Amy R. Johnson

Amy R. Johnson

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Amy R. Johnson

Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, United Kingdom

Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 April 2021 in Developmental Cognitive Neuroscience
Verified
Journal Article
Open access
AJAmy Johnson
Amy Johnson
JBJoe Bathelt
Joe Bathelt
DADanyal Akarca
Danyal Akarca
GCGemma Crickmore
Gemma Crickmore
DADuncan E. Astle
Duncan E. Astle
Previous studies have identified localized associations between childhood environment - namely their socio-economic status (SES) - and particular neural structures. The primary aim of the current study was to test whether associations between SES and brain structure are widespread or limited to specific neural pathways. We employed advances in whole-brain structural connectomics to address this. Diffusion tensor imaging was used to construct whole-brain connectomes in 113 6-12 year olds. We then applied an adapted multi-block partial-least squares (PLS) regression to explore how connectome organisation is associated with childhood SES (parental income, education levels, and neighbourhood deprivation). The Fractional Anisotropy (FA) connectome was significantly associated with childhood SES and this effect was widespread. We then pursued a secondary aim, and demonstrated that the connectome mediated the relationship between SES and cognitive ability (matrix reasoning and vocabulary). However, the connectome did not significantly mediate SES relationships with academic ability (maths and reading) or internalising and externalising behavior. This multivariate approach is important for advancing our theoretical understanding of how brain development may be shaped by childhood environment, and the role that it plays in predicting key outcomes. We also discuss the limitations with this new methodological approach.

2 December 2014 in The FASEB Journal
Verified
Journal Article
Open access
PDF file
LSLaila C. Schenkel
Laila C. Schenkel
RSRatnesh K. Singh
Ratnesh K. Singh
VMVera Michel
Vera Michel
Steven ZeiselSteven Zeisel
Steven Zeisel
KCKerry‐Ann da Costa
Kerry‐Ann da Costa
Marica BakovicMarica Bakovic
Marica Bakovic
Fibroblasts from a patient with postural orthostatic tachycardia syndrome (POTS), who presented with low plasma choline and betaine, were studied to determine the metabolic characteristics of the choline deficiency. Choline is required for the synthesis of the phospholipid phosphatidylcholine (PC) and for betaine, an important osmoregulator. Here, choline transport, lipid homeostasis, and mitochondria function were analyzed in skin fibroblasts from POTS and compared with control cells. The choline transporter‐like protein 1/solute carrier 44A1 (CTL1/SLC44A1) and mRNA expression were 2‐3 times lower in POTS fibroblasts, and choline uptake was reduced 60% ( P < 0.05). Disturbances of membrane homeostasis were observed by reduced ratios between PC:phosphatidylethanolamine and sphingomyelin:cholesterol, as well as by modified phospholipid fatty acid composition. Choline deficiency also impaired mitochondria function, which was observed by a reduction in oxygen consumption, mitochondrial potential, and glycolytic activity. When POTS cells were treated with choline, transporter was up‐regulated, and uptake of choline increased, offering an option for patient treatment. The characteristics of the POTS fibroblasts described here represent a first model of choline and CTL1/SLC44A1 deficiency, in which choline transport, membrane homeostasis, and mitochondrial function are impaired.—Schenkel, L. C., Singh, R. K., Michel, V., Zeisel, S. H., da Costa, K.‐A., Johnson, A. R., Mudd, H. S., Bakovic, M. Mechanism of choline deficiency and membrane alteration in postural orthostatic tachycardia syndrome primary skin fibroblasts. FASEB J. 29, 1663‐1675 (2015). www.fasebj.org