lifelong olfactory deprivation, cerebral morphological alterations are limited. The changes observed are primarily localized around the olfactory sulcus and likely attributed to the absence of olfactory bulbs. The possibility of the olfactory cerebral system being occupied by other functions in these individuals, which would limit morphological changes, should be further investigated. |