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Brain 5-HT function in bipolar affective disorder
- A.H. Young, J.H. Hughes, C.H. Ashton
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- Journal:
- Acta Neuropsychiatrica / Volume 12 / Issue 3 / September 2000
- Published online by Cambridge University Press:
- 18 September 2015, pp. 91-95
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- Article
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Background: Previous studies suggest that brain serotonin neurotransmission may mediate the actions of lithium carbonate. Acute tryptophan depletion (ATD) reduces brain serotonin and allows the study of this neurotransmitter in patient groups. Serotonin modulates electroencephalographic (EEG) activity, which is abnormal in bipolar disorder, and EEG abnormalities persist in euthymic bipolar patients. The EEG may therefore be a sensitive marker of 5-HT function in bipolar disorder.
Aims: This study examined the effects of ATD on mood, suicidal ideation and EEG activity in bipolar patients who were symptomatically stable on lithium.
Methods: 19 subjects satisfying DSM-IV criteria for bipolar I disorder participated in a within-subject, double-blind, placebo-controlled random-order crossover study. Following acute tryptophan depletion (induced by a 100g amino acid drink following an overnight fast) symptoms were evaluated, quantitative power spectrum brain mapping and measurement of auditory evoked potentials were carried out.
Results: ATD produced a significant fall in the amplitude of N1P2 and P300 components of the auditory evoked potential, but no significant changes in the power spectrum. There was an 83% reduction in plasma tryptophan (p<0.05, paired t-test) after the depleting but not the control drink. No significant changes in mood or suicidally scores were recorded after ATD.
Conclusions: ATD attenuates auditory evoked potentials in bipolar disorder but does not reverse lithium's effects on mood and suicidally in bipolar disorder.
Contributors
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- By Lassi Alvesalo, Alberto Anta, Juan Luis Arsuaga, Shara E. Bailey, Priscilla Bayle, José María Bermúdez de Castro, Tracy K. Betsinger, Luca Bondioli, Scott E. Burnett, Concepcion de la Rúa, William N. Duncan, Ryan M. Durner, Heather J.H. Edgar, Scott M. Fitzpatrick, Michael R. Fong, Ana Gracia-Téllez, Theresa M. Grieco, Debbie Guatelli-Steinberg, Tsunehiko Hanihara, Brian E. Hemphill, Leslea J. Hlusko, Michael W. Holmes, Jean-Jacques Hublin, Toby E. Hughes, John P. Hunter, Joel D. Irish, Kent M. Johnson, Sri Kuswandari, Christine Lee, John R. Lukacs, Roberto Macchiarelli, Laura Martín-Francés, Ignacio Martínez, María Martinón-Torres, Arnaud Mazurier, Yuji Mizoguchi, Stephanie Moormann, Greg C. Nelson, Stephen D. Ousley, Oliver T. Rizk, G. Richard Scott, Roman Schomberg, Kes Schroer, Christopher M. Stojanowski, Grant C. Townsend, Christy G. Turner, Theresia C. Weston, Bernard Wood, Clément Zanolli, Linhu Zhang
- Edited by G. Richard Scott, University of Alaska, Fairbanks, Joel D. Irish, Liverpool John Moores University
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- Book:
- Anthropological Perspectives on Tooth Morphology
- Published online:
- 05 March 2013
- Print publication:
- 21 February 2013, pp viii-xi
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2 - DATA ANALYSIS
- Edited by M. K. Hughes, P. M. Kelly, J. R. Pilcher, V. C. LaMarche, Jr.
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- Book:
- Climate from Tree Rings
- Published online:
- 05 October 2010
- Print publication:
- 17 June 1982, pp 32-77
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Summary
INTRODUCTION
The Editors
In the previous chapter, various methods of enhancing the climate signal in tree-ring chronologies have been mentioned. In order to reconstruct climate, it is necessary to extract this signal – to separate climatic factors from the many other environmental variables limiting the plant processes which control growth. The climate-growth response is complex, and reliable theoretical models have yet to be developed. Semi-empirical techniques have, therefore, been developed in order to extract the climate signal. Response functions are used to describe associations between climate data and annual ring measurements. Transfer functions are used to calibrate the ring measurements with climate data in order to provide regression equations for climate reconstruction. Both techniques employ multivariate statistical methods such as principal component or eigenvector analysis and canonical correlation and regression.
The response of the growth of trees to climate and other environmental factors is discussed by Fritts. He highlights the need for semi-empirical techniques to define and extract the macroclimatic signal from tree-ring chronologies. The response function provides an empirical method of describing the nature of the climatic factors that influence tree growth. As Hughes and Milsom point out, the response function does not measure the climategrowth response but rather the effectiveness of a particular statistical model at predicting the element of tree-ring variation forced by external factors. The response function has proved to be a valuable tool for analysing the climate-growth relationship. Guiot, Berger and Munaut review various methods of calculating response functions.