Impact of signal-to-noise on functional MRI of the human amygdala

Kevin S. LaBar*, Darren R. Gitelman, M. Marsel Mesulam, Todd B. Parrish

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

87 Scopus citations


The impact of signal-to-noise (SNR) on fMRI of the amygdala was investigated during a picture encoding task. The SNR value required to observe reliable activation was determined by computer simulations. Blood oxygen level-dependent (BOLD) sensitivity maps were generated to indicate brain regions with sufficient SNR to test the statistical hypotheses. The results showed that the medial aspect of the amygdala had insufficient SNR to detect a 1% peak BOLD signal change for a t-test comparison in a majority of subjects. None of these subjects showed activation in regions with unacceptable SNR values, indicating a low false positive rate. Furthermore, hemispheric asymmetries in the BOLD sensitivity maps mirrored asymmetries in the activation patterns. Impoverished SNR was also found in the basal forebrain and orbitofrontal cortex. These findings emphasize the importance of considering SNR when interpreting fMRI results in the limbic forebrain.

Original languageEnglish (US)
Pages (from-to)3461-3464
Number of pages4
Issue number16
StatePublished - Nov 16 2001


  • Affect
  • Emotion
  • Fear
  • Limbic system
  • Neuroimaging

ASJC Scopus subject areas

  • Neuroscience(all)


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