Emilie Sogn Falch

• Kransberg, Jonas Moe; Bråthen, Anne Cecilie Sjøli; Falch, Emilie Sogn; Øverbye, Knut Eiliv Ødegård; Garrido, Pablo F. & Fjell, Anders Martin [Vis alle 10 forfattere av denne artikkelen] (2026). Failure to detect entorhinal grid-like signals in a passive navigation human fMRI study. Imaging Neuroscience. 4. doi: 10.1162/imag.a.1196. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Grid cells in the human entorhinal cortex (EC) play a critical role in spatial navigation and memory. The EC is also one of the first regions affected by ageing and Alzheimer’s disease. This pre-registered functional magnetic resonance imaging (fMRI) study aimed to detect grid-cell-like signals (GLS) in a passive virtual navigation task. Contrary to our hypotheses and previous findings, we did not observe significant GLS at a population level, even in younger participants. Further exploratory analyses investigated the impact of task-engagement, as inferred from object-location memory performance, and showed no relationship with GLS magnitude. We also examined potential influences of a confounding one-fold directional signal and various data-processing choices but observed no consistent patterns. Our findings, consistent with recent null results from similar studies, suggest that passive navigation paradigms may be insufficient for reliably eliciting grid-like signals in human fMRI.

• Garrido, Pablo Fernandez; Bråthen, Anne Cecilie Sjøli; Falch, Emilie Sogn; Kransberg, Jonas Moe; Fjell, Anders Martin & Sørensen, Øystein [Vis alle 7 forfattere av denne artikkelen] (2026). Unwrapping the mirror tracing task. Behavior Research Methods. ISSN 1554-351X. 58. doi: 10.3758/s13428-025-02845-6. Fulltekst i vitenarkiv Vis sammendrag

  The Mirror Tracing Task (MTT) is a method used to study visuomotor skills learning. It is traditionally evaluated by counting the number of times a person draws outside of the borders of a figure, typically a star, while looking at its mirror reflection. While insightful for overall performance, this metric lacks a precise analysis of the tracing, such as details on errors in specific regions. We propose a new MTT analysis method that studies the drawing as a function of the angle around the figure’s center. Two new variables are introduced: residuals, which measure deviation from the ideal drawing, and density, which measures how often a specific path is retraced. These variables are defined per angle or region, allowing a more detailed analysis, highlighting the most challenging parts of the drawing for each person, and enabling comparison across trials or finding common patterns between individuals. We applied this approach to the first MTT trial of 210 participants using age as a variable of interest. Residuals and density were summarized as a single value and compared with the traditional approach, providing similar results. When analyzed as a function of the angle, these variables enabled the identification of specific regions of the star where the errors are age-sensitive. Additionally, a time series-like approach enabled us to cluster drawings and quantify their similarity. The code used for this new method has been made openly accessible to make it easier for its applications in new research or the reanalysis of previous projects.

• Padrela, Beatriz E.; Teceläo, Sandra Raquel Ramos; Kirsebom, Bjørn-Eivind; Geier, Oliver Marcel; Tranfa, Mario & Masserini, Federico [Vis alle 22 forfattere av denne artikkelen] (2025). Blood-brain barrier water exchange in relation to amyloid, cognition and cerebrovascular burden. NeuroImage: Clinical. 49. doi: 10.1016/j.nicl.2025.103926. Fulltekst i vitenarkiv Vis sammendrag

  Blood-brain barrier (BBB) water exchange may serve as a sensitive early biomarker for Alzheimer’s disease and age-related cognitive decline. This study applied a non-invasive multi-echo arterial spin labeling (ASL) technique to measure BBB water exchange time (Tex), cerebral blood flow (CBF), and arterial transit time (ATT) in 160 adults aged 50 years and older. Participants were classified as cognitively normal (CN), having subjective cognitive decline (SCD), or mild cognitive impairment (MCI). They were assessed for amyloid status and cerebrovascular burden. Compared to CN participants, Tex was significantly lower in both SCD (−9.5 %) and MCI (−14.5 %) groups, suggesting that reductions in BBB water exchange emerge early in the course of cognitive decline. In contrast, CBF was reduced only in MCI participants (−20.8 % compared to CN), and ATT was significantly increased only in individuals with severe cerebrovascular burden (Fazekas score 3). Notably, Tex showed a stepwise decrease with increasing Fazekas scores (1–2), supporting its sensitivity to moderate small vessel disease. No associations were found between Tex and amyloid positivity after adjusting for age and sex. These findings indicate that Tex alterations may precede changes in traditional perfusion markers and are more closely related to vascular and early cognitive changes than to amyloid pathology. BBB water exchange mapping may therefore provide a promising, non-invasive tool to detect early neurovascular dysfunction that contributes to cognitive decline in aging populations, potentially offering a useful biomarker for early intervention trials targeting vascular contributions to dementia.

• Ravndal, Anne; Fjell, Anders Martin; Vidal-Piñeiro, Didac; Sørensen, Øystein; Falch, Emilie Sogn & Kropiunig, Julia [Vis alle 21 forfattere av denne artikkelen] (2025). Sex differences in healthy brain aging are unlikely to explain higher Alzheimer’s disease prevalence in women. Proceedings of the National Academy of Sciences of the United States of America (PNAS). ISSN 0027-8424. 122(42). doi: 10.1073/pnas.2510486122. Fulltekst i vitenarkiv Vis sammendrag

  As Alzheimer’s disease (AD) is diagnosed more frequently in women, understanding the role of sex has become a key priority in AD research. However, despite aging being the primary risk factor for AD, it remains unclear whether men and women differ in the extent of brain decline with age. Using 12,638 longitudinal brain MRIs from 4,726 participants aged 17 to 95 y across 14 cohorts, we examined sex differences in structural brain changes over time, controlling for differences in head size. Men showed greater cortical thickness (CT) decline in the cuneus, lingual, parahippocampal, and pericalcarine regions; surface area decline in the fusiform and postcentral regions; and in older adults, greater subcortical decline in the caudate, nucleus accumbens, putamen, and pallidum. In contrast, women only showed greater surface area decline in the banks of the superior temporal sulcus and greater ventricular expansion in older adults. These results suggest that sex differences in age-related brain decline are unlikely to contribute to the higher AD diagnosis prevalence in women, necessitating research into alternative explanations.

• Roe, James Michael; Vidal-Piñeiro, Didac; Sørensen, Øystein; Grydeland, Håkon; Leonardsen, Esten Høyland & Iakunchykova, Olena [Vis alle 35 forfattere av denne artikkelen] (2024). Brain change trajectories in healthy adults correlate with Alzheimer’s related genetic variation and memory decline across life. Nature Communications. 15(1). doi: 10.1038/s41467-024-53548-z. Fulltekst i vitenarkiv Vis sammendrag

  Throughout adulthood and ageing our brains undergo structural loss in an average pattern resembling faster atrophy in Alzheimer’s disease (AD). Using a longitudinal adult lifespan sample (aged 30-89; 2–7 timepoints) and four polygenic scores for AD, we show that change in AD-sensitive brain features correlates with genetic AD-risk and memory decline in healthy adults. We first show genetic risk links with more brain loss than expected for age in early Braak regions, and find this extends beyond APOE genotype. Next, we run machine learning on AD-control data from the Alzheimer’s Disease Neuroimaging Initiative using brain change trajectories conditioned on age, to identify AD-sensitive features and model their change in healthy adults. Genetic AD-risk linked with multivariate change across many AD-sensitive features, and we show most individuals over age ~50 are on an accelerated trajectory of brain loss in AD-sensitive regions. Finally, high genetic risk adults with elevated brain change showed more memory decline through adulthood, compared to high genetic risk adults with less brain change. Our findings suggest quantitative AD risk factors are detectable in healthy individuals, via a shared pattern of ageing- and AD-related neurodegeneration that occurs along a continuum and tracks memory decline through adulthood.

• Kransberg, Jonas; Sneve, Markus Handal; Falch, Emilie Sogn; Bråthen, Anne Cecilie Sjøli; Fjell, Anders Martin & Walhovd, Kristine B (2024). Failure to replicate detection of grid-cell like representations in human fMRI. Alzheimer's & Dementia. ISSN 1552-5260. 20, s. e086080–e086080. doi: 10.1002/alz.086080. Fulltekst i vitenarkiv

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• Garrido, Pablo F.; Bråthen, Anne Cecilie Sjøli; Falch, Emilie Sogn; Kransberg, Jonas; Sørensen, Øystein & Walhovd, Kristine B (2024). A novel analysis approach to Mirror Tracing Task performance to detect fine-grained age-related differences. Alzheimer's & Dementia. ISSN 1552-5260. 20, s. e092273–e092273. doi: 10.1002/alz.092273. Fulltekst i vitenarkiv

Se alle arbeider i NVA