Amplitude of low frequency fluctuations

Amplitude of Low Frequency Fluctuations (ALFF) and fractional Amplitude of Low Frequency Fluctuations (f/ALFF) are neuroimaging methods used to measure spontaneous fluctuations in BOLD-fMRI signal intensity for a given region in the resting brain. Whole-brain ALFF shows greater signal in posterior cingulate, precuneus, and medial prefrontal areas of the default mode network,[1] but also in non-cortical areas near the ventricles, cisterns and large blood vessels. f/ALFF reduces the sensitivity of ALFF to physiological noise by taking the ratio of each frequency (0.01-0.08 Hz) to the total frequency range (0-0.25 Hz).[2] Both measures have been investigated as part of reliable[3] biomarkers for many neurological conditions including schizophrenia,[4][5] ADHD,[1] and major depressive disorder.[6]

References

  1. 1 2 Zang, Y. F.; He, Y; Zhu, C. Z.; Cao, Q. J.; Sui, M. Q.; Liang, M; Tian, L. X.; Jiang, T. Z.; Wang, Y. F. (2007). "Altered baseline brain activity in children with ADHD revealed by resting-state functional MRI". Brain and Development. 29 (2): 83–91. doi:10.1016/j.braindev.2006.07.002. PMID 16919409.
  2. ↑ Wallis, I; Ellis, L; Suh, K; Pfenninger, K. H. (1985). "Immunolocalization of a neuronal growth-dependent membrane glycoprotein". The Journal of Cell Biology. 101 (5 Pt 1): 1990–8. doi:10.1083/jcb.101.5.1990. PMC 2113966Freely accessible. PMID 3902859.
  3. ↑ Tachibana, M; Kaneko, A (1988). "Retinal bipolar cells receive negative feedback input from GABAergic amacrine cells". Visual neuroscience. 1 (3): 297–305. PMID 2856476.
  4. ↑ Böhme, R; Aeckerle, S; Malchow, D (1987). "A high-affinity plasma membrane Ca2+-ATPase in Dictyostelium discoideum: Its relation to cAMP-induced Ca2+ fluxes". Biochimica et Biophysica Acta. 904 (1): 125–30. doi:10.1016/0005-2736(87)90093-9. PMID 2822110. |first2= missing |last2= in Authors list (help)
  5. ↑ Kayser, K; Shaver, M; Modlinger, F; Postl, K; Moyers, J. J. (1986). "Neighborhood analysis of low magnification structures (glands) in healthy, adenomatous, and carcinomatous colon mucosa". Pathology, research and practice. 181 (2): 153–8. PMID 3737471.
  6. ↑ Bohigian, G. M.; Olk, R. J. (1986). "Factors associated with a poor visual result in endophthalmitis". American journal of ophthalmology. 101 (3): 332–41. PMID 3485382.


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