Psychopharmacology

, 193:31

Modulation of neural response to happy and sad faces by acute tryptophan depletion

  • Paolo Fusar-Poli
  • Paul Allen
  • Francis Lee
  • Simon Surguladze
  • Nigel Tunstall
  • Cynthia H. Y. Fu
  • Michael J. Brammer
  • Anthony J. Cleare
  • Philip K. McGuire
Original Investigation

DOI: 10.1007/s00213-007-0757-4

Cite this article as:
Fusar-Poli, P., Allen, P., Lee, F. et al. Psychopharmacology (2007) 193: 31. doi:10.1007/s00213-007-0757-4

Abstract

Background

Central serotonin (5HT) plays a major role in emotional processing. We used functional neuroimaging (fMRI) to investigate the effects of experimental manipulation of central 5HT levels on the regional neural response to happy and sad facial expressions.

Methods

Ten healthy participants (eight men and two women) were scanned during an implicit emotional processing task after receiving a tryptophan-free (acute tryptophan depletion, ATD) or a balanced amino acid drink in a double-blind design.

Results

ATD lowered total plasma tryptophan concentration by 80%. There was no significant effect on subjective mood ratings, on response accuracy and on reaction times. Compared to sham depletion, ATD attenuated activation in the right medial/inferior frontal gyrus, the posterior cingulate cortex, the occipital and parietal cortex bilaterally, the right hippocampus, claustrum and insula. Conversely, ATD was associated with relatively increased activation in the left inferior frontal gyrus. ATD had differential effects on activation during the processing of happy and sad faces in the right putamen and in the left superior temporal gyrus.

Conclusions

In both cortical and sub-cortical regions, the neural response associated with processing emotional faces is significantly modulated by 5HT manipulation resulting from ATD. Moreover, in certain areas, this effect of 5HT depends on the emotional valence of the stimulus.

Keywords

Acute tryptophan depletion Serotonin fMRI Emotional processing Ekman faces Depression 

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Paolo Fusar-Poli
    • 1
    • 2
  • Paul Allen
    • 2
  • Francis Lee
    • 2
  • Simon Surguladze
    • 2
  • Nigel Tunstall
    • 2
  • Cynthia H. Y. Fu
    • 2
    • 3
  • Michael J. Brammer
    • 4
  • Anthony J. Cleare
    • 2
  • Philip K. McGuire
    • 2
  1. 1.Department of Applied and Psychobehavioural Health SciencesUniversity of PaviaPaviaItaly
  2. 2.Neuroimaging Section, Division of Psychological Medicine, Institute of PsychiatryKing’s College LondonLondonUK
  3. 3.Social Genetic and Developmental Psychiatry CentreKing’s College LondonLondonUK
  4. 4.Brain Image Analysis Unit, Department of Biostatistics and Computing, Institute of PsychiatryKing’s College LondonLondonUK